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5.2 CHANGE OF THE ADMINISTRATIVE AFFILIATION FOR THE CORRESPONDANCE OF THE ADMINISTRATIVE CLASSIFICATION TO THE ECOLOGICAL CLASSIFICATION

The administrative affiliation for settlement has been changed (the highest classification score has been used in classification functions) and Discriminant Analysis has been repeated. This procedure is iterative. (It is need about 10 iterations)

It appears that only 3 of 236 settlements are incorrectly classified by such procedure. It appears also that Sarnensky Region may be excluded from list of Regions; then the ecological conditions of the settlements including in the Sarnensky Region are classified as Beresnovsky.

The result of such iterative operations of the Discriminant Analysis is indicated in Figure 3. (In legend of Figure 3 there are 6 Regions only).

Fig. 3. The correspondence of the ecological classification to the administrative classification.

6. Assignment of the score to MREI

In our example the expert scores 1, 2,…6 for the clusters “Bereznovsky”, “Vladimiresky”, “Goschansky”, “Dubrovitsky”, “Zarechensky”, ”Rokitnovsky” (Figure3) as MREI were assigned. The score “1” was assigned for cluster “Goschansky” which was estimated by experts as the most favourable.

Note:

ξ The scores 1,…6 are the group centroids in the clusters “Bereznovsky”, “Vladimiresky”, “Goschansky”, “Dubrovitsky”, “Zarechensky”,”Rokitnovsky, respectively.

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4.Bartlett M.S (1965). “Multidimensional Statistics” in Theoretical and Mathematical Biology”, Edited by Talbot H. Waterman and Harold J. Morowitz, Yale University, Blaisdell Publishing Company New York, Toronto, London

5.Code “Statistica for Windows”, StatSoft Inc., Release 4.3, 1993;

6.Maurice G.Kendall, Alan Stuart (1966) “The Advanced Theory of Statistics”, V.3, Design and Analysis, and Time – Series, Second Edition, Charles Griffin&Company Limited, London;

7.S.S.Wilks (1967) “Mathematical Statistics”, “Science” Publishers, Moscow (in Russian);

8.“Dosimetric certification of settlements of Ukraine which has exposed from radiological contamination resulting Chernobyl Accident”, Volumes 1- 5, Kiev, Minzdrav of Ukraine, 1991 - 1995

ECOLOGICAL RISK ASSESSMENTY AS A METHOD FOR INTEGRATING RISKS FROM MULTIPLE STRESSORS AT HAZARDOUS WASTE SITES

R. MORRIS

TREC, Inc., 4276 E 300 N, Rigby, ID 83442,

UNITED STATES OF AMERICA

R. VANHOM

Idaho National Engineering and Environmental Laboratory, Idaho Falls, ID, 83402, UNITED STATES OF AMERICA

1. Introduction

Recent experience with human impacts on the environment has demonstrated a need for methodologies to determine protective levels of radiation dose, toxic chemical concentration, and physical stressors. Although there is a continuing need for research into mechanisms and effects, particularly for nonhuman components of the environment, the precautionary principle demands development of methodologies to establish sound regulatory standards in the absence of complete knowledge. These methodologies need not necessarily be based on a scientifically elegant or intellectually satisfying understanding of mechanisms, but would instead be pragmatic systems which offer real protection.

Ecological risk assessment is one method developed to analyze potential risks to the environment and allow the setting and application of regulatory standards in the presence of significant uncertainty. Although ecological risk assessment has been successfully applied to radiological, chemical, and physical hazards, methods have not been developed to consider these three types of stressors in a common framework. Analysing the three stressor types in a common framework is desirable because of the synergistic and antagonistic interactions known to exist between them. Separate analyses cannot account for these interactions.

The objective of this paper is to suggest some approaches which might enhance our ability to analyze radiological, chemical, and physical hazards jointly. These approaches are not offered as a final solution to the problem, but as models to stimulate discussion. To this end, it is worthwhile to consider the methods by which each of these stressor types has been analysed separately.

2. Ecological risk assessment

Ecological risk assessment is a science-based process to qualitatively or quantitatively determine potential harm to the environment from human activities. For the purpose of this definition, the environment that can be harmed is defined as populations of non-human biota (plants and animals), individual members of Threatened or Endangered species, or special habitats (e.g., caves, wetlands).

A focus on populations of plants and animals rather than on individual members of those populations is a philosophical stance reflected in most western cultures, reflected in our wildlife and land management laws and regulations. However, it is not shared by all cultures and may be changing in those cultures

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© 2005 Springer. Printed in the Netherlands.

