environmental risk assessment, audit and water quality modelling

National institute of technology, Rourkela

ENVIRONMENTAL MANAGEMENT

Assignment III

Ashish Kumar

Roll Number: - 110MN0496

DEPARTMENT OF MINING ENGINEERING

Environmental Risk Assessment, Audit and Water

Quality Modelling

CONTENTS

Sl.

No

Description Page

Number

1 Environmental Risk Assessment 1-8

Introduction

Ecological Risk Assessment Framework

The Importance of Professional Judgment

Problem Formulation

Discussion Between the Risk Assessor and Risk Manager (Planning)

Stressor Characteristics, Ecosystem Potentially at Risk, and Ecological

Effects

Characterization of' Exposure

Stressor Characterization: Distribution or Pattern of Change

Risk characterization

Risk Estimation

Integration of Stressor-Response and Exposure Profiles

Comparing Single Effect and Exposure Values

Conducting Simulation Modeling

1

1-4

4

4

4-5

5-6

6

6

6-7

7

7

7-8

8

2 Environmental Audit 9-14

What is an Environmental Audit?

Planning an Environmental Audit

Conducting an Environmental Audit

Audit tools and technology

Environmental auditing in India

9

9-10

10-12

12-13

13-14

3 Water Quality Modelling 15-18

Introduction

Establishing Ambient Water Quality Standards

Water-Use Criteria

Water Quality Model Use

15

15-16

16-17

17-18

4 References 19

National Institute of Technology, Rourkela Page 1

Environmental Risk Assessment

Introduction

Public, private, and government sectors of society are increasingly aware of ecological issues

including global climate change, habitat loss, acid deposition, a decrease in biological diversity,

and the ecological impacts of xenobiotic compounds such as pesticides and toxic chemicals. To

help assess these and other ecological problems, the U.S. Environmental Protection Agency (EPA)

has developed this report, Framework for Ecological Risk Assessment, which describes the basic elements, or framework, of a process for evaluating scientific information on the adverse effects

of stressors on the environment. The term stressor is defined here as any physical, chemical, or biological entity that can induce an adverse effect (see box1). Adverse ecological effects

encompass a wide range of disturbances ranging from mortality in an individual organism to a loss

in ecosystem function.

This introductory section describes the purpose, scope, and intended audience for this report;

discusses the definition and application of ecological risk assessment; outlines the basic elements

of the proposed framework; and describes the organization of this report.

Ecological risk assessment is defined as a process that evaluates the likelihood that adverse

ecological effects may occur or are occurring as a result of exposure to one or more stressors. A

risk does not exist unless (1) the stressor has the inherent ability to cause one or more adverse

effects and (2) it cooccurs with or contacts an ecological component (i.e., organisms, populations,

communities, or ecosystems) long enough and at a sufficient intensity to elicit the identified

adverse effect. Ecological risk assessment may evaluate one or many stressors and ecological

components.

Ecological risk may be expressed in a variety of ways. While some ecological risk assessments

may provide true probabilistic estimates of both the adverse effect and exposure elements, others

may be deterministic or even qualitative in nature. In these cases, the likelihood of adverse effects

is expressed through a semiquantitative or qualitative comparison of effects and exposure.

Ecological risk assessments can help identify environmental problems, establish priorities, and

provide a scientific basis for regulatory actions. The process can identify existing risks or forecast

the risks of stressors not yet present in the environment. However, while ecological risk

assessments can play an important role in identifying and resolving environmental problems, risk

assessments are not a solution for addressing all environmental problems, nor are they always a

prerequisite for environmental management. Many environmental matters such as the protection

of habitats and endangered species are compelling enough that there may not be enough time or

data to do a risk assessment. In such cases, professional judgment and the mandates of a particular

statute will be the driving forces in making decisions.

Ecological Risk Assessment Framework

The distinctive nature of the framework results primarily from three differences in

emphasis relative to previous risk assessment approaches. First, ecological risk assessment can

consider effects beyond those on individuals of a single species and may examine population,

NATIONAL INSTITUTE OF TECHNOLOGY, ROURKELA 2

community, or ecosystem impacts. Second, there is no one set of assessment endpoints

(environmental values to be protected) that can be generally applied. Rather, assessment endpoints

are selected from a very large number of possibilities based on both scientific and policy

considerations. Finally, a comprehensive approach to ecological risk assessment may go beyond

the traditional emphasis on chemical effects to consider the possible effects of non-chemical stressors.

