sediment oxygen demand and its effects on dissolved oxygen

Technical Report W-94-1March 1994

US Army Corpsof Engineers AD-A279 327Waterways Experiment ON IStation

Water Quality Research Program

Sediment Oxygen Demand and ItsEffects on Dissolved OxygenConcentrations and NutrientRelease; Initial Laboratory Studies

by Cynthia B. Price, Carl Cerco, Douglas Gunnison

DTICELECTE

,'IMAY. 1 7,19K

Approved For Public Release; Distribution Is Unlimited

94-14755

NIflIIitIlIl!HII II 9 4 5 1 7 0 0 6

Prepared for Headquarters, U.S. Army Corps of Engineers

The contents of this report are not to be used for advertising.publication, or promotional purposes. Citation of trade namesdoes not constitute an official endorsement or approval of the useof such commercial products.

O IINTEDON 3UCYO.D PAt

Water Quality Research Program Technical Report W-94-1March 1994

Sediment Oxygen Demand and ItsEffects on Dissolved OxygenConcentrations and NutrientRelease; Initial Laboratory Studies

by Cynthia B. Price, Carl Cerco, Douglas Gunnison

U.S. Army Corps of EngineersWaterways Experiment Station3909 Halls Ferry RoadVicksburg, MS 39180-6199

Final reportApproved for public release; disftibution Is unlimited

Prepared for U.S. Army Corps of EngineersWVashington, DC 20314-1000

Under Work Unit 32694

US Army Corpsof EngineersWaterways Experiment toNg-c DataStation

ML40MO IIUA WOA

Price, Cynthia B.Sediment oxygen demand and its effects on dissolved oxygen concentrations

and nutrient release :initial laboratory studies I by Cynthia B. Price, Gait Cerco,Douglas Gunnison ; prepared for U.S. Army Corps of Engineers.

54 p. :11I. ; 28 cm. -- (Technical report ; W-94-1)Includes bibliographical references.1. River sediments. 2. Water - Dissolved oxygen. 3. Lake sediments. 4. Es-

tuauine sediments. I. Cerco, John C. II. Gunnison, Douglas. Ill. United States.Army. Corps of Engineers. IV. U.S. Army Engineer Waterways Experiment Sta-tion. V. Water Quality Research Program. VI. Tritle. VII. Series: Technical re-port (U.S. Army Engineer Waterways Experiment Station) ; W-94-1 .TA7 W34"no.W-94-1

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Contents Dit Spo ,

Preface ................................................ iv

I-Introduction ........................................... I

Background ........................................... IObjectives ............................................ 2

2- Materials and Methods ................................... 3

Sample Collection ....................................... 3Test-Tube Studies ....................................... 5Column Studies ......................................... 6

3-Computation of Sediment-Water Fluxes ...................... 10

Test-Tube Measures .................................... 10Nutrient and Carbon Fluxes in Columns ...................... 10Sediment Oxygen Demand in Columns ....................... 12

4- Results ............................................. 14

Test Tube Study I ...................................... 14Test Tube Study II ..................................... 14Brown's Lake Column Study .............................. 15Rathbun Lake Column Study .............................. 16Chesapeake Bay Column Study ............................ 23Eau Galle Reservoir Column Study .......................... 26Chicago River Column Study .............................. 29

5- Discussion ........................................... 36

Test Tube Study I ...................................... 36Test Tube Study II ..................................... 36Column Studies ........................................ 37

6-Conclusions and Plans for Future Activities .................... 39

References ............................................. 40

Appendix A: Data for Column Studies ......................... Al

SF 298

Wii

Preface

The work reported herein was conducted as part of the Water QualityResearch Program (WQRP), Work Unit 32694. The WQRP is sponsored bythe Headquarters, U.S. Army Corps of Engineers (HQUSACE), and is assignedto the U.S. Army Engineer Waterways Experiment Station (WES) under thepurview of the Environmental Laboratory (EL). Funding was provided underDepartment of the Army Appropriation No. 96X3121, General Investigation."Tbe WQRP is managed under the Environmental Resources Research andAssistance Programs (ERRAP), Mr. J. L. Decell, Manager. Mr. Robei" C.Gunkel was Assistant Manager, ERRAP, for the WQRP. Technical Monitorsduring this study were Mr. Frederick B. Juhle, Mr. Rixie Hardy, and Dr. JohnBushman, HQUSACE.

The study was conducted by Ms. Cynthia B. Price of the Ecosystem Pro-cesses and Effects Branch (EPEB), EL, WES. Laboratory support in conduct-ing this investigation was provided by Mr. Scott P. Towne of the EPEB.Dr. Carl Cerco of the Water Quality and Contaminant Modeling Branch(WQCMB) and Dr. Douglas Gunnison of the EPEB, EL, assisted with techni-cal review of the study and preparation of the reporL

The study was conducted under the direct supervision of Dr. Richard E.Price, Acting Chief, EPEB, and under the general supervision ofMr. Donald L. Robey, Chief, Environmental Processes and Effects Division,EL, and Dr. John Harrison, Director, EL. The report was reviewed byDr. James Brannon and Dr. Craig Smith, EPEB.

At the time of publication of this report, Director of WES wasDr. Robert W. Whalin. Commander was COL Bruce K. Howard, EN.

This report should be cited as follows:

Price, C. B., Cerco, C., and Gunnison, D. (1994). "Sedimentoxygen demand and its effects on dissolved oxygen concentrationsand nutrient release; initial laboratory studies," Technical ReportW-94-1, U.S. Army Engineer Waterways Experiment Station,Vicksburg, MS.

iv

1 Introduction

Background

Dissolved oxygen (DO) in the water column of rivers, lakes, and estuariesis an important determinant of water quality. Sediment oxygen demand (SOD)is a key contributor to undesirable low DO levels (Giga and Uchrin 1990).SOD is the rate of oxygen removal from the overlying water column due tothe decomposition of settled organic matter. SOD encompasses oxygenconsumption through biological activity in sediments and through the chemicaloxidation of reduced species, including FW+, Mn2÷, and S2- (Wang 1981). Inaddition to DO depletion, degradation of organic matter in the sediment resultsin the release of nutrients and metals, such as ammonium, phosphorus, nitro-gen, iron, and manganese, into the water column. DO depletion may alsocause release of toxic substances. Anoxic conditions combined with release oftoxic substances can lead to severe water quality problems (Gunnison, Chen,and Brannon 1983).

Understanding SOD and its related processes is necessary to assess theimpacts of sediment-water interactions on U.S. Army Corps of Engineers (CE)water resource projects, including reservoirs, navigation projects, and water-control structures. Predicting the effects of CE projects on water quality hasbeen difficult due to the lack of standard methods to accurately measure,quantify, and predict SOD.

