Canadian Environmental

Protection Act

Priority Substances ListAssessment Report No. 2

Governmentof Canada

EnvironmentCanada

HealthCanada

Gouvernementdu Canada

EnvironnementCanada

SantéCanada

Effluents from PulpMills Using Bleaching

Canada CANADA'S GREEN PLAN

Canadian Environmental Protection Act

Priority Substances List AssessmentReport No. 2

Effluents from Pulp Mills Using Bleaching

CANADIAN CATALOGUING IN PUBLICATION DATA

Main entry under title:

Priority substances list assessmentreport no. 2 : effluents from pulp millsusing bleaching

At head of title: Canadian EnvironmentalProtection Act.Includes an abstract in French.Includes bibliographical references.ISBN 0-662-18734-2DSS cat. no. En40-215/2E

1. Wood-pulp industry -- Canada -- Wastedisposal. 2. Wood-pulp -- Canada –Bleaching. 3. Factory and trade waste –Canada. I. Canada. Environment Canada.II. Title: Effluents from pulp millsusing bleaching.

TD899.W65P74 363.72’8C91-098617-7

Cette publication est aussi disponible en français sous le titre

Liste des substances d'intérêt prioritaire,rapport d’évaluation n0 2: effluents des usines de pâte blanchie.

Pour l’obtenir, s’adresser à:

PublicationsProtection de l’environnementConservation et ProtectionEnvironnement CanadaOttawa (Ontario)K1A 0H3

©Minister of Supply and Services Canada 1991Catalogue No. En 40-215/2E

ISBN 0-662-1X734-2

iii

Preface

Worldwide technical literature, together with unpublishedinformation on effluents from pulp mills employing chlorinebleaching, have been studied to determine whether these effluentsare "toxic", as defined under Section 11 of the CanadianEnvironmental Protection Act (CEPA), to the environment, to theenvironment on which human health depends, or to human health.The impacts of chlorinated "dioxins" and "furans" were notexamined specifically in this report, even though they are found inbleached pulp mill effluents, since they were specificallynominated to the Priority Substances List for independentassessment. Total Suspended Solids (TSS) and BiochemicalOxygen Demand (BOD), characteristic of pulp mill effluents, arecurrently regulated under the Fisheries Act as deleterioussubstances; therefore, they were not examined specifically in thisassessment of effluents from bleached pulp mills.

This report is an assessment of the risk associated with the releaseof chlorinated organic material in bleached pulp mill effluents andtherefore of the need to invoke the Canadian EnvironmentalProtection Act. It also contains an overview of CEPA, the riskassessment criteria employed, a brief description of the scope ofthe investigation, an overview of factual data, and the conclusionsof the risk assessment.

* The units of concentration employed throughout this report are parts pertrillion (ppt), parts per billion (ppb), and parts per million (ppm) on aweight per volume basis for water (e.g., 1 ppm = 1 mg/L, 1 g/m3, etc.) oron a weight per weight basis for aquatic organisms and sediment (e.g., 1ppm = 1 µg/g, etc.).

iv

Avant-propos

On a étudié de la documentation technique du monde entier ainsique des données inédites portant sur les effluents des usines depâte blanchie au chlore pour déterminer si ces effluents sonttoxiques au sens de l’article 11 de la Loi canadienne sur laprotection de l’environnement (LCPE), c’est-à-dire sont nocifspour l’environnement, pour l’environnement dont dépend la viehumaine ou pour la santé des humains. Dans le présent rapport, onn’a pas étudié de façon particu1ière les effets des dioxines et desfuranes chlorés, bien que ces composés se retrouvent dans leseffluents des usines de pate blanchie, puisqu’il était expressémentindiqué dans la Liste des substances d’intérêt prioritaire qu’ilsdevaient faire l’objet d’une évaluation distincte. La teneur enmatières en suspension (MES) et la demande biochimique enoxygène (DBO) caractéristiques des effluents des usines de pateblanchie sont actuellement rég1ementées en vertu de la Loi sur lespêches en tant que substances nocives; c’est pourquoi elles n’ontpas non plus été étudiées de façon particu1ière dans la présenteévaluation des effluents des usines de pâte blanchie.

Le présent rapport évalue le risque lié au rejet de matièresorganiques chlorées dans les effluents des usines de pâte blanchieet, par conséquent, la nécessité d'invoquer la LCPE. Il donneégalement un aperçu de Ia LCPE, les critères d’évaluation durisque employés, une brève description de la portée de l’étude, unaperçu des résultats ainsi que la conclusion de l’évaluation durisque.

Les unités de concentration emp1oyées dans le présent rapport sont les partiespar billion ou 10

12 (désignées par 1'abréviation «ppt», pour parts per trillion),

les parties par milliard ou 109 (désignées par 1'abréviation «ppb», pour parts per

billion) et les parties par million ou 106 (ppm), en unités de masse par unité de

volume pour l'eau (par exemple, 1 ppm = 1 mg/L, 1 g/m3, etc.) on en unités demasse par unité de masse pour les organismes aquatiques et les sédiments (parexemple, 1 ppm = 1 µg/g, etc.).

v

Table of Contents

Preface ........................................................................................................................................... iiiAvant-propos ................................................................................................................................ ivList of Figures.............................................................................................................................. viiList of Tables ............................................................................................................................... viiSummary ..................................................................................................................................... viiiAcknowledgements........................................................................................................................ x

Section 1The Canadian Environmental Protection Act .............................................................................. 1

Section 2Risk Assessment Criteria .............................................................................................................. 3

Section 3Scope of the Investigation of Effluents from Pulp MillsUsing Bleaching ............................................................................................................................. 5

Section 4Overview of Findings .................................................................................................................... 74.1 Scientific and Technical Literature.................................................................................... 74.2 Definitions of Bleached Pulp Manufacturing Processes..................................................... 74.2.1 Pulping ................................................................................................................................ 74.2.2 Bleaching............................................................................................................................. 74.2.3 Effluent Treatment .............................................................................................................. 84.3 Important Chemical and Physical Properties of Chlorinated Organic Pulp Mill

Effluents .............................................................................................................................. 84.4 Composition of Chlorine-bleached Pulp Mill Effluents ..................................................... 84.5 Analytical Methodology for Chlorinated Organics in Bleached Pulp Mill Effluents ...... 104.6 Regulations Governing Pulp and Paper Mill Effluent ..................................................... 134.6.1 Canadian Regulations........................................................................................................ 134.6.2 Foreign Regulations .......................................................................................................... 134.6.3 Non-regulated Parameters................................................................................................. 144.7 Quantities of Chlorinated Organic Compounds Entering the Environment .................... 154.8 Environmental Fate and Levels......................................................................................... 164.8.1 Fate and Persistence of Chlorinated Organic Compounds Discharged from

Bleached Pulp Mills.......................................................................................................... 164.8.2 Levels and Distribution of Chlorinated Organic Compounds in the

Aquatic Environment ........................................................................................................ 19

vi

4.9 Effects of Bleached Pulp Mill Effluents on the Aquatic Environment ........................... 264.9.1 Acute Lethality.................................................................................................................. 264.9.2 Chronic Effects.................................................................................................................. 284.9.3 Other Effects ..................................................................................................................... 33

Section 5Risk Assessment, Conclusions and Future Considerations ..................................................... 375.1 Source Assessment............................................................................................................ 375.2 Distribution and Fate Assessment..................................................................................... 385.3 Exposure and Effects Assessment..................................................................................... 405.4 Risk Assessment................................................................................................................ 415.5 Conclusion......................................................................................................................... 415.6 Future Considerations ....................................................................................................... 41

References.................................................................................................................................... 43

vii

List of Figures

1 Locations of Canadian Pulp Mills Employing Chlorine Bleaching………………………9

2 Compounds Detected in Canadian Bleached Pulp Mill Effluents……………………… 11

3 Specific Compounds Discharged from Bleached Pulp Mills……………………………12

List of Tables

1 Regulatory Schedule for Discharge of Organochlorine Compounds from Pulp Millswhich Employ Chlorine Bleaching………………………………………………………14

2 European Regulatory Schedules for Source-Control of Chlorinated OrganicCompounds………………………………………………………………………………15

3 Bioconcentration Factors of Compounds Discharged from Bleached Pulp Mills……… 20

4 Canadian Adsorbable Organic Halogen Measurements (1989)………………………… 21

5 Range of AOX Concentrations in the Effluent and Immediate Receiving WatersDuring Mean and Minimal Daily Watercourse Flows (Freshwater)…………………….21

6 Concentration Range and LC5Os of Bleached Pulp Mill-Generated CompoundsFound in Biologically-Treated Effluents from Kraft and Sulphite Mills………………..27

viii

Summary

There were 47 pulp mills employing chlorine bleaching in operationin Canada at the time of writing this risk assessment report. Themolecular chlorine or chlorine-containing compounds currently usedas bleaching agents by the pulp and paper sector react with materialsreleased from wood during the pulping process, resulting in theformation of chlorinated organic compounds which are in partdischarged into the aquatic environment via effluents.

Canadian mills are estimated to use over 610 000 tonnes of chlorineannually to produce over 10 million tonnes of bleached pulp and torelease over a million tonnes of chlorinated organic compounds tothe aquatic environment. The assessment report concentrates uponthese materials, in accordance with the recommendation of theReport of the Ministers' Priority Substances Advisory Panel (1988)to consider the "full range of compounds found in those effluents,particularly organochlorine compounds." Other materials commonlyfound in bleached pulp mill effluents include resin and fatty acidsand these were examined briefly.

This assessment report does not include polychlorinateddibenzodioxins and polychlorinated dibenzofurans, total suspendedsolids (TSS) or biochemical oxygen demand (BOD) in the evaluationof bleached pulp mill effluents. The dioxins and furans were notconsidered as they were concluded to be "toxic" under Sections11(a) and 11(c) of the Canadian Environmental Protection Act(Reported in Priority Substances List Assessment Report No. 1 andpublished in the Canada Gazette, Part 1, March 17, 1990, p.949). Apreliminary review of other organochlorine components of bleachedpulp mill effluents found insufficient data to be able to judge theirimpact on the quality of fish for human consumption or on drinkingwater. TSS and BOD are regulated under Sections 34 and 36 of theFisheries Act.

The chemical composition of bleached pulp mill effluents is variableand not well characterized. Approximately 250 compounds havebeen identified in bleachery effluents but many more remainunidentified. Thus, substantial quantities of chlorinated organiccompounds, both of known and of unknown composition, enter theCanadian aquatic environment from bleached pulp mill discharges.

Many of these chlorinated organic compounds are persistent andhave been detected in water, sediments and biota up to 1400 km

ix

from bleached pulp mills outfalls. Compounds with low chlorinesubstitution degrade within hours to days, whereas highlychlorinated organic compounds may persist from days to weeks orlonger. Persistence may be longer in winter, especially under ice.Some chlorinated organic compounds can be biologically degradedor transformed and transformation may lead to more persistent andbioaccumulative compounds. Chloroveratroles, for example,transformation products of chloroguaiacols which are unique tobleached pulp mill effluents, are capable of accumulating in fish upto 25 000 times the concentration in water. Some other chlorinatedorganic compounds detected in biological tissues downstream ofbleached pulp mills reflect repeated or long-term exposure ratherthan high bioaccumulative potentials.

Seventy-five percent of Canadian bleached pulp mills dischargeeffluents that are acutely lethal to fish, sometimes at concentrationsas low as 3.2% effluent. A few individual chlorinated organiccompounds in these effluents approach or surpass concentrations thatcause mortalities in aquatic organisms ranging from algae to fish.Seventy percent of Canadian freshwater bleached pulp millsdischarge whole effluent that, even upon dilution by the receivingwaters, are at levels which cause chronic effects. Chronic effects,such as reproductive anomalies, biochemical changes, andbehavioural alterations in aquatic organisms, have been observed inCanadian field studies at 0.5 to 5 % whole effluent. Laboratorystudies using individual chlorinated organic compounds that arecommonly discharged from bleached pulp mills have demonstratedsuch chronic effects as deformities, and embryo and larvalmortalities in fish. These chronic effects include significantirreversible factors which jeopardize the continuance of the speciesand the integrity of the ecosystem.

Thus, the levels of whole effluents discharged from Canadianbleached pulp mills to the aquatic environment and the resultingacute and chronic effects observed both in the field and in thelaboratory combine to represent a significant risk to the aquaticecosystem.

Based on these considerations, the Minister of Environment and theMinister of Health and Welfare have accepted the conclusion that thesubstance "Effluents from Pulp Mills using Bleaching" is enteringthe environment in a quantity or concentration or under conditionshaving an immediate and long-term harmful effects on theenvironment. This substance is therefore considered to be "toxic" asdefined under Paragraph 11(a) of the Canadian EnvironmentalProtection Act.

x

Acknowledgements

This report has been prepared for the Ministers of Environment andof National Health and Welfare by the Task Group on Effluents fromPulp Mills using Bleaching:

D. Halliburton, Task Group leader (Environment Canada)S.A. Jones, principal author (Environment Canada)J.H. Carey (Environment Canada)D.B. Carlisle (Environment Canada)A.G. Colodey (Environment Canada)A. Myres (Health and Welfare Canada)W.L. Lockhart (Fisheries and Oceans)I.H. Rogers (Fisheries and Oceans)

1

Section 1The Canadian Environmental Protection Act

The Canadian Environmental ProtectionAct (1,2) was created to protect theenvironment and human health from adverseeffects associated with the entire life cycle ofsubstances (manufacture, distribution, use,transportation, storage and disposal). TheMinisters of Environment and of NationalHealth and Welfare share responsibility forthe Act and are required under the Act toassess the effects of selected substances onthe environment, on the environment onwhich human health depends, and on humanhealth.

The Canadian Environmental Protection Act(CEPA) is federal legislation whichincorporates and expands upon theEnvironmental Contaminants Act (1975)(temporarily excluding Subsection 4(6)), theClean Air Act (1971), the Ocean DumpingControl Act (1975) and Part III of theCanada Water Act (1970). Through theamalgamation of these Acts, CEPA providesa comprehensive total ecosystem approachto the protection of our air, water, soils, andthe marine environment. CEPA does not,however, have any jurisdiction over subjectmatter regulated by such statutes as theFisheries Act, the Food and Drug Act andthe Pest Control Products Act. In instanceswhere an aspect of a substance is regulatedby any other federal statute, Section 34(3) ofCEPA will not permit the making of aregulation.

CEPA defines substances as "anydistinguishable kind of organic or inorganicmatter, whether animate or inanimate".Included in this definition are chemicals,products of biotechnology, and mixturesincluding emissions and effluents. CEPAdefines a substance as "toxic" if it can causedirect or indirect harmful effects on theenvironment or human health.

Section 12 of the Act requires the Ministersto compile a Priority Substances List (PSL).Following consultation with academia,industry, environmental public interestgroups, and provincial governments(3), a listof 44 substances was compiled andpublished in 1989(4). Section 12 also permitsthe Minister to amend this list from time totime.

Assessment reports for each of thesubstances on the PSL are required and areexpected to be completed within three tofive years of the PSL publication date. Theorder in which substances are addresseddepends on the amount of investigationrequired, their status with respect to thedevelopment of regulations, and the degreeof environmental or public concern.

For the purpose of assessing a substance'stoxicity or for developing regulations,Sections 16 and 18 of CEPA allow theMinister of the Environment to requirepersons to provide toxicological orquantitative information and samples of thesubstance(s) in question. Any person towhom such a Notice is directed (such as:manufacturers or users) must comply subjectto the penalties provided in Section 112 ofthe Act.

According to Section 11 of the Act, asubstance is "toxic" if it: "is entering or mayenter the environment in a quantity orconcentration or under conditions:

a) having or that may have an immediate orlong-term harmful effect on theenvironment;

b) constituting or that may constitute adanger to the environment on whichhuman life depends; or

2

c) constituting or that may constitute adanger in Canada to human life orhealth."

If a substance is deemed to be "toxic" to theenvironment and/or human health, theMinisters of Environment Canada and Healthand Welfare Canada may recommend thedevelopment of regulations. The Governor in

Council, if satisfied with the evidencedeclaring a substance "toxic", and on therecommendation of the Ministers, may orderthe substance to be placed on the List ofToxic Substances in Schedule I of CEPA(Section 33(1)) and regulations to beenacted. A substance may be added to thisList in advance of the development ofregulations.

3

Section 2

Risk Assessment Criteria

The goal of this CEPA risk assessment is todetermine the degree of environmental riskfrom effluents discharged by pulp mills usingchlorine bleach. For purposes of this report,"discharge" is defined as the release or entryof a substance into the environment undercurrent manufacturing conditions.

Four discrete approaches to risk assessmentare available:

• field evidence of harmful effects on biotacaused by exposure to bleached pulp milleffluents can be taken as evidence of ahigh degree of risk;

• measured aquatic exposure data can becorrelated with laboratory environmentaleffects data; if, for example, the level of atested substance in the environmentapproaches or exceeds the concentrationknown to induce chronic effects, then thedegree of risk that chronic effects willoccur in aquatic species will be very high;

• evidence of a threat to any species namedin the vulnerable, threatened orendangered categories by the Committeeon Status of Endangered Wildlife inCanada or designated as endangered bythe provinces or territories, or to thehabitat of such species, represents anunacceptable risk; and

• the presence of residues or metabolites inbiota exposed to bleached pulp milleffluents corresponding to or exceedingknown threshold levels is also stronglypredictive of either short- or long-termharmful effects.

In instances where there is evidence of anyone or more of these criteria, the substance

would be deemed to be "toxic" pursuant toParagraph 11(a) of CEPA.

No Canadian information was foundconcerning the exposure of endangeredspecies within the zone of influence ofbleached pulp mills or information showingresidues in excess of threshold levels in biotaor tissues either for whole bleached pulp milleffluents or for any of their knownconstituents.

Many factors influence the degree of"immediate or long-term harmful effect on theenvironment" (Paragraph 11(a) of CEPA)."Harmful effect" is not defined in the Act. Forthe purposes of this risk assessment report,"immediate harmful effect" includes acutetoxicity and "long-term harmful effects"includes significant, irreversible, chroniceffects which will continue (or worsen) duringthe entire period of exposure of the ecosystemto the substance. Ideally a risk assessmentinvolves the comparison of exposure levelswith harmful effects levels using both fieldand laboratory data on the most sensitiveknown species over at least one full life cycle.Frequently, however, as in the presentinvestigation, initial field observations havenot yet been followed up with laboratorystudies, and specific stages of a sensitiveorganism's life-cycle remain to beinvestigated. The approach taken in this riskevaluation is to place the greatest weight onthe most sensitive species for which field dataor laboratory data are available.

A major component of this risk assessmentinvolved the critical examination of the qualityand quantity of the data associated with avariety of bleached pulp mill effluent studies.The criteria for assessment of this type ofinformation included: determining

4

whether or not the reference sites wereuncompromised; evaluating the statistical andanalytical methods employed; comparinglimits of detection and quantitation withreported concentrations; examining theconsistency of reported data with other relatedinformation; and evaluating observed fieldeffects for causality by means of criteriaoriginally established by Popper(5),i.e.,determining the degree to which othercontrolled parameters, such as BOD, couldinfluence the observed effects. Authors,experts or peers were often consulted whenquestions of data quality or interpretation

arose. In cases where insufficient informationwas available, reasonable estimates were madeon the basis of related data or"worst-case" estimates were produced.

The conclusion of this report is based on asynthesis of the results of all of the abovecritical evaluations, i.e., it is based on theweight of all available evidence. Newinformation, especially in key areas such asamounts released to the aquatic environment,exposure levels, observed effects in the field,and harmful effects levels could modify orchange our estimate of the degree of risk.

5

Section 3Scope of the Investigation of Effluents from Pulp MillsUsing Bleaching

The risk assessment process involvessearching chemical, biological, medical, legal,technological, and environmental literatureand supplementing this information, wherepossible, with actual testing, monitoring, andresearch. Information of particular importanceincludes environmental effects and humantoxicity data, as well as data dealing with theroutes, levels and effects of short- and long-term exposure. Additional information, in thisinstance, was acquired through a CEPASection 18 notice requiring bleached pulpmills to submit specific information abouttheir operations and discharges.

Chlorinated organic constituents of effluentsfrom bleached pulp mills are the primary focalpoint of this assessment report, asrecommended by the Ministers' PrioritySubstances Advisory Panel(3). Chlorinated"dioxins" and "furans" (also found in bleachedpulp mill effluents) were evaluated in aprevious assessment report(6).The effects ofTotal Suspended Solids (TSS) andBiochemical Oxygen Demand (BOD)(characteristic of pulp mill effluents) were notevaluated as they are regulated under theFisheries Act.

The toxic effects of bleached pulp milleffluents on human health have not beenwidely studied. The toxicity of dioxins andfurans, as well as their potential to harmhuman health, has been well established andthey were the first substances on the PrioritySubstances List (PSL) to be declared "toxic"under CEPA. Insufficient data were found in apreliminary review on other organochlorinecomponents of bleached pulp mill effluents tobe able to judge their effects on the quality offish for human consumption or on drinkingwater. This assessment therefore focused on

the environmental impacts of pulp milleffluents.

Similarly, no information was found whichsuggested that any of the constituents ofbleached pulp mill effluents affected theenvironment on which human health depends."Toxic" effects as defined by Paragraphs 11(b)and 11(c) of the Act, therefore, are beyond thescope of this assessment. This does notpreclude future use of CEPA in these areasshould new information arise.

This investigation of effluents from pulp millsemploying bleaching included the followingactivities:

1. The technology of bleached pulpmanufacture was studied to provide a basisfor evaluating biological information.

2. The physical and chemical properties ofselected chlorinated organic compounds inbleached pulp mill effluents werereviewed. Particular emphasis was placedon those properties that influence chemicalanalysis, environmental persistence anddistribution, and aquatic toxicity.

3. The complexity of bleached pulp milleffluents was explored and availableinformation on generic and specificreleases from bleached pulp mills to theaquatic environment was evaluated.

4. Analytical methods employed to measureorganochlorine concentrations in bleachedpulp mill effluents were examined.Particular emphasis was placed onsurrogate measurements, such asAdsorbable Organic Halogen (AOX),

6

for the estimation of the organochlorineContent in effluents and receiving waters.

5. Existing and proposed guidelines,regulations, and legislation relating to thecontrol of organochlorine pollution of theaquatic environment by bleached pulpmills were reviewed and compared forCanada, the United States, Scandinavia,and Europe.

6. Canadian statistics on quantities ofchlorine consumed, effluents discharged,and bleached pulp produced werecollected and analyzed, and an estimate ofthe chlorinated matter released was made.

7. The environmental distribution and fate ofchlorinated substances released in bleachedpulp mill effluents were investigated.Particular emphasis was placed on themanner in which bleached pulp milleffluent constituents are partitioned amongvarious environmental compartments(water, sediments, and biological tissues),how long they persist in thesecompartments, the potential for physicaland biological degradation and thetransformation, and the

degree to which they are bioaccumulatedin the aquatic environment.

8. Canadian levels of chlorinated organiccompounds detected in bleached pulp milleffluents, receiving waters, sediments, andaquatic organisms were reviewed andcompared when possible with the levelsfound in Scandinavia. This informationwas examined for organochlorineconcentration gradients in the aquaticenvironment to determine if the exposurelevels involved in extensive Scandinavianstudies are comparable to those found inCanada.

9. The acute and chronic toxicities to aquaticorganisms associated with whole bleachedpulp mill effluent and its knownorganochlorine constituents were reviewedfor both field and laboratory conditions.Emphasis was given to relating, wherepossible, the levels of these compoundsmeasured in water, sediments, and biota tothe levels required to induce acute orchronic effects in exposed aquatic life.Comparable data on exposure and effectsfrom other countries were included, whenavailable.