The ecological risk assessment framework is shown in figure 1. The risk assessment

process is based on two major elements: characterization of exposure and characterization of

ecological effects. Although these two elements are most prominent during the analysis phase,

aspects of both exposure and effects also are considered during problem formulation, as

illustrated by the arrows in the diagram. The arrows also flow to risk characterization, where the

exposure and effects elements are integrated to estimate risk. The framework is conceptually

similar to the National Research Council (NRC) paradigm for human health risk assessments

(NRC, 1983).

The first phase of the framework is problem formulation. Problem formulation includes a

preliminary characterization of exposure and effects, as well as examination of scientific data and

data needs, policy and regulatory issues, and site-specific factors to define the feasibility, scope,

and objectives for the ecological risk assessment. The level of detail and the information that will

be needed to complete the assessment also are determined.

The first phase of the framework is problem formulation. Problem formulation includes a

preliminary characterization of exposure and effects, as well as examination of scientific data and

data needs, policy and regulatory issues, and site-specific factors to define the feasibility, scope,

and objectives for the ecological risk assessment. The level of detail and the information that will

be needed to complete the assessment also are determined. This systematic planning phase

is proposed because ecological risk assessments often address the risks of stressors to many

species as well as risks to communities and ecosystems. In addition, there may be many ways a

stressor can elicit adverse effects (e.g., direct effects on mortality and growth and indirect effects

such as decreased food supply). Problem formulation provides an early identification of key

factors to be considered, which in turn will produce a more scientifically sound risk assessment.

The second phase of the framework is termed analysis and consists of two activities,

characterization of exposure and characterization of ecological effects. The purpose of

characterization of exposure is to predict or measure the spatial and temporal distribution of a

stressor and its cooccurrence or contact with the ecological components of concern, while the

purpose of characterization of ecological effects is to identify and quantify the adverse effects

elicited by a stressor and, to the extent possible, to evaluate cause-and-effect relationships.

The third phase of the framework is risk characterization. Risk characterization uses the results of

the exposure and ecological effects analyses to evaluate the likelihood of adverse ecological effects


associated with exposure to a stressor. It includes a summary of the assumptions used, the scientific

uncertainties, and the strengths and weaknesses of the analyses.

Figure 1 also indicates a role for verification and monitoring in the framework. Verification can

include validation of the ecological risk assessment process as well as confirmation of specific

predictions made during a risk assessment. Monitoring can aid in the verification process and may

identify additional topics for risk assessment. Verification and monitoring can help determine the

overall effectiveness of the framework approach, provide necessary feedback concerning the need

for future modifications of the framework, help evaluate the effectiveness and practicality of policy

decisions, and point out the need for new or improved scientific techniques (U.S. EPA, in press-

a).

The interaction between data acquisition and ecological risk assessment is also shown in figure 1.

In this report, a distinction is made between data acquisition (which is outside of the risk

assessment process) and data analysis (which is an integral part of an ecological risk assessment).


In the problem formulation and analysis phases, the risk assessor may identify the need for

additional data to complete an analysis. At this point, the risk assessment stops until the necessary

data are acquired. When a need for additional data is recognized in risk characterization, new

information generally is used in the analysis or problem formulation phases. The distinction

between data acquisition and analysis generally is maintained in all of EPA's risk assessment

guidelines; guidance on data acquisition procedures are provided in documents prepared for

specific EPA programs.

The Importance of Professional Judgment

Ecological risk assessments, like human health risk assessments, are based on scientific data that

are frequently difficult and complex, conflicting or ambiguous, or incomplete. Analyses of such

data for risk assessment purposes depends on professional judgment based on scientific

expertise. Professional judgment is necessary to:

1. design and conceptualize the risk assessment;

2. evaluate and select methods and models;

3. determine the relevance of available data to the risk assessment;

4. develop assumptions based on logic and scientific principles to fill data gaps; and

5. Interpret the ecological significance of predicted or observed effects.

Problem formulation

Problem formulation is the first phase of ecological risk assessment and establishes the goals,

breadth, and focus of the assessment. It is a systematic planning step that identifies the major

factors to be considered in a particular assessment, and it is linked to the regulatory and policy

context of the assessment.

