5.1 Protection of an aquatic species requires prevention of unacceptable effects on populations in natural habitats. Toxicity tests are conducted to provide data that may be used to predict what changes in numbers and weights of individuals might result from similar exposure to the test material in the natural aquatic environment. Information might also be obtained on the effects of the material on the health of the species.

5.2 Results of life-cycle tests with D. magna are used to predict chronic effects likely to occur on daphnids in field situations as a result of exposure under comparable conditions.

5.2.1 Life-cycle tests with D. magna are used to compare the chronic sensitivities of different species, the chronic toxicities of different materials, and study the effects of various environmental factors on the results of such tests.

5.2.2 Life-cycle tests with D. magna are used to assess the risk of materials to aquatic organisms (see Guide E1023) or derive water quality criteria for aquatic organisms (1).³

5.2.3 Life-cycle tests with D. magna are used to predict the results of chronic toxicity tests on the same test material with the same species in another water or with another species in the same or a different water. Most such predictions take into account the results of acute toxicity tests, and so the usefulness of the results of a life-cycle test with D. magna is greatly increased by also reporting the results of an acute toxicity test (see Guide E729) conducted under the same conditions. In addition to conducting an acute toxicity test with unfed D. magna, it may be desirable to conduct an acute test in which the daphnids are fed the same as in the life-cycle test to see if the presence of that concentration of that food affects the results of the acute test and the acute-chronic ratio (ACR) (see 10.3.1).

5.2.4 Life-cycle tests are used to evaluate the biological availability of, and structure-activity relationships between, test materials and test organisms.

5.3 Results of life-cycle tests with D. magna might be influenced by temperature (2), quality of food, composition of dilution water, condition of test organisms, and other factors.

1.1 This guide covers procedures for obtaining laboratory data concerning the adverse effects of a test material (added to dilution water, but not to food) on Daphnia magna Straus, 1820, during continuous exposure throughout a life-cycle using the renewal or flow-through techniques. These procedures also should be useful for conducting life-cycle toxicity tests with other invertebrate species, although modifications might be necessary.

1.2 These procedures are applicable to most chemicals, either individually or in formulations, commercial products, or known mixtures. With appropriate modifications, these procedures can be used to conduct tests on temperature, dissolved oxygen, pH, and on such materials as aqueous effluents (also see Guide E1192), leachates, oils, particulate matter, sediments, and surface waters. The technique, (renewal or flow-through), will be selected based on the chemical characteristics of the test material such as high oxygen demand, volatility, susceptibility to transformation (biologically or chemically), or sorption to glass.

1.3 Modification of these procedures might be justified by special needs or circumstances. Although using appropriate procedures is more important than following prescribed procedures, results of tests conducted using unusual procedures are not likely to be comparable to results of standard test procedures. Comparison of results obtained using modified and unmodified versions of these procedures might provide useful information on new concepts and procedures for conducting life-cycle toxicity tests with D. magna.

1.4 This guide is arranged as follows:

Section

Referenced Documents

2

Terminology

3

Summary of Guide

4

Significance and Use

5

Apparatus

6

 Facilities

6.1

 Construction Materials

6.2

 Test Chambers

6.3

 Cleaning

6.4

 Acceptability

6.5

Reagents

7

 Purity of Reagents

7.1

Hazards

8

Dilution Water

9

 Requirements

9.1

 Source

9.2

 Treatment

9.3

 Characterization

9.4

Test Material

10

 General

10.1

 Stock Solutions

10.2

 Test Concentrations(s)

10.3

Test Organisms

11

 Species

11.1

 Age

11.2

 Source

11.3

 Brood Stock

11.4

 Food

11.5

 Handling

11.6

 Harvesting Young

11.7

 Quality

11.8

Procedure

12

 Experimental Design

12.1

 Dissolved Oxygen

12.2

 Temperature

12.3

 Loading

12.4

 Selection of Test System

12.5

 Beginning the Test

12.6

 Care and Maintenance

12.7

 Feeding

12.8

 Duration

12.9

 Biological Data

12.10

 Other Measurements

12.11

Analytical Methodology

13

Acceptability of Test

14

Calculation of Results

15

Report

16

Keywords

17

Appendixes

 