Several different measurement techniques for determining SOD are cur-rently being used by various agencies. These include in situ techniques inwhich an enclosed chamber is installed at the sediment surface and techniquesin which sediments are removed to the laboratory for analysis. Both methodshave advantages and disadvantages. In situ measurements minimize sedimentdisturbance. The major disadvantage of this type of system is that the DOlevel in the water trapped under the chamber declines during measurementmaking it necessary to periodically aerate the chamber in order to continue toobtain reliable SOD fluxes. Ensuring a good seal to the sediment surface isanother difficulty. Laboratory measurements allow for closer control of systemvariables, such as temperature, water velocity, and light. However, a keydisadvantage in laboratory SOD measurements is the necessity for fieldverification.

ChapWr I Inouucion

Objectives

One objective of this project is to develop a measurement technique forSOD that is easily applicable and requires a minimum of equipment. This hasnecessitated the development of an integrated, universally applicable CE-widemethod to analyze SOD in both freshwater and estuarine systems.

The U.S. Army Engineer Waterways Experiment Station (WES) is currentlydeveloping laboratory techniques interactively with model development tomeasure, evaluate, and predict SOD for CE water resource projects. Initialinvestigations by the WES consisted of conducting a literature review andhosting a workshop to determine the state of the art of SOD research (Cerco,Gunnison, and Price 1991 and Price 1991). The panel discussion conductedduring the workshop focussed on process- and modeling-related issues, interac-tive laboratory and model development, and the relative significance of SODprocesses and optimum representation of such processes in models.

These initial laboratory experiments were conducted to provide a methodfor measurement of SOD and to evaluate major sources of SOD in a definedsystem. The studies have also provided a database for investigating anavailable mechanistic model of SOD and nutrient release. The existing sedi-ment model has been extensively employed in only one system, ChesapeakeBay. Its applicability for a wide range of systems needs to be tested.Comparison of model and laboratory experiments will indicate pathways forimproving and modifying both the model and existing laboratory techniques.

2 Chiapr I Inmdruction

2 Materials and Methods

Test tubes and 20-1 columns were used to simulate bedded sediments withan overlying water column. The systems were allowed to develop anaerobicconditions naturally. Nutrient release and DO depletion were followed overtime. Analytical methods for DO, ammonium-nitrogen, orthophosphate-phosphorus, nitrate-nitrogen, total organic carbon, and total inorganic carbonare presented in Table 1. Initial studies employed test tubes to allow for fasterformation of anaerobic conditions due to the small DO capacity of the over-lying water column. The replacement of water removed through sampling wasalso avoided because the test tubes were used as sacrificial samples. Thesecond tube study was initiated to compare the SOD rates of sediments con-taining different concentrations of organic matter. Tubes were again used toavoid water replacement and to allow for a greater number of samples. Large-scale (20 f) column testing was conducted to allow for lengthy experimentswith DO manipulation of the overlying water column. The large water volumeof the columns allowed water lost through sampling to be replaced withoutcreating major changes in the water column chemical composition throughdilution with makeup water.

Sample Collection

Sediments used in the laboratory studies included Brown's Lake, WES,Vicksburg, MS; Rathbun Lake, Wayne County, 10; Chesapeake Bay, upperbay Station R-64, MD; Eau Galle Reservoir, WI; and the north branch of theChicago River, IL. Sediments were collected using a ponar grab dredge andwere refrigerated in sealed containers at 40C prior to use. The first sedimentinvestigated, Brown's Lake, was selected because of its availability, knownphysical characteristics, and use in past studies. The remaining sediments wereselected due to their variability in origin and physical characteristics (Table 2).

Chpr 2 Mal-t-` w Me o• 3

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Table 2Sediments Used In Test Tube and Column Studies

FraPtrioIal size

Sedinent Location Solids %OM' %Sand %Silt %Ciay

Brown's Lake Mississippi 0.4513 1.82 5 70 25

Ralhbun Lake Iowa 0.6505 2.09 88 8 4

Chesapeake Bay Maryland 0,7496 2.85 52 38 10

Eau Galle Reservoir Wisconsin 0.3827 6.62 52.5 40 7.5

Chicao River Illinois 0.303 6.96 25 17.5 7.5

'%OM - Percent Organic Maner.

Test-Tube Studies

Study I

Initial laboratory studies consisted of test tubes simulating a bedded sediment with an overlying water column. Fifty-milliliter glass test tubes wereloaded with 10 g of Brown's Lake sediment amended with 1-percent organicmatter. Freeze-dried Hydrilla, an available and easilydegradable plant material,was used for all organic matter amendments. The sediment was covered with40-ml distilled-deionized water, and the tubes were sealed with rubber stop-pers. All tubes were incubated at room temperature (23°C). Dissolved oxygenconsumption and nutrient release were determined over a 36-day period. Sam-pling for DO, ammonium-nitrogen, and orthophosphate-phosphorus was con-ducted on days 0, 1, 3, 7, 11, 31, and 36 of the incubation period. Threeseparate tubes were sacrificed at each sampling time.

Study II

Tests in Study II were identical to Study I, except samples were also takenfor nitrate-nitrogen and total organic carbon (TOC). Additional sets of testtubes containing sediment amended with 1-, 5-, and 10-percent organic matterwere used for this study. Sample times also varied; samples were taken ondays 0, 1, 2, 6, 11, 16, 23, and 36.

Chapter 2 Mai-.I"s and Method 5

Column Studies

Twenty-liter Plexiglas columns were used to determine SOD and the releaseof nutrients from bedded sediments to the overlying water. All measures wererun in triplicate. Columns were loaded with approximately 15 cm of sediment(3.600 g wet wt.) and overlaid with 102-cm distilled water (15.7 1). The col-umns were incubated at 250C in a walk-in environmental chamber. Dissolvedoxygen, ammonium-nitrogen, orthophosphate-phosphomus, nitrate-nitrogen, totalorganic carbon, and total inorganic carbon were measured according to thefollowing schedule. Four samples (60 ml each) were taken the first week, ondays 0, 1, 5, and 8. All other samples were collected at 7-day intervals start-ing on day 8. Duration of experiments varied. In some instances, in order todistinguish aerobic from anaerobic sediment-water exchanges. columns werereaerated during the experiments. Duration of experiments and occurrence ofreaeration intervals are summarized in Table 3. Analytical methods wereidentical to those in the test tube studies.

Table 3

Duration of Column Studies

Sediment Source Duration, Days Aerated Dt 7

Brown's Lake 67 107

Chesapeake Bay 178 49. 132

Chicago River 118 93

Eau Gals Reservoir 118 93

Rathbun Lake 132 42. 99

Two methods were employed to seal the sediment-water systems from theatmosphere. For the Brown's Lake sediments, a 2-cm layer of mineral oil wasapplied to the water surface to seal the system from atmospheric contact(Figure 1). A plunger was lowered into the water column of each unit and leftin place. The plungers were used to thoroughly mix the water columns daily.For the remaining experiments, sealing from atmospheric contact was accom-plished using Plexiglas lids (Figure 2). These lids provided an improved sealfrom the atmosphere. The sealed Plexiglas column covers required a fixedvolume of water overlying the sediments. Therefore, water removed duringsampling was replaced with nitrogen-sparged distilled water. The overlyingwater was continuously mixed by means of micro-circulating pumps at a speedof 210 ml/min.