Entry into the ecological risk assessment process may be triggered by either an observed ecological

effect, such as visible damage to trees m a forest, or by the identification of a stressor or activity

of concern, such as the planned filling of a marsh or the manufacture of a new chemical. The

problem formulation process (figure 2) then begins with the Initial stages of characterizing

exposure and ecological effects, including evaluating the stressor characteristics, the ecosystem

potentially at risk, and the ecological effects expected or observed. Next, the assessment and

measurement endpoints are identified. (Measurement endpoints are ecological characteristics that

can be related to the assessment endpoint.) The outcome of problem formulation is a conceptual

model that describes how a given stressor might affect the ecological components in the

environment. The conceptual model also describes the relationships among the assessment and

measurement endpoints, the data required, and the Methodologies that will be used to analyze the

data. The conceptual model serves as input to the analysis phase of the assessment.

Discussion Between the Risk Assessor and Risk Manager (Planning)

To be meaningful and effective, ecological risk assessments must be relevant to regulatory needs

and public concerns as well as scientifically valid. Although risk assessment and risk management


are distinct processes, establishing a two--way dialogue between risk assessors and risk managers

during the problem formulation phase can be a constructive means of achieving both societal and

scientific goals. By bringing the management perspective to the discussion, risk managers charged

with protecting societal values can ensure that the risk assessment will provide relevant

information to making decisions on the issue under consideration. By bringing scientific

knowledge to the discussion, the ecological risk assessor ensures that the assessment addresses all

important ecological concerns. Both perspectives are necessary to appropriately utilize resources

to produce scientifically sound risk assessments that are relevant to management decisions and

public concerns.

Stressor Characteristics, Ecosystem Potentially at Risk, and Ecological Effects

The initial steps in problem formulation are the identification and preliminary characterization of

stressors, the ecosystem potentially at risk, and ecological effects. Performing this analysis is an

interactive process that contributes to both the selection of assessment and measurement endpoints

and the development of a conceptual model.ANALYSIS PHASE

The analysis phase of ecological risk assessment (figure 3) consists of the technical evaluation of

data on the potential effects and exposure of the stressor. The analysis phase is based on the

conceptual model developed during problem formulation. Although this phase consists of

characterization of ecological effects and characterization of exposure, the dotted line in figure 3

illustrates that the two are performed interactively. An interaction between the two elements will

ensure that the ecological effects characterized are compatible with the biota and exposure

pathways identified in the exposure characterization. The output of ecological effects


characterization and exposure characterization are summary profiles that are used in the risk

characterization phase (section 4). Discussion of uncertainty analysis, which is an important part

of the analysis phase, may be found in section 4.1.2.

Characterization of exposure and ecological effects often requires the application of statistical

methods. While the discussion of specific statistical methods is beyond the scope of this document,

selection of an appropriate statistical method involves both method assumptions (e.g.,

independence of errors, normality, and equality of variances) and data set characteristics (e.g.,

distribution, presence of outliers or influential data). It should be noted that statistical significance

does not always reflect biological significance, and profound biological changes may not be

detected by statistical tests. Professional judgment often is required to evaluate the relationship

between statistical and biological significance.

Characterization of' Exposure

Characterization of exposure (half of the analysis phase shown in figure 3) evaluates the interaction

of the stressor with the ecological component. Exposure can be expressed as co-occurrence or

contact depending on the stressor and the ecological component involved. An exposure profile is

developed that quantifies the magnitude and spatial and temporal distributions of exposure for the

scenarios developed during problem formulation and serves as input to the risk characterization.

Stressor Characterization: Distribution or Pattern of Change

Stressor characterization involves determining the stressor's distribution or pattern of change.

Many techniques can be applied to assist in this stressor characterization process. For chemical

stressors, a combination of modeling and monitoring data often is used. Available monitoring data

may include measures of releases into the environment and media concentrations over space and

time. Fate and transport models often are used that rely on physical and chemical characteristics

of the chemical coupled with the characteristics of the ecosystem. For nonchemical stressors such

as physical alterations or harvesting, the pattern of change may depend on resource management

or land-use practices. Depending on the scale of the disturbance, the data for stressor

characterization can be provided by a variety of techniques, including ground reconnaissance,

aerial photographs, or satellite imagery.