7

Section 4

Overview of Findings

4.1 Scientific and Technical Literature

A survey of the published and unpublishedscientific literature on bleached pulp milleffluents, including two recent unpublishedreviews by A.G. Colodey(7) and by J.B.Sprague and A.G. Colodey(8), together withcomments from selected reviewers providedmuch of the background informationnecessary for this risk assessment.

The acute lethality of pulp mill effluents hasbeen documented extensively in the scientificliterature, but there has been less emphasis onchronic toxicity or fate. The present worldtrend of rapidly increasing environmentalawareness, coupled with the relatively recentdiscovery of chlorinated dioxins and furans inbleached pulp mill effluents, however, hasspurred a greater research effort, particularlyin the areas of chronic effects and fate. As aresult, scientific information on such topics asbleached pulp mill effluent composition,effects, and ultimate fate is expected toimprove dramatically in the next few years.

4.2 Definitions of Bleached PulpManufacturing Processes

4.2.1 PulpingThe main objective of the pulping process is toseparate cellulose fibre from lignin to free thefibres for papermaking. The two main types ofpulping processes are mechanical andchemical. Mechanical pulping utilizes heatand mechanical forces to break down thelignin and results in a light-coloured pulpwhich requires little bleaching. This reportfocuses on chemical wood pulping asrecommended by the Ministers' PrioritySubstances Advisory Panel(3).

As the name implies, chemical pulping uses amixture of chemicals to separate the cellulosefibres from the lignin. The two major chemicalprocesses are kraft and sulphite pulping. Kraftpulping is carried out in an alkaline mediumand releases fibres by dissolving lignin in acaustic solution of sodium hydroxide andsodium sulphide. In contrast, the sulphiteprocess is carried out under acidic conditionsand solubilizes lignin through sulphonationusing a solution of sulphur dioxide andalkaline oxides such as sodium, magnesium,ammonium, or calcium(9),Both chemicalprocesses produce a relatively dark-colouredpulp which requires bleaching. The vastmajority of the 47 bleached pulp mills inCanada employ the kraft pulping process (fivemills employ the sulphite pulping process).

Oxygen delignification, which may beemployed as an additional stage in either thesulphite or kraft pulping process, breaks downthe lignin further, reducing the amount ofbleaching agent required in the subsequentstage.

4.2.2 BleachingThe bleaching of cellulose fibres is anextension of the delignification whichcommenced in the pulping stage. Mechanicalpulp is generally brightened by hydrogenperoxide. As no chlorine or chlorine- basedchemicals are used, no chlorinated organiccompounds are generated.

Bleaching of chemical pulps is generally acomplex process consisting of a series ofstages, each of which may use severalchlorine-based chemicals. In the first stage,the pulp is dispersed in water and contactedwith a chlorine-water solution. More recently,chlorine dioxide has been substituted

8

for a growing percentage of the chlorine gas atthis stage to reduce the formation ofchlorinated organic compounds. Chlorine andchlorine dioxide are effective in breakingdown lignin, but little colour is removed atthis stage. The second stage of bleaching isusually caustic extraction. The caustic solution(sodium hydroxide) dissolves most of themodified lignin. In the third stage, chlorinedioxide or hypochlorite are added to the pulp.Subsequent bleaching stages and thechemicals used depend on the brightnessrequired and the quality demands of thefinished products(10).

The locations of Canadian pulp mills thatemploy chlorine-bleaching are shown inFigure 1.

4.2.3 Effluent TreatmentThe effluents from pulping and bleachingoperations are combined and, in most cases,treated prior to discharge. Primary treatmentremoves suspended solids through screeningand settling, thereby reducing the biologicaloxygen demand (BOD) of the effluents on theaquatic environment. Secondary treatmentinvolves contact with bacteria whichdecompose organic substances in the effluent.This process removes oxygen- consumingsubstances and also many substances toxic tofish. In Canada, 49% of bleached pulp millsemploy secondary treatment, 43% employonly primary treatment, and 9% of the millsemploy no effluent treatment. These statisticscan be further broken down as follows:

Number of MillsInland Coastal

No treatment 2 2Primary treatmentonly

12 8

Secondary treatment 20 3

In contrast, all U.S. bleached pulp mills arerequired by law to apply secondary treatmentto their effluents.

4.3 Important Chemical andPhysical Properties ofChlorinated Organic Pulp MillEffluents

A chlorinated organic substance is any organiccompound that has one or more chlorineatoms attached to the molecule. On the otherhand, the term organochlorine (a short formfor "organic chlorine"), refers to the chlorine(only) that is attached to a chlorinated organicmolecule. This distinction is quite important inconsideration of the weights of materialinvolved. For the compounds found inbleached pulp mill effluents, the mass(weight) expressed as organically boundchlorine is usually about 1/13 (8%) of themass of the same compounds expressed aschlorinated organic substances(11).

It is beyond the scope of this assessment reportto discuss the physical and chemical propertiesof all the individual chlorinated organicsubstances found in bleached pulp mill effluentsto date. Interested readers are referred to arecent review(12) which describes manyenvironmentally relevant properties of over 250chemicals identified in pulp mill effluents. Ofparticular environmental importance are thegeneral characteristics of chlorinatedcompounds, such as: specific octanol/waterpartition coefficients; water solubilities; vapourpressures; and bioconcentration potentials. Incomparison with their nonchlorinated analogues,chlorinated organic compounds may become:more toxic (13-19); more lipophilic and thereforebioaccumulative (12,17,20,21); less biodegradable(15,19,22); and mutagenic (15,20,23,24).

4.4 Composition ofChlorine-bleached Pulp Mill Effluents

Generally, unbleached pulp mill effluentscontain resin acids and soaps, fatty acids,

MILES 100 50 0 100 200 300 400 500 MILES

KILOMETERS 100 0 100 200 300 400 500 600 700 800 KILOMETERS

BR

I TI S

H

C O L U M B I A

AL B E R T A

S A S K A T C H E W A N M A N I T O B A O N T A R I O

Q U E B E CA

L B E R T A

S A S K A T C H E W A N M A N I T O B A O N T A R I O

Q U E B E C

N

A

EW

F O U ND

L

ND

YU

KO

NT

ER

RI T

OR

Y

N.W.T.

N.B.

P.E.I.

N.S.

ATHOLVILLE

NEWCASTLE

PORT HAWKESBURY

NEW GLASGOW PT.

SAINT JOHN

NACKAWIC

JONQUIÈRE

ST.FÉLICIEN

LA TUQUETROIS

RIVIÈRES

LEBEL-SUR-QUEVILLON

THURSO

EDMUNDSTON

WINDSOR

THOROLD

CORNWALL

TEMISCAMING

PORTAGE-DU-FORT

ESPANOLA

SMOOTH ROCK FALLS

MARATHON

TERRACE BAY

RED ROCK

DRYDEN

L. SUPERIORL

.M

ICH

IGA

N

L.H

UR

ON

L. E

RIE

L. ONTARIO

FORT FRANCES

PRINCE ALBERT

CRANBROOKCASTLEGAR

KAMLOOPS

HINTON

GRANDE PRAIRIE

MACKENZIE

PRINCE GEORGE

PRINCE GEORGE

PRINCEGEORGE

QUESNEL

POWELL RIVER

SQUAMISH

PORT MELLON

CROFTON

NANAIMO

PORT ALBERNI

CAMPBELL RIVER

GOLD RIVER

PORT ALICE

PRINCE RUPERT

THUNDER BAY

U.S

.A.

CANADA.

U.S.A.

CANADA.

Figure 1 Locations of Canadian Pulp Mills Employing Chlorine Bleaching

9

10

diterpene alcohols, and phytosterols. Afterchlorine bleaching, the effluents contain thesechemicals as well as chlorinated phenols,chlorinated acids, alcohols, aldehydes,ketones, sugars, and aliphatic and aromatichydrocarbons (8,9,12,25)(see Figure 2).Numerous volatile sulphur-containingcompounds are also found in pulp milleffluents(25).

It has been estimated that only 10 to 40% ofthe low molecular weight (mw < 1000)chlorinated organic compounds in bleachedpulp mill effluents have beencharacterized(9,16,26-28). In general, the majorityof the chlorinated organic compounds inbleachery effluents, approximately 70 to 80%,are of high molecular mass (mw > 1000)(9,29-

31). Many of the high molecular masschlorinated organic compounds formed duringthe pulping and bleaching processes, aretransformed in either secondary treatmentlagoons or the receiving environment, intooften more toxic and persistent low molecularmass compounds; compounds of mw < 1000are able to pass through biological membraneswhile those of a higher molecular weight arerarely able to do so(9,29).

Complicating the characterization of pulp milleffluents are the effects of such factors as thetype of wood used, in-plant processes(including bleaching sequences) and theeffluent treatment procedures employed(29). Ingeneral, softwood produces greater quantitiesof phenolic by-products than hardwood.Chlorinated softwood effluent containschlorophenols, chloroguaiacols,chlorocatechols, and chlorovanillins. Inaddition to the previously mentionedchlorophenolics, hardwood effluents alsocontain chlorinated syringols and chlorinatedsyringaldehydes(32) .

The type of pulping and bleaching proceduresemployed by a mill, influence the character ofthe effluent. The most common chlorinatedphenolics in bleached kraft pulp mill effluentsare tri- and tetra-chloroguaiacols, whereas

trichlorophenol is the principal chlorinatedphenol in bleached sulphite discharges (seeFigure 3). The substitution of chlorine dioxidefor chlorine in the bleaching stage also alterseffluent composition. In one instance,catechols and guaiacols together comprised77% of the total chlorinated phenolic contentwhen chlorine alone was used in the bleachingstage. When a 70:30 C102:C12 ratio was usedin the first stage, the catechol and guaiacolportion decreased to 46%, and at 100%chlorine dioxide substitution, only 10% of thechlorinated phenolics were of the catechol andguaiacol type(33).

Many chlorinated compounds have beenreported in untreated effluent from thebleaching process, but comparatively few havebeen reported in biologically-treated bleachedkraft and sulphite mill effluent(9,26,28).

For an exhaustive listing of chemicals foundin pulp mill effluents to date readers arereferred to references 9, 12 and 25.

4.5 Analytical Methodology for Chlorinated Organics inBleached Pulp Mill Effluents

Many analyses have been performed onindividual constituents of pulp mill effluents,chiefly by gas-liquid chromatography (GLC)(16,30,34-37); Because of the variables known toaffect the composition of these effluents andsince it is unlikely that all chlorinatedcompounds in bleached pulp mill effluentswill ever be identified, it is not practical toattempt to completely characterize effluentson the basis of individual substances. It ismore reasonable as an interim measure,therefore, to measure the total organic chlorineloading from bleached pulp mills in theaquatic environment.

Generic tests, such as Adsorbable OrganicHalogen (AOX) and Extractable OrganicChlorine (EOCl), provide indices of totalorganochlorine concentrations in effluent,receiving waters, sediments, and biota(38).

11

Figure 2 Compounds Detected in Canadian Bleached Pulp Mill Effluents

OH

OH

Cl

Cl

Cl

345 -TC C

3,4,5,-Trichlorocatechol

OH

OH

Cl

Cl

Cl

Cl

TECCCOOH

Tetrachlorocatechol

Linoleic Acid Methanol

Glucose

Toluene

Pentadecane

2-Butanone

Chlorinatedsyringaldehyde

Dehydroabietic Acid

CHO

OCH3

OH3CH

CH3O

CH3

C H O18 32 2

C H O6 12 6

C H15 32

CH3 C

O

CH3CH2

OH

ClX

12

Figure 3 Specific Compounds Discharged from Bleached Pulp Mills

OH

OCH3

CI

345-TCG

OH

CI

CI

CI

246-TCP

OCH3

OH

CI

CI

CI

CI

TECG

CI

CI

Tetrachloroguaiacol

3,4,5-Trichloroguaiacol

2,4,6-Trichlorophenol

Adsorbable Organic Halogen is a widely accepted generic measurement used throughout this report to indicate the organic chlorine loading by a pulp mill using chlorine bleaching. In this procedure, a water sample is passed through activated carbon to adsorb organic substances. After the carbon has been washed to remove inorganic halides, it is combusted and the gaseous products are analyzed for total halogens. in effluents from bleached pulp mills, the halogen ("X") component of AOX is almost entirely chlorine.

Other surrogate measurements used to detect organic chlorine downstream of bleached pulp mills include EOC1, Total Organic Chlorine (TOC1) and Total Organic Halogen (TOX).Extractable Organic Chlorine is the analytical method used to determine the extractable organic chlorine from sediments and animal tissue samples. The TOC1 method has been frequently used, particularly in Scandinavia. This is a measure similar to AOX, but yields a result that is often about 75% of the AOX

8value( ). Total Organic Chlorine values may be converted to AOX by using formulae

developed from a bank of corresponding TOC1 and AOX determinations made at the Pulp and Paper Research Institute of Canada

33(PAPRICAN)( ). The TOX method is sometimes used in the United States, and is

29very similar to the AOX method( ).

Adsorbable Organic Halogen is the measurement most commonly used to analyze bleached pulp mill effluents because of its repeatability, comparative ease of use, and low cost. One of the major limitations of surrogate tests, however, is that they do not provide estimates of the potential toxicity, persistence, or bioaccumulation of specific chlorinated organic substances. Equal AOX or equal EOC1 values indicate neither identical composition of effluents nor equivalent toxicity to aquatic life.

The concentration of organic chlorine recoverable from sediment and/or animal tissue samples depends on the extraction and

(39)analytical techniques used and on the lipophilicity of the chlorinated organic compounds. Chlorinated organics of low

13

lipophilicity would not be adsorbed bysediments and would have a short half-life inanimal tissues. The amount of chlorinatedorganic compounds recovered from sedimentsamples is also very dependent on thesediment composition, e.g., sediment with ahigh organic carbon content would beexpected to have a much higher EOCI valuethan sandy sediment(40).

The Pulp and Paper Research Institute ofCanada in collaboration with EnvironmentCanada have developed a draft protocol forthe determination of Adsorbable OrganicHalogen (AOX) in pulp mill effluents. Thedraft protocol is undergoing round-robintesting throughout Canada. Interested readerson AOX analytical methodology are alsoreferred to Sjostrom et al. (41) in which twoTOX methods are compared.

4.6 Regulations Governing Pulp and Paper Mill Effluent

4.6.1 Canadian RegulationsCanadian pulp mills have been regulatedunder the Pulp and Paper Effluent Regulationssection (s.36-42) of the Fisheries Act since1971. At present, the regulations apply only tomills that were built, expanded, or modifiedafter promulgation of the Act. Mills that werebuilt before 1971 are not regulated(29, 42).

The federal government is extending theapplication of the Pulp and Paper Regulationsto include all mills and, among other things, isdeveloping stricter enforcement policies toverify compliance. The revised regulations areexpected to be published in the CanadaGazette in 1991. Regulations are also beingdeveloped to control the discharge ofchlorinated dibenzo-dioxins and -furans frombleached pulp mill effluents.

At the provincial level, Ontario hasestablished AOX discharge limits for kraftmill operating licences issued by theprovince(43). Ontario plans to introduceregulations under its Municipal-Industrial

Strategy for Abatement (MISA) program in1992 to control bleached pulp mill effluentdischarges. These may include setting stricterdischarge limits in kraft mill operating permitsbased on best available technology andeconomic feasibility.

The provincial government of BritishColumbia has announced that they intend toregulate organochlorine discharges from theirkraft pulp mills and have proposed AOXlimits(43). The controls include a regulatoryschedule for source control of chlorinatedorganic substances and mandatory installationof secondary treatment at all mills in BritishColumbia which employ chlorine bleachingby 1991. The announcement followed thefederal government's decision in 1988, andagain in 1989, to close several west coastfisheries adjacent to coastal bleached pulpmills because of high levels of dioxin(44).

The Quebec provincial government hasannounced AOX limits which their bleachedkraft pulp mills must attain by 1993.

Although Alberta has not announced AOXlimits, the provincial government has decreedthat all four of the new or expanding bleachedkraft pulp mills in Alberta must install state-of-the-art technologies(44,45). The latestAlberta-Pacific (ALPAC) proposal suggestsextended delignification, 100% chlorinedioxide substitution and peroxide bleaching toachieve an AOX loading of less than 1kilogram per Air Dried tonne of pulp(kg/ADt)46).

Provincial regulatory schedules for controllingthe discharge of organochlorine compoundsfrom pulp mills which employ chlorinebleaching are summarized in Table 1.

4.6.2 Foreign RegulationsThe greatest European regulatory actiontowards the reduction of organochlorinelevels has occurred in Scandinavia(9).Swedish authorities are focusing uponprocesses within pulp mills to reduce the

14

production of total chlorinated organics ratherTable 1 Regulatory Schedule for Discharge of Organochlorine Compounds from

Pulp Mills which Employ Chlorine BleachingAOX discharge Target

Location (kg/t) Date

Ontario (kraft mill permit) 2.5 1991

Quebec (Existing softwood) 2.5 1993

(Existing hardwood) 1.5 1993

(New softwood) 1.5 1993

(New hardwood) 1.0 1993

Alberta (kraft mill permit) 1.5 1990

British Columbia 2.5 1991

than on studies of specific organochlorinesthat may have detrimental environmentaleffects(47) . By 1990, all Swedish bleachedkraft pulp mills except two, will have installedoxygen bleaching(29) . Finland, on the otherhand, is focusing much of its effort on lowmolecular weight chlorinated organics, whichare associated with acute and chronic toxicity,in the belief that the installation of secondarytreatment facilities will sufficiently reduce thetotal amount of chlorinated organics releasedto the aquatic environment(47,48). Pulp mills inSweden and Finland must also apply for alicence or permit to pollute the aquaticenvironment(29).

The German and French regulatory approachis to tax the pulp mill based on the amount oforganochlorines in effluents(44). The onus is onthe mills to implement or develop thetechnology necessary to reduce the levels ofchlorinated organic substances discharged tothe receiving waters.

The regulatory schedules of some Europeancountries as of late 1988 for source-control ofchlorinated organic compounds(8) are shown inTable 2.

The United States is intending to reduce levelsof chlorinated organic substances byregulating chlorine consumption by the mills.Although the Environmental ProtectionAgency (U.S. EPA) has not taken any formalaction as yet, it is believed that the UnitedStates will adopt a generic (AOX) approach toorganochlorine control(8) . As of October 1988,the U.S. EPA described a "Proposed InterimChlorine Minimization Program" with severalstages of reduced chlorine use, tests ofeffluents, and reporting(49) .

4.6.3 Non-regulated ParametersThe regulating of organochlorines in bleachedpulp mill effluents is a relatively new concern.All countries, including Canada, arecomparatively similar in their existing orproposed regulations. They are primarilyconcerned with setting AOX limits and withincorporating state-of-the-art process andtreatment technology. However, numerousareas are not regulated. No Canadianprovincial, federal or foreign regulations werefound which pertain to the disposal ofchlorinated organic contaminated sludge from

15

Table 2 European Regulatory Schedules for Source-Control of Chlorinated OrganicCompounds

TOC1 or AOX TargetLocation Discharge (kg/t) Date

West Germany 1.0 1989

Finland 2.5 1994

Norway 2 to 2.5 1991

Baltic 2.5 1994

Sweden 1.0 to 2.0 1992

Sweden 0.5 to l.0 1995

Sweden 0.3 to 0.5 1999

the secondary treatment lagoons. Presently,only two methods exist for the disposal ofsludge: incineration, which is currently asuspected source of dioxin(50) and dumpingat landfill sites(47). Also absent areregulations on emissions to the atmosphere,chlorine consumption by the bleached pulpmills, "safe" organochlorine levels in fishfor human consumption, or long-termstudies of the aquatic biota.

4.7 Quantities of Chlorinated Organic Compounds Enteringthe Environment

Bleached pulp and paper industries use largeamounts of water, consume considerablequantities of chlorine, and discharge largequantities of chlorinated organic matter intorivers, lakes, and oceans(42) .

The pulp and paper industry is the largestsingle commercial user of water in Canada.In 1989, the total mill effluent dischargedfrom Canadian bleached pulp mills averaged137 cubic metres per tonne or 104 000 m3/d(ranging from: 25 300 to 311 100 m3/d)which is roughly equal to the flow of the St.

Lawrence River at Cornwall, Ontario or tothat of the Columbia River in BritishColumbia. Total mill effluent volumesdepend on the grade and amount of pulpbeing produced.

Canadian bleached pulp mills consumed anaverage of 47.8 tonnes of chlorine per day(ranging from: 2.5 to 175.0 t/d) in 1989.Chlorine useage by pulp mills depends onthe type of wood used, the pulping andbleaching systems employed, and thedesired grade of the final product. Onaverage, in 1989, Canadian pulp and papermills bleached 678 tonnes of pulp per millper day (ranging from: 100 to 1 430 t/d).

It is estimated that the cumulative dischargeof organic chlorine by bleached kraft pulpmills to Canadian receiving waters in 1989was 86 000 tonnes (or 1 000 000 tonnes ofchlorinated organic compounds).

Laboratory studies have shown a linearrelationship exists between the amount ofelemental chlorine added as either molecularchlorine or chlorine dioxide and the formationof AOX(51). Less AOX is produced when

16

chlorine dioxide is the principal bleachingagent. No commercially proven method,however, is available to bleach pulp to thelevel of brightness currently demanded by themarket without the use of chlorine-containingbleaching agents(29).

In principle, numerous internal and externalplant methods exist for reducingorganochlorine discharges from bleachingplants. Internal mill measures which can beapplied are:

1) extended and/or oxygen delignification;

2) more efficient washing of pulp beforebleaching;

3) replacement or substitution of chlorine bychemicals with lower or no chlorinecontent or reactivity (e.g., chlorinedioxide, hydrogen peroxide); and

4) recovery of spent bleaching liquors(33,48,52)

Secondary treatment of bleach plant effluentsis the optimal external measure for reducingorganochlorine concentrations(7,8,52).

4.8 Environmental Fate and Levels

4.8.1 Fate and Persistence of Chlorinated Organic Compounds Discharged from Bleached Pulp Mills

Adsorption. The adsorption of hydrophobicchlorinated organic compounds by sedimentsand suspended particulate matter is animportant factor influencing the distributionand fate of chlorinated organic compounds inthe aquatic environment(34-53). This is evidentfrom the observed declining concentrationgradients in sediments and water withincreasing distance from bleached pulp milleffluent outfalls (40,53,54).

The adsorption of constituents of bleachedpulp mill effluents on sediments andsuspended particulate matter depends on pH,the organic carbon content of the potential

sorbent, and the partition coefficients of thechlorinated organic compounds between thewater and solid phase(55-57).

Chlorinated organic compounds bound tosediments and suspended particulate matterare not necessarily unavailable to the aquaticbiota. Organochlorine concentrations havebeen found in benthic invertebrates, whichlive and/or feed on sediments in watersreceiving effluents from pulp mills usingchlorine bleaching(30,35,40,58-65). Fish feed onthese contaminated benthic invertebrates,thereby accumulating organochlorines(25).These are then further accumulated by fish-eating birds(25) .

Laboratory and field investigations have bothshown that sedimented chlorinated materialoriginating from bleached pulp mills can actas a continuing source of organochlorinecompounds to the aquatic environment(66). Forexample, comparable concentrations ofextractable organic chlorine (EOCI) weremeasured in lipid of fish caught sixteenmonths after the closure of a Norwegiansulphite pulp mill and when the mill was inoperation(66). Samples collected 3.5 years afterthe mill had closed found AOX (TOC1)concentrations in water to have returned tobackground levels and fish tissueconcentrations (EOC1) to have decreased by90% of the pre-closure levels. Although nosedimentation rate and transportation studieswere conducted, it was concluded thatsufficient natural sedimentation had occurredto cover the contaminated sediments, therebymaking the chlorinated organic compoundsless available to the aquatic environment(66).