In order to isolate sediment-water exchanges from processes occurring inthe water column alone, water samples were collected at each sample intervalnd incubated in 60-ml biochemical oxygen demand (BOD) bottles. Sampleswere incubated for 7-day periods before analysis was conducted for DO, nutri-ents, and carbon.

6 Ch&Ptr 2 Mahwials and Methods

Plunger

]-Mineral Oil Layer

Water Column

Sampling Port

Sediment Layer

Figure 1. Plexiglas coklmn used to determine SOD and nutrient release from Brown's Lakesediment

Ch•,-r2 M.:jkand Msho, 7

Motor Controller 00 -Pump

Water Column

Z' Sampling Port

Sediment Layer

Figure 2. Revised Plexiglas column including sealing lid and pump

8 Chapter 2 Maerials and Method

Reaeration rate studies were conducted to determine if the columnsexchanged DO with the atmosphere. These studies were conducted on col-umns containing 20 1 of distilled water only. The water was sparged withnitrogen to force DO below saturation concentration. Dissolved oxygen wasmonitored over time. An increase in DO indicated exchange with theatmosphere.

Chaptr 2 Matrials and Methods

3 Computation of Sediment-Water Fluxes

Test-Tube Measures

Sediment-water exchanges can be measured in numerous fashions. Onemethod, adopted here, is to enclose a fixed volume of sediment and overlyingwater. Sediment-water exchanges are inferred from concentration changes inthe water column. A concentration increase means material moved from sedi-ments to water. A concentration decrease means material moved froL . fer tosediments. An equation based on this principle was employed to quantitysediment-water fluxes in the test-tube studies:

Fsw = V (Cf - Ci)At (1)A

Fsw = sediment-water flux (M L2 Tr)

V = volume of overlying water (13)

A = area of sediment-water interface (L2 )

Cf= concentration in water at end of incubation (M L 3)

Ci= concentration in water at beginning of incubation (M L-3)

At = length of incubation (M)

Nutrient and Carbon Fluxes In Columns

Flux computation via Equation I can be confounded by substancetransformations in the water column. For example, nitrification of ammoniumto nitrate would influence the computaion of sediment-water fluxes of both

10 Chapler 3 Computabon of Sedmnt-Wazr F'

these nitrogen fractions. In order to correctly compute sediment-waterexchange, a "blank" or "control" incubation of water alone must be conducted.Transformations in the water alone are subtracted from transformations in thesediment-water column to isolate sediment-water exchanges. The previouslydescribed BOD bottle incubations served as "controls" in these experiments.

The computation of sediment-water fluxes is based on a mass-balance equa-tion that describes the water column:

ACT = Fsw At + TwAt (2)H

ACT = concentration change in water column (M L" T-)

H= depth of water column (L)

Tw= transformation in water column (M L"3 T71 )

Equation 2 states that total concentration change in the water is the sum ofsediment-water fluxes and water column transformations. Flux from sedimentto water is defined as positive. Concentration change and water-column trans-formations can be expressed in terms of quantities measured in the experi-ments:

Cf - c . + (BODf - BODi)At (3)

BODf = concentration in BOD bottle at end of incubation (g -3)

BODi = concentration in BOD bottle at beginning of incubation (g _3)

In the experiments, initial concentration in the water and BOD bottle wereequal. Substituting this equivalence into Equation 3 and solving for fluxyields:

F - H (Cf - BODf) (4)At

Choplsr 3 Con'putabon of Sedment-Walsr Fluxes 1

Sediment Oxygen Demand In Columns

During the incubations, no exchange of nutrients or carbon with the exter-nal environment takes place. Some exchange of DO oxygen with the atmo-sphere is inevitable, however, during lengthy incubations. These exchangesoccur when samples are collected or else through leakage. Small exchanges ofoxygen are no problem but must be accounted for in the computation of sedi-ment oxygen demand.

Several experiments were conducted to examineTable 4 and quantify atmospheric oxygen exchange. For theReaCratlon In Oil-Seated oil-sealed columns, no definitive increase in oxygenColumns occurred when samples were collected (Table 4).

tDhoovd o /96% Dissolved oxygen did increase over a 14-day incu-Day M,,, bation, however, indicating diffusion through the oilfilm or leakage in the apparatus. The oxygeno 2.22 exchange was treated as a reaeration process. The1 3.03 reaeration rate was determined by fitting the data to2 3.23 the equation:

3 3.23 K (5)6 3.23 D(t) = Doe -

7 3.23 D(t) = DO deficit at time t (g m 3)9 3.51

14 4.31 Do = initial DO deficit (g in")

K = reaeration rate (m day' )

The reaeration rate for the oil-sealed columns was 0.021 m day-'(R2 = 0.82). The mass-balance equation (Equation 2) was modified to reflectreaeration:

Cf-Ci=FAt KC-C H =- + (BODf - BODi)At + (Csat - Cm) (6)

Cut = saturation DO concentration (g M-3)

Cm = mean DO during incubation interval (g m-3)

Noting the equivalence of initial concentrations in the water column andBOD bottles and solving for flux yields:

12 Chapts 3 Computaton of Ssdmmnt-Wawr Fluxes

SOD . H4 (Cf - BODf) - K (Ct - Cm) (7)

By convention in this report, negative sediment oxygen demand is transferof oxygen from water to sediments.

Following the initial set of sediment-water flux measurements, the oil-sealon top of the columns was replaced with a fixed seaL An experiment indi-cated no atmospheric oxygen seeped into the redesigned columns (Table 5).

ReseraUon In Completely Sealed Columns

D1 whe

Oxygen

Di

e Oxygen

Day

No Ss

ple• Repboune

n1,m Wt,,

Sam *

*]:•

m at

,

0

4.00

3.99

1 4.00 4.13

3 3.98 4.347 3.99

4.49

Some oxygen (- 0.15 g m73) was introduced by sample replacement, however.The mass-balance equation was modified to account for the dissolved oxygenintroduced by sample replacement:

C f - C i - A. + (BOD f - BO Di)A t + ACs (8)H

ACs = dissolved oxygen introduced by sample replacement (g in")

Noting the equivalence of initial concentrations in the water column and BODbottles and solving for flux yields:

SOD =• H(Cf - BODf -ACS) (9)At

chepm 3 Co,,pumM on of sidment-W aw Rum 13

4 Results

Test Tube Study I

Results for these measures ame presented in Figure 3 and Table 6. Dis-solved oxygen concentrations dropped fromn 9.0 to 0.20 nmg/1 in 36 days.Initially, DO declined rapidly and reached a steady state within the first week.The SOD flux raged from -300 to -3.0 mg~ni2/day. Positive numbers repre-sent DO release from the sediment.

Ammonium-nitrogen levels measured in the overlying water increased overtime reaching a peak of 0.048 mg/I at 30 days and leveling off to 0.042mg/I. Orthophosphate-phosphorus concentrations also increased, measuring0. 165 mng/1 in 36 days. A sharp increase in concentration occurred betweensample days 31 and 36.