Risk characterization

Risk characterization (figure 4) is the final phase of risk assessment. During this phase, the likelihood of

adverse effects occurring as a result of exposure to a stressor are evaluated. Risk characterization contains

two major steps: risk estimation and risk description. The stressor-response profile and the exposure profile

from the analysis phase serve as input to risk estimation. The uncertainties identified during all phases of

the risk assessment also are analyzed and summarized. The estimated risks are discussed by considering

the types and magnitude of effects anticipated, the spatial and temporal extent of the effects, and recovery

potential. Supporting information in the form of a weight-of-evidence discussion also is presented during

this step. The results of the risk assessment, including the relevance of the identified risks to the original

goals of the risk assessment, then are discussed with the risk manager.


Risk Estimation

Risk estimation consists of comparing the exposure and stressor-response profiles as well as

estimating and summarizing the associated uncertainties.

Integration of Stressor-Response and Exposure Profiles

Three general approaches are discussed to illustrate the integration of the stressor-response and

exposure profiles: (1) comparing single effect and exposure values; (2) comparing distributions of

effects and exposure; and (3) conducting simulation modeling. Because these are areas of active

research, particularly in the assessment of community- and landscape-level perturbations,

additional integration approaches are likely to be available in the future. The final choice as to

which approach will be selected depends on the original purpose of the assessment as well as time

and data constraints.

Comparing Single Effect and Exposure Values

Many risk assessments compare single effect values with predicted or measured levels of the

stressor. The effect values from the stressor-response profile may be used as is, or more commonly,

uncertainty or safety factors may be used to adjust the value. The ratio or quotient of the exposure

value to the effect value provides the risk estimate if the quotient is one or more, an adverse effect

is considered likely to occur. This approach, known as the Quotient Method (Barnthouse et al.,

1986), has been used extensively to evaluate the risks of chemical stressors (Nabholz 1991; Urban

and Cook, 1986). Although the Quotient Method is commonly used and accepted, it is the least

probabilistic of the approaches described here. Also, correct usage of the Quotient Method is

highly dependent on professional judgment, particularly in instances when the quotient approaches


one. Greater insight into the magnitude of the effects expected at various levels of exposure can

be obtained by evaluating the full stressor-response curve instead of a single point and by

considering the frequency, timing, and duration of the exposure.

Conducting Simulation Modeling

Simulation models that can integrate both the stressor-response profile and exposure profile are

useful for obtaining probabilistic estimates of risk. Two categories of simulation models are used

for ecological risk assessment: single-species population models are used to predict direct effects

on a single population of concern using measurement endpoints at the individual level, while multi-

species models include aquatic food web models and terrestrial plant succession models and are

useful for evaluating both direct and indirect effects.

When selecting a model, it is important to determine the appropriateness of the model for a

particular application. For example, if indirect effects are of concern, a model of community-level

interactions will be needed. Direct effects to a particular population of concern may be better

addressed with population models. The validation status and use history of a model also are

important considerations in model selection. Although simulation models are not commonly used

for ecological risk assessment at the present time, this is an area of active research, and the use of

simulation models is likely to increase.

In addition to providing estimates of risks, simulation models also can be useful in discussing the

results of the risk characterization to the risk manager. This dialogue is particularly effective when

the relationship between risks to certain measurement endpoints and the assessment endpoint are

not readily apparent (e.g., certain indirect effects and large-scale ecosystem-level disturbances).


Environmental Audit

What is an Environmental Audit?

Image Environmental auditing is a systematic, documented, periodic and objective process in

assessing an organization's activities and services in relation to:

1. Assessing compliance with relevant statutory and internal requirements 2. Facilitating management control of environmental practices 3. Promoting good environmental management 4. Maintaining credibility with the public 5. Raising staff awareness and enforcing commitment to departmental environmental policy 6. Exploring improvement opportunities 7. Establishing the performance baseline for developing an Environmental Management

System (EMS)

Image of Resource Conducting an environmental audit is no longer an option but a sound

precaution and a proactive measure in today's heavily regulated environment. Indeed, evidence

suggests that EA has a valuable role to play, encouraging systematic incorporation of

environmental perspectives into many aspects of an organizations overall operation, helping to trigger new awareness and new priorities in policies and practices.