Volatilization. Studies have demonstrated thatsome chlorinated lipophilic substances, such aschlorophenols, originating from bleached pulpmills are volatile and that a low percentage canbe expected to escape to the air when dischargedinto well-mixed receiving waters(59-67). However,recent Canadian winter monitoring studies ofrivers completely covered by ice reveal thatvolatilization has no role in the removal of,

17

for example, chloroguaiacols, from the aquaticenvironment and that the chlorophenols are infact quite persistent under ice(68, 69) .

Photolysis. Many chlorophenol isomers foundin bleached pulp mill effluents are degraded tosome extent by ultraviolet (UV) light(57).Photolysis dechlorinates the molecule(70,71) butthe rate is affected by the number and positionof chlorine substituents on the molecule(57).For example, dichlorophenols andchloroguaiacols are expected to be stable tolight in the aquatic environment and remain inthe water column for hours to days and weeksto months, respectively(72). Turbidity andcolour of the receiving waters limits thepentration of light and therefore inhibitsphotolysis.

Biodegradation. Chlorinated organicsubstances can be metabolized by certainmicroorganisms in water(71,72,73,74) andsediment(73, 75) This decomposition is oftenquite rapid with half-lives ranging anywherefrom hours to days(57).

Many factors influence the rate ofbiodegradation of chlorinated organiccompounds in bleached pulp mill effluents.Generally, compounds which are highlychlorinated or have chlorine atoms situated inthe meta position are more stable, moreresistant to microbial degradation and,therefore, more persistent in the aquaticenvironment than those without(76).

Microorganisms that have been previouslyexposed to a chlorinated organic compoundare usually able to metabolize it immediatelywhen re-exposed, and at a faster rate than non-acclimated organisms(74, 77). Microorganismsnot previously exposed often exhibit a lagtime of as much as several days before theybegin to degrade the compound(78). Similarly,prior exposure to a structurally-relatedcompound can facilitate the metabolism ofchlorophenols, indicating that the enzymeinduced by the original compound issomewhat nonspecific (57, 79) .The

time lag exhibited by non-acclimatedmicroorganisms has implications whenconsidering the construction of a bleachedpulp mill in an area previouslyuncontaminated by constituents of bleachedpulp mill effluents. The effects on the aquaticenvironment would predictably be greatestduring the initial operations.

Many researchers have concluded thatbiodegradation between the water-biofilminterface and not volatilization is the majorfactor influencing the fate of dehydroabieticacid and chlorophenols in the aquaticenvironment(72,80,81). For example, turbidity ora rocky substrate with little biofilmdegradation would result in the retention ofchlorophenols in the water column for weeks.Photolysis photodegradation) would thenbecome the primary degradation pathway(72) .

The results of laboratory studies suggest thatbiodegradation is most rapid in aerobic soilsand sediments, and is reduced in anaerobic ornutrient-poor habitats(57). Field studies supportthese conclusions, since sediment cores, whichcontain layers several decades old and arepresumably anaerobic, contain detectablelevels of tetrachlorophenol,pentachlorophenol, and dehydroabieticacid (18,82-84). Dehydroabietic acid, a resin acidcommonly discharged in pulp mill effluents,was found to remain in sediments for 21years(80).

The rate of removal of chlorinated organiccompounds in wastewater treatment facilitiesdepends greatly upon operating conditions andcan be quite low(27, 38, 85). Bleached pulp milleffluent constituents most resistant tomicrobial degradation (5-day aerated lagoon)and, therefore, most likely to be dischargedinto receiving waters aredichlorodehydroabietic acid andtetrachloroguaiacol (degradation rates of 18and 8.4 µg/mg biomass/d, respectively)(25).Chlorinated phenols, guaiacols, catechols,vanillins, and veratroles are also easilydetectable in biologically-treated, as well as

18

nonbiologically-treated, bleached pulp milleffluents(9,32,81).

An analysis by a Canadian "state-of-the-art"bleached kraft mill of its biologically-treatedeffluents found its aerated lagoons effectivelytreated chlorinated vanillins and guaiacolswith up to 82% and 76% removal,respectively(86). In contrast, the same lagoonswere not as effective in removing chlorinatedcatechols (12%) and phenols (44%). Incomparison, the lagoons of a similar Europeanpulp mill were only capable of removingbetween 13% and 54% of the chloroguaiacolsfrom the effluents(50) .

Biotransformation. Some chlorinated organiccompounds from bleached pulp mill effluentscan be biologically transformed into moretoxic, more accumulative compounds, such aschloroanisoles and chloroveratroles in highyields(87-89). Through bacterial O-methylation,3,4,5-trichloroguaiacol is transformed into3,4,5-trichloro -veratrole, -syringol, and -catechol(90).

The possibility that the biotransformation ofchloroguaiacols was a laboratory artifact, anddid not occur in the natural environment, wasresolved by finding elevated concentrations ofchlorinated veratroles in Baltic Sea fishtissue(88,89) and sediments(54) in the vicinity ofbleached pulp mill outfalls. Since no othersource of polychlorinated veratroles is known,it must be concluded that these substancesoriginated from microbial transformation ofthe corresponding guaiacols (90).

Although chloroveratroles have been detectedin Canadian bleached pulp mill effluents andreceiving waters(69,91), they have not beensought in Canadian fish tissue. It is believedthat fish have inducible liver de-O-methylationenzymes which quickly convertchloroveratroles back to chloroguaiacols andchlorocatechols (92) . This conjecture issupported by laboratory experiments with zebrafish in which chloroveratroles within the fishwere de-O-methylated to the corresponding

chloroguaiacols and chlorocatechols andexcreted as aqueous sulphate and glucuronideconjugates(93).

O-methylation is expected to be restricted toaerobic or at least micro-aerophiliclocations(94). Oxygen-depleting fibre matsoften cover the sediments in the immediatevicinity of bleached pulp mill outfallsrendering the sediments anoxic by extensivemicrobial activity. In a laboratory study,chloroveratroles and chloroguaiacols wererapidly de-O-methylated to the correspondingcatechols (95). These findings explain the failureto recover chlorinated veratroles fromanaerobic sediments. The study also revealedan anomaly as chloroguaiacols were notrecovered(95). A possible explanation for thedifference in the chemical extractability ofchloroguaiacols and chlorocatechols may bethat these compounds are "bound" insediments by different mechanisms. Furtherexperiments(95) have shown chlorocatechols tobe unstable under anaerobic conditions.

A laboratory experiment using low substrateconcentrations of 3,4,5-trichloroguaiacolunder anoxic conditions resulted in 3,4,5-trichloroveratrole as the biotransformationproduct; however, at higher concentrations,3,4,5,-trichlorosyringol and 1,2,3-trichloro-4,5,6-trimethoxybenzene became thedominant products(94).

Bioaccumulation. Many toxic anthropogenicorganic compounds enter the aquaticenvironment. There, living organisms havedeveloped internal mechanisms for thesequestering, detoxification and/or eliminationof these compounds for self-protection. Somechlorinated organic compounds which aredischarged from bleached pulp mills are,however, bioaccumulative, magnifying thepotential harmful effects to the organisms andto other organisms which feed upon them.

The potential for aquatic organisms toaccumulate constituents of bleached pulp milleffluents above background (water)

19

concentrations (bioconcentration factor orBCF) is usually small(57). The results ofseveral laboratory BCF studies of compoundsdischarged from bleached pulp mills are listedin Table 3.

Tetrachloroveratrole, a biotransformationproduct of bleached pulp mill effluents, hasthe potential to be accumulated in fish tissue25 000 times above the backgroundconcentration(25,89). Again, the importance ofunderstanding the fate of both products andby-products found in bleached pulp milleffluents is emphasized.

The results of most bioaccumulation studiesindicate that bioconcentration ofchlorophenols is positively correlated with thenumber of chlorine atoms present in themolecule(96). The higher BCF with increasingchlorine substitution most likely results fromthe high partition coefficient or the lowerdissociation constant(57). Other experimentalconditions, such as length of exposure,exposure concentration, pH, ionic strength,water hardness and salinity, may alsocontribute to the substantial range of BCFvalues(97).

Clearance rates by fish of certain lipophilicand bioconcentrating chlorinated phenoliccompounds present in bleached pulp milleffluents are rapid (58). For example, 2,4,6-trichlorophenol and tetrachloroguaiacol wereeliminated from rainbow trout livers 21 and 10days, respectively after dosing wasdiscontinued(58). Similarly, 84 to 92% of 2,4,5-trichlorophenol was lost from fatheadminnows in the first day after exposure(98).The rapid elimination of these contaminantsby fish in laboratory studies may indicate thatthe observed bioaccumulation in fieldsituations is a result of long-term, low-levelexposure rather high bioaccumulativepotentials (58). In nature, however, manyaquatic organisms cannot or will not leavecontaminated waters(29,99), and, therefore, theeffectiveness of detoxification via excretion islimited in practice.

4.8.2 Levels and Distribution of Chlorinated Organic Compounds inthe Aquatic Environment

Water. In 1989, the Canadian Pulp and PaperAssociation (CPPA) conducted a NationalDioxin Characterization Program of Canada's47 bleached chemical pulp mills. Effluentsamples were analyzed by private consultants.The CPPA monitoring program included AOXmeasurements and the results are listed inTable 4.

Only with good design and carefulmanagement can effluent treatment result in alow AOX value. The lowest AOX value in1989 for a Canadian bleached pulp mill withno effluent treatment was 3.0 kg/ADt; one millwith primary treatment achieved an effluentAOX level of 1.0 kg/ADt, while the best resultfor a Canadian mill with secondary effluenttreatment was 0.5 kg/ADt. Poor design ormanagement of an effluent treatment facility,however, may lead to values above 10kg/ADt.

Inland Canadian pulp mills using chlorinebleaching, discharge effluents which mayform a substantial portion of the immediatereceiving waters. At one mill, the river flow ofthe immediate receiving waters was only fourtimes that of the effluent, so that the millprovided 20% of the watercourse flow. Onaverage, the effluents from the 24 Canadianbleached pulp mills situated inland on rivershave been estimated (based on AOX levelscompiled by the CPPA monitoring program in1989) to comprise 2.8% of the immediatereceiving waters during minimum flowconditions. The estimated concentration rangeof total chlorinated organic substances in thefinal effluent and in the immediate receivingwaters during mean and minimal dailywatercourse flows are shown in Table 5.

The concentration of chlorinated organiccompounds in the effluents discharged frombleached pulp mills is diluted upon mixingwith the immediate receiving waters;however, during low flow conditions, some

20

Table 3 Bioconcentration Factors of Compounds Discharged from Bleached Pulp Mills

Chemical Organism BCF Reference

2-Monochlorophenol Bluegill 214 100

2,4-Dichlorophenol Brown trout 10 25

2,4, 6-Trichlorophenol Snail (adult) 3 020 101

2,4, 6-Trichlorophenol Marine worm 20 269 102

2,4,5-Trichlorophenol Fathead minnow 1 900 98

2,3,4,6-Tetrachlorophenol Blue mussel 45-60 103

2,3 ,4,6-Tetrachlorophenol Roach 200 104

2,3,4,5-Tetrachlorophenol Marine worm 17 625 102

2,3,5,6-Tetrachlorophenol Catfish (liver) 8 608 105

Pentachlorophenol Roach 60 104

3,5-Dichlorocatechol Brown trout 2 25

Tetrachlorocatechol Brown trout 4 25

3,4,5-Trichloroguaiacol Rainbow trout 268 106

4,5 ,6-Trichloroguaiacol Rainbow trout 98 106

4,5,6-Trichloroguaiacol Bleaks 390 25,107

Tetrachloroguaiacol Bleaks 400 25,107

Tetrachloroguaiacol Rainbow trout 189 106

Tetrachloroveratrole Zebra fish 25 000 25,89

Chlorovanillins Rainbow trout <5 106

3,4,5-Trichlorosyringol Rainbow trout 125 106

receiving waters do not have adequate dilutioncapacity. Data from field measurements ofeffluent dilutions in several eastern Canadianrivers and lakes concur with theseestimates(25,36,108-111). Even when mills

are situated on lakes, the effluent may exist inmeasurable concentrations over a large area.Two mills located on Nipigon Bay in LakeSuperior, required a distance of 4 km toachieve a dilution to 0.1% of effluent(36,103).

21

Table 4 Canadian Adsorbable Organic Halogen Measurements (1989)

AOX (kg/ADt)Number

Region of Mills Range Mean

Pacific & Yukon 18 0.8 to 14.9 5.0

Western & Northern 3 1.1 to 2.9 2.2

Ontario 10 0.5 to 8.0 3.1

Quebec 9 0.6 to 7.9 3.1

Atlantic 7 1.2 to 5.9 3.4

Table 5 Range of AOX Concentrations in the Effluent and Immediate ReceivingWaters During Mean and Minimal Daily Watercourse Flows (Freshwater)

Range of AOX Concentrations (ppm)

Final effluent 3.8 to 62.5 (mean 26.6)

Immediate receiving waters, mean flow 0.003 to 3.7 (mean 0.32)

Immediate receiving waters, minimal flow 0.008 to 12.5 (mean 1.07)

The most consistently measured chlorinatedorganic compounds in waters receivingbleached pulp mill effluents arechlorophenolics(40,60-65).The range ofconcentrations detected along the BritishColumbia coast in the general vicinity ofbleached pulp mills is:

2,4,6-Trichlorophenol 1.6 to 20.0 ppb2,3,4,6-Tetrachlorophenol 1.0 to 7.1 ppbPentachlorophenol 1.7 to 2.8 ppb3,4,5-Trichloroguaiacol 8 to 30.5 ppbTetrachloroguaiacol 1.1 to 58.5 ppb3,4,5-Trichlorocatechol 1.0 to 16.0 ppbTetrachlorocatechol 3.0 to 17.0 ppb

Future coastal monitoring studies in BritishColumbia must analyze for other chlorinated

organic compounds as the levels of thosecompounds sampled do not adequately reflectthe total effluent AOX. For example, the AOXconcentrations in effluents from five coastalbleached pulp mills ranged from 16 to 48ppm(60-63,65).

Chloroveratroles, products ofbiotransformation, have been detected in theeffluents of bleached pulp mills; they havenot, however, been detected in the receivingwaters(69,81,91). Concentrations ofdichloroveratrole, 3,4,5-trichloroveratrole and1,2,3,4-tetrachloro- 5 ,6-veratrole have beenfound in bleached pulp mill effluents at 7, 36and 28 ppb, respectively(69,81,91).

22

Concentration gradients of AOX, resin acids,and specific chlorinated organics, which areassociated with pulp mills using chlorinebleaching, have been observed in Canadianwaters(63,81,112) The AOX concentrationdeclined, for example, from 102 ppm at 1 kmto less than 10 ppm at 7 km from the outfall ofa coastal bleached pulp mill(64).Dehydroabietic acid concentrations rangedfrom 130 ppb in the effluent to 100 ppb at 1.0km and finally to 0.1 ppb over 6 km awayfrom a bleached pulp mill on Nipigon Bay(81).A recent monitoring study on the St. MauriceRiver in Quebec revealed concentrations of3,4,5-trichloroguaiacol, 4,5,6-trichloroguaiacol, tetrachloroguaiacol, 2,4,6-trichlorophenol and 2,4-dichiorophenol to be80, 35, 30, 30 and 18 ppt, respectively,immediately downstream of the outfall of ableached pulp mill(112). The concentrations ofthese compounds decreased logarithmically to45, 9, 4.5, 10.5 and 5.5 ppt, respectively, overa distance covering 96 km. AOX levelsdecreased at a significantly slower rate.

Gradients of AOX and chlorinated organiccompounds have also been observeddownstream of bleached pulp mills inScandinavia(113).Finnish and Swedish studiesof the Gulf of Bothnia found AOX levelshighest near the outfall of bleached pulp mills(260 ppb) and only falling to backgroundlevels after 15 km and 12 km, respectively(113, 114). It has been reported that the naturalbackground level of AOX in both marine andfresh Scandinavian waters ranges from 10 to50 ppb(66,115,116). These levels have beenattributed to naturally occurring organic acids,e.g., humic and fulvic acids, which can havechlorine concentrations of 0.1 to 1% (115).

Numerous Canadian studies have discoveredbleached pulp mill-generated chlorinatedorganic compounds in fresh water over 600 kmfrom the source(41,50,68,81,117-122) A monitoringsurvey of the Athabasca River in November1988 found concentrations of 3,4,5-trichloroguaiacol and tetrachloroguaiacol 20 kmdownstream of a bleached pulp mill to be 307

and 186 ppt, respectively. No chloroguaiacolswere detected above the mill(118). A lateranalysis of chlorophenols (February, 1990)detected relatively high levels of thesechloroguaiacols (30 and 40 ppt, respectively)650 km downstream of the same outfall(68).Other chlorinated organic compounds specific tobleached pulp mill effluents, such asacetosyringol (5 to 50 ppb) and vanillin (0.1 to0.5 ppb), have been detected in the AthabascaRiver over 20 and 200 km downstream of themill, respectively(69).

The long-range transportation of bleached pulpmill effluents has also been demonstrated incoastal (40,41,60-65,117,120). Furthermore, effluent"slugs" have been observed to remain in themarine water column at the same depth as themill outfall for over 36 km (40,60-65). SurfaceAOX measurements, therefore, may notaccurately reflect the effluent concentration ordemonstrate an AOX gradient in the receivingwaters. At the outfall of one coastal mill (2 mbelow the water surface), for example, the AOXlevel was 357 ppb and an obvious concentrationgradient was observed at the same depth over adistance of 36 km at which the concentrationwas 64 ppb(65) .The surface AOX concentration,in comparison, was only 14 ppb at the outfalland decreased rapidly with increasing distanceto non-detectable. It is important to rememberthat considerable amounts of high molecularweight compounds may be accessible forbiological degradation and transformation topotentially bioaccumulative and toxicsubstances at even greater distances from thegeneral vicinity of the bleached pulp milleffluent discharge site(41).

Several studies have documented changes inAOX and chlorophenol concentrations inreceiving waters as a result of winterconditions(68,114,119,123,124) example, the FraserRiver has an average winter bleached pulpmill effluent concentration of 3% (123), butthe annual effluent concentration of the riveris estimated to be 1 to 3%(123).Chlorophenols have been detected in Lake

23

Athabasca, which is 1400 km downstream ofthe nearest bleached pulp mill outfall, whenthe Athabasca River is frozen over(125). AFinnish freshwater study found AOX andchlorophenol levels to be elevated duringwinter months(114). These data demonstrate themajor influence of ice cover on the persistenceof otherwise fairly volatile compounds in theaquatic environment. Ice cover preventsevaporation and reduces photolytic andbacterial decomposition.

Sediments. Canadian monitoring studiessuggest widespread contamination ofsediments by chlorinated organic compoundsdischarged from pulp mills using chlorinebleaching(40,60-65,126,127). Tetrachlorocatecholand chloroguaiacols are present in FraserRiver sediments up to 50 km and 700 km,respectively, downstream of the nearestbleached pulp mill(126,127). Large concentrationranges of chlorinated organic compoundsunique to the effluents of bleached pulp millshave been found in the coastal sediments ofthe Strait of Georgia, British Columbia(40,60-65).For example, the concentrations oftrichloroguaiacol, tetrachloroguaiacol,trichlorocatechol and tetrachlorocatecholranged from nondetectable to 606, 893, 630,1000 ppt, respectively within a 3 km range ofthe mills(60-63,65). Tetrachloroguaiacol wasdetected (2.0 ppt) in coastal sediments over 36km from the nearest bleached pulp mill(65).Chlorophenols, such as di-, tri-, tetra- andpenta-chlorophenol, were also identifiedthroughout this British Columbia surveyarea(40,60-65).

Recent Canadian monitoring studies haverevealed concentration gradients of individualchlorinated organic compounds in sedimentswith increasing distance from bleached pulpmill effluent outfalls (40,60-65). Concentrationsof these compounds in sediments along theBritish Columbia coast were greatest closestto the mill outfalls and, in most cases,decreased in a north-south direction. Incontrast, the EOC1 sediment concentrationdemonstrated no discernible gradient but

remained consistently at 10 ppb within theStrait of Georgia(60-63,65), and therefore is oflimited usefulness in monitoring.

Trace amounts of tri- and tetrachloroveratroles(<5 ppt) were detected in sediment extractsnear an Atlantic coastal bleached mill(91). Thepresence of chloroveratroles at this site maybe explained by the flushing, and presumably,aeration influence of the tides(91). Also,dehydroabietic acid, a predominant resin acidfound in sediments adjacent to bleached pulpmill effluent outfalls, was detected 1 km froma bleached pulp mill on Nipigon Bay, LakeSuperior at 150 ppb(81) and ranged between 5to 100 ppb within the surficial sediments(80).

The sediments of the Gulf of Bothnia havebeen extensively sampled and analyzed forspecific and general chlorinated organiccompounds(128-129). Numerous studies havefound gradients of individual chlorinatedorganic compounds and of EOC1 in sedimentsnear various Swedish pulp mill effluents. Thepredominant chlorinated organic compoundsunique to bleached pulp mill effluents whichare found in the sediments of the Gulf ofBothnia within 1 km of an outfall are 2,4,6-trichlorophenol, 4,5-dichloroguaiacol, 3,4,5-trichloroguaiacol and tetrachloroguaiacol(54).Sediment EOC1 concentrations ranged from500 to 6000 ppb within 10 km of bleachedpulp mills and fell to background levels at adistance of 20 km(130).

Background levels of extractable organicchlorine (EOC1) in the Baltic and Swedishcoastal fjords and in lake sediments rangedfrom 10 to 30 ppb(115,130). These backgroundEOC1 levels are considered to reflectcontamination from the atmosphere with ananthropogenic source, or perhaps naturallyoccurring chlorinated organic acids(115,131).Diffuse leakage of EOCI from land sourcesdid not explain the gradients found near pulpmills (128). Petrochemical, steel and municipalsewage discharges were also eliminated asmajor sources of EOC1(130).

24

Animal Tissues. Chlorophenol andchloroguaiacol uptake has been reported inmuscle tissue of whitefish (Prosopiumwilliamsoni), suckers (Catostomusmacrocheilus), pink salmon (Oncorhynchusgorbuscha) and chinook salmon(Onchorhynchus tshawytscha) inhabiting a650-km stretch of the Fraser River(117,122,132).Overwintering juvenile chinook salmon,collected in the lower Fraser River, 117 kmfrom the mouth and over 650 km downstreamfrom the nearest bleached pulp mill effluentoutfall had body burdens of tri-, tetra- andpenta- chlorophenol averaging (on a wetweight basis) 10.7, 15.2 and 38.3 ppt(122).Trichloroguaiacol and tetrachloroguaiacolwere also found in salmon over 650 kmdownstream of the bleached pulp mills atlevels of 48 and 24 ppt, respectively(122). Thehighest concentrations of these two substances(304 and 136 ppt, respectively) were found 8km below the nearest outfall on the FraserRiver(122). Because these chinook salmon werejuveniles (fry and presmolts) and as such havenever entered marine waters, and sincechloroguaiacols are unique to bleached pulpmills, it can be assumed that the chlorinatedorganic body burdens found in fish in thelower Fraser River represent the accumulationof chloroguaiacols discharged from the millsover 650 km upstream. Furthermore, inlaboratory studies, chinook salmonbioconcentrated chloroguaiacols from FraserRiver water(122), substantiating the widespreadcontamination along the Fraser River system.

Tri- and tetra-chloroguaiacol have been foundin the liver and muscle of burbot (Lota lota)and walleye (Stizostedion vitreum) in theSlave River, NWT at 2.13 and 0.95 ppt,respectively(131a). This sampling site is over1 500 km downstream of the nearest bleachedpulp mills which are located in Alberta.