Test Tube Study 11

Data for this study are presented in Table 7. Dissolved oxygen concen-trations decreased from 8.80 mng/i to 0.29 mg/I during the 36-day test interval(Figure 4). DO depletion levels of the three organic matter treatments did notdiffer significantly at any time. Sediment oxygen demand ranged from-525 mg/m2lday at time 0 to -2.0 ng/mn2/day on day 36 (Figure 4). Overlying

watr ntrint oncntrtions are presented in Figure 5. Ammonium-nitrogenconcentrations increased in all three amendments over time. Initial concentra-tions in the water measured 0.002 mg/1 with final concentrations averaging0.068 mng/I on day 36. Ammonium concentration data revealed no significantdifference between the three treatments. Orthophosphate-phosphonisconcentrations increased to 0.140 mng/I on sample day 6 and decreased to anaverage of 0.066 mg/I by day 36. The different amendments showed no sig-nificant effect on phosphorus concentrations. Concentrations of nitrate-nitrogen initially increased to an average of 0. 118 mng/I on sample day 6 anddecreased to an average of 0.066 mg/I by day 36. The three sample treat-ments showed no significant difference. Total organic carbon concentrationsincreased fnxom0mg/ to an average of 32.8 mg/1 by day 6. Following this,TOC levels began decreasing to an average final cnettinof 12.8 mg/I.

14 C#apiw 4 Rmuft

TEST TUBE STUDY I

10 100

0

cý 6 NoP 04 -100

04 V -200

0 2 - 0V, -300

o 0 4 . ......... .. ... -0

I I I I i -400 I I I

0 10 20 30 40 0 10 20 30 40

Time, days Time. days

0.2 , 0.06

*0.05E

1." E 0.04

0.1 z 0.03E. 0.02

o E00

*- •

0 0.0 s 0.00SI I .I I I I

0 10 20 30 40 0 10 20 30 40

Time, days Time, days

Figure 3. Dissolved oxygen and nutrient concentrations measured in the overlying water ofBrown's Lake sediment

with the 10-percent organic matter-amended tubes maintaining the highestTOC of 14.5 mg/I on sample day 36.

Brown's Lake Column Study

Dissolved oxygen, nutrient, and carbon concentrations and fluxes are pre-sented in Figures 6 and 7. Sediment-water fluxes are summarized in Table 8.Results are presented separately for DO greater than 2 g mi3 and less

15ChIr4 Result

Table 6

Dissolved Oxygen and Nutrient Concentrations1 Measured In the OverlyingWater of Test Tube Study I

Sample DO Ammo~ni AmmoumDeft DO Flu mNr eNitrogen Fhx Pphon so Flux

0 9.12 0.001 0.003

1 6.85 -328.52 0.0003 -0.096 0.004 0.096

3 2.22 -334.54 0.026 1.85 0.021 1.27

7 0.37 - 66.84 0.031 0.169 0.036 0.53

11 0.46 3.25 0.023 -0.289 0.012 -0.867

31 0.21 -1.78 0.048 0.185 0.046 0.246

36 0.2 -0.29 0.042 -0.193 0.036 -0.289

so 0.63 4.44 0.026 -0.158 0.165 1.33

1 All concentrations are in mg/i

than 2 g m 3. The separation allows for the influence that DO exerts onsediment-water fluxes. Concentrations and fluxes are listed completely inAppendix A. Dissolved oxygen concentrations decreased from initial levels of9.15 mg/U to 0.60 mg/a in 50 days. An initial rapid decrease in DO occurredup to day 7T this was followed by a slower decline over the duration of thestudy. Ammonium-nitrogen concentrations increased from 0.002 at time 0 to0.024 mg/1 by day 7, then fell back to <0.01 mg/l. Orthophosphate-phosphorus increased to 0.45 mg/U on day 19 and began to decline, reaching0.029 mg/1 by day 50. Nitrate-nitrogen rose to 0.228 mg/1 on day 12, thendecreased to 0.007 mg/1, and remained relatively stable for the remainder ofthe study period. Total organic carbon measurements fluctuated, reaching apeak of 11.7 mg/U by day 19 decreasing to 1.77 mg/0 by sample day 50. Totalorganic carbon levels fluctuated around a level of 8 mg/U for the first 35 daysof incubation, then fell off after time.

Rathbun Lake Column Study

Dissolved oxygen, nutrient, and carbon concentrations and fluxes are pre-sented in Figures 8 and 9. Sediment-water fluxes are summarized in Table 9.Results are presented separately for DO greater than 2 g m-3 and less than2 g mi 3. Concentrations and fluxes are listed completely in Appendix A.During three successive aerobic/anaerobic cycles, DO concentrations consis-tently exhibited initial rapid declines in the first 7 days after aeration. All DOlevels fell to an average of 0.50 mg/U at the end of each cycle. Ammonium-nitrogen levels increased over the course of each cycle and peaked

16 Chaptr 4 Results

0IZS~~ CV a O' 00

3C,! 8*"5-c0 ~ ~ ~ . 0) CS 6) 4d 4d 6 0S 4 C

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0

CC

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10

LEGENDS-* 1% OM

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C

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to

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0

0 9 9.

III I I

0 10 20 30 40 50

100

0 ,

-100

o

S-200E

E -300 Vd0U, -400

-500

-600 I I I I0 10 20 30 40 50

Time, days

Figure 4. Dissolved oxygen concentrations and SOD calculated for Brow•'s Lake sedkmet

Chapfw 4 Rest, 19

0

-0:

1/6W 'd-elieqdsotqdoLfpQ 1/Bw '001.

f 0

E 8

d d d

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20 Chopqer 4 Resuls

10 0.5

� -810.0E E

~ 6 ~-0.5E

X -1.0

.V 4 E

> c; -1.50 0

S2 - 2.0

0 -2.5

0 10 20 30 40 50 60 0 20 40 60 80

Time. days Time, days

0.03 0.6

S0.5 -

S0.3

.2 0.01 Q 0.20.00

< 00 0.0

I I II I I I I0.0 0.0 203 0 0

0 10 20 30 40 50 60 10 20 30 40 50 60


0.4

14

0.34 12

E -10

z0.2 5E 8

C. C 600.1 0z J 4

0.0 2I I I I I I 0 ii

0 10 20 30 40 50 60 0 20 40 60 80Time, days Time. days

Figure 6. Dissolved Oxygen measured and SOD flux calculated in Brown's Lake anaerobic

column study

ChpVW 4 Peaft 21

30 - I 100

280* 20

C14

E 60S10 0

ES40Ex S0

a.. 20-* -

-0 0

-20 I I -20 I I I

0 20 40 60 80 100 120 0 20 40 60 80 100 120


50,6 I

40

- 30 022

2 20 2 o

10 - E 0

z 0°3 -2

S-10 o-4

z -20

-30 * -6 I I i

0 20 40 60 80 100 120 0 20 40 60 80 100 120

Time. days Time. days

Figure 7. Nutrient fluxes calculated in Brown's Lake anaerobic column

approximately 30 days after reaeration. Concentrations reached peaks of0.040, 0.066, and 0.047 mg/I in each cycle, respectively. Orthophosphate-phosphorus concentrations increased in each cycle and reached steady stateafter approximately 30 days into each run. Peak concentrations were 0.040,0.066, and 0.041 mg/I in cycles I through M.1, respectively. Concentrations ofnitrate-nitrogen initially increased after loading and reaeration, followed byrapid declines in the first and second cycles. No data were obtained for nitrateduring the third cycle. Total organic carbon levels exhibited an initial rapid