Planning an Environmental Audit

Any premises that wishes to conduct an environmental audit must have a clear idea of the

objectives of the exercise and the steps required to achieve it. Before commencing an

environmental audit, the following requirements must be fulfilled:

i. Commitment

a. Obtain commitment at the Directorate level b. Communicate commitment to personnel at all levels

ii. Define Audit Scope and Audit Site(s) c. To include:

i. Audit site and boundary ii. Audit objective(s)

iii. Areas of audit d. Audit objectives typically entail:

i. Verification of legislative and regulatory compliance ii. Assessment of internal policy and procedural conformance


iii. Establishment of current practice status iv. Identification of improvement opportunities

e. Areas of audit normally encompass:

i. Material management, savings and alternatives ii. Energy management and savings

iii. Water management and economy of use iv. Waste generation, management and disposal v. Noise reduction, evaluation and control

vi. Air emissions and indoor air quality vii. Environmental emergency prevention and preparedness

viii. Transportation and travelling practices ix. Staff awareness, participation and training in environmental issues x. Environmental information publicity

xi. Public enquiry and complaints response xii. Environmental management system set up, suitability and performance

iii. Assemble An Audit Team

An Audit Management Committee (AMC) established by management at Directorate level, is responsible for:

Overseeing the audit process

Appointing an Audit Team Leader to be in charge of the audit. Securing the necessary resources and funding Reviewing the Audit Report Reporting to the organization Directorate

The AMC in conjunction with the Audit Team Leader to:

Appoint Audit Team Members Assess requirement for external assistance to ensure. thoroughness and objectivity

of audit Secure financial resources if external assistance is required Confirm availability of

Audit Team members

Conducting an Environmental Audit

An environmental audit is typically undertaken in three phases:

1. Pre-audit 2. On-site audit 3. Post-audit

Following up an Environmental Audit

Develop Action Plan


Upon endorsement of the Audit Report, an Action Plan with the appropriate targets and objectives

for environmental improvement may be developed in consultation with audit site senior

management.

An action plan should cover:

i. Action objectives; ii. Specific actions required;

iii. Responsible party(ies); iv. Budget allotted; and v. Implementation program

Implement Action Plan

Responsible party(ies)to undertake actions according to the allotted budget, and the agreed

timescale for completion.

Checking and Monitoring

To monitor progress of Action Plan implementation, a status report should be carried out and

should include information on:

i. Progress of action(s) undertaken ii. Problem(s) encountered when action(s) taken

iii. Proposed solution(s) and revised timescale for completion

Review Action Plan

Review the Action Plan upon completion of Action Plan implementation.

Key points to review include:

i. Review results of action plan implementation ii. Establish levels of performance improvement achieved

iii. Address possible need for changes to Green management policy, objective(s) and procedure(s)

iv. Next audit scope and schedule


Each of these phases comprises a number of clearly defined Objectives, with each objective to be

achieved through specific Actions, and these actions yielding results in the form of Outputs at the

end of each phase.

Environmental Audit Process - An Overview

Audit tools and technology

The term "protocol" means the checklist used by environmental auditors as the guide for

conducting the audit activities. There is no standard protocol, either in form or content. Typically,

companies develop their own protocols to meet their specific compliance requirements and


management systems. Audit firms frequently develop general protocols that can be applied to a

broad range of companies/operations.

Current technology supports many versions of computer-based protocols that attempt to simplify

the audit process by converting regulatory requirements into questions with "yes", "no" and "not

applicable" check boxes. Many companies and auditors find these useful and there are several such

protocol systems commercially available. Other auditors (typically those with many years of

environmental auditing experience) use the regulations/permits directly as protocols. There is a

long standing debate among environmental audit professionals on the value of large, highly

detailed and prescriptive protocols (i.e., that can, in theory, be completed by an auditor with little

or no technical experience) versus more flexible protocols that rely on the expertise and knowledge

of experienced auditors and source documents (regulations, permits, etc.) directly. However usage

of structured and prescriptive protocols in ISO 14001 audits allows easier review by other parties,

either internal to the Certification Body (e.g. technical reviewers and certification managers) or

external (accreditation bodies).