Chlorinated organic compounds generatedby pulp mills using chlorine bleaching arealso widespread in coastal waters (40,60-65).Five bleached pulp mills spanningapproximately 200 km of the British

Columbia coast were studied. In one instance,tetrachloroguaiacol was detected in fishmuscle (8.0 ppt, wet weight) over 36 km fromthe nearest mill(65).

Numerous monitoring surveys have beenconducted along the British Columbia coast inthe past year(40,60-65)and several trends can benoted. Generally, only highly chlorinatedphenolic compounds, such astrichloroguaiacol, tetrachloroguaiacol, andtrichlorocatechol excludingtetrachlorocatechol, have been accumulated byclams, oysters, shrimp, crabs, and fish. Anexception is pentachlorophenol which wasusually present at no more than the detectionlimit; in one instance, however, 9.0 ppt (wetweight) of pentachlorophenol was detected inthe hepatopancreas of crabs 1.5 km from ableached pulp mill effluent outfall(65). Tissueconcentrations of these chlorinated phenolsranged from nondetectable to 6.0 ppt forclams, oysters, and shrimp; 13 ppt for crabs;and 7.0 ppt for (60-63,65).

Trichloroguaiacol was the chlorinatedphenolic compound most often detected and inthe greatest concentrations in fish(61-63,65).The maximum concentrations oftrichloroguaiacol (13 ppt) occurred in fishcaptured within the immediate receivingwaters although tetrachloroguaiacol wasdetected at 36.0 ppt over 6 km from onemill

(65). A maximum concentration of 100 ppttetrachloroguaiacol was discovered in crabs 1km from the mill(65).

Chlorinated compounds have also beendetected in shellfish and fish collected near theoutfall of a bleached pulp mill on the Atlanticcoast; however, the maximum concentrationsare almost three orders of magnitude greaterthan those found in organisms along thePacific coast:2,4-dichlorophenol (3.73 ppb), 2,4,6-trichlorophenol (3.48 ppb), trichloroguaiacol(2.4 ppb), tetrachloroguaiacol (2.13 ppb) andpentachlorophenol (7.9 ppb)(91). It should benoted that the bleached pulp mill on the

25

Atlantic coast closest to where the fish werecaptured does not treat its effluents, whereasthe majority of the Pacific coast mills subjecttheir effluents to primary treatment.

Dehydroabietic acid has been detected usingGas Chromatography/Mass Spectrometry(GCMS), but not quantified, in various fishspecies from Nipigon Bay, Lake Superior(133).Seston, found 4 km downstream of a bleachedpulp mill effluent outfall in the same bay, hadlevels of 35 ppb dehydroabietic acid and aconcentration gradient was observed(81).

Surveys of the Strait of Georgia, B.C. alsorevealed an organochlorine concentrationgradient in animal tissues with increasingdistance from the bleached pulp mills(60-63,65).These gradients, observed in crabs and fishonly, indicate continuous exposure, possiblepersistence, and, most importantly,bioaccumulation of bleached pulp millgenerated chlorinated organic compounds byaquatic organisms. Fish demonstrated a typicalconcentration gradient with levels consistentlyfalling with increasing distance from thebleached pulp mill effluent outfall(61,63-65). Onthe other hand, the concentrations ofchloroguaiacols in crabs near outfalls peaked(7.8 to 13 ppt) 4 km from these mills(62,63) andthen decreased with increasing distance fromthe mill(61-63). The survey results indicated thatclams, oysters, and shrimps are poor indicatorsof contamination by chlorinated organiccompounds generated by bleached pulp mills,since they do not reflect levels found insediments, fish, and crabs at similar distancesfrom the outfalls (60-63,65).

Laboratory and field studies havedemonstrated that hepatopancreas and liverare the organs which accumulateconcentrations of chlorinated organicsdischarged from bleached pulp mills at levelsmost similar to those in water(40,60,62-65,134,135).Skeletal muscle tissues display the lowestpotential for bioaccumulation(40,60,62-65,134,135).

Swedish investigators have reported EOC1concentration gradients in animal tissueswhich reflect those found in sediments andwater (136).

A Swedish study on a mill undergoing "start-up" conditions (at Norrsundet), found thehighest EOC1 concentrations in perch muscleclosest to the mill (>400 ppm) and a decreasewith distance to 50 to 120 ppm at 11 km.Extractable Organic Chlorine levels in perchnear an unbleached mill in Sandarne were 12to 66 ppm and did not demonstrate a gradientwith distance. Snails (Lymnea sp.), collectednear the same bleached kraft mill(Norrsundet), had EOC1 levels approximatelyten times the concentrations (0.7 ppm) insnails from an area not receiving effluentsfrom bleached pulp mills (8). Fish, sampled in aNorwegian lake, were found to maintainconsistent EOC1 concentrations (220 to 620ppm) up to 16 months after the closure of ableached sulphite mill(66). Extractable OragnicChlorine concentrations in fish tissue returnedto background levels 3.5 years after the millclosure. Of particular interest is the fact thatfish tissue concentrations of individualchlorinated organic compounds, such asmono- and di- chlorocymene and tri-, tetra-and penta- chlorophenol, fell to nondetectablelevels (<60 ppb) within the same 16-monthperiod(66). Clearly, other chlorinated organicsubstituents of bleached pulp mills that werenot individually measured in the study wereresponsible for the continued elevation ofEOC1 concentrations in fish. Fish have beenfound to contain up to 2000 ppm of organicchlorine in fat tissue; however, the identifiedcompounds accounted for only a few percentof the total amount of chlorine measured(66).

Although chloroveratroles have not beendetected in Canadian fish, they have beendetected in fish tissue in the Baltic Sea (400 ppbin liver fat)(89). Possible explanations for thediscrepancy are that Canadian researchers do notanalyze fish tissue for chloroveratroles or that

26

concentrations in Canadian receiving watersdo not reach levels which affect the enzymicde-O-methylation of chloroveratroles tochloroguaiacols and chlorocatechols.

Few, if any studies, have been conducted todate on chlorinated organic compoundsdischarged from bleached pulp millsconcerning their fate, distribution, and levelsin aquatic plants or in wildlife.

4.9 Effects of Bleached Pulp Mill Effluents on the Aquatic Environment

4.9.1 Acute LethalitySome attempts have been made to assess theacute toxicity of whole effluent from bleachedpulp mills by assuming that each individualchlorinated organic compound contributes tothe overall toxicity(126,137). An estimate of thistype based on nine representative compoundscommon to bleached pulp mill effluents(chlorinated catechols, guaiacols, phenols,resin acids and fatty acids) resulted in apredicted additive toxic action of 2.2 times theobserved lethal level(137), whereas anotherstudy estimated a toxicity of only 0.2 of themeasured lethal level(138). Clearly, the mostaccurate evaluation will result from the directmeasurement of toxicity of whole bleach planteffluent, or direct comparison of effects ofbleached with unbleached pulp milleffluents(8).

Effluents from the bleaching stage account forapproximately half of the acute lethality ofbleached pulp mills' total dischargedeffluents(8).

Toxicity Emission Factors (TEF), the totalamount of toxic material discharged by a pulpmill per tonne of pulp produced, in one mill,for example, ranged from 300 to 740 TEF forbleach plant effluent to 610 to 1400 units forthe whole mill effluent (36,139).The toxiccontributions of the various streams withinbleached pulp mills, when totalled, produce areasonably accurate estimate of the toxicity ofwhole effluent(8).

The concentrations of compounds found inbiotreated bleached effluents, exceptingtetrachloroguaiacol, trichlorophenol, andchlorodehydroabietic acid, are a small fractionof the levels that are acutely lethal to fish orother aquatic life(25). The concentration range(ppb) of bleached pulp mill-generatedcompounds found in biologically-treated kraftand sulphite pulp mill effluents as well as theircorresponding LC50s to aquatic organisms arelisted in Table 6.

Three quarters of the effluents from the 47Canadian bleached pulp mills are acutely toxicto trout (data gathered under the FisheriesAct). Analysis of these data suggests acorrelation between the results of acutelethality tests and the degree of wastewatertreatment. Almost all effluents from Canadianbleached pulp mills which have primary or noeffluent treatment are acutely lethal. At onesuch mill, the lethal concentration for rainbowtrout occurred at 3.2% whole effluent. Onlyhalt of the biologically-treated bleached pulpmill effluents in Canada are not acutely lethalto trout at 100% whole (undiluted) effluent.Biologically-treated effluents from twoOntario kraft mills were more lethal (LC50 of21%) than six equivalent Ontario mills withprimary effluent treatment only(LC50>32%)(140,141). No correlations wereobserved between effluent AOXconcentrations and effluent toxicity.

It has been estimated that 16% whole effluentis the mean lethal concentration (LC50) forCanadian bleached mills (8). Effluents frombleached pulp mills comprise anywhere from<1 to 20% of the immediate receiving waters;therefore, the possibility for kills of aquaticorganisms is real.

For many Canadian bleached pulp mills,acute lethality to fish would not be expectedoutside a small plume after the dilution ofeffluents in the receiving water, as long as theeffluents are rapidly diluted 20-fold (8).Unfortunately, many instances exist where the

27

Table 6 Concentration Range and LC50s of Bleached Pulp Mill-generatedCompounds Found in Biologically-treated Effluents from Kraft and SulphitePulp Mills

96-h LC50 Effluent ConcentrationCompound (ppb) Kraft Sulphite Reference

2,4-Dichlorophenol 2800 9 to 15 4 to 10 25

Dichloroguaiacols 2300 22 to 100 6 to 12 25,142

Dichlorocatechol 500 to 1000 12 to 90 - 25,142

2,4,6-Trichlorophenol 450 to 2600 1 to 51 3 to 764 25

Trichloroguaiacols 700 to 1500 10 to 340 16 to 39 16,25

Trichlorocatechols 1000 to 1500 120 to 270 - 25,142

Tetrachlorophenol 500 - - 96

Tetrachloroguaiacol 200 to 1700 10 to 620 12 to 130 16,25

Tetrachlorocatechol 400 to 1500 22 to 420 - 25,96

Pentachlorophenol 200 - - 96

Dehydroabietic acid 500 to 2000 - - 143

Chlorodehydroabietic acid 600 to 900 10 to 750 10 to 900 25,143

Dichlorodehydroabietic acid 600 to 1200 10 to 420 10 to 40 16,25

discharge of effluents into rivers, lakes, andcoastal waters does not result in rapiddilution(25,36,41,50,110,111,144) In addition, in mostlocations, chronic as well as acute effects canresult, possibly extending over large areas(8).

Generally, the levels of individual compoundsspecific to bleached pulp mill effluentsdetected in the Canadian aquatic environment,particularly those which are chlorinated, arewell below levels demonstrated to cause 96-hacute lethality. Some effluent concentrationsof individual compounds, however, didapproach the 96-h LC50. For example,dehydroabietic acid maintained a consistentconcentration (25% of the LC50) in the

effluents and in the immediate receivingwaters of Nipigon Bay(143). Levels ofdichlorophenol, trichlorophenol,trichloroguaiacol, and tetrachloroguaiacolwere detected in fish at 23%, 29%, 50% and95% of their respective LC50s in thenontreated effluents of an Atlantic coastbleached pulp mill(91).

Fish are generally more sensitive thaninvertebrates to the lethal action of bleachedpulp mill effluents (8,25).There is a significantcorrelation (r2 = 0.68) between low molecularweight (mw<1000) TOX discharges and acutetoxicity (based on trout bioassays); therefore,low molecular weight TOX may be used as areasonably accurate indicator of toxicity to

28

fish(47,145). There is no compelling evidencethat indicates common species of fish differgreatly in their resistance to lethal levels ofbleached pulp mill effluents(146,147), althoughrainbow trout (Salmo gairdneri) are thespecies used most often (25). It is difficult tocompare sensitivities of species to the lethalaction of bleached pulp mill effluents from theexisting literature as various stages of the lifecycle are studied. For example, trout are moresensitive to the effluents of bleached pulpmills than the crustacean Gammarus,generally considered a susceptible organism,which in turn are more sensitive thanmosquito larvae. The waterflea, Daphniamagna, and midge larvae are more resistant tothe lethal action of these effluents than arerainbow trout(147,148).

Swedish studies found acutely toxic effects atmuch lower concentrations than are generallydetermined by North American research. Fieldand artificial ecosystem studies indicateconsistent measurable effects at 0.25%effluent (0.01 of the LC50) and occasionalmeaningful effects at 0.1% effluent or 0.004LC50

(8). The discrepancy in lethalconcentrations between North American andScandinavian aquatic environments may be aresult of:

1) lower water consumption and thereforehigher "end-of-pipe" concentrations fromScandinavian mills;

2) Scandinavian pulp mill effluents generallyreceive primary treatment only; and

3) other toxicants in the Baltic Sea may haveeither a synergistic effect with thosedischarged from bleached pulp mills ormay act independently of them, loweringthe apparent effect-concentrations.

Many other components of bleached pulp milleffluents can cause mortality of aquaticorganisms. Lethality may be caused byextremes in temperature, pH, and dissolved

oxygen(8,149,150). Studies have alsodemonstrated that toxic effects of theseeffluents to sockeye and coho salmon areenhanced under low dissolved oxygen(hypoxic) conditions(149).Researchers andliterature reviewers have concluded that, ingeneral, a reduction in dissolved oxygen from100% to 80% of air saturation will causeincreased mortality of fish exposed to some ofthe contaminants generated by pulp millsusing chlorine bleaching(151,152).

Many of the other variables involved inbleached pulp mill processing, such as thetype of wood, the bleaching sequence, and thedegree of effluent treatment, affect thelethality of the effluents to aquaticorganisms(8,29,33,140,141,153,154). Softwoods aremore acutely toxic to Daphnia, for example,than hardwoods pulped under comparableconditions(153). The greater the chlorinedioxide substitution for chlorine during thebleaching process, the less toxic the effluent(e.g., as the chlorine to chlorine dioxide ratiodecreases from 90:10 to 35:65 to 10:90, thetoxicity decreases)(33). Well designed,operated, and managed secondary effluenttreatment facilities are estimated to removebetween 50% and 90% of the effluent acutetoxicity(8,29,154).

4.9.2 Chronic EffectsUnlike acute lethality, chronic toxicitynormally does not result in the immediatedeath of an organism upon exposure to apollutant. Chronic effects typically developafter continuous, long-term exposure to lowdoses of toxic material. In many instances, theeffects a pollutant may exert on the individualorganism, although subtle, may be importantto the continuance of the species, e.g.,reproduction, growth, or survival.

As difficult and important as it is to identifythe exact effect a compound may have on anorganism, it is often even more difficult toidentify the ecological significance of theseoften subtle responses in the population(155).Unfortunately, there is incomplete

29

information on the chronic effects ofindividual chlorinated organic compoundsdischarged in bleached pulp mill effluents.Also, predicting the toxicity of a mixture ofthese compounds from that of the individualcomponents, which is achievable in the case ofacute toxicity, is at present a nearly hopelesstask at the chronic level.

The literature on chronic toxicity of wholebleached pulp mill effluents is extensive(7,156-

163), and detailed reviews have been providedby Canadians Davis, Kovacs, andMcLeay(126,161-163). Many countries haveconducted various chronic studies using wholeeffluent. Swedish researchers have examinedeffluents from various bleaching processesthrough the use of artificial ecosystems. TheNational Council for Air and StreamImprovement (NCASI), an affiliation of theU.S. pulp and paper industry, has conductedlong-term studies on warm and cold waterartificial streams using well-treated secondaryeffluents(164,168).

The known chronic effects of bleached pulpmill effluents on the aquatic environment arecategorized and summarized in the followingtext.

Reproductive and Life-cycle Effects.Reproductive performance of aquaticorganisms exposed to bleached pulp milleffluents for one or more entire life cyclesshould be among the most sensitive andrelevant evaluations of chronic effects.Unfortunately, most researchers haveconducted experiments which deal witheffects only on early life-cycle stages or somelimited aspect of reproduction.

Reduced gonad size and inhibited gonaddevelopment have been observed in fishdownstream of bleached pulp milloutfalls (112,169-171).The gonad-somatic index(relationship between gonad and body size)was significantly smaller in white suckers(Catostomus commersoni), particularly matureadult females, up to 96 km downstream of a

Quebec bleached pulp mill compared to thecontrols (112). Sexually immature adultsmallmouth bass (Micropterus sp.) and whitesuckers have been found downstream ofbleached pulp mill effluent outfalls in the St.Maurice River, Quebec and Terrace Bay,Ontario, respectively(112,172). Bleached pulp milleffluent concentrations in the receiving waterswere not estimated in either study to determinethe level associated with reduced gonad sizeand inhibited gonadal development in fish.These effects, however, occurred only in areasexposed to the effluents and did not occur inthe control sites. In some instances(112),individual chlorinated organic compoundsspecific to bleached pulp mill effluents weremeasured in the receiving waters; however, nolaboratory effects studies were conducted toprove possible causality. Similar observationswere made with perch (Perca fluviatilis) in theBaltic Sea 10 km from a bleached kraft pulpmill(170). No changes in female gonaddevelopment were observed near anunbleached kraft pulp mill in Sweden(136).

Swedish studies on fish in the vicinity of theseoutfalls showed that embryos had high levels ofdeformities, were generally smaller at hatching,and therefore had lower hatching success. Eggslaid in clean areas hatched successfully(173).Experimental stream studies found an increasednumber of egg mortalities and a reduction inhatching success of trout exposed to 1.3%effluent(168). No Canadian field studies relatingto the hatching success of fish have beenreported. NCASI findings and conclusions aresimilar to those of the Swedish investigations inthat the decrease in hatching success could beattributable to poor quality sperm or eggsproduced by the parents exposed to wholebleached pulp mill effluent(168,173).

Laboratory experiments have found 5-chlorouracil and 4-chlororesorcinol, whichthe authors suggest are formed by thereaction of chlorine with organic matter, tosignificantly lower (P<0.05) the hatchingsuccess of carp eggs at concentrations as lowas 1.0 ppb(174). Significant effects both on

30

embryo and on larval mortality of zebra fish(Brachydanio rerio) were demonstrated withpentachloroanisole and tetrachloroveratrole,products of biotransformation, at 2.8 ppb and100 ppb, respectively (78). The fecundity of theharpacticoid copepod (Nitocra spinipes), amarine crustacean, was reduced by 50% at 37ppb of tetrachloroguaiacol(107).All the variousfield and artificial stream studies performeddealt with the observed effects on aquaticorganisms of whole bleached pulp milleffluents. No effort was made to determinewhich chlorinated organic compound(s) wereresponsible for the observed embryo andhatching effects.

Multi-generation laboratory studies usingkillifish (Rivulus marmoratus), zebra fish, andviviparous blennies (Blennius viviparus) haverevealed that offspring of parental fishexposed to bleached pulp mill effluents aresensitized to these effluents(89,175,176). Parentalmortality, hatching success and eggdeformities of killifish exposed to 2,3,4,6-tetrachlorophenol at 5 to 20% of the96-h LC50 (0.055 to 0.22 ppm) were similar tothe control fish. There was, however, a cleardose response to the organochlorinecompound in the survival of the offspring.Offspring of exposed parents sufferedmortalities, and fin and gill erosion(176). Otherstudies, involving the exposure of zebra fishand viviparous blennies to individual chemicalconstituents of bleached pulp mill effluentsand 2.5% whole effluent, respectively, foundsimilar results; concentrations oftrichloroguaiacol, tetrachloroguaiacol,trichlorocatechol, tetrachlorocatechol,trichloroveratrole, tetrachloroveratrole, andpentachloroanisole which did not kill theparents did cause mortalities to larvae andunborn fry at 200, 200, 200, 150, 300, 50, and2.8 ppb, respectively(89).

Recruitment failure (maintenance or growthof a specific stock of species throughmaturation of offspring) was observed in fish,particularly in those species with freeswimming (pelagic) larvae, near the outfall of

a Swedish bleached pulp mill effluent(173). Therecruitment damage caused low parental stockdensities, and the population was sustainedlargely by immigration(173). Percent effluentconcentrations in the receiving waters werenot reported.

Biochemical and Physiological Changes.Whole bleached pulp mill effluent has beenshown in field and laboratory studies to elicitbiochemical and physiological changes infish(112,172,177-181). Liver and blood parametersare most commonly examined for thesebiochemical and physiological disturbances.

Liver enzyme induction has beendemonstrated in Canadian field populations offish near bleached pulp mills. Preliminary datafrom studies at St. Maurice River, Quebec andTerrace Bay and the Kaministiquia River,Ontario found a 5 to 10-fold increase inhepatic mixed function oxidase (MFO) inwhite suckers downstream of the bleachedpulp mills (107,172,180). Whole effluentconcentrations in the receiving waters werenot reported. Juvenile chinook salmon(Oncorhynchus tshawytscha) captured nearbleached pulp mills on the Fraser Rivershowed up to 55-fold induction of 7-ethoxyresorufin-O-deethylase (EROD), amixed function oxidase of the liver(182).Induction of EROD is a sensitive subcellularresponse to the presence of certain toxiccompounds. Fish in the Baltic Sea exhibited adefinite gradient response to bleached pulpmill effluents, with EROD induction occurringup to 10 km from the source(169). Suckersinhabiting the Kaministiquia Riverdownstream of a bleached pulp mill alsoshowed a 3.3-fold reduction of UDP-glucuronyl-transferase(180).

A study of locations 2.5 km or less downstreamof a bleached pulp mill on the Wapiti River,Alberta showed that fish carrying residues ofmill-derived chlorinated organic compounds hadreduced levels of liver glycogen even though thebiologically-treated effluent was nonlethal inacute toxicity tests(34). Juvenile coho salmon

31

(Oncorhynchus kisutch) exposed to laboratory-treated bleached pulp mill effluent hadsignificantly decreased liver and muscleglycogen reserves at 0.2 and 1.0 of the LC50value (183). Changes in liver glycogen andenzyme activation levels may cause increasedenergy expenditure and other physiologicaldysfunctions related to steroid hormoneimbalance and reproductive inhibition(158,159,171,184,185).The dependence of fish onmuscle glycogen reserves suggests theimpairment of stamina, making the fish moresusceptible to fishing pressure, predation and/orstarvation(183).

Reduced gonad size and gonad immaturity,observed in white suckers downstream ofbleached pulp mill effluent outfalls on the St.Maurice River, Quebec and Terrace Bay,Ontario, are reflected in imbalances of steroidhormone levels (112,172). Serum levels oftestosterone were significantly reduced in malesuckers at both sites. Female suckersdownstream of the Terrace Bay mill exhibitedsignificantly-reduced serum levels of estradiol(172). On the other hand, female suckers in theSt. Maurice River had raised estradiolconcentrations up to 96 km downstream of thebleached pulp mill(112).

Swedish field studies demonstrated abiochemical and physiological responsegradient in fish with the disturbances beingmost pronounced in fish living up to 4.5 kmfrom the outfall of bleached pulp mills.Disruptions in enzyme levels could still befound in fish caught 8 to 10 km from the kraftpulp mills (113,169,170).When the total Swedishfield results are compared to laboratoryexposures, however, only the liver somaticindex and the EROD effects appear to have anysignificance. Liver enlargement and ERODinduction may be linked to the parallelobservation of impaired ovarian maturation in aminority of Norrsundet perch(186).

Few studies have attempted to identify thefraction(s) of whole effluents responsible forthe induction of biochemical and physiological

changes in aquatic organisms(137,186).Laboratory investigations of resin acids havefound varying degrees of enzyme induction(178,187). A mixture of resin acids significantlyincreased liver EROD activity of channelcatfish (Ictalurus punctauls) but only slightlyinduced EROD activity in trout (178,187). In thetrout study, however, the induction abilities ofresin acids were compared with those of2,3,7,8-TCDD -an extremely strong (200 x)inducer of trout liver EROD at low doses.Unfortunately, biochemical studies are in theirinfancy and no effort has been made todistinguish between the potency of the inducerand the degree of induction. No studies werefound that investigated the ability of specificchlorinated resin acids common to bleachedpulp mill effluents to elicit biochemical andphysiological disturbances in aquaticorganisms.