22 Cha 4 Ruf

Table 8Brown's Lake Sediment-Water Fluxes1

Number of Flux Itandard ErroSubonwe DO wW# Meauree mg/m~lday _M_2_c _

Sediment > 2 4 -1120 299OxygenDemand <2 11 -329 205

Ammonium > 2 4 -7.57 1.00

< 2 11 7.34 3.49

Nitrate >2 4 8.71 1.10

< 2 11 4.77 4.61

Phosphate > 2 4 -4.39 3.43

< 2 11 21.3 11.3

Total Organic > 2 4 -1284 1275Carbon

< 2 9 725 707

Total Inorganic > 2 2 1405 1208Carbon

c2 0

I Positive fluxes am from sediment to water.

increase followed by a sharp decrease in the first cycle after loading. Concen-trations averaged 9.06 mg/U at day 1 and fell to 0.998 mg/U by day 40. Totalorganic carbon levels remained low for the remainder of the study. Totalinorganic carbon level followed the same trends as the TOC except for a rapidhigh peak in the first few days of cycle H.

Chesapeake Bay Column Study

Dissolved oxygen, nutrient, and carbon concentrations and fluxes are pre-sented in Figures 10 and 11. Sediment-water fluxes are summarized inTable 10. Results are presented separately for DO greater than 2 g m3 andless than 2 g m-3 . Concentrations and fluxes are listed completely inAppendix A. Dissolved oxygen levels followed the same trends as in theprevious tube and column studies. Concentrations decreased from 7.84 mg/Uto an average of 0.01 mg/U over a 42-day period. Ammonium-nitrogen levelsinitially increased followed by a decline to steady state in approximately30 days as in the previous column studies. Ammonium levels reached a peakof 0.055 mg/. Orthophosphate-phosphonis levels exhibited the same trend,reaching a peak 0.053 mg/U at day 14. Concentrations of nitrate-nitrogenrapidly increased and began to sharply decline within 2 weeks after initiationof testing. Total organic and inorganic carbon concentrations exhibited

Chapter 4 Results 23

10 -- 0.07-

8 YL ~Iz CYCLE D CYCLE al 0-06 -~z CYCL Iyui

E 0.05e

E(U 6 zý 0.04X0 tE 0.03

> 0 0.02

. 2 0.01 -

0.00

0 20 40 60 80 100 120 140 0 20 40 60 80 100120140


0.07 , , ,0.08 , , , , ,

"7,' 0.06 CYCLEI CYC ' CYCLE UI 0.07 CYCLE I CYCLE 0

£ 0.05 0.06

a-

0. 0.0 4 , E 0.05 "o 0.04 oc0.0.03~0c 0. /J00.32

oz 0.02

~0. 0.01

0.00 ' 0.000 20 40 60 80 100120140 0 20 40 60 80 100 120 140


10 , , i15 I i '

CYCLE I CYCLE 1I CYCLE R1 CYCLE I CYCLE UI CYCLE ID

6 o10

E EG 4

0 o •_ 5

2

0 0i * t, i .1' I

I I I' I I I I

0 20 40 60 80 100120140 0 20 40 60 80 100120140


Figure 8. Dissolved oxygen and nutrient concentrations measured in the overtying water ofthe Rathbun Lake aerobic/anaerobic column study

24 chpe 4 Resuis

0.2 6

0.0 0-4

0 -0.2 CN

E EN-0.6

E 0E_0.5

o0 -1.0

-1.2CYCLE I CYCLE 1 CYCLE II Z CYCLE U CYCLE

--1.4 i , i-4 7CL, , , !i

0 20 40 60 80 100120140 0 20 40 60 80 100120140


o CYCLE I CYCLE U"2 "a 8

E E-0 x 4-

x

Z 2o -

02a.-2 0 "

CYC... LE.......L......A I IY I I :C CL i2nI


l~j I

CYCLE I CYCLE 1 CYCyLE II CYCLE I CYCLE U1 CYCLE 13I0 2 2

NE 6 E 1

E 4 E

-x . 4,_.

C-) 01

o cI- cczx vu

0 20 40 60 80 100 120 140 0 20 40 60 80 100 120 40

Time, daoys Time, days

10ur9 Seimn oxyge deman and nuten flxe caclae In Rt Lake

2 -

a ca6com t

-2 h ' IRIu:1 20 20 40 60 80 100 120140 0 20 40 60 80 100 120 14C


Figure 9. ,edirmnt oxygen demand and nutrient fluxes calculated In Rathbun Lakeaerobic/anaerobic column study

chaptr 4 Results 25

Table 9Rathbun Lake Sediment-Water Flux. 1

oNumbr . Flux d ErSubela, DOL. 1-'-es "M (MWM2/4dy) (_____2__y)

Sediment 2 8 -4M0 145OxygenDemand 2 11 -46 28

Ammonium > 2 8 1.2 0.62

< 2 11 - 1.0 0.49

Nitrate > 2 8 4.36 0.86

< 2 11 1.36 0.36

Phosphate > 2 8 1.26 0.39

< 2 11 - 0.42 0.35

Total Organic > 2 8 1060 1070Carbon

<2 11 -69 69

Total Inorganic >2 8 564 309Carbon

2 11 -227 145

t Positive fluxes are from sediment to water.

identical trends with initial rapid increases followed by slower decreases inconcentration.

Eau Galle Reservoir Column Study

Dissolved oxygen, nutrient, and carbon concentrations and fluxes are pre-sented in Figures 12 and 13. Sediment-water fluxes are summarized inTable 11. Results are presented separately for DO greater than 2 g m3 andless than 2 g m-3 . Concentrations and fluxes are listed completely inAppendix A. Dissolved oxygen concentrations decreased from 8.00to 0.03 mg/I over an 86-day period. Ammonium-nitrogen levels exhibitedsimilar trends to the previous sediments. Concentrations reached a steady stateof 0.050 mg/I in 2 months, then declined after day 80. Phosphate concentra-tions also remained at high levels for 60 days and then began to decline. Totalorganic carbon levels initially increased and then dropped, fluctuating around0.050 mg/I after 30 days. Total inorganic carbon concentrations rapidlyincreased after day 0, and then began a slow decline to 2A5 mg/I by the endof the study.

