5.1 Adverse effects on natural populations of aquatic organisms and their uses have demonstrated the need to assess the hazards of many new, and some presently used, materials. The process described herein will help producers, users, regulatory agencies, and others to efficiently and adequately compare alternative materials, completely assess a final candidate material, or reassess the hazard of a material already in use.

5.2 Sequential assessment and feedback allow appropriate judgments concerning efficient use of resources, thereby minimizing unnecessary testing and focusing effort on the information most pertinent to each material. For different materials and situations, assessment of hazard will appropriately be based on substantially different amounts and kinds of biological, chemical, physical, and toxicological data.

5.3 Assessment of the hazard of a material to aquatic organisms and their uses should never be considered complete for all time. Reassessment should be considered if the amount of production, use, or disposal increases, new uses are discovered, or new information on biological, chemical, physical, or toxicological properties becomes available. Periodic review will help assure that new circumstances and information receive prompt appropriate attention.

5.4 If there is substantial transformation to another material, the hazard of both materials may need to be assessed.

5.5 In many cases, consideration of adverse effects should not end with completion of the hazard assessment. Additional steps should often include risk assessment, decisions concerning acceptability of identified hazards and risks, and mitigative actions.

5.6 Because this practice deals mostly with adverse effects on aquatic organisms and their uses, it is important that mitigative actions, such as improved treatment of aqueous effluents, not result in unacceptable effects on non-aquatic organisms. Thus, this standard should be used with other information in order to assess hazard to both aquatic and non-aquatic organisms.

1.1 This guide describes a stepwise process for using information concerning the biological, chemical, physical, and toxicological properties of a material to identify adverse effects likely to occur to aquatic organisms and their uses as a result of release of the material to the environment. The material will usually be a specific chemical, although it might be a group of chemicals that have very similar biological, chemical, physical, and toxicological properties and are usually produced, used, and discarded together.

1.2 The hazard assessment process is complex and requires decisions at a number of points; thus, the validity of a hazard assessment depends on the soundness of those decisions, as well as the accuracy of the information used. All decisions should be based on reasonable worst-case analyses so that an appropriate assessment can be completed for the least cost that is consistent with scientific validity.

1.3 This guide assumes that the reader is knowledgeable in aquatic toxicology and related pertinent areas. A list of general references is provided (1).2

1.4 This guide does not describe or reference detailed procedures for estimating or measuring environmental concentrations, or procedures for determining the maximum concentration of test material that is acceptable in the food of predators of aquatic life. However, this guide does describe how such information should be used when assessing the hazard of a material to aquatic organisms and their uses.

1.5 Because assessment of hazard to aquatic organisms and their uses is a relatively new activity within aquatic toxicology, most of the guidance provided herein is qualitative rather than quantitative. When possible, confidence limits should be calculated and taken into account.

1.6 This guide provides guidance for assessing hazard but does not provide guidance on how to take into account social considerations in order to judge the acceptability of the hazard. Judgments concerning acceptability are social as well as scientific, and are outside the scope of this guide.

1.7 This guide is arranged as follows:

Section

Referenced Documents

2 

Descriptions of Terms Specific to This Standard

3 

Summary of Guide

4 

Significance and Use

5 

Four Basic Concepts

6 

 The Iteration

6.1

 The Two Elements

6.2

 The Possible Decisions

6.3

 The Phased Approach

6.4

Phase I—Use of Low-Cost (Existing) Information

7 

 Collection of Available Data

7.1

 Initial Estimates of Environmental Concentrations

7.2

 Initial Estimate of Toxicity to Aquatic Organisms

7.3

 Initial Estimate of Bioaccumulation by Aquatic Organ-
  isms

 
7.4

 Phase I Hazard Assessment

7.5

Phase II—Use of Medium-Cost Information

8 

 Improved Estimates of Environmental Concentrations

8.2

 Acute Toxicity to Aquatic Animals

8.3

 Toxicity to Algae

8.4

 Expansion of Short-Term Testing

8.5

 Bioaccumulation

8.6

 Phase II Hazard Assessment

8.7

Phase III—Use of High-Cost Information

9 

 Refined Estimates of Environmental Concentrations

9.2

 Chronic Toxicity to Aquatic Animals

9.3

 Use of Acute-Chronic Ratios

9.4

 Toxicity to Aquatic Plants

9.5

 Bioconcentration

9.6

 Bioaccumulation from Food

9.7

 Phase III Hazard Assessment

9.8

Appendixes

 Appendix X1 Production, Use, Disposal, and Other Release

 Appendix X2 Biological Considerations

 Appendix X3 Chemical Considerations

 Appendix X4 Physical Considerations

 Appendix X5 Toxicological Considerations

 Appendix X6 Estimating Environmental Concentrations

 Appendix X7 Selection of Test Species

 Appendix X8 Long-Term Toxicity Tests

1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.9 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.