Few laboratory enzyme activation studieshave been conducted with chlorinated organiccompounds other than chlorinated dioxins andfurans. A chlorinated phenolic mixture,composed of dichlorophenol,pentachlorophenol and tetrachlorocatechol,significantly increased hepatic catalase andpalmitoyl coenzyme-A oxidase (PCO) activityin channel catfish(178). Upon separation of themixture, pentachlorophenol was found to beresponsible for these biochemicaldisturbances. Increases in peroxisomalenzyme activities, such as PCO, in exposedfish are of concern because of the correlationbetween such increases in enzyme activitiesand hepatocarcinogenesis in mammalianmodels (178).

Morphology. Various degrees of skeletaldeformities as well as fin and gill erosion havebeen reported in fish from areas near bleachedpulp mill discharge (171,188-190). Highincidences of spinal deformities (e.g.,curvature of the spine) have been found in fishnear bleached and unbleached pulp mills inthe Baltic Sea(171,188-190). Unfortunately, fieldstudies have neither identified theconstituent(s) nor the concentration of pulp

32

mill effluents necessary to invoke theseresponses. The existence of these deformities,however, suggests that either a chemical(s)common to both bleached and unbleached pulpmill effluents (e.g., resin acids) or some otherfactor that may be non-pulp mill-related (e.g.,other Baltic Sea pollutants such as polycyclicaromatic hydrocarbons)(191), are responsible forthese particular changes in morphology. It mustbe kept in mind that effluents from Scandinavianpulp mills have, at best, undergone primarytreatment and that aerated lagoons readilybiodegrade such substances as resin acids(163).Laboratory studies have not demonstrated theinduction of severe spinal deformities.

Vertebral deformities, which impair thestrength of spinal columns, have been inducedin laboratory studies and observed in Canadianfield studies(37,89,90,192).Juvenile fourhornsculpin (Myoxocephalus quadricornis),exposed to 0.5 ppm tetrachloro-1,2-benzoquinone (TCQ) for 4.5 months,developed vertebral deformities and vertebraeweakness(192). Another study induced vertebraldeformities in zebra fish at 2.8 and 50 ppb ofpentachloroanisole and tetrachloroveratrole,respectively(89). Tetrachloroveratrole has beendetected in fish collected near Swedishbleached pulp mill effluent outfalls at 40 to 400ppb (liver fat)(89). It is noteable that thelaboratory induced vertebral alterationsdemonstrated in fish are a result of exposure tobiotransformation products - compounds thatare generally not looked for in bleached pulpmill effluents.

Pike (Esox lucius) near bleached pulp mills inthe Baltic Sea were found to have severe skulldeformations (bull-head)(113). Bull-headed pikehave not been found in the Baltic Sea everyyear sampled(113), nor has the bull-headedphenomenon been observed by other countriesor in other species of fish. The scientificliterature shows no laboratory induction ofskull deformities.

Conversely, fin and gill erosion, which havebeen observed in perch near bleached kraft

mills in the Baltic Sea, can be induced in thelaboratory(176,193). Fish exposed to 1.6 to 4%(0.1 to 0.25 LC50)untreated effluents for 40 to60 days had higher incidences of fin necrosisand damaged gills than the unexposed fish.These changes may indicate a loss ofresistance by the fish to bacterial pathogensand a significant stress-related effect of theseeffluents(193).In a previously mentionedlaboratory experiment, which demonstrated aheightened sensitivity by offspring of parentsexposed to 2,3,4,6-tetrachlorophenol (TeCP),fin and gill erosion were induced at 0.055 to0.22 ppm (5 to 20% LC50) of 2,3,4,6-TCP(176).

Mutagenicity. Bleached pulp mill effluentshave been found to be mutagenic usingstandard tests(194-196). Untreated wholebleached pulp mill effluent is usually weaklymutagenic (25,197-200). The strongest mutageniccomponent of these effluents is generallyeffluent from the bleaching stage, but theaddition of the caustic extraction effluentsubstantially reduces theconcentration(24,25,195,197-199,202).

Studies have shown that many of themutagenic compounds in spent bleach liquorsfrom kraft and sulphite pulp mills are thesame(203). The concentrations of the identifiedmutagens in the effluents from chlorinatedkraft pulp are, however, much higher thanthose reported in effluents from chlorinatedsulphite pulps(204). This indicates that the kraftpulping process creates more precursors ofmutagenic compounds than the sulphitepulping process(203). Also, oxygendelignification of sulphite pulp but not kraftpulp before chlorine bleaching increases themutagenicity of the effluent(203,205).

Of the 27 mutagenic compounds isolated andidentified, no particular pattern emerges,although three-quarters of the compoundscontain chlorine(25). The most abundantmutagenic compounds in effluents frombleached pulp mills are chloroform,2,4,6-trichlorophenol(206),chloroacetones(203,207), 2-chloropropenal and

33

3-chloro-4-dichloromethyl-5-hydroxy-2(5H)-furanone(204). The concentrations do not,however, approach those required to inducemutagenicity. For a more complete listing ofmutagenic compounds in bleached pulp milleffluents, interested readers are referred toreferences 26 and 199.

There are few field observations to confirmthe laboratory studies on mutagenicity of pulpmill wastes. Japanese researchers report anapparent association between bleached pulpmill effluents and neoplasms in fish(208,209);however, details, such as controls and pulpmill processes are poorly documented. Two ofthe chemicals identified by the Japanese,2,4,6-trichlorophenol and tetrachloroguaiacol,are known mutagens.

Mutagenic compounds can be eliminated orreduced in concentration through such millprocesses as: the addition of alkali to the spentbleaching liquor(197,203); increased chlorinedioxide substitution for chlorine (24,195,197,198,202);and secondary waste treatment(197).

Carcinogenicity. A number of compoundsfound in bleached pulp mill effluents havebeen identified as carcinogens on the basis ofstandard methods of mammalian testing.Among these are chloroform, carbontetrachloride, and safrole(9,210-212). Some othercompounds, such as various chlorinatedbenzenes and phenols, epoxystearic acid anddichloromethane, have been classified assuspected carcinogens(9).

Physiological alterations have been found inwhite suckers downstream of a bleached pulpmill on the Kaministiquia River, ThunderBay, Ontario. Fish exposed to these effluentsexhibited increased incidences of liverneoplasms (2.1%) and bile duct disease(21%) compared to control fish(180). Inrelation to the liver neoplasms, non-carcinogenic effects have also been observed.Significant liver enlargement has beendemonstrated in white suckers of the St.Maurice River up to 96 km downstream of

the bleached pulp mill effluent outfall(112).Swedish field and laboratory studies havealso demonstrated liver enlargement in fishcollected near outfalls of bleached pulpmills (170,177). No effort was made to determinewhich chlorinated organic compound(s) wereresponsible for the observed effects.

4.9.3 Other EffectsBehaviour Modification. Limited informationexists on the behavioural response of aquaticorganisms to whole effluent. Unfortunately,the information that does exist cannotdifferentiate which fraction of bleached pulpmill effluent, such as chlorinated organicsubstances, BOD, dissolved oxygen, pH,turbidity or suspended fibres, is responsiblefor behavioural modification(151,213-215).

Laboratory experiments, which regulated suchparameters as BOD, dissolved oxygen, andsuspended fibres, demonstrated limited or nobehavioural response by fish(216,217).Conversely, field studies and in situ bioassayshave observed both avoidance and preferencebehaviour by fish exposed to bleached pulpmill effluents(151,213-215)

In situ bioassays have demonstrated thatseveral species of juvenile fish, which bynature are surface water oriented, avoidsurface waters receiving bleached pulp milleffluents for up to 10 km from thesource(99,151,215).Furthermore, mortalities occurwhen these fish are confined, by caging, tosurface waters near the outfalls (151,215).

Lethal conditions have been reported in thesurface waters of many Canadian west coastestuaries during salmon spawningmigrations(151). Successful migration orsurvival of salmonids is not guaranteed by"diving" beneath the surface waters as in situbioassays have shown that lethal conditionsexist at depths greater than 4.0 m(151,213).Dissolved oxygen and pH have been shownstatistically to be the most significant waterquality parameters in explaining the depthpreferences by fish(151,215). Surface water

34

discharge of pulp mill effluent inhibitsphytoplankton photosynthesis in the deeperwaters, resulting in depressed levels ofdissolved oxygen(213). Researchers have foundthat the toxic effects of pulp mill effluent tosalmonids are enhanced under hypoxicconditions(149,218).Temperature and salinityhave been eliminated as possible influences onavoidance behaviour since fluctuations arewithin ranges tolerable to the fish(151,213)

A telemetry study conducted on white suckersin Nipigon Bay, Lake Superior found fishbecame disoriented for as much as severalhours, then appeared to search for"background" conditions when released intohigh discharge concentrations of bleached pulpmill effluents (>15% dilution by volume)(214).Fish released into low discharge concentrations(<15%) immediately initiated an avoidancereaction. No effort was undertaken todetermine which constituent(s) of the effluentsor which water quality parameters wereresponsible for the behavioural modification. Adensity analysis of the aquatic organisms inareas near bleached pulp mill effluent outfallsrevealed fairly dense populations of fish andbenthic invertebrates of limited speciesdiversity, seemingly contradicting the observedavoidance behaviour(214,219-220). However,telemetry indicated that the residence time offish in the area of altered water quality wasshort(214). The preference behaviour of certainfish species for areas of affected water qualitysuggests that the feeding response to highbenthic biomass and the innate behavioural traitto occupy surface waters overrides theavoidance reaction to the effluents even underadverse (lethal) conditions (151,214,221). It is likelythat these fish will continually strive to occupyspecific habitats, probably to theirdetriment(151).

Swimming stamina and ventilatory water flowwere impaired in juvenile coho salmon at 20%of the 4-day LC50

(25). Sublethal concentrationsof filtered, aerated, neutralized effluents frombleached pulp mills reduced

arterial oxygen tension in salmon at 33 to 47% ofthe 96-h LC50 (static bioassay)(222). Davisconcluded that “it seems highly likely that a toxicmechanism affecting swimming ability inbleached pulp mill effluents is related toventilatory abnormality and reduced oxygensaturation of arterial blood”(222). As this studydealt with aerated, neutralized, filtered effluents,probably most of the more volatile toxicants wereabsent, as they would be in all 96-h LC50 tests.

Bleached pulp mill effluents have been foundto affect organisms that salmon feed upon.Static 117-h bioassays with these effluentsinterfered with the reproductive behaviour ofthe marine amphipod, Anisogammaruspugettensis and, at high concentrations (40%of whole effluent), mating ceased(223).

It is highly probable that the combined effectsof chemicals and water quality parametersassociated with bleached pulp mill effluentsexert significant influence on preference-avoidance behaviour(151,214,215).

Species Diversity. Numerous studies havedocumented shifts in species dominance nearpulp mills using chlorine bleaching(2l4,224-226) Itis difficult to establish a cause and effectrelationship between bleached pulp milleffluents and changes in species diversity, as aclear separation cannot be made between theinfluence of eutrophication and specificchlorinated organic compounds(214,225).

A study at Nipigon Bay, Ontario observed aspecies shift from perch to suckersdownstream of a bleached pulp mill whichemploys primary effluent treatment. Theobserved species shift is likely the result of thefishes response to both the effluent and thehabitat alterations (e.g., eutrophication)(214).

Species shifts have also been identified in theBaltic Sea(225,226). Virtually no shallow waterfish were found within 1000 m of theNorrsundet bleached pulp mill compared to anabundance of shallow water fish within 100 mof the unbleached pulp mill in Sandarne(226).

35

A superabundance of small shallow waterspecies, known to inhabit areas ofeutrophication, could be found up to 6 kmfrom the bleached mill. Populations of larger,deeper-water fish were depressed for up to 4km from the bleached pulp mill(225).It isimplied that bleached pulp mill effluents affectspecies diversity through a combination ofeutrophic and toxic properties. The limitationsof the Norrsundet study, such as theabnormally high chlorine loading to theaquatic environment, as a result of in-plantprocess changes and the lack of secondarytreatment, were taken into consideration.Situations exist in Canada, however, wherepoor or nonexistent effluent treatment resultsin the release of relatively high levels oforganochlorines and also produces turbiditywhich may influence species diversity veryclose to the mills (214).

Evidence exists that bleached pulp milleffluents affect the dominance of floralspecies. The community structure of theperiphyton in a southern U.S. river shiftedtoward a heterotrophic population near thebleached pulp mill effluent discharge point butrecovered to control characteristics atdownstream stations(224). A more widespreadsituation exists in the Baltic Sea.

Particular constituents of bleached pulp milleffluents have been identified as the reason forshifts in species populations. Chlorate, whichis a by-product of chlorine dioxide bleachingand is released in bleached pulp mill effluents,is highly toxic to seaweeds, particularly brownalgae(29,52,227). Through laboratory, modelecosystems and field testing, chlorate has beenidentified as the causal agent for thedisappearance of the bladder-wrackcommunity (Fucus vesiculosus) in the BalticSea(228,229). Chlorate levels of 10 to 20 ppb aresufficient to reduce Fucus numbers(227). Nochlorate levels within the immediate receivingenvironment were reported.

Fucus, a genus of brown alga, is abundant inshallow, hard bottom environments and is

found along the east and west coasts ofCanada and in the Baltic Sea. The bladder-wracks are one of the most important plantcomponents of the Baltic coastal ecosystemand form a prominent spawning, nursery andfeeding area for a great number (>70%) of themacroscopic animal species, includingfish(230). Severe decreases in crustacean andgastropod populations have occurred as aresult of the disappearance of Fucus(231). Fromthese studies, extending no more than oneyear, it was confirmed that the elimination ofFucus from the system induces a shift fromthe herbivorous and omnivorous species todetritivorous fish species(231). Based upon themodel ecosystem data, it is estimated that anarea supported by a healthy Fucus populationwould have an annual fish production of 12 to15 tonnes. Presently, however, it is estimatedthat the decrease in annual fish production,due to spawning and nursery habitatdestruction and a shift in food species, wouldbe in the order of 10 tonnes(227).

The substitution of chlorine dioxide forchlorine will enhance the generation ofchlorate. Secondary biological treatmentsystems reduce chlorate concentrations toenvironmentally safe levels (29); however, themajority of the Canadian coastal bleachedkraft mills do not employ secondary treatment.Fucus populations and chlorate levels have notbeen monitored in Canadian waters; therefore,the effect of chlorate discharged from pulpmills using chlorine bleaching on Fucus andon its habitat is unknown.

Tainting. Whole bleached pulp mill effluentscan cause tainting in commercial species offish and shellfish. Several reviews listconstituents of bleached pulp mill effluentsresponsible for tainting(126,163,232,233). Fishtainting may be caused by chlorinated ornonchlorinated components of bleached orunbleached pulp mill effluents. It may alsoarise from naturally occurring watercontaminants. This makes identification of

36

the causative agents in bleached whole milleffluents difficult(38).

Bleaching was not considered to be asignificant contributor to tainting(138) untilrecent work found that biotransformationproducts of chlorophenols, tri- and tetra-chloroveratrole, cause tainting(89). Simpleaeration and/or secondary waste treatmentmay reduce tainting by a factor of 2 to 10 (234-

236).

The degree of tainting contributed by specificeffluent constituents or their derivatives has

yet to be determined(38). Whole bleached pulpmill effluent can cause tainting in fish atconcentrations as low as 0.5(234,235,237-239). Forperspective, concentrations of 1% elicit themore sensitive sublethal effects in fish(234).Field studies confirm that tainting may occurat that concentration, although some resultsappear to be confounded with natural "off-flavours". For example, a field study on theOttawa River found fish that had been cagedfor 48 hours became tainted as far as 2.5 kmdownstream of the bleached pulp mill effluentdischarge site(240).

37

Section 5Risk Assessment, Conclusions and Future Considerations5.1 Source Assessment

In Canada, as of July 1990, there were 47 pulpmills (42 kraft and five sulphite) which usechlorine bleaching. Much variety exists amongthese mills resulting in different effluentqualities, for example: pulping, bleaching andwastewater treatment processes; type of woodpulped; and the quality of the pulp product.Many of these bleached pulp mills areintegrated; therefore, in addition to theirproduction of bleached pulp, the mills (53%)also produce such semi-bleached andunbleached pulp and paper products such asnewsprint and paperboard.

In 1989, the Canadian bleached pulp industrydischarged between 25 000 and 310 000 m3 ofwastewater per day per mill. Pulp millsconsumed between 10 to 110 kg of chlorineper day per tonne of pulp produced (or 2.5 to175 tonnes of chlorine per day). This producedapproximately 100 to 1 400 tonnes ofbleached pulp per day. On this basis, it isestimated that 610 000 tonnes of chlorine wereused to produce 10.2 million tonnes ofbleached pulp in 1989.

Effluents from pulp mills using chlorinebleaching contain a wide variety ofchlorinated and unchlorinated organiccompounds. The chlorinated compounds areproduced as a result of complex reactionsbetween lignin and its breakdown products,released during the chemical pulping process,and the chlorine bleaching agent. It isestimated that the Canadian pulp and papersector discharges over one million tonnes ofchlorinated organic material to the aquaticenvironment annually.

Seventy to eighty percent of the dissolvedmatter in bleached pulp mill effluents consists

of high molecular weight chlorinated organiccompounds. Although approximately 250individual compounds have been characterizedin bleachery effluents, they have beenestimated to represent only 10 to 40% of thetotal low molecular weight materials present.High molecular weight chlorinated materialsare not generally considered to represent adirect threat to aquatic biota, however, theyhave been observed to be microbiologicallytransformed or degraded into low molecularweight compounds that add to the total lowmolecular weight loading.

The predominant classes of low molecularweight compounds reported in Canadianbleached pulp mill effluents are: chlorinatedand nonchlorinated resin and fatty acids,phenols, alcohols, aldehydes, ketones, sugarsand aliphatic and aromatic hydrocarbons.Numerous volatile sulphur-containingcompounds, such as hydrogen sulphide,thiophenes, and methyl mercaptan, are alsofound in bleached pulp mill effluents. Thecomposition of bleached pulp mill effluents isnot constant from mill to mill but depends on,for example, the chemical pulping andbleaching processes and the degree and typeof wastewater treatment. For example, tri-andtetra-chloroguaiacols are the major lowmolecular weight chlorinated phenolics inbleached kraft mill effluents, whereas 2,4,6-trichlorophenol is the predominant chlorinatedphenol discharged from bleached sulphitemills.

As the majority of chlorinated organicmaterials released in bleached pulp milleffluents have not been identified, analyticalefforts have focused on developing generalindicators or surrogate measures of the totalquantity of chlorinated organic compounds in

38

a particular environmental matrix. For water,the most commonly used approach is knownas the Adsorbable Organic Halogen (AOX)analytical method. The halogen component("X") of bleached pulp mill effluents is almostentirely composed of chlorine. The AOXmethod is only applicable to water and not tosediments and tissues; therefore, anotherrelated method, known as Extractable OrganicChlorine (EOC1), may be used to determinethe organochlorine content of sediments andbiological tissues. The major limitation ofsuch surrogate tests is the fact that equal AOXvalues (or equal EOC1 values) give noindication of effluent composition nor of itspotential toxicity, persistence, or fate.

Adsorbable Organic Halogen values measuredin Canadian bleached pulp mill effluents inearly 1989 ranged between 0.5 and 14.9 kg perair-dried tonne of pulp (kg/ADt) with anaverage of 3.8 kg/ADt. The AOX level inbleached pulp mill effluents is directly related,for example, to the degree of chlorinationapplied during the bleaching process and towastewater treatment. The greater the degreeof chlorine dioxide substitution for chlorine asthe bleaching agent, the lower the AOX value,in general. In addition, effluents frombleached pulp mills which employ secondarywastewater treatment have lower AOX valuesthan those mills with either primary or noeffluent treatment facilities.

The 47 Canadian bleached pulp millstogether annually discharge over onemillion tonnes of chlorinated organiccompounds to the aquatic environment.Approximately 250 compounds have beenidentified but many more remainunidentified. The chemical composition ofbleached pulp mill effluents is complex,variable, and not well characterized. Thus,substantial quantities of chlorinatedorganic matter, both of known andunknown composition, enter the Canadianaquatic environment from bleached pulpmill discharges.

5.2 Distribution and Fate Assessment

A number of chlorinated organic compoundsgenerated by pulp mills using chlorinebleaching have been detected and measured ineffluents, water, sediments and biota. Watercurrents, sediment composition, salinity andtemperature gradients, and discharge depth ofbleached pulp mill effluents affect thedistribution of organochlorine throughout theaquatic environment. Tetrachloroguaiacol, forexample, has been detected in all aquaticenvironmental compartments at distancesvarying up to 1400 km downstream from thenearest bleached pulp mill outfalls.

The persistence of chlorinated organiccompounds over time within various aquaticenvironmental compartments depends onsuch variables as the water pH, organiccarbon content of suspended particulatematter and sediments, presence of a biofilmlayer, partition coefficients, water solubility,temperature, light, and microbial populationof the receiving environment, but the twomost influential variables are the degree ofchlorine substitution in the dischargedcompound and the time of year. Compoundswith low chlorine substitution (e.g.,dichlorophenols) biodegrade within hours todays whereas highly chlorinated organiccompounds may persist within the aquaticenvironment anywhere from days to weeks orlonger, especially in winter. Substances suchas chloroguaiacols, therefore, have beendiscovered in water hundreds of kilometresdownstream of bleached pulp mill effluentoutfalls during winter conditions. Findings oflong-range transportation of chlorinatedphenols under ice are not unexpected;however, Canadian field studies havepredominantly been conducted in the summermonths rather than on a year round basis.Also, under conditions of low flow,particulate matter may settle out relativelyclose to the outfall; however, underconditions of high flow, for example, a springfreshet or a coastal storm, resuspension

39

occurs which may distribute the contaminatedsediments over greater distances.

Nonchlorinated resin acids, such asdehydroabietic acid, have also been found topersist both spatially and temporally withinthe various environmental compartments(water, sediments and biota), especially wherethe mills concerned did not practice adequatesecondary wastewater treatment.

Some chlorinated organic compounds can bemicrobially degraded in water or sedimentsand metabolized in tissues. Generally, the rateof decomposition depends on such factors as:the degree of chlorine substitution of theorganic molecule; the organic carbon contentof the substrate; ambient oxygenconcentration; temperature; and the previousexposure of bacteria to individual orstructurally-related chlorinated organiccompounds generated by bleached pulp mills.Dichlorodehydroabietic acid andtetrachloroguaiacol are the most resistant tobacterial degradation of the well-characterizedcompounds discharged in bleached pulp milleffluents and, as such, are commonly detectedin biologically-treated wastewaters and in theaquatic receiving environment.

The degree of wastewater treatment that theseeffluents receive can greatly influence both thelevels and the types of compounds detected inthe receiving waters. Bleached pulp milleffluents from well-managed, biologically-treated, aerated lagoons would be expected tocontain less chlorophenols and their associatedby-products than those mills with minimal orno wastewater treatment facilities. This is ageneral observation within the Canadianbleached pulp and paper sector.

Chlorinated organic compounds may also bemicrobially transformed into more persistentand bioaccumulative compounds. Biologicaltransformation of chloroguaiacols andchlorocatechols, for example, occurs underaerobic conditions producing chloroveratroles

and chloroanisoles, respectively. Under anoxicconditions, the reverse reaction takes place.The biotransformation products ofchloroguaiacols, therefore, would not beexpected and have not in fact been detected inthe anaerobic sediments in the immediatevicinity of bleached pulp mill effluent outfalls.Chloroveratroles have, however, been detectedin aerobic bleached pulp mill effluents,receiving waters and sediments in Canada andin fish tissues from the Baltic Sea.