26 chapter 4 Results

10 0.06

8 8. 0.05

E 0.046

0.03X 20 4 4V 0.02

S2 EE 0.01

5 0 0.00

0 10 20 30 40 50 0 10 20 30 40 50


0.06 0.08 1 F

S0.052 _ 0.06

0.04E

- 0.03 - 0.04

200.0S0.0 0.02"-'0.01z,

0.00 10 2 0.00 II II I I I I I

0 10 20 30 40 50 0 10 20 30 40 50


8 16

7 14

6 12

0)- <' 105. MSE 8

40

42 2

1 I 10 I I0 10 20 30 40 50 0 10 20 30 40 50


Figure 10. Dissolved oxygen and nutrient concentrations obtained In the overlying water of the

Chesapeake Bay column study

ChapW 4 Rac,,fts 27

0.2 3 f I

'1- 0. 1 4EE 1 -E

EE 0c 0.0 z" I-

-0.1 I -2

5 10 15 20 25 30 35 40 45 5 10 15 20 25 30 35 40 45Time, days Time, days

3 52 0 4V 2 - "

04, CNJ 3E EN. 1 - • • 2E E

0 X

a-2o -4)-100

""--20 z-3 -3 I I I I I

5 10 15 20 25 30 35 40 45 5 10 15 20 25 30 35 40 45

Time. days Time, days0.4 0.8

>, 0.3 0.6V 0.2 0- "0 0.4E 0.1 0

N.1 0.2E 0.0

00. --0.3 -0.4

-0.4 -0.6

5 10 15 20 25 30 35 40 45 5 10 15 20 25 30 35 40 45


Figure 11. Sediment oxygen demand and nutrient fluxes calculated for the Chesapeake Bay

column std28

chmpW4 Rowift

Table 10Chesapeake Bay Sediment-Water Fluxes1

Number of Fax Stwd ErorSubstance DO mg/I Mmure g/m12 dWj mgWlM 2 day

Sediment > 2 4 275 182OxygenDemand < 2 14 -9 16

Ammonium > 2 4 -0.34 1.18

< 2 14 0.16 0.31

Nitate > 2 0

< 2 5 0.32 1.12

Phosphate > 2 4 -0.55 0.94

< 2 14 -0.09 0.30

Total Organic > 2 4 30 35Carbon

< 2 11 -32 49


<2 11 77 96

Positie fluxes are from sediment to water.

Chicago River Column Study

Dissolved oxygen, nutrient, and carbon concentrations and fluxes arepresented in Figures 14 and 15. Sediment-water fluxes are summarized inTable 12. Results are presented separately for DO greater than 2 g m-3 andless than 2 g m-3 . Concentrations and fluxes are listed completely inAppendix A. Chicago DO and nutrient concentrations exhibited very similarbehavior to those of the Eau Galle study. Dissolved oxygen levels decreasedto an average of 0.04 mg/I in 86 days. Anmnonium-nitrogen concentrationsreached a steady state of 0.057 mg/I in 40 days, then declined after 80 days.Orthophosphate increased over 80 days and then declined. Total organic car-bon concentrations initially increased and declined to an average of 0.060 mg/Iin approximately 30 days. Total inorganic carbon levels increased to6.37 mg/U and then slowly declined to 3.2 at the end of the study.

Chapter 4 Retilts 29

10

S8Ec6

o 4"4)

0 2

0I I I I

0 20 40 60 80 100

Time. days

0.06 , 0.06

0.05 - 0.05N Ec"E 0.04 - 0.04

0.03 - 0.03

"*E 0.02 0.020E 0010.01 0 0.01

0 0.0000.0I I I 00.0 I I I I

0 20 40 60 80 100 0 20 40 60 80 100

Time. days Time, days7

1.8 6

1.5 5

"O 1.2E

60.9 L;33I-""_

0.6 2

0.3 1

p I I I 0 I I I I

0 20 40 60 80 100 0 20 40 60 80 100


Figure 12. Dissolved oxygen and nutrient concentrations measured in the overlying water ofthe Eau Gale Reservoir column study

30 Cholamr 4Reft

0.3 I

o 0.2C4

EN 0.1E6(0 0.0

- 0 .1 1 k I 1 ,10 20 30 40 50 60 70 80 90

Time. days

1.0 1.5 , , ,

> 0.5 o 1.0 -o *"*0N

S0.0 0.5E E

-0.5 0.0

-1.0 -0.5

z -1.5 t -1.0

-2.0 I I I I I - 1.5 I I I I I10 20 30 40 50 60 70 80 90 10 20 30 40 50 60 70 80 90

Time. days Time. days0.06 ' 0.10

"0.04,0.08N N 0.06

(N ('N

N 0.02 EN 0.04

E E0.00 0.02

, 00 0.00-0.02 - 0 •" -002-0.04 I -0.04

10 20 30 40 50 60 70 80 90 10 20 30 40 50 60 70 80 90


Figure 13. Sediment oxygen demand and nutrient fluxes calculated for the Eau Galle

Reservoir column study

Chqps 4 Pa-tji, 31

Table 11Eau Galle Reservoir Sediment-Water Fluxes1

Numb. of Fofx "Mm lwd EnwSIubIIe1 DO mWI eao e usgidw Mlm 2 /dW

Sedimnt >2 2 16 53OxygenDemand < 2 8 32 19

Ammonium > 2 2 -0.74 0.16

< 2 a -0.53 0.24

Nirae > 2 0

-c 2 0

Phosphat > 2 2 -0.87 0.20

<_ 2 8 -0.14 0.23

Toa Organic > 2 2 52 2Carbon

-c 2 6 6 7


I < 6 53 181 Positve fluxes are rom sediment to water.

32 Chapter 4 Resits

101 f

Ee 6

4 40 2

4)

.U)

0

0 20 40 60 80 100

Time, days

0.06 ' i 0.07

'- 005 S0.060.0

E 004E 0.05

E 0. 04 42F 0.03

E 0.03 0.03ro 0.02 0 .0E C

0.01 2 I ' 0.020

<- 0.01

0. 00 r0.000 20 40 60 80 100 0 20 40 60 80 100

Time, days Time. daysI '7

1.8

1.5 5

E 1.2 -a 4E E

6T

0.6

10.3 0

0 20 40 60 80 100 0 20 40 60 80 100


Figure 14. Dissolved oxygen and nutrient concentrations measured in the overlying water ofthe Chicago River column study

Chapls4 Re-Its 33

0.05

0.060

04 0.04E

E 0.02C;0A 0.00-

-0.02

10 20 30 40 50 60 70 80 90

Time, days

0.5 - 0.5 ,

o0 >, 0.0N 0.0 i

E c -0.511 Q EE CD)z E -1.0

.2 -1.0 a:LA-. I -1.5z 0

/-1.5 ":c o -2.0

z

-2.0 -2.5I I I I10 20 30 40 50 60 70 80 90 10 20 30 40 50 60 70 80 90


0.06 0.7

" 0.04 0.6

0.0 2a 0.50.02 0.4E E 0.4

= x" 0.2- 0.02 0.3

0 "0 0.1-0.04 1 - 0.0

-0.06 -0.110 20 30 40 50 60 70 80 90 10 20 30 40 50 60 70 80 90


Figure 15. Sediment oxygen demand and nutrient fluxes calculated for the Chicago River

column study

34 Chaptr 4 RPsuft

Table 12

Chicago River Sediment-Water Fluxes1

Number of Flux steldid ErMro

tSubstanc DO mg/e MeMm mgm21day mg/m 2lday

Sediment > 2 0OxygenDemand <2 a 17 10

Ammonium > 2 0

< 2 8 - 0.79 0.26

Nitrate 22 0

< 2 0

Phosphate _> 2 0

< 2 8 -0.84 0.31

Total )rganlc > 2 0Carton <2 7 012

Total .notjwji > ? 0

<2 8 91 72

Positive fluxes are from sediment to water.