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where it exists. Thus, while it seems a reasonable initial position, it is important to bear in mind it may not always be tenable to the stakeholders our regulations affect. This subject is discussed in more detail in a recent International Atomic Energy Agency (IAEA) document [1].

The above definition of ecological risk assessment also requires an explanation of which human activities can be evaluated. For this paper, the stressors of interest are grouped into three categories: ionizing radiation, toxic chemicals, and physical disturbance.

Since the inception of radiation protection as a profession, the focus of its activity has been on protecting human health. There are currently no universally agreed criteria or methodologies for explicitly protecting non-human parts of the environment. For many, the International Commission on Radiological Protection (ICRP) provided the basis for protecting the environment with the statement:

The Commission believes that the standard of environmental control needed to protect man to the degree currently thought desirable will ensure that other species are not put at risk [2].

This “belief” is no longer universally accepted [1] because, 1) there is a large degree of variability in radiosensitivity between species, 2) non-human species may be exposed to environmental radioactivity through pathways not normally available to humans, and 3) much of the basis for protection of humans is based on excluding them from contaminated environments. Non-human species cannot always be similarly excluded. Thus it has become necessary for authorities to demonstrate their regulations are protective of non-human organisms and methods are under development in many countries to do so [3, 4, 5]. Many of these methods are based upon an ecological risk assessment framework.

The non-human components of the environment are also adversely affected in a variety of ways by toxic chemicals. These effects range from direct mortality to subtle genetic damage resulting in decreased evolutionary fitness. The ecological risk assessment approach was originally developed to evaluate risks to the environment from toxic chemicals. [6, 7] It has been successfully applied to this problem at hazardous waste sites across the world, and, although the methodology is continually under improvement, it is a well-developed and well-accepted approach.

Physical disturbance of the environment, ranging from direct mortality, to habitat destruction, habitat Fragmentation, or noise disturbance, has not been well analysed in an ecological risk assessment framework. This is not so much because the methods are not applicable, as because of the historical development of ecological risk assessment as an approach for evaluating risks from toxic chemicals.

2.1 GENERAL PRINCIPLES

There are some general principles for ecological risk assessment that are shared in common between the three types of analysis.

2.1.1. Begin from a conceptual model

In every risk assessment, it is important to begin by developing a wellsupported conceptual model of how the environment under consideration is organized and how the stressor might adversely affect it. For chemical toxins and radioactivity, this should include consideration of the exposure pathways. The

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conceptual model allows the assessors to determine and focus on those components of the environment where adverse effects are most likely to be found and, thus, increase the efficiency of their assessment.

2.1.2. Monitor the correct pathways

Most existing environmental monitoring programs for radioactive or chemical stressors are intended to assist in protecting humans from negative impacts of environmental contamination. Thus, they monitor those pathways by which humans are most likely to be exposed. However, non-human organisms are likely to be exposed by transport pathways not usually available to humans. It is important to ensure that the data used in the assessment are appropriate for the organisms of concern. The same general principle applies to assessments of physical hazards. While humans might not be greatly affected by a stream diversion or road construction, the organisms that inhabit the stream or those whose migration corridor is severed by the road might be greatly affected.

2.1.3. Graded approach

Ecological risk assessment professionals have long recognized that a graded approach is the most cost-effective and efficient method of conducting assessments. After an initial data assembly phase, during which appropriate conceptual models are developed, supported, and documented, a screening assessment is conducted. This screening assessment uses general models with conservative parameters, i.e., models which err on the side of showing risk where none exists. If the activity being assessed with these models passes the screen, assessors can be confident that no risk exists. If the activity fails the screen, then a process of iteration with progressively more complex and site-specific models is conducted. This continues until it is either demonstrated the activity poses an acceptable level of risk, or it is concluded unacceptable risks exist which must be mitigated.

2.1.4. Compliance with a standard

In order for risk managers to make practical use of the results of an ecological risk assessment, there must exist some agreed upon standard; a value which regulators and stakeholders agree represents the limit of acceptable risk. In most cases, for ionizing radiation, this has been a dose limit or, more basically, an activity concentration in an environmental medium. For chemical toxins a Lowest Observed Adverse Effect Level (LOAEL) or No Observed Adverse Affect Level (NOAEL) has been applied. There is no generally accepted or universally applied standard for physical disturbance. These general principles are applicable to any ecological risk assessment. It is now useful to consider how they are applied within each of the given hazard types.

3. Assessing ecological risks from ionizing radiation

In this paper, the U.S. Department of Energy’s (DOE) Graded Approach [3] is used as the model for assessing risks to the environment from ionizing radiation. This is not because it is the only approach which might be effective, but