Most chlorinated organic compoundsgenerated by bleached pulp mills are notappreciably bioaccumulated within the tissuesof aquatic organisms, however,trichlorophenols, tetrachlorophenols andchloroveratroles are often accumulated farabove those concentrations found in water.Chloroveratroles are capable of accumulatingin fish up to 25 000 times the concentration inwater. The bioaccumulation ofchloroveratroles is of particular interest asthey are products of biotransformation and arenot monitored within the variousenvironmental compartments.

Chlorinated organic compounds frombleached pulp mills have been detected inwater, sediments, and biota up to 1400 kmfrom bleached pulp mill outfalls.Compounds with low chlorine substitutiondegrade within hours to days whereashighly chlorinated compounds may persistfrom days to weeks or longer. Persistence islonger in winter especially under ice. Somechlorinated organic compounds can bebiologically degraded or transformed, andtransformation may lead to more persistentand bioaccumulative compounds.Chloroveratroles, for example,transformation products of chloroguaiacols,are capable of accumulating in fish up to 25000 times the concentration in water. Othercompounds detected in fish tissues reflectrepeated or long-term exposure rather thanhigh bioaccumulative potentials.

40

5.3 Exposure and Effects Assessment

Seventy-five percent of Canadian bleached pulpmills discharge effluents that have been shownto be acutely lethal to rainbow trout inmandatory laboratory tests. Canadian effluentconcentrations as low as 3.2% have beenreported to cause mortalities in fish, and theaverage concentration required to kill 50% ofthe test organisms within 96 hours (96-h LC50)is 16% effluent. A strong correlation existsbetween the results of the acute toxicity testsand the degree of wastewater treatmentemployed. Effluents from bleached pulp millswhich employ well-managed secondarytreatment are often nontoxic to rainbow trout,whereas those from mills with only primary orno wastewater treatment are toxic. Accidentalspills and in-plant malfunctions can alsocontribute to acute toxicity. The acute lethalityof whole bleached pulp mill effluent to aquaticorganisms is also enhanced during periods ofdepressed, dissolved oxygen levels.

There is an appreciable amount of lethal toxicityinformation on some of the individualchlorinated organic compounds generated bybleached pulp mills, with 96-h LC50s rangingfrom 200 to 2 800 ppb. Chlorinated phenolics,particularly guaiacols and catechols, andchlorinated resin acids have been identified asmajor toxicants in bleached pulp mill effluents.Although few bleached pulp mill effluents havebeen monitored for individual chlorinatedorganic compounds, the limited informationsuggests that the concentration of any singlecompound in the effluent does not usuallyapproach its 96-h LC50 even if the effluent takenas a whole is acutely toxic. Concentrations oftetrachloroguaiacol, trichlorophenol, andchlorodehydroabietic acid, however, onoccasion approach or surpass the 96-h LC50concentrations. It is important to note thatdifferences are small between acutely toxic andnontoxic concentrations of chlorinatedcompounds to specific organisms. For instance,in solutions of tetrachloroguaiacol, 100% fishmortality occurred by 96 hours at a

concentration of 350 ppb, but there were nodeaths after this interval of time at aconcentration of 300 ppb.

In addition to the acute lethality of effluentsfrom bleached pulp mills, whole bleached pulpmill effluents have been observed to cause suchchronic toxic effects as reproductive anomalies,deformities, biochemical changes andbehavioral alterations in aquatic organisms. Ingeneral, chronic effects were observed in theCanadian aquatic environment at 0.5 to 5%bleached pulp mill effluent (e.g., atconcentrations of only one-tenth of the 96-hLC50). Artificial stream studies conducted bythe U.S. National Council for Air and StreamImprovement (NCASI) are compatible withCanadian findings in that they demonstratechronic toxicity at the same dilution level of theeffluents. Laboratory studies of individualchlorinated organic compounds induced suchchronic effects as vertebral deformities, andembryo and larval mortality in fish at levels aslow as 2.8 ppb.

The effluents from bleached pulp mills arediluted by local receiving waters to a degreewhich depends upon watercourse flow, tides,time of year, and other factors. Prom the limiteddata available, predominantly from freshwatermills, the receiving waters even after dilution inthe mixing zone usually have concentrations ofbleached pulp mill effluents well into the rangenecessary to exhibit chronic effects. In fact,seventy percent of the Canadian bleached pulpmill effluents discharged to freshwater systemsare not diluted below the concentrations whichhave been associated with chronic effects.

The acute or chronic toxicity of wholebleached pulp mill effluent cannot beexplained by the toxicity of individualchlorinated organic compounds which have sofar been characterized. The toxicity of thoseindividual chlorinated organic compoundsgenerated by bleached pulp mills which havebeen studied in the laboratory does notsummate to more than a few percent of theobserved toxicity of the effluents. The

41

few detailed biological studies conducteddownstream of representative Canadianbleached pulp mills all demonstrated continuedand repetitive chronic effects on the aquaticbiota. The observed chronic effects, such asreproductive anomalies, are significantirreversible factors which jeopardize thecontinuance of the species and the integrity ofthe ecosystem.

Seventy-five percent of Canadian bleachedpulp mills discharge effluents that areacutely lethal, and even after dilution by thereceiving waters seventy percent of thefreshwater bleached pulp mill effluents arestill within the range of chronic toxicity. Thechronic effects observed downstream ofCanadian bleached pulp mills includesignificant irreversible factors whichjeopardize the continuance of the speciesand the integrity of the ecosystem.

5.4 Risk Assessment

Canadian bleached pulp mills discharge overone million tonnes of chlorinated organicmaterials to the aquatic environment annually.Some constituents of this material are of highspatial and temporal persistence; somedemonstrate a large potential forbioaccumulation. Some individual chlorinatedorganic compounds have been isolated frombleached pulp mill effluents at levels whichoften approach or surpass concentrations thatcause acute toxicity. The summated toxicity ofall these chlorinated organic compoundsrepresents a high level of risk.

Seventy-five percent of the effluents fromCanadian bleached pulp mills are acutelytoxic to rainbow trout. Even after dilution bythe receiving waters, seventy percent of theeffluents from freshwater bleached pulp millproduce significant chronic effects whichjeopardize the continuance of the species andthe integrity of the ecosystem. Thus, thelevels of whole effluent discharged fromCanadian bleached pulp mills to the aquaticenvironment and the acute and chronic toxic

effects observed both in the field and in thelaboratory combine to represent a significantrisk to the aquatic ecosystem.

5.5 Conclusion

The conclusion based on this risk assessment,is that the substance "effluents from pulp millsusing bleach" is entering the environment in aquantity or concentration or under conditionshaving immediate and long-term harmfuleffects on the environment. Effluents frompulp mills employing bleaching are thereforeconsidered to be "toxic" as defined underParagraph 11(a) of the CanadianEnvironmental Protection Act.

5.6 Future Considerations

Numerous and extensive information gapswere observed during the evaluation of dataon bleached pulp mill effluents. Informationgaps that have been identified and should befilled include acute toxicities and chroniceffects of individual chlorinated organiccompounds, especially chlorinated phenolics,which constitute a significant portion of thetoxic loading of bleached pulp mill effluents.

The evaluation of bleached pulp mill effluentstudies revealed many errors in experimentaldesign. Future field studies should endeavor toselect enough suitable control sites so that, forexample, appropriate statistical analyses canbe applied.

Due to the complexity of bleached pulp milleffluents, analytical methods should befocused on developing general indicators orsurrogate measures of the total quantity ofchlorinated organic compounds in particularmatrices. These surrogate measures includeAOX for water and EOC1 for sediments andbiological tissues. It should be emphasized,however, that the AOX and EOCI parametershave many severe limitations. Of primaryimportance is their inability to provide anaccurate estimate of the potential toxicity,persistence or bioaccumulation of specificchlorinated organic compounds. Efforts must

42

be made to determine and report all limits ofdetection and of quantitation for all analyticalmethods employed

The amount of chlorinated organic compoundsformed during the pulping and bleachingprocesses must be reduced. Such in-plantprocess changes as oxygen delignification,improvements in pulp washing andsubstituting other bleaching agents forchlorine gas will reduce the amount ofchlorinated organic compounds produced by ableached pulp mill. In addition, the amount ofchlorinated organic compounds released willbe reduced through the installation ofsecondary wastewater treatment facilitieswhere these do not already exist. It should benoted, however, that wastewater treatmentleads to the generation of sludges whichcontain large amounts of chlorinated organiccompounds for which as yet no monitoring ordisposal strategy has been developed.

Many of the reported acute and chronic toxiceffects have been associated with chlorinatedphenolic compounds. Accordingly, futureconsiderations should include the monitoringof a range of these compounds in bleachedpulp mill effluents, water, sediments andanimal tissues, together with theirenvironmental effects. A strategy should alsobe devised to compel the bleached pulp

industry to undertake biomonitoring of thelocal aquatic ecosystem. The data generatedfrom this enforceable monitoring programwould allow the organochlorineconcentrations and aquatic effects at Canadianbleached pulp mills to be compared andcontrasted. Only then will it be possible todetermine if the proposed Fisheries Actnational effluent regulation and the CEPAdioxin and furan effluent regulations areadequately protecting the aquatic environmentor if a need for further regulations exists.

The members of the Task Group on"Effluents from Pulp Mills usingBleaching" believe that mandatoryreporting by mills of their output oforganically bound chlorine and of a rangeof chlorophenolic compounds in effluents,water, sediments or biological tissuesshould be established. Environmentaleffects monitoring should also be required.Given the difficulty of dealing with thesecontaminants, and their transformationproducts, future regulations if necessaryshould place maximum emphasis onpreventing the formation of chlorinatedorganic compounds through the use ofalternative technologies and better processcontrol. Properly designed and managedsecondary effluent treatment will alsoreduce the organic chlorine loading to theaquatic environment.

43

References

1 The Canadian Environmental ProtectionAct, 1988. R.S., c.16, 4th Supplement(1988).

2 The Canadian Environmental ProtectionAct Amendment, S.C., c.9 (1989).

3 Hall, R.H., D.J. Ecobichon, W.C.Ferguson, D. Green, D. MacKay, W.A.Neff, A.E. Robinson, C.R. Rubin, J.Siemiatycki and S. Sullivan, "Report ofthe Ministers' Priority SubstancesAdvisory Panel", 23 pp. (1988).

4 Canada Gazette, "Priorities SubstancesList", Part I, p.543-545 (1989).

5 Susser, M., "The logics of Sir Karl Popperand the Practice of Epidemiology", Amer.J. Epidemiol., 124: 711-718 (1986).

6 Boddington, M.J., A.P. Gilman, R.C.Newhook, B.M. Braune, D.J. Hay and V.Shantora, "Priority Substances ListAssessment Report No. 1: PolychlorinatedDibenzodioxins and PolychlorinatedDibenzofurans", prepared for:Environment Canada and National Healthand Welfare, 56 pp. (1990).

7 Colodey, A.G., "Environmental Impact ofBleached Pulp and Paper Mill Effluents inSweden, Finland, and Norway:Implications to the Canadianenvironment", unpublished report forEnvironment Canada, IP-99, 158 pp.(June, 1989).

8 Sprague, J.B. and A.G. Colodey, "Toxicityto Aquatic Organisms of OrganochlorineSubstances in Kraft Mill Effluents",unpublished report for EnvironmentCanada, IP-100, 53 pp. (June, 1989).

9 Kringstad, K.P. and K. Lindstrom, "SpentLiquors from Pulp Bleaching", Environ.Sci. Technol., 18(8): 236A-248A (1984).

10 Claeys, R.R., L.E. LaFleur and D.L.Borton, "Chlorinated Organics in BleachPlant Effluents of Pulp and Paper Mills",in Water Chlorination, Vol. 3, R.L. Jolley,W.A. Brungs, R.B. Cumming and V.A.Jacobs (eds.) Ann Arbor SciencePublishers Inc., Ann Arbor, MI, Chap.31,p.335-345 (1979).

11 Bengtsson, B.E. and L. Renberg, "The Useof Chemical and Biological Parameters toCharacterize Complex IndustrialEffluents", Reg. Toxicol. Pharmacol., 6:238-247 (1986).

12 Suntio, L.R., W.Y. Shiu and D. Mackay,"A Review of the Nature and Properties ofChemicals Present in Pulp Mill Effluents,Chemosphere, 17(7): 1249-1290 (1988).

13 Carlson, R.M., H.L. Kopperman, R. Capleand R.E. Carlson, "Structure-activityRelationships Applied", in: ConferenceProceedings, International JointCommission, Windsor, Chap.3, p.57,(March 11-13, 1975).

14 Cherr, G.N., J.M. Shenker, C. Lundmarkand K.O. Turner, "Toxic Effects ofSelected Bleached Kraft Mill EffluentConstitutents on the Sea Urchin SpermCell", Environ. toxol. Chem., 6: 561-569(1987).

15 Kringstad, K.P., L.G. Stockinan and L.M.Stromberg, "The Nature andEnvironmental Significance of SpentBleach Liquor Toxicants: Present State ofKnowledge", J. Wood Chem. AndTechnol., 4(3): 389-404 (1984).

44

16 Leach, J.M. and A.N. Thakore, "Isolationand Identification of Constitutents Toxicto Juvenile Rainbow Trout (Salmogairdneri) in Caustic Extraction EffluentsFrom Kraft Pulp Mill Bleach Plants", J.Fish. Res. Bd Canada, 32:1249-1257(1975).

17 LeBlanc, G.A., B. Hilgenberg and B.J.Cochrane, "Relationships Between theStructures of Chlorinated Phenols, TheirToxicity, and Their Ability to InduceGlutathione S-transferase Activity inDaphnia magna", Aquat. Tox., 12: 147-156 (1988).

18 Salkinoja-Salonen, M., J.L. Saxelin, J.Pere, T. Jaakkola, J. Saarikoski, R.Hakulinen and O. Koistinen, "Analysis ofToxicity and Biodegradability ofOrganochlorine Compounds Released intothe Environment in Bleaching Effluents ofKraft Pulping", in: Advances in theIdentification of Organic Products, L.H.Keith (ed.), Chap. 56, pp. 1131-1164(1980).

19 Zitko, V., "Structure-activityRelationships in Fish Toxicology" in:Conference Proceedings, InternationalJoint Commission, Windsor, Chap. 1, p.7(March 11-13, 1975).

20 Carlberg, G.E., S. Johnsen, L.H.Landmark, B.E. Bengtsson, B. Bergstrom,J. Skramstad and H. Storflor,"Investigations of ChlorinatedThiophenes: A Group of BioaccumulableCompounds Identified in the Effluentsfrom Kraft Bleaching", Wat. Schi. Tech.,20(2): 37-48 (1988).

21 Pereira, W.E., C.E. Rostad, C.T. Chiou,T.I. Brinton, L.B. Barber, D.K. Demcheckand C.R. Demas, "Contamination ofEstuarine Water, Biota, and Sediment byHalogenated Organic Compounds: A FieldStudy", Environ. Sci. Technol., 22: 772-778 (1988).

22 Oliver, B.G., "Biouptake of ChlorinatedHydrocarbons from Laboratory-spiked andField Sediments by Oligochaete Worms",Environ. Sci. Technol., 21(8): 785-790(1987).

23 Douglas, G.R., E.R. Nestmann, J.L. Betts,J.C. Mueller, E.G.H. Lee, H.F. Stich,R.H.C. San, R.J.P. Brouzes, A.L.Chmelauskas, H.D. Paavila and C.C.Walden, "Mutagenic Activity in Pulp MillEffluents", in: Water Chlorination.Environmental Impact and Health Effects,Vol.3, Chap. 76, R.L. Jolley, W.A.Brungs, R.B. Cumming, V.A. Jacobs(eds.)Ann Arbor Science Publishers Inc.,Ann Arbor, MI, p.865-880 (1980).

24 Rannug, U., D. Jenssen, C. Ramel, .E.Eriksson and K. Kringstad, "MutagenicEffects of Effluents from ChlorineBleaching of Pulp", J. Toxicol. Environ.Health, 7: 33-47 (1981).

25 Walden, C.C., D.J. McLeay and A.B.McKague, "Cellulose ProductionProcess", in: The Handbook forEnvironmental Chemistry, O. Hutzinger(ed.), Springer-Verlag Berlin Heidelberg,Germany, Volume 3, Part D, 1-34 (1986).

26 Bjorseth, A., G.E. Carlberg, N. Gjos, M.Moller and G. Tveten, "HalogenatedOrganic Compounds in Spent BleachLiquors: Determination, Mutagenicity,Testing and Bioaccumulation", in.Advances in the Identification andAnalysis of Organic Pollutants in Water,Vol. 2, L.A. Keith (ed.), Ann ArborScience Publishers Inc., Ann Arbor, MI,Chap. 55, p. 1115-1 164 (1976).

27 Leach, J.M., "Loadings and Effects ofChlorinated Organics from Bleached PulpMills", in: Water Chlorination,Environmental Impact and Health Effects,Vol. 3, Chap. 30, R.L. Jolley, W.A.Brungs, R.B. Cumming, and V.A.

45

Jacobs (eds.) Ann Arbor SciencePublishers Inc., Ann Arbor, MI, p. 325-334 (1980).

28 McKague, A.B., "Characterization andIdentification of Organic ChlorineCompounds in Bleach Plant Effluents" in:Proc. Colloquim on Measurement ofOrganochlorines, Pulp & Paper Res.Centre, Univ. of Toronto, Toronto,Ontario (Feb. 16-17, 1988).

29 Fandry, C.B., R.E. Johannes and P.J.Nelson, "Pulp Mills: Modem Technologyand Environmental Protection", Report toSenator the Hon. John Button, Minister forIndustry, Technology and Commerce,Commonwealth of Australia, 68 pp.(1989).

30 Martinsen, K., A. Kringstad and G.E.Carlberg, "Methods for Determination ofSum Parameters and Characterization ofOrganochlorine Compounds in SpentBleach Liquors from Pulp Mills andWater, Sediement and Biological Samplesfrom Receiving Waters", Wat. Sci. Tech.,20(2): 13-24 (1988).

31 SSLV, [Stiftelsen SkogsindustriemasVatten och Luftvaresforskning] Risker forpaverkan pa miljon genom utslap avblekeriavlopp. Projektet utfordes 1982-1985. SSVL-85 Rapport Nr 44,Slutrapport delprojekt 4, Framstallning avblekt massa. AF-IPK, Box 8309, 104 20Stockholm, 84 p. [Environmental impactof bleach plant effluent. Project carried out1982-1985. SSVL-85 Report No. 44, FinalReport subproject 4, Manufacture ofbleached pulp.] (1985).

32 Fleming, B.I., T. Kovacs, C.E. Luthe, R.H.Voss, R.M. Berry and P.E. Wrist, "ADiscussion of the Use of the AOXParameter as a Tool for EnvironmentalProtection", Report prepared byPAPRICAN, 26 pp. (1990).

33 Liebergott, N., B. van Lierop, A. Nolin,M. Faubert, and J. Laflamme, "Modifyingthe Bleaching Process to Decrease AOXFormation", Pulp and Paper ResearchInstitute of Canada, 24 pp. (1989).

34 Alberta Environment Centre, "Toxicityand Environmental Chemistry ofWastewater from a Kraft Pulp and PaperMill: Fish Toxicity Studies", AlbertaEnvironmental Centre, Vegreville,Alberta, Report AECV87-R4, 67 pp.(1987).

35 Carlberg, G.E., H. Drangsholt, N. Gjos, G.Tveten, "Analysis of OrganochlorineCompounds in Water, Sediment and Fishfrom Iddefjorden", in: Proceedings fromthe Seventeenth Nordic Symposium onWater Research, Porsgrunn, NordforskPublication 1, p.131-140 (1981).

36 Craig, G.R., M.F. Holloran, K. Schiefer,R.W. Wilson and A. Burt, "Study of in-mill Toxicity and the Impact of MillEffluent on Lake Superior", A report forJames River-marathon ltd., Marathon,Ontario; Submitted to Ontario Ministry ofthe Environment, Beak Consultants Ltd.,Mississauga, Ontario, Report No. 2243.2(1986).

37 Hardig, J., T. Andersson, B.E. Bengtsson,L. Forlin and A. Larsson, "Long-termEffects of BKME on Red and WhiteBlood Cell Status, Ion Balance andVertebral Structure in Fish", Ecotox. &Environ. Safety, 15: 96-106 (1988).

38 Mehrle, P.M., K. Dickson, R. Hartung, R.Huggett, D. McLeay, A. Oikari and J.Sprague, "Pulping Effluents in theAquatic Environment", Report preparedby: The Scientific Panel on PulpingEffluents in the Aquatic Environment,prepared for: Proctor and Gamble

46

Company, Cincinatti, OH, Aug. 11/89, 44pp. (1989).

39 Remberger, M., P-A. Hynning and A.H.Neilson, "Comparison of Procedures forRecovering Chloroguaiacols andChlorocatechols from ContaminatedSediments", Environ. Toxol. Chem., 7:795-805 (1988).

40 Dwernychuk, L.W. [Hatfield ConsultantsLtd.], "Bottom Sediments and BiologicalTissues: A Baseline OrganochlorineContamination Survey in Howe Sound",January/February 1989, prepared for:Howe Sound Pulp and Paper Limited andWestern Pulp Limited Partnership (1989).

41 Sjostrom L., R. Radestrom, G.E. Carlbergand A. Kringstad, "Comparison of TwoMethods for the Determination of TotalOrganic Halogen (TOX) in ReceivingWaters", Chemosphere, 14(8): 1107-1113(1985).

42 Sinclair, W.F., t'Controlling Pollution fromCanadian Pulp and Paper Manufacturers:A Federal Perspective", EnvironmentCanada, 360 pp. (1990).

43 Canadian Environmental Control Bulletin,"Control of Pulp Mill ChlorinatedOrganics Announced by B.C.", July 20,1989, No. 392 (1989).

44 Liu, S. (Memo), Subject: WestcoastEnvironmental Law ResearchFoundation's Environment WeekPresentation on "Poison in Paradise: PulpPollution in B.C." (1989).

45 McGrath, R., "Discoveries About DioxinFormation Have Changed Some MillOperations", Pulp & Paper, p.133-136(April, 1989).

46 Alberta/Pacific Environmental ImpactAssessment Review Panel (ALPAC)(1989).

47 Severeid, D.E., "Pilot Plant Evaluation ofAlternative Bleach Sequences - EffluentToxicity and Chlorinated Organics",Research Report for WeyerhaeuserCanada, 19 pp. (1986).

48 Committee for the Gulf of Bothnia,"Water Pollution Problems in the Finnishand Swedish Pulp and Paper Industries:Priorities and Management Options inFuture Pollution Control Work", Report ofthe Special Working Group, April 1988, 9pp. (1988).

49 Amendola, G.A., "U.S. EPA Bench ScaleWastewater Treatability Study. Pulp andPaper Mill Discharges of 2,3,7,8-TCDDand 2,3,7,8-TCDF. Proposed InterimControl Measures", Interim NPDESPermit Strategy, Preliminary Report, U.S.Environmental Protection Agency, Region5, Environ. Sciences Div., Westlake, OH,26 pp. (1988).

50 Siuda, J.F., "Natural Production ofOrganohalogens", in: WaterChlorination", Vol.3, R.L. Jolley, W.A.Brungs, R.B. Cumming and V.A. Jacobs,(eds.) Ann Arbor Science Publishers Inc.,Ann Arbor, MI, Chap. 6, p.63-72 (1979).

51 Germgard, U. and S. Larsson, "OxygenBleaching in the Modern Softwood KraftPulp Mill", Paperi Ja Puu, 65: 287-290(1983).