In the US, permits for air emissions, wastewater discharges and other operational aspects, many

times establish the primary legal compliance standards for companies. In these cases, auditing only

to the regulations is inadequate. However, as these permits are site specific, standard protocols are

not commercially available that reflect every permit condition for every company/site. Therefore,

permit holders and the auditors they hire must identify the permit requirements and determine the

most effective way to audit against those requirements.

During the past 20 years, advances in technology have had major impacts on auditing. Laptop

computers, portable printers, CD/DVDs, the internet, email and wireless internet access have all

been used to improve audits, increase/improve auditor access to regulatory information and create

audit reports on-site. At one point in the 1990s, one major company invested significant resources

in testing "video audits" where the auditor (located at the corporate headquarters) used real-time

video conferencing technology to direct staff at a site to carry live video cameras to specific areas

of the plant. While initially promising, this technology/concept did not prove acceptable.

The current "disruptive technology" in environmental auditing is Apple Computer's iPad. At this

time, one audit consulting firm is using the iPad extensively for environmental audits, which

includes specific protocols for the new technology.

Environmental auditing in India

1. Auditing in India

The Supreme Audit Institution (SAI) in India is headed by the Comptroller and Auditor General

(CAG) of India who is a constitutional authority. The CAG of India derives his mandate from

Articles 148 to 151 of the Indian Constitution. The CAGs (Duties, Powers and Conditions of Service) Act, 1971 prescribes functions, duties and powers of the CAG. While fulfilling his

constitutional obligations, the CAG examines various aspects of government expenditure and

revenues. The audit conducted by CAG is broadly classified into Financial, Compliance and

Performance Audit. Environmental audit by SAI India is conducted within the broad framework

of Compliance and Performance Audit.

2.Environment protection in India


Main article: Ministry of Environment and Forests (India)

The Ministry of Environment & Forests is the nodal agency in the administrative structure of the

Central Government of India, for the planning, promotion, coordination and overseeing the

implementation of environmental and forestry programmes. The Ministry is also the Nodal agency

in the country for the United Nations Environment Programme (UNEP). In the states, the

Department of Environment and Forest is the main agency for implementation of environment

programmes.

i. The principal activities undertaken by Ministry of Environment & Forests consist of ii. Conservation & survey of flora, fauna, forests and wildlife;

iii. Prevention & control of pollution; afforestation and regeneration of degraded areas; and iv. Protection of environment, in the frame work of legislation. v. Major policy initiatives by Ministry of Environment and Forests include:

vi. National Environment Policy, 2006; vii. Conservation Strategy and Policy Statement on Environment and Development,1992;

viii. Policy Statement for Abatement of Pollution; ix. National Forest Policy


Water Quality Modelling

Introduction

The most fundamental human needs for water are for drinking, cooking and personal hygiene. To

meet these needs, the quality of the water used must pose no risk to human health. The quality of

the water in nature also affects the condition of ecosystems that all living organisms depend on.

At the same time, humans use water bodies as convenient sinks for the disposal of domestic,

industrial and agricultural wastewaters. This of course degrades the quality of those water bodies.

Water resources management involves the monitoring and management of water quality as much

as the monitoring and management of water quantity. Various models have been developed to

assist in predicting the water quality impacts of alternative land and water management policies

and practices. This chapter introduces some of the main principles of water quality modelling.

Water quality management is a critical component of overall integrated water resources

management. Most users of water depend on adequate levels of water quality. When these levels

are not met, these water users must either pay an additional cost for water treatment or incur at

least increased risks of damage or loss. As populations and economies grow, more pollutants are

generated. Many of these are waterborne, and hence can end up in surface and groundwater bodies.

Increasingly, the major efforts and costs involved in water management are devoted to water

quality protection and management. Conflicts among various users of water are increasingly over

issues involving water quality as well as water quantity.

Natural water bodies are able to serve many uses, including the transport and assimilation of

waterborne wastes. But as natural water bodies assimilate these wastes, their quality changes. If

the quality drops to the extent that other beneficial uses are adversely affected, the assimilative

capacities of those water bodies have been exceeded with respect to those affected uses. Water

quality management measures are actions taken to ensure that the total pollutant loads discharged

into receiving water bodies do not exceed the ability of those water bodies to assimilate those loads

while maintaining the levels of quality specified by quality standards set for those waters.