Chapter 4 Results 35

5 Discussion

Test Tube Study I

Dissolved oxygen concentrations in this study showed a decrease in the rateof DO depletion once oxygen levels fell below 2 mg/t Similar findings werereported by Wang (1981), who observed sharp initial decreases of residualoxygen, followed by a tendency to taper off after levels fell below 2 mg/t

Ammonium will diffuse to the surface of a sediment and if oxygen ispresent, will be nitrified to nitrate. Ammonium-nitrogen levels in the testincreased over time and leveled off after day 15. If a system is anaerobic,nitrification does not occur and ammonium accumulates in the water column(Klapwijk and Snodgrass 1986). Ammonium releases to the water columnmay have leveled off due to limitations in the organic nitrogen levels in thesediment In anaerobic systems, microbial activity may result in directmobilization of inorganic phosphorus through the degradation of organicmatter or through dissolution of phosphate-adsorbing iron oxyhydroxides(Ryding 1985). The sharp increase in orthophosphate concentrations by day36 of the sample interval may have resulted from these processes. At thistime. DO levels in the water column were essentially 0.

Test Tube Study II

No significant differences were observed in DO depletion or nutrient releaseamong the three organic matter treatment levels. These results suggest that therate of oxygen supply to the sediment limited the utilization of these sub-strates. Dissolved oxygen depletion rates exhibited the same behavior as inStudy I. The SOD rate mirrored the dissolved oxygen depletion rate. Dis-solved oxygen concentrations in water overlying sediments can be considered afactor affecting SOD rates; as the DO concentration decreases, so does theSOD rate (Hicks 1990).

Ammonium-nitrogen levels increased in all amendments, but did not leveloff as in Study 1. This may be a result of the addition of a source of organic

36 ChiW 5 Discussion

matter which allowed for a prolonged period of mineralization of organic-nitrogen to ammonium. Differences among treatments were not significant.

Phosphorus release can be promoted in anaerobic bottom waters due to themicrobially mediated reduction of Fe3+ to Fe2+, and dissolution of thephosphate-adsorbing ferric oxyhydroxide (Ryding 1985). Orthophosphate-phosphorus concentrations initially increased and then decreased in all threeamendments. The decline in phosphorus concentrations may be a result ofphosphate interacting with Al3+ or Ca2+ to form insoluble precipitates. Alter-natively, phosphate may be sorbed to colloidal oxides, hydroxides, and carbon-ates (Ryding 1985).

Nitrate-nitrogen concentrations increased as initial releases of ammoniumwere nitrified. Nitrate levels decreased markedly when DO concentrationsreached approximately 1 mg/a. Nitrate did not completely disappear from thesystem, indicating the presence of some oxygen in the overlying water. Nitratewill move downward by diffusion and undergo denitrification in the sediment(Ponnampernma 1972). However, very little denitrification takes place until alloxygen has been depleted (Gunnison, Engler, and Patrick 1985).

Total organic carbon levels in the overlying water began to decrease whenDO levels fell below I mg/R. Gunnison, Chen, and Brannon (1983) reportedthat a decrease in concentration of soluble TOC in the water column wasstrongly correlated with a decrease in DO depletion rate. Dissolved oxygendepletion rates decreased by day II of sampling, corresponding to a decreasein TOC in the same period.

Column Studies

Much of the activity observed in the sediment-water columns took place inthe water. Often, transformations in the BOD bottles equaled or exceededactivity in the columns. Mean sediment-water fluxes, corrected for activity inthe water alone, were small relative to fluxes reported for sediments similar tothose in the WES studies. Many of the mean fluxes that were measuredcannot be differed significantly from zero. Several hypotheses can beadvanced to explain the inert nature of the sediments. No single hypothesisexplains all the experiments. Several are likely to have influenced the WESresults. Sediments may be inert for the following reasons:

a. System characteristics. Substantial SOD and nutrient release occur onlyfrom sediments that receive substantial loads of organic particles. Oneor more of the WES sediments may have come from a system whichreceived minimal organic loading.

b. Sample collection time. Deposition to sediments varies throughout theyear. For example, deposition is usually large following an algal bloomin surface waters. One or more of the WES sediment samples mayhave been collected at a time in which deposition was minimal.

Chaptar 5 Discussion 37

c. Sample holding time. The WES samples were held in a cold room for1 to 7 months following collection. Although the cold storage shouldhave restricted activity in the sediments, the holding time may still havebeen too long.

d. Sample collection method. Sediment activity decreases as a function ofdepth below the sediment-water interface. Deeper sediments are olderand contain little or no remaining reactive organic matter. The dredgewas intended to sample only active, surficial sediments, but a largefraction of deeper, inert sediments may have been collected as well.

38 Cbapwr 5 Discussion

6 Conclusions and Plans forFuture Activities

The WES team has developed apparatus and protocol suitable for laboratoryinvestigations of sediment-water exchange processes. The apparatus may alsobe suitable for laboratory measurement of actual environmental sediment-wateroxygen and nutrient fluxes.

One purpose of these experiments was creation of a database for testingpredictive SOD and nutrient flux model. Observations collected in the experi-ments are presently being examined within the model framework. Initialmodel simulations of the WES experiments have been conducted. This workwill be the subject of an upcoming report

In June, a field trip is planned for observation of in situ sediment fluxmeasurement in QCesapeake Bay. One purpose of this trip is to evaluate thesuitability of the device for use by the Corps. Sediments will be collected atthe same time the in situ measures are conducted. These sediments will bereturned to WES and immediately set up in the WES measurement device.These measures will be compared with the in situ measures collected in theBay. The comparison will provide the first indication whether the WES deviceis suitable for measuring fluxes in the environment. The comparison will alsoprovide insight into the effects of sample collection and holding time on theWES measurements.

As part of the modeling activity, prediction of sediment iron and manganeserelease is being added to the sediment model. The initial formulation of themodel is complete. Comparison to existing Corps observations of iron andmanganese release is next. Collection of additional observations to validatethe model may be necessary. In that case, WES investigators will add ironand manganese to the suite of variables observed in the laboratoryexperiments.