52 Brannland, R. and G. Fossum, "How toCope with TOC1", TAPPI Proceedings,1987 Pulping Conference, p.243-248(1987).

53 Xie, T.M., K. Abrahamsson, E. Fogerqvistand B. Josefsson, "Distribution ofChlorophenolics in a MarineEnvironment", Environ. Sci. Technol., 20:457-463 (1986).

54 de Sousa, F., L.M. Stromberg and K.P.Kringstad, "The Fate of Spent Bleach

47

Liquor Material in Receiving Waters:Characterization of Chloroorganics inSediments", Wat. Sci. Tech., 20(2):153-160 (1988).

55 Howard, P.H., J. Saxena and H. Sikka,"Determining the Fate of Chemicals",Environ. Sci. Technol., 12(4): 398-407(1978).

56 Choi, J. and S. Aomine, "Adsorption ofPentachlorophenol by Soils, Soil Sci.Plant Nutr., 20(2): 135-144 (1974).

57 WHO, "Chlorophenosl Other thanPentachlorophenol", EnvironmentalHealth Criteria 93, World HealthOrganization, Geneva, 208 pp. (1989).

58 Landner, L., K. Lindstrom, M. Karlsson, J.Nordin, L. Sorensen, "Bioaccumulation ofFish of Chlorinated Phenols from kraftPulp Mill Bleachery Effluents", Bull.Environ. Contam. Toxicol., 18: 663-673(1977).

59 Wesen, C., "Chemical Characterization ofChlorinated Lignin Derivatives inOrganisms, Sediment and Air", Wat. Sci.Tech., 20(2): 185-188 (1988).

60 Dwernychuk, L.W. [Hatfield ConsultantsLtd.], "Effluent, Receiving Water, BottomSediments and Biological Tissues: ABaseline Organochlorine ContaminationSurvey, January/February, 1990",prepared for: Fletcher Challenge CanadaLimited – Elk Falls Pulp and Paper(1990).

61 Dwernychuk, L.W. [Hatfield ConsultantsLtd.], "Effluent, Receiving Water, BottomSediments and Biological Tissues: ABaseline Organochlorine ContaminationSurvey", January/February, 1990,prepared for: MacMillan Bloedel Limited– Harmac Division (1990).

62 Dwernychuk, L.W. [Hatfield ConsultantsLtd.], "Effluent, Receiving Water, BottomSediments and Biological Tissues: ABaseline Organochlorine ContaminationSurvey", January/February, 1990,prepared for: Fletcher Challenge CanadaLimited - Crofton Pulp and Paper (1990).

63 Dwernychuk, L.W. [Hatfield ConsultantsLtd.], "Effluent, Receiving Water, BottomSediments and Biological Tissues: ABaseline Organochlorine ContaminationSurvey", January/February, 1990,prepared for: MacMillan Bloedel Limited– Powell River Division (1990).

64 Dwernychuk, L.W. [Hatfield ConsultantsLtd.], "The Marine ReceivingEnvironment near MacMillan BloedelLimited, Powell River Division: a Studyon the Physical, Chemical and BiologicalComponents of Intertidal and SubtidalSystems", prepared for: MacMillanBloedel Limited – Powell River Division(1990).

65 Beak Associates Consulting (B.C.) Ltd.,"Baseline Organochlorine MonitoringProgram", prepared for: Canadian PacificForest Products Limited – Gold RiverMill, Project No. 14-163-01-01 (1990).

66 Carlberg, G.E., A. Kringstad, K.Martinsen and O. Nashaug,"Environmental Impact of OrganochlorineCompounds Discharged from the Pulp andPaper Industry", Paperi Ja Puu., 69: 337-342 (1987).

67 Leuenberger, C., W. Giger, R. Coney,J.W. Graydon and E. Molanr-Kubica,"Persistent Chemicals in Pulp MillEffluents", Water Res., 19(7): 885-894(1985).

68 Brownlee, B., Memo to Leigh Noton Re:Chlorophenolics Analysis of Athabasca,Peace and Slave River Water (May 4,1990).

48

69 Noton, L.R. and R.D. Shaw, "WinterWater Quality in the Athabasca RiverSystem 1988 and 1989", AlbertaEnvironment, 200 pp. (1989).

70 Boule, P., C. Guyon and J. Lemaire,"Photochemistry and Environment. IV.Photochemical Behaviour ofMonochlorophenols in Dilute AqueousSolution", Chemosphere, 11(12): 1179-1188 (1982).

71 Hwang, H.M., R.E. Hodson, and R.F. Lee,"Degradation of Phenol andChlorophenols by Sunlight and Microbesin Estuarine Waters", Environ. Sci.Technol., 20(10): 1002-1007 (1986).

72 Carey, J.H., M.E. Fox, B.G. Brownlee,J.L. Metcalfe and R.F. Platford,"Disappearance Kinetics of 2,4- and 3,4-dichlorophenol in a Fluvial System", Can.J. Physiol. Pharmacol., 62: 971-975(1984).

73 Baker, M.D., C.I. Mayfield and W.E.limes, "Degradation of Chlorophenols inSoil, Sediment and Water at LowTemperature", Water Res., 14(12): 1765-1771(1980).

74 Blades - Fillmore, L.A., W.H. Clementand S.D. Faust, "The Effect of Sedimenton the Biodegradation of 2,4,6-trichlorophenol in Delaware River Water",J. Environ. Sci. Health, A17(6): 797-818(1982).

75 Lee, R.F. and C. Ryan, "MicrobialDegradation of OrganochlorineCompounds in Estuarine Waters andSediments", in: Proceedings of theWorks/i op on Microbial Degradation ofPollutants in Marine Environments,Pennisicola Beach, Florida, 9-14 April1978, Bourquin A.W. & P.H. Pritchard(eds.), Washington, DC, U.S. EPA, pp.443-450 (EPA Report No. 60/9-79-012)(1979).

76 Baker, M.D. and C.I. Mayfield, "Microbialand Non-biological Decomposition ofChlorophenols and Phenol in Soil", WaterAir Soil Pollul., 13(4): 411-424 (1980).

77 Pal, H.S., T. Murphy, A.C. Carter andS.W. Drew, "Rapid Assays for MicrobialDegradation of 2-chlorophenol",Blacksburg, Virginia, Virginia WaterResources Research Center, VirginiaPolytechnic Institute and State University(Report No. 128) (1980).

78 de Kreuk, J.F. and A.O. Hantsveit,"Determination of the Biodegradability ofthe Organic Fraction of Chemical Wasters,Chemosphere, 10(6): 561-573 (1981).

79 Chu, J. and E.J. Kirsch, "Utilization ofHalophenols by a PentachlorophenolMetabolizing Bacterium", Dev. Ind.Microbiol., 14: 264-273 (1973).

80 Brownlee, B., M.E. Fox, W.M.J. Strachanand S.R. Joshi, "Distribution ofDehydroabietic Acid in SedimentsAdjacent to a Kraft Pulp and Paper Mill",J. Fish. Res. Board Can., 34: 838-843(1977).

81 Brownlee, B. and W.M.J. Strachan,"Distribution of Some OrganicCompounds in the Receiving Waters of aKraft Pulp and Paper Mill", J. Fish. Res.Board Can., 34: 830-837 (1977).

82 Horowitz, A., D.R. Shelton, C.P. Cornelland J.M. Tiedje, "Anaerobic Degradationof Aromatic Compounds in: Sedimentsand Digested Sludge, in: Proceedings ofthe 38th General Meeting of the Society ofIndustrial Microbiology, Richmond,Virginia, 9-14 August, 1981, p.435-444(1982).

83 Pignatello, J.J., L.K. Johnson, M.M.Martinson, R.E. Carlson and R.L.

49

Crawford, "Response of the Microflorain Outdoor Experimental Streams toPentachlorophenol: EnvironmentalFactors", Can. J. Microbiol.,-32: 38-46(1986).

84 Leach, J.M. and A.N. Thakore, "Isolationand Identification of Constitutents Toxicto Juvenile Rainbow Trout (Salmogairdneri) in Caustic Extraction Effluentsfrom Kraft Pulp Mill Bleach Plants", J.Fish. Res. Board Can., 32:1249-1257(1975).

85 Deprez, R.D., C. Oliver, and W.Halteman, "Variations in RespiratoryDisease Morbidity Among Pulp and PaperMill Town Residents", J. Occup. Med.,28(7): 486-91(1986).

86 E.B. Eddy Inc., Mr. C.R. Cook, personalcommunication (1989).

87 Allard, A.S., M. Remberger, T. Viktor,and A.H. Neilson, "Environmental Fate ofChloroguaiacols and Chlorocatechols",Wat. Sci. Tech., 20(2): 131-141(1988).

88 Neilson, A.H., A.S. Allard, P.A. Hynning,M. Remberger, and L. Landner, "BacterialMethylation of Chlorinated Phenols andGuaiacols: Formation of Veratroles fromGuaiacols and High-molecular-weightChlorinated Lignin", Appl. Environ.Micro., 45(3): 774-783 (1983).

89 Neilson, A.H., A.S. Allard, S. Reiland, M.Remberger, A. Tarnholm, T. Viktor, andL. Landner, "Tri- and Tetra-chloroveratrole, Metabolites Produced byBacterial O-methylation of tri- and tetra-chloroguaiacol: An Assessment of TheirBioconcentration Potential and TheirEffects on Fish Reproduction", Can. J.Fish Aquatic Sci., 41:1502-1512 (1984).

90 Landner, L., "Experimental Procedures forHazard Assessment in the Marine

Environment", in: EcotoxicologicalTesting for the Marine Environment, G.Persoone, E. Jaspers and C. Claus (eds.),State Univ. Ghent and Inst. Mar. Scient.Res., Bredene, Belgium., Vol. 1, p.657-687 (1984).

91 New Brunswick Research and ProductivityCouncil, "Bioaccumulation of ToxicCompounds in Pulp Mill Effluents byAquatic Organisms in Receiving Waters",Environment Canada, CPAR Secretariat,Ottawa, CPAR Project Report 675-1, 45pp. (1978).

92 DIAND, "Studies to Determine whetherthe Condition of Fish from the LowerMackenzie River is Related toHydrocarbon Exposure", EnvironmentalStudies No. 61, Department of IndianAffairs and Northern Development,Ottawa, 84 pp. (1989).

93 Neilson, A.H., H. Blanck, L. Forlin, L.Landner, P. Part, A. Rosemarin and M.Doserstrom, Chemicals in the AquaticEnvironment, L. Landner (ed.), Springer-Verlag, p.329 (1989).

94 Neilson, A.H., A.S. Allard, P.A. Hynning,M. Remberger and T. Viktor, "TheEnvironmental Fate of ChlorophenolicConstitutents of Bleachery Effluents",Tappi Journal, p. 239-247 (March, 1990).

95 Neilson, A.H., A.S. Allard, C. Lindgren,and M. Remberger, "Transformation ofChloroguaiacols, Chloroveratroles, andChlorocatechols by Stable Consortia ofAnaerobic Bacteria", Appl. Environ.Microbiol., 53(10): 2511-2519 (1987).

96 Hattula, M.L., V.M. Wasenius, H.Reunanen, and A.U. Arstila, "AcuteToxicity of Some Chlorinated Phenols,Catechols and Cresols to Trout", Bull.Environ. Contam. Toxicol., 26: 295-298(1981).

50

97 Jones, P.A., "Chlorophenols and TheirImpurities in the Canadian Environment",Ottawa, Environmental Protection service,Environment Canada, Report No. EPS-3-EP-84-3, 93 pp. (1981).

98 Call, D.J., L.T. Brooke and P.Y. Lu,Uptake, Elimination, and Metabolism ofThree Phenols by Fathead Minnows",Arch. Environ. Contam. Toxicol., 9: 699-714 (1980).

99 Birtwell, I.K., "A Field Technique forStudying the Avoidance of Fish toPollutants", Environmental ProtectionService Tech. Report No. EPS-5-AR-77-1,Halifax, Canada, p. 69-86 (1977).

100 Barrows, M.E., S.R. Petrocelli, K.J.Macek, and J.J. Carroll, "Bioconcentrationand Elimination of Selected WaterPollutants by Bluegill Sunfish (Lepomismacrochirus)", in: Dynamics Exposureand hazard Assessment of "ToxicChemicals", R. Hague (ed.), Ann ArborScience Publishers Inc., Ann Arbor, MI, p.379-392 (1980).

101 Virtanen, M.T. and M.L. Hattula, "TheFate of 2,4,6-trichlorophenol in anAquatic Continuous Flow-system",Chemosphere, 11(7): 641-649 (1982).

102 Ernst, W. and K. Weber, "ChlorinatedPhenols in Selected Estuarine BottomFauna", Chemosphere, 7(11): 867-872(1978).

103 Folke, J., J. Birklund, A.K. Sorensen, andU. Lund, "The Impact on th Ecology ofPolychlorinated Phenols and OtherOrganics Dumped at the Bank of a SmallMarine Inlet", in. Analysis of OrganicMicropollutants in Water; Proceedings ofthe 3rd European Symposium, Oslo, 19-21 September, 1983, Angeletti G. and A.Bjorseth (eds.), Luxembourg,

Commission of the EuropeanCommunities, p.242-254 (1984).

104 Paasivirta, J., K. Heinola, T. Humppi, A.Karjalainen, J. Knuutinen, K.Mantykoski,R. Paukko, T. Piilola, K. Surma-Aho, J.Tarhanen, L. Welling, and H. Vihonen,"Polychlorinated Phenols, Guaiacols andCatechols in the Environment",Chemosphere, 14(5): 469-491(1985).

105 Pierce, R.H. and D.M. Victor, "The Fateof Pentachlorophenol in an AquaticEcosystem", in: Pentachlorophenol:Chemistry, Pharmacology, andEnvironmental Toxicilogy, K.R. Rao(ed.), New York, London, Plenum Press,p.41-52 (1978).

106 Niimi, A.J., H.B. Lee, and G.P. Kissoon,"Kinetics of Chloroguaiacols and OtherChlorinated Phenolic Derivatives inRainbow Trout (Salmo gairdneri)",Environ. Toxicol. Chem., 9(5): 649-653(1990).

107 Renberg, L., O. Svanberg, B.E.Bengtsson, and G. Sundstrom,"Chlorinated Guaiacols and CathecholsBioaccumulation Potential in Bleaks(Alburnus alburnus, Pisces) andReproductive and Toxic Effects on theHarpacticoid Nitocra spinipes (Crustacea)", Chemosphere, 9:143-150 (1980).

108 Beak Consultants Ltd., "Non-conventional Contaminants in Pulp andPaper Mill Effluents" prepared forOntario Forest Industries Association,Beak Consultants Ltd., Mississauga,Ontario, Report No. 4080.1 (1987).

109 Boudrea, C.A., M.P. Guilcher, G.F.Westlake, and W.R. Parker, "Dispersionof Effluent Plumes from Three Pulp andPaper Mills in Northern New BrunswickRivers and Effects on the Behaviour ofJuvenile Atlantic Salmon", Environment

51

Canada, Environmental Protection,Dartmouth, N.S., Report No.EP-5-AR-88-6 (1988).

110 Kay, B.H., "West Coast MarineEnvironmental Quality: TechnicalReview", Environment Canada, RegionalProgram Report 86-01, 167 pp. (1986).

111 Kelso, J.R.M., C.K. Minns, and R.J.P.Brouzes, "Pulp and Paper Mill Effluent ina Freshwater Environment", J. Fish. Res.Bd. Canada, 34: 771-775 (1977).

112 Carey, J. and P.V. Hodson, "Pulp MillEffects Monitoring Program of the St.Maurice River, Quebec, 1989", presentedat the 3rd Workshop on EnvironmentalEffects Monitoring at Pulp and PaperMills Discharging to the FreshwaterEnvironment, March 20, 1990, Hull,Quebec (1990).

113 Sodergren, A. (ed.), "Biological Effects ofBleached Pulp Mill Effluents, FinalReport from the Environment/Cellulose IProject", ISSN 0282-7298, 139 pp. (1989).

114 Priha, M. and A. Langi, FFPRI, Helsinki,pers. commun. with A.G. Colodey, (1989).

115 Wigilius, B., H. Boren and A. Grimvall,"Determination of Adsorbable OrganicHalogens (AOX) and Their MolecularWeight Distribution in Surface WaterSamples", in: Isolation, Characterizationand Risk Analysis of OrganicMicropollutants in Water, Wigilius, B.(ed.), Linkoping Studies in Arts andScience, No. 20, Chap. 5, p. 1-14(1988).

116 Grimvall, A., H. Boren, S. Jonsson, S.Karlsson and R. Savenhed,"Organohalogens of Natural and IndustrialOrigin in Large Recipients of Bleach-plantEffluents", Proc. 3rd IA WPRC Symposiumon Forest Industry

Wastewaters, June 5-8, 1990, Tampere,Finland (1990).

117 Voss, R.H. and M.B. Yurker, "A Study ofChlorinated Phenolics Discharged in KraftMill Receiving Waters", prepared for TheCouncil of Forest Industries TechnicalAdvisory Committee, 131 pp. (1983).

118 Unpublished data. Pulp & Paper MillSurvey, 1988. Analyzed by J. Carey.

119 Noton, L.R., A.M. Anderson, T.B.Reynoldson, and J. Kostler, "WaterQuality in the Wapiti-Smoky RiverSystem Downstream of the Procter andGamble Pulp Mill, 1983", prepared for:Alberta Environment, 1989, 113 pp.(1989).

120 Fogelqvist, E., B. Josefason and C. Roos,"Halocarbons as Tracer Substances inStudies of the Distribution Patterns ofChlorinated Waters in Coastal Areas",Environ. Sci. Technol., 16: 479 (1982).

121 Oikari, A., B. Holmbom, E. Anas, and H.Bister, "Distribution in a Recipient Lakeand Bioaccumulation in Fish of ResinAcids From Kiaft Pulp Mill WasteWaters", Paperi Ja Puu, 62, p.193 (1980).

122Rogers, I.H., J.A. Servizi, and C.D.Levings, "Bioconcentration ofChlorophenols by Juvenile ChinookSalmon (Onchorhynchus tshawytscha)Overwintering in the Upper FraserRiver:Field and Laboratory Tests", WaterPoll. Res. J. Canada, 23(1): 100-113(1988).

123Derksen, B., "File Report on the Status ofPulp Mill Effluent Concentrations in theFraser River Drainage", Report,Environment Canada, EnvironmentalProtection, Freshwater Group, WestVancouver, B.C. 14 pp. (1988).

52

124Kruzynski, G.M., "Some effects ofdehydroabietic acid (DHA) onhydromineral balance and otherparameters in juvenile chinook salmon(Oncorhynchus nerka)", University ofBritish Columbia, Dept. of Zoology, Ph.D.thesis (1979).

125Brownlee, B., personal communications,NWRI (1990).

126McLeay, D.J. [D. McLeay and AssociatesLtd], "Aquatic Toxicity of Pulp and PaperMill Effluent: A Review", EnvironmentCanada, Ottawa, Report EPS 4/PF/1, 191pp. (1987).

127Rogers, I.H., I.K. Birtwell and G.M.Kruzynski, "Organic Contaminant Uptakein Eulachons Thaleichthy~ pacificusMigrating Through the Fraser RiverEstuary", p.83 in: Proc. Internat. Sympos.Fate and Effects of Toxic Chemicals inLarge Rivers and Their Estuaries, Oct. 10-14, 1988, Quebec, Canada (1988).

128Jonsson, P., B. Jonsson, L. Hakansson,and K. Martinsen, [Distribution ofchlorinated organic substances frompaper... [In Swedish] Swedish NationalEnvironment Protection Board, Solna(Stockholm), SNV Report No. 3228(1986).

129 Kierkegaard, A. and L. Renberg,[Chloroguaiacols in sediments offIggesund.) [In Swedish] Swedish NationalEnvironment Protection Board, Solna(Stockholm), SNV Report No. 1987-02(1987).

130Hakanson, L., P. Jonsson, and B. Jonsson,"Distribution of Chlorinated OrganicSubstances from Paper and PulpIndustries", Wat. Sci. Technol., 20(2): 25-36 (1988).

131Asplund, G., A. Grimvall, and C.Pettersson, "Naturally Produced

Adsorbable Organic Halogens (AOX) inHumic Substances From Soil andWater", Sci. TotaL Environ., 81/82:239-248 (1989).

131aLockhart, W.L., D.A. Metner, R.W.Danell, and S. Harbicht, "Liver Enzymesof Fish from the Slave River at FortSmith, 1989", unpublished report, Dept.of Indian Affairs and NorthernDevelopment, Yellowknife, NWT, 20 pp.(1990).

132Servizi, J.A., R.W. Gordon, and J.H.Carey, "Bioconcentration ofChlorophenols by Early Life Stages ofFraser River Pink and Chinook Salmon",Water Poll. Research J. Canada, 23(1):88-99 (1988).

133Kaiser, K. L.E., "Organic ContaminatedResidues in Fishes From Nipigon Bay,Lake Superior", J. Fish Res. Board Can.,24: 850-855 (1977).

134Oikari, A., B. Holmbom, and H. Bister,"Uptake of Resin Acids into Tissues ofTrout (Salmo gairdneri Richardson), Ann.Zool. Fennici, 19: 61-64 (1982).

135 Wesen, C. and L. Okla, "Uptake byAquatic Organisms of 36C1-labelledOrganic Compounds From Pulp MillEffluents", Ecol. Bull, 36:154-158 (1984).

136 Sodergren, A., B.E. Bengtsson, P.Jonsson, S. Lagergren, L. Larsson, M.Olsson, and L. Renberg, "Summary ofResults from the Swedish ProjectEnvironment/Cellulose ", Water Sci.TechnoL, 20(1): 49-60(1988).

137Bonsor, N., N. McCubbin, and J.B.Sprague, "Kraft Mill Effluents in Ontario",Report of the Expert Committee on KraftMill Toxicity to Pulp and Paper Section,MISA, Ontario Ministry of theEnvironment, Toronto, Ontario, 260 pp.(1988).

53

138Kovacs, T.G., R.H. Voss, and A. Wong,"Chlorinated Phenolics of Bleached KraftMill Origin, An Olfactory Evaluation",Water Res., 18: 911-916 (1984).

139Scroggins, R.P., "In-plant ToxicityBalances for a Bleached Kraft Pulp Mill,Pulp & Paper Canada, 87(9): T344-T348(1986).

140MOE, "Report on the 1986 IndustrialDirect Discharges in Ontario", OntarioMinistry of the Environment, Toronto,Ontario (Oct., 1987).

141MOE, "Toxicity of Pulp and PaperEffluents in Ontario (January, 1969 toDecember 1985)", Ontario Ministry of theEnvironment, Water Resources Branch,Aquatic Toxicity Unit, Toronto, Ontario,116 pp. (March, 1987).

142Holmbom, B.R. and K.J. Lehtinen, PaperiPuu, 62, p.673 (1980).

143Rogers, I.H. et al., "Fish Toxicants inKraft Effluents", TAPPI 58: 136-140(1975).

144Servizi, J.A., R.W. Gordon, and D.W.Martens, "Toxicity of Two ChlorinatedCatechols, Possible Components of KraftPulp Mill Bleach Waste", Int. Pac. SalmonFish. Comm. Prog. Report, 17, 43 pp.(1968).

145Bryant, C.W. and G.L. Amy, "OrganicHalide in Kraft Mill Wastewaters: FactorsAffecting In-mill Formation and Removalby Biological Treatment", TAPPIProceedings, p.435-438 (1988).

146Hutchins, F.E., "Toxicity of Pulp andPaper Mill Effluent. A Literature Review",U.S. Environmental Protection Agency,Environ. Res. La., Corvallis, Oregan, EPA600/3-79/013 (1979).