What uses depend on water quality? One can identify almost any use. All living organisms require

water of sufficient quantity and quality to survive, although different aquatic species can tolerate

different levels of water quality. Regrettably, in most parts of the developed world it is no longer

safe to drink natural surface or ground waters; they usually need to be treated before they become

fit for human consumption. Treatment is not a practical option for recreational bathing, or for

maintaining the health of fish, shellfish and other organisms found in natural aquatic ecosystems.

Thus, standards specifying minimum acceptable levels of quality are set for most ambient waters.

Various other uses have their own standards as well. Irrigation water must not be too saline or

contain toxic substances that can be absorbed by the plants or destroy microorganisms in the soil.

Water quality standards for industry can be very demanding, depending of course on the particular

industrial processes.

Establishing Ambient Water Quality Standards

Identifying the intended uses of a water body whether a lake, a section of a stream or an estuary is a first step in setting water quality standards for that body. The most restrictive of the specific


desired uses of a water body is termed a designated use. Barriers to achieving the designated use

are the presence of pollutants, or hydrological and geomorphic changes that affect the water

quality.

The designated use dictates the appropriate type of water quality standard. For example, a

designated use of human recreation should protect humans from exposure to microbial pathogens

while swimming, wading or boating. Other uses include those designed to protect humans and

wildlife from consuming harmful substances in water, in fish and in shellfish. Aquatic-life uses

include the protection and propagation of fish, shellfish and wildlife resources.

Standards set upstream may affect the uses of water downstream. For example, small headwater

streams may have aesthetic value but may not be able to support extensive recreational uses.

However, their condition may affect the ability of a downstream area to achieve a particular

designated use such as fishable or swimmable. In this case, the designated use for the smaller upstream water body may be defined in terms of achieving the designated use of the larger

downstream water body.

In many areas, human activities have altered the landscape and aquatic ecosystems to the point

where they cannot be restored to their pre-disturbance condition. For example, someones desire to establish a trout fish-farm in downtown Paris, Phnom Penh, Prague or Pretoria may not be

attainable because of the development history of these areas or the altered hydrological regimes of

the rivers flowing through them. Similarly, someone might wish to designate an area near the

outfall of a sewage treatment plant for shellfish harvesting, but health considerations would

preclude any such use. Ambient water quality standards must be realistic.

Designating the appropriate use for a water body is a policy decision that can be informed by the

use of water quality prediction models of the type discussed in this chapter. However, the final

standard selection should reflect a social consensus made while bearing in mind the current

condition of the watershed, its pre-disturbance condition, the advantages derived from a certain

designated use, and the costs of achieving that use.

Water-Use Criteria

The designated use is a qualitative description of the desired condition of a water body. A criterion

is a measurable indicator surrogate for use attainment. The criterion may be positioned at any point

in the causal chain of boxes shown in Figure 12.1.

In Box 1 of Figure 12.1 are measures of the pollutant discharge from a treatment plant (such as

biological oxygen demand, ammonia (NH3), pathogens and suspended sediments) or the amount

of a pollutant entering the edge of a stream from runoff. A criterion at this position is referred to

as an effluent standard. Criteria in Boxes 2 and 3 are possible measures of ambient water quality

conditions. Box 2 includes measures of a water quality parameter such as dissolved oxygen (DO),

pH, total phosphorus concentration, suspended sediment or temperature. Criteria closer to the

designated use (e.g. Box 3)


Factors considered when determining designated use and associated water quality standards.

include more combined or comprehensive measures of the biological community as a whole, such

as the condition of the algal community (chlorophyll a) or a measure of contaminant concentration

in fish tissue. Box 4 represents criteria that are associated with sources of pollution other than

pollutants. These criteria might include measures such as flow timing and pattern ( a hydrological

criterion), abundance of non-indigenous taxa, or some quantification of channel modification ( e.g.

a decrease in sinuosity) (NRC, 2001).

The more precise the statement of the designated use, the more accurate the criterion will be as an

indicator of that use. For example, the criterion of fecal coliform count may be a suitable criterion

for water contact recreation. The maximum allowable count itself may differ among water bodies

that have water contact as their designated use, however.