Chaptqr 6 Condusions wnd Pitns kow Future AciviMls 39

References

Cerco, C., Gunnison, D., and Price, C. B. (1991). "'Proceedings, US ArmyCorps of Engineers workshop on sediment oxygen demand, Providence,Rhode Island, 21-22 August 1990," Miscellaneous Paper W-91-1,U.S. Army Engineer Waterways Experiment Station, Vicksburg, MS.

Giga, J. V., and Uchrin, C. G. (1990). "Laboratory and in situ sedimentoxygen demand determinations for a passaic river (NJ) case study," Journalof Environmental Science and Health A25, 833-845.

Gunnison, D., Chen, R. L., and Brannon, J. M. (1983). "Relationships ofmaterials in flooded soils and sediments to the water quality ofreservoirs - I. Oxygen consumption rates," Water Research 17, 1609-1617.

Gunnison, D., Engler, R. M., and Patrick, W. H., Jr. (1985). "Chemistry andmicrobiology of newly flooded soils: relationship to reservoir-waterquality." Microbial processes in reservoirs. D. Gunnison, ed., Dr. W.Junk, Boston, 39-57.

Hargrave, B. T. (1972). "Oxidation-reduction potentials, oxygen concentration,and oxygen uptake of profundal sediments in a eutrophic lake," Oikos 23,167-177.

Hicks, D. B. (1990). "Environmental Protection Agency Region IV perspec-tive on SOD." Proceedings: US Army Corps of Engineers workshop onsediment oxygen demand, Providence, 110-119.

Klapwijk, A., and Snodgrass, W. J. (1986). "Concepts for calculating thestabilization rate of sediments." Sediment oxygen demand processes,modeling, and measurement. K. J. Hatcher, ed., Institute of NaturalResources, University of Georgia, Athens, 75-97.

Ponnampenima, F. N. (1972). '"he chemistry of submerged soils," Advancesin Agronomy 24, 29-96.

40

Price, C. B. (1991). "Sediment oxygen demand and its effects on waterquality," Water operations technical support, Vol E-91-2, 5-7. U.S. ArmyEngineer Waterways Experiment Station, Vicksburg, MS.

Ryding. S. (1985). "Chemical and microbiological processes as regulators ofthe exchange of substances between sediments and water in eutrophiclakes," Int. Revue-ges. Hydrobiol. 70(5), 675-702.

Wang, W. (1981). "Kinetics of sediment oxygen demand," Water Research15, 475-482.

41

Appendix AData for Column Studies

Appwdx A Dm for Col•mn Sft.. Al

d .d d. 0 09909 ddd

4 E0*

~I

0 l 0 0 0 0 0 0 0 0 0 0 0 0 0

- - - - - - - - - - - - -- - - - - - - - - - - - -

§1~~I 1 I!

CDN-

A2 ~ ~~~~~~~Ap eciA DaafrClm h n

--- -i ;;9- -

4 ~ ;z.1

2w9 9 o 9~

.3

.c

0

A I ig ý v $I3.a1 JAp""9 A 9a o ,nnfmA

-~ ~ g --- -

0

___ !~~91

104

0 a 1 I

IQ 10vi ICtIl~ d

allA R e N8

A4 Appmnidx A Daf fo Coumn Skmas

11

d 0 0 tllC 9 0 9

N 0

ILI---A aafr oxn unA

00, t! r4

Ti a

Ia 0 0 0 0 d a a d

ASApwd A Dftfo ClmnSlcls

000 0 000

e0

009 0 90

c- . 0 d - a 0 0 0 a 0 i 0 d 0 0

0 9

7 C? IC? C? 2tM1jE

E-0

.0 co c

10--

sic 0

Appn- 0 0 0 0 0 9 8aafrClmnSunA

dm~ u '0 0,0* 0 ' 0* 0

E904 0990d

El

c~~~aC 9 -9 7 9 2

ItI A4D .2S

!Q s P! 0 t V0

* - - - -

A8~~ ~ EpwxADt o ounS~

lcom AW~ovedREPORT DOCUMENTATION PAGE Oms Nor 00ro4v8

PUbIKc ePIORing burden for this collection Of information is ettmats d to aver age i hour e reipOne, icluding the time fozr re Ueing ,nstu ons, warching *Xttng dta sourcel.athern and instaiIng che data uwaded, and ig and revbowunI the coll1ction Of infortflaeon. Slandcomments re~rdeng thus burden estimate or any Other aspe0t Of fth

collectionof infor . i:c:ludrg sug•est•os for roeaducing this burden. to Washington 4eftduarters Services. Diretorate or information Operations Nd Reporti. 121 JeffersonODais Highway. Wlte 1204. Arlington• VA 222024302. and to the Office of Management and Sudget. Paeiirwork Reduction Project (0704-01N). Washington, DC 2003.

1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE I 3. REPORT TYPE AND DATES COVEREDI March 1994i Final report

4. TITLE AND SUBTITLE S. FUNDING NUMBERSSediment Oxygen Demand and Its Effects on Dissolved Oxygen Concentrationsand Nutrient Release; Initial Laboratory Studies 96X3121

WU 32694

6. AUTHOR(S)Cynthia B. Price, Carl Cerco, Douglas Gunnison

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) B. PERFORMING ORGANIZATIONU.S. Army Engineer Waterways Experiment Station REPORT NUMBER

3909 Halls Ferry Road Technical ReportVicksburg, MS 39180-6199 W-94-1

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSORING/MONITORING

U.S. Army Corps of Engineers AGENCY REPORT NUMBER

Washington. DC 20314-1000

11. SUPPLEMENTARY NOTES

Available from National Technical Information Service, 5285 Port Royal Road, Springfield, VA 22161.

12S. DISTRIBUTION/AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE

Approved for public release; distribution is unlimited.

13. ABSTRACT (Maximum 200 words)

Three different approaches for examining sediment oxygen demand (SOD) are discussed. These include the useof freshwater sediment amended with organic matter as a source of energy to drive SOD processes, the use of suc-cessive aerobic/anaerobic cycles to determine the flux of organic and reduced inorganic chemical species releasedfrom the sediment to the water column as a result of SOD, and the evaluation of interactions occurring between thesediment and water column in relation to SOD-driven processes occuring within the sediment. Results are sum-marized ard discussed in terms of measurement and analytical techniques used to describe SOD interaction in freshand saltwater sediments.

14. SUBJECT TERMS 15. NUMBER OF PAGESDissolved oxygen Sediment-water interactions 54Nutrient flux SOD 16. PRICE CODESediment oxygen demand Water quality

17. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION 19. SECURITY CLASSIFICATION 20. LIMITATION OF ABSTRACTOF REPORT OF THIS PAGE OF ABSTRACT

UNCLASSIFIED UNCLASSIFIED

NSN 7540-01-280-5500 Standard Form 298 (Rev. 2-89)Prescribed by ANSI Std Z39.11298-102

sediment oxygen demand and its effects on dissolved oxygen

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