147Zanella, E.F., M. Proulx, and S. Berben,"A Comparison of Selected WarmwaterAnimals as Bioassay Test Organisms forPulp and Paper Mill Effluents", Proc.1982 TAPPI Environ. Conf., p.13-19(1982).

148Fahmy, F.K. and O.L. Lush, "Sensitivityof Major Aquatic Food Chain Organismsto Kraft Mill Effluents Treated byDifferent Methods", Environment Canada,CPAR Secretariat, Ottawa, CPAR ProjectReport 356-1, 41 pp. (1974).

149Alderdice, D.F. and J.R. Brett, "SomeEffects of Kraft Mill Effluent on YoungPacific Salmon", J. Fish. Res. Bd. Can.,14: 783-795 (1957).

150Howard, T.E. and C.C. Walden, "Pollutionand Toxicity Characteristics of Kraft PulpMill Effluents", TAPPI, 48(3): 136-141(1965).

151Birtwell, I.K. and G.M. Kruzynski, "In-situ and Laboratory Studies on theBehaviour and Survival of Pacific Salmon(genus Oncorhynchus), Hydrobiologia,188/189: 543-560 (1989).

152Sprague, J.B., "Factors that ModifyToxicity", Chap. 6 in: Fundamentals ofAquatic Toxicology, G.M. Rand and S.R.Petrocelli (eds.), Hemisphere Publ. Corp.,Washington, 666 pp. (1985).

153Gergov, M., M. Prika, E. Talka, and 0.Valttila, "Chlorinated Organic Compoundsin Effluent Treatment at Kraft Mills",TAPPI, TI (12): 175-184 (1988).

154McKean, W.T., "Pulp and Paper Industry",in: Introduction to EnvironmentalToxicology, Guthrie, F. E. and J.J. Perry(eds.), Elsevier, New York, Chap. 16,p.210-225 (19--).

54

155Rosenthal, H. and D.F. Alderdice,"Sublethal Effects of EnvironmentalStressors, Natural and Pollutional, onMarine Fish Eggs and Larvae", J. Fish.Res. Board Can., 33: 2047-2065 (1976).

156Mattsoff, L. and M. Nikinmaa, "Effects ofPlasma Proteins on the DehydroabieticAcid-induced Red Cell Breakdown",Ecotox. Environ. Safety, 14:157-163(1987).

157Mattsoff, L. and A. Oikari, "AcuteHyperbilirubinaemia in Rainbow TroutCaused by Resin Acids", Comp. Biochem.Physiol., 88C: 263-268 (1987).

158Oikari, A., T. Nakari, and B. Holmbom,"Sublethal Actions of Simulated KraftMill Effluents (KME) in Salmo gairdneriResidues of Toxicants, and Effects onBlood and Liver", Ann. Zool. Fennici, 21:45-53 (1984).

159Tana, J.J., "Sublethal Effects ofChlorinated Phenols and Resin Acids onRainbow Trout (Salmo gairdneri), Wat.Sci. Tech 20(2): 77-85 (1988).

160Tuurala, H. and A. Soivio, "Structural andCirculatory Changes in the SecondaryLamellae of Salmo gairdneri Gills",Aquatic Toxicology, 2: 21-29 (1982).

161Davis, J.C., "Bioassay Procedures andSublethal Effect Studies with BleachedKraft Pulp Mill Effluent and PacificSalmon", Pulp & Paper MagazineCanada, July 1974: D13-D1S (1974).

162Davis, J.C., "Progress in Sublethal EffectStudies with Kraft Pulp Mill Effluent andSalmonids", J. Fish Res. Bd Canada, 33:2031-2035 (1976).

163Kovacs, T.G., "Effects of Bleached KraftMill Effluents on Freshwater Fish: ACanadian Perspective", Water PollutionResearch Journal of Canada, 21: 91-118(1986).

164NCASI, "Effects of BiologicallyStabilized Bleach Kraft Mill Effluents onCold Water Stream Productivity asDetermined in Experimental StreamChannels - 1st Progress Report", NationalCouncil of the Paper Industry for Air andStream Improvement, Inc., New York,N.Y., NCASI Tech. Bull. No. 368 (1982).

165NCASI, "Effects of BiologicallyStabilized Bleach Kraft Mill Effluents onCold Water Stream Productivity asDetermined in Experimental StreamChannels" - 2nd Progress Report, NationalCouncil of the Paper Industry for Air andStream Improvement, Inc., New York,N.Y., NCASI Tech. Bull. No. 413 (1983).

166NCASI, "Effects of BiologicallyStabilized Bleach Kraft Mill Effluents onCold Water Stream Productivity asDetermined in Experimental StreamChannels" - 3rd Progress Report, NationalCouncil of the Paper Industry for Air andStream Improvement, Inc., New York,N.Y., NCASI Tech. Bull. No. 445 (1984).

167NCASI, "Effects of BiologicallyStabilized Bleach Kraft Mill Effluents onCold Water Stream Productivity asDetermined in Experimental StreamChannels" - 4th Progress Report, NationalCouncil of the Paper Industry for Air andStream Improvement, Inc., New York,N.Y., NCASI Tech. Bull. No. 474, 175 pp.(1985).

168NCASI, "Effects of BiologicallyStabilized Bleach Kraft Mill Effluents onCold Water Stream Productivity asDetermined in Experimental StreamChannels" - 5th Progress Report, NationalCouncil of the Paper Industry for Air andStream Improvement, Inc., New York,N.Y., NCASI Tech. Bull. No. 566, 127 pp.(1989).

55

169 Andersson, T., L. Forlin, J. Hardig, and A.Larsson, "Biochemical and PhysiologicalDisturbances in Fish Inhabiting CoastalWaters Polluted with BKME", Mar.Environ. Research, 24: 233-236 (1988).

170 Larsson, L., T. Andersson, L. Forlin andJ. Hardig, "Physiological Disturbances inFish Exposed to Bleached Kraft MillEffluents", Water Sci. Technol., 20(2): 67-76 (1988).

171 Sandstrom, O., E. Neuman, and P. Karas,"Effects of Bleached Pulp Mill Effluent onGrowth and Gonad Function in BalticCoastal Fish", Water Sci. Technol., 20(2):107-118 (1988).

172Munkittrick, K.R., C. Portt, G.J. Van derKraak, I.R. Smith, and D. Rokosh,"Impact of Bleached Kraft Mill Effluenton Liver MFO Activity, Serum Steroidsand White Sucker PopulationCharacteristics", Abstract No. 333,Abstracts of the 10th Annual Meeting ofthe Society of Environmental Toxicologyand Chemistry, Toronto, Ontario (October28 - November 2, 1989).

173 Sandstrom, 0., P. Karas, and E. Neuman,"Recruitment and Fish Populations",Abstract No. 263, Abstracts of the /0thAnnual Meeting of the Society ofEnvironmental Toxicology and Chemistry,Toronto, Ontario (October 28 - November2, 1989).

174 Gehrs, C.W., L.D. Eyman, R.J. Jolley,and J.E. Thompson, "Effects of StableChlorine-containing Organics on AquaticEnvironments", Nature, 249: 675-676(1974).

175 Jacobsson, A., E. Neuman, and G.Thoresson, "The Viviparous Blenny as anIndicator of Environmental Effects ofHarmful Substances", Ambio, 15(4): 236-238 (1986).

176Koenig, C.C. and C. McLean, "Rivulusmarmoratus: A Unique Fish Useful inChronic Marine Bioassays of HalogenatedOrganics", in: Water Chlorination:Environmental Impact and Health Effects,Jolley, R.L., H. Gorchev, and D.H.Hamilton (eds.), Vol.2, Chap. 72, AnnArbor Science Pub. Inc., Ann Arbor, MI(1980).

177Andersson, T., B.E. Bengtsson, L. Forlin,J. Hardig, and L. Larsson, "Long-termEffects of Kraft Mill Effluents onCarbohydrate Metabolism and HepaticXenobiotic Biotransformation Enzymes inFish", Ecotoxicol. Environ. Safety, 13: 53-60 (1987).

178Mather-Mihaich, E. and R.T. Di Giulio,"Peroxisomal Enzyme, Mixed-functionOxidase and Oxidant-mediated Responsesof Chlorinated Phenolics and Resin Acidsin Channel Catfish", Abstract No. 334,Abstracts of the 10th Annual Meeting of theSociety of Environmental Toxicology andChemistry, Toronto, Ontario (October 28 -November 2, 1989).

179Oikari, A. and T. Kunnamo-Ojala,Tracing of Xenobiotic Contamination inWater with the Aid of Fish BileMetabolites: A Field Study with CagedRainbow Trout (Salmo gairdneri)",Aquatic Toxicol., 9: 327-341 (1987).

180Smith, I.R. and D.A. Rokosh, "AnEpidemiological Study of a White Sucker(Catostomus commersoni) PopulationInhabiting the Kaministiquia River,Thunder Bay, Ontario", Abstract No. 262,Abstracts of the 10th Annual Meeting ofthe Society of Environmental Toxiciologyand Chemistry, Toronto, Ontario (October28 - November 2, 1989).

181Tana, J. and E. Nikunen, "PhysiologicalResponses of Rainbow Trout in a Pulp

56

and Paper Mill Recipient During FourSeasons", Ecotoxicol. En "iron. Safety, 13:27-34 (1986).

182Rogers, I.H., C.D. Levings, W.L.Lockhart, and R.J. Norstrom,"Observations of Overwintering JuvenileChinook Salmon (Oncorhynchustshawytscha) Exposed to Bleached KraftMill Effluent in the Upper Fraser River,British Columbia, Chemosphere, 19:1853-1868(1989).

183McLeay, D.J. and D.A. Brown, "Stressand Chronic Effects of Untreated andTreated Bleached Kraft Pulp Mill Effluenton the Biochemistry and Stamina ofJuvenile Coho Salmon (Oncorhynchuskisutch), J. Fish. Res. Board Can.,36:1049-1059 (1979).

184Johnson, L.L., E. Casillas, T.K. Collier,B.B. McCain, and U. Varanasi,"Contaminant Effects on OvarianDevelopment in English Sole (Parophrysvetulus) from Puget Sound, Canadian J.Fish. Aquat. Sci., 45: 2133-2146 (1988).

185Scott, G.I. and D.P. Middaugh, "SeasonalChronic Toxicity of Chlorination to theAmerican Oyster, Crassostrea virginica",in: Water Chlorination, Vol. 2, R.L.Jolley, H. Gorchev and D.H. Hamilton(eds.) Ann Arbor Science Publishers Inc.,Ann Arbor, MI, Chap. 23, p. 311-328(1977).

186Owens, J.W., Comments re: A.G.Colodey's unpublished background report"Environmental Impact of Bleached Pulpand Paper Mill Effluents in Sweden,Finland, and Norway: Implications to theCanadian Environment", Submission toEnvironment Canada, Proctor & GambleCo., Dec. 1989, 28 pp. (1989).

187Oikari, A. and P. Lindstrom-Seppa,"Responses of Biotransformation

Enzymes in Fish Liver: Experimentswith Pulp Mill Effluents and TheirComponents", Abstract in the NinthInternational Symposium on ChlorinatedDioxins and Related Compounds,Toronto, Ontario (Sept. 17-22, 1989).

188Bengtsson, B.E., "Effects of Pulp MillEffluents on Skeletal Parameters in Fish -A Progress Report", Wat. Sci. Tech.,20(2): 87-94 (1988).

189 Lindesjoo, E. and J. Thulin, "Fin Erosionof Perch (Perca fluviatalis) in a Pulp MillEffluent", Bull, Eur. Ass. Fish Pathol.,7(1): 11-14(1987).

190Thulin, J., J. Hoglung, and E. Lindesjoo,"Diseases and Parasites of Fish in a KraftMill Effluent", Water Sci. Technol., 20(2):179-180 (1988).

191 Bengtsson, B.E., "Vertebral Damage inFish Induced by Pollutants, in: SublethalEffects of Toxic Chemicals on AquaticAnimals", Koeman, J.H. and J.J.T.W.A.Strik (eds.), Elsevier, The Netherlands,p.23-29 (1975).

192Bengtsson, B.E., A. Larsson, A.Bengtsson, and L. Renberg, "SublethalEffects of Tetrachloro-1,2-benzoquinone -A Component in Bleachery Effluents fromPulp Mills - On Vertebral Quality andPhysiological Parameters of FourhornSculpin", Ecotox. & Environ. Safety, 15:62-71(1988).

193 Couillard, C.M., R.A. Berman and J.C.Panisset, "Histopathology of RainbowTrout Exposed to a Bleached Kraft PulpMill Effluent", Arch. Environ. Contam.Toxicol., 17: 319-323 (1988).

194Ander, P., K.E. Eriksson, M.C. Kolar, andK. Kringstad, "Studies on the MutagenicProperties of Bleaching Effluents", Sven.Paperstidn, 80: 454-459(1977).

57

195Eriksson, K.E., N.C. Kilar, and K.Kringstad, "Studies on the MutagenicProperties of Bleaching Effluents", Part 2,Sven. Papperstidn, 82: 95-104 (1979).

196 Ames, B.N., J. McCann, and E.Yamasaki, in: Handbook of Mutageniciy-Test Procedure, Wilbey, B.J. et al. (eds.)Elsevier, Amsterdam, The Netherlands(1975).

197B.C. Research, "Biological Characteristicsof Pulp Mill Effluents, (British ColumbiaResearch Council), Environment Canada,CPAR Secretariat, Ottawa, CPAR ProjectReport 678, 178 p. (1979).

198 Hoglund, C., A.S. Allard, A.H. Neilson,and L. Landner, "Is the MutagenicActivity of Bleach Plant EffluentsPersistent in the Environment?" SvenskPapperstidning, 82(15): 447-449 (1979).

199Langi, A. and M. Priha, "Mutagenicity inPulp and Paper Mill Effluents and inRecipient, Water Sci. Technol. 20(2): 143-152 (1988).

200Stockman, L., L. Stromberg, and F. deSousa, "Mutagenic Properties of BleachKraft Plant Effluents: Present State ofKnowledge", Cellulose Chem. Technol.,14: 517-526 (1980).

201Fevolden, S.E. and M. Moller, "Ames'mutagemtetstest anvendt paavlopsvann"[Ames mutagenicity test applied to wastewater.), Miljovardssekretariatet,Nordforsk, Norway, Publication, 1978/2:85-93 (1978).

202Nazar, M.A. and W.H. Rapson,"Elimination of the Mutagenicity ofBleach Plant Effluents", Pulp & PaperCanada, 81(8): T191-T196 (1980).

203Carlberg, G.E., H. Drangsholt, and N.Gjos, "Identification of Chlorinated

Compounds in the Spent ChlorinationLiquor from Differently TreatedSulphite Pulps with Special Emphasis onMutagenic Compounds, Sci. TotalEnviron., 48:157-167 (1986).

204McKague, A.B., E.G.H. Lee, and G.R.Douglas, "Chloroacetones: MutagenicConstituents of Bleached KraftChlorination Effluents", Mutat. Res., 91:301-306 (1981).

205Carlberg, G.E., N. Gjos, M. Moller, K.O.Gustavsen, G. Tveten, and L. Renberg,"Chemical Characterization andMutagenicity Testing of ChlorinatedTrihydroxybenzenes Identified in SpentBleach Liquors From a Sulphite Plant",Sci. Total Environ., 15: 3-15 (1980).

206Beak Consultants Ltd., "Non-conventionalContaminants in Pulp and Paper MillEffluents", Prepared for Ontario ForestIndustries Association, Beak ConsultantsLtd., Mississauga, Ontario, Report No.4080.1 (1987).

207 Holmbom, B.R., R.H. Voss, R.D.Mortimer, and A. Wong, "Fractionation,Isolation and Characterization of AmesMutagenic Compounds in KraftChlorination Effluents", Environ. Sci.Technol., 18(5): 333-337 (1984).

208Kinae, N., T. hashizume, T. Makita, I.Tomita, I. Kimura, and H. Kanamori,"Studies on the Toxicity of Pulp and PaperMill Effluents, II. Mutagenicity of theExtracts of the Liver from Spotted SeaTrout (Nibea mitsukurii)", Water Res., 15:25-30 (1981).

209 Klein, A.W., W. Klein, W. Kordel, andM. Weiss, "Structure-activityRelationships for Selecting and SettingPriorities for Existing Chemicals – AComputer-assisted Approach", Environ.Toxol. Chem., 7: 455-467 (1988).

58

210 Fishbein, I. and C.R. Morris, "PotentialIndustrial Carcinogens and Mutagens",EPA Publ. No. 560/5-77-005, U.S.Environmental Protection Agency,Washington, DC (1977).

211 Lee, E.G.H., J.C. Mueller, and C.C.Walden, "Biological Characteristics ofPulp Effluent (Part I)", CPAR Report No.678-1, Environment Canada, Ottawa,Ontario (1979).

212Searle, C.E., "Chemical Carcinogens",Monograph No. 173, American ChemicalSociety, Washington, DC (1976).

213 Birtwell, I.K. and R.M. Harho, "Pulp MillImpact Studies at Port Alberni and PortMellon, B.C.", Transactions of theTechnical Section, 6(4): 85-89 (1980).

214Kelso, J.R.M., "Density, Distribution, andMovement of Nipigon Bay Fishes inRelation to a Pulp and Paper Effluent", J.Fish. Res. Board Can., 34: 879-885(1977).

215McGreer, E.R. and G.A. Vigers,"Development and Validation of an in situFish Preference-avoidance Technique forEnvironmental Monitoring of Pulp MillEffluents'', in: Aquatic Toxicology andHazard Assessment: 6th Symposium,ASTM Sm 802, W.E. Bishop, R.D.Cardwell & B.B. Heidolph (eds.),American Society for Testing andMaterials, Philadelphia, p.519-529 (1983).

216 Gordon, M.R. and D.J. McLeay,"Avoidance Reactions of Salmonids toPulp Mill Effluents", EnvironmentCanada, CPAR Secretariat, Ottawa, CPARProject Report 688-1, 55 pp. (1978).

217Sprague, J.B. and D.E. Drury, "AvoidanceReactions of Salmonid Fish

to Representative Pollutants", in:Advances in Water Pollution Research,Proc. Fourth Internat. Conf., S.H.Jenkins (ed.), Prague, Oxford:Permagon Press, Vol. 1, p.169-179(1969).

218Hicks, D.B. and J.W. DeWitt, "Effects ofDissolved Oxygen on Kraft Pulp MillEffluent Toxicity", Wat. Res. 5: 693-701(1971).

219Beak, T.W., "Biological Survey ofNipigon Bay - 1970", Consult. Report, 13(1971).

220Vander Wal, J., "Relation BetweenNipigon Bay Benthic Macroinvertebratesand Selected Aspects of Their Habitat", J.Fish Res. Board Can. 34: 824-829 (1977).

221Jones, B.F., C.E. Warren, C.E. Bond, andP. Doudoroff, "Avoidance Reactions ofSalmonid Fishes to Pulp Mill Effluents",Sewage Indust. Wastes, 28: 1403-1413(1956).

222Davis, J.C., "Sublethal Effects of BleachedKraft Pulp Mill Effluent on Respirationand Circulation in Sockeye Salmon(Oncorhynchus nerka), J. Fish. Res. BoardCan., 30: 369-377 (1973).

223 Davis, J.D., "Technical Note: Disruptionof Precopulatory Behaviour in theAmphipod Anisogammarus pugettensisUpon Exposure to Bleached Kraft PulpMill Effluent", Water Res., 12: 273-275(1978).

224 Davis, T.M., B.D. Vance, and J.H.Rodgers, "Productivity Responses ofPeriphyton and Phytoplankton to BleachKraft Mill Effluent", Aquatic Tox., 12: 83-106 (1988).

225Neuman, E. and P. Karas, "Effects of PulpMill Effluent on a Baltic Coastal

59

Fish Community", Wat. Sci. Tech.,20(2): 95-106 (1988).

226Sodergren, A., B.E. Bengtsson, P.Jonsson, K. Kringstad, S. Lagergren, M.Olsson, and L. Renberg, "EnvironmentCellulose II: Biological Effects of WaterDischarges by the Forest Industry", SNVReport 3430, 42 pp. (1988).

227Lehtinen, J-J, M. Motini, J. Mattsson, andL. Landner, "Disappearance of Bladder-Wrack (Fucus vesiculosus) in the BalticSea: Relation to Pulp-mill Chlorate",Ambio, 17(6): 387-393 (1988).

228 Mattsson, J.E. Nylen, and K.J. Lehtinen,"Effects of Chlorate on the Bladder-wrack(Fucus vesiculosus)", Swedish ForestIndustries, Water and Air PollutionResearch Foundation (SSVL), SSVL 85,Report No.26.7 (In Swedish) (1984).

229 Rosemarin, A., K.J. Lehtinen, and M.Notini, "Uptake of Chlorate by Fucusvesiculosus", Swedish EnvironmentalResearch Group (SERG), Report No. K-5014:2 (1985).

230Haage, P., "Quantitative Investigation ofthe Baltic Fucus Belt Macrofauna",Quantitative seasonal fluctuations,Contrib. Asko Lab. Univ. Stockholm,No.9, p.1-88 (1975).

231Rosemarin, A., M. Notini, M. Soderstrom,S. Jensen, and L. Landner, "Fate andEffects of Pulp Mill Chlorophenolic 4,5,6-trichloroguaiacol in a Model BrackishWater Ecosystem", Sci. Total Environ.,92: 69-90 (1990).

232 Brouzes, R.J.P., "Fish Toxicity withSpecific Reference to the Pulp and PaperIndustry", in: Water Pollution AbatementTechnology in The Pulp and PaperIndustry, Environment Canada,Environmental Protection Service,

Economic and Technical Review ReportEPS 3-WP-76-4, p.81-124 (1976).

233Persson, P.E., "Uptake and Release ofEnvironmentally Occurring OdorousCompounds by Fish", Water Res. 18:1263-1271(1984).

234 Cook, W.H., F.A. Farmer, O.E.Kristiansen, K. Reid, J. Reid, and R.Rowbottom, "The Effect of Pulp andPaper Mill Effluents on the taste andOdour of the Receiving Water and theFish Therein", Pulp and Paper MagazineCanada, 74: 97-106 (1973).

235 Gordon, M.R., J.C. Mueller, and C.C.Walden, "Effect of Biotreatment on FishTainting Propensity of Bleached KraftWhole Mill Effluent", Canadian Pulp andPaper Assoc., Trans. of Tech. Section,March 1980, 6(1): TR2-TR8 (1980).

236 Miettinen, V., B.E. Lonn, and A. Oikan,"Effects of Biological Treatment on theToxicity for Fish of Combined Debardingand Kraft Pulp Bleaching Effluent",Paperi ja Puu, 64: (Special No.4): 251-254 (1982).

237Liem, A.J., V.A. Naish, and R.S.Rowbottom, "Evaluation of the Effect ofInplant Treatment Systems on theAbatement of Air and Water PollutionFrom a Hardwood Kraft Pulp Mill",Environment Canada, CPAR Secretariat,Ottawa, CPAR Project Report 484: 81 pp.(1977).

238Shumway, D.L. and G.G. Chadwick,"Influence of Kraft Mill Effluent on theFlavor of Salmon Flesh", Water Res., 5:997-1003 (1971).

239Whittle, D.M. and K.W. Flood,"Assessment of the Acute Toxicity,Growth Impairment and Flesh TaintingPotential of a Bleached Kraft Mill Effluenton Rainbow Trout (Salmo

60

gairdneri), J Fish. Res. Bd. Canada, 34:869-878 (1977).

240Pawson, T.W., J.R. Munro, G.R. Craig,and M. Thomson, "Fish Lethality and

Taining in the Ottawa River in theVicinity of the Canadian InternationalPaper Mill, Hawkesbury, Ontario",Toxicity Unit, Quality Protection Section(1982).