Surrogate indicators are often selected for use as criteria because they are easy to measure and in

some cases are politically appealing. Although a surrogate indicator may have these appealing

attributes, its usefulness can be limited unless it can be logically related to a designated use.

Water Quality Model Use

Monitoring data are the preferred form of information for identifying impaired waters.Model

predictions might be used in addition to or instead of monitoring data for several reasons:

a. Modelling might be feasible in some situations where monitoring is not. b. Integrated monitoring and modelling systems could provide better information than

one or the other alone for the same total cost. For example, regression analyses that

correlate pollutant concentration with some more easily measurable factor (such as

streamflow) could be used to extend monitoring data for preliminary listing (of

impared status) purposes. Models can also be used in a Bayesian framework to

determine preliminary probability distributions of impairment that can help direct

monitoring efforts and reduce the quantity of monitoring data needed for making

listing decisions at a given level of reliability (see Chapter 7).


c. Modelling can be used to assess (predict) future water quality situations resulting from different management strategies. For example, assessing the improvement in

water quality after a new wastewater treatment plant is built, or the effect of

increased industrial growth and effluent discharges.

A simple but useful modelling approach that may be used in the absence of monitoring data is

dilution calculations. In this approach the rate of pollutant loading from point sources in a water body is divided by the stream flow to give a set of estimated pollutant concentrations that may be

compared to the standard. Simple dilution calculations assume conservative movement of

pollutants. Thus, the use of dilution calculations will tend to be conservative and predict higher

than actual concentrations for decaying pollutants. Of course, one could include a best estimate of

the effects of decay processes in the dilution model.

Combined runoff and water quality prediction models link stressors (sources of pollutants and

pollution) to responses. Stressors include human activities likely to cause impairment, such as the

presence of impervious surfaces in a watershed, cultivation of fields close to the stream, over-

irrigation of crops with resulting polluted return flows, the discharge of domestic and industrial

effluents into water bodies, installing dams and other channelization works, introduction of non-

indigenous taxa and over-harvesting of fish. Indirect effects of humans include land cover changes

that alter the rates of delivery of water, pollutants and sediment to water bodies.

A review of direct and indirect effects of human activities suggests five major types of

environmental stressors:

a. alterations in physical habitat b. modifications in the seasonal flow of water c. changes in the food base of the system d. Changes in interactions within the stream biota release of contaminants

(conventional pollutants) (Karr, 1990; NRC, 1992, 2001).

Ideally, models designed to manage water quality should consider all five types of alternative

management measures. A broad-based approach that considers these five features provides a more

integrative approach to reduce the cause or causes of degradation (NRC, 1992).

Models that relate stressors to responses can be of varying levels of complexity. Sometimes, they

are simple qualitative conceptual representations of the relationships among important variables

and indicators of those variables, such as the statement human activities in a watershed affect water quality, including the condition of the river biota. More quantitative models can be used to make predictions about the assimilative capacity of a water body, the movement of a pollutant

from various point and non-point sources through a watershed, or the effectiveness of certain best

management practices.


References

1. U.S. Department of the Interior. (1987). Injury to fish and wildlife species. Type B

Technical information document. CERCLA 301 Project. Washington, DC. U.S. EPA. See

U.S. Environmental Protection Agency.

2. U.S. Environmental Protection Agency. (1979). Toxic Substances Control Act. Discussion of premanufacture testing policies and technical issues; Request for comment. 44 Federal

Register 16240-16292.

3. U.S. Environmental Protection Agency. (1990a). Environmental Monitoring and Assessment Program.

4. Ecological Indicators. EPA/60/3-90/060, Office of Research and Development, Washington, DC.

5. U.S. Environmental Protection Agency. (1990b). Reducing Risk: Setting Priorities and Strategies for Environmental Protection. Science Advisory Board SAB--EC-90-02 I,

Washington, DC.

6. U.S. Environmental Protection Agency. (1991). Summary Report on Issues in Ecological Risk Assessment. EPA/625/3-91/018, Risk Assessment Forum, Washington, DC.

7. http://en.wikipedia.org/wiki/Environmental_audit 8. http://en.wikipedia.org/wiki/Ecological_assessment 9. http://en.wikipedia.org/wiki/Risk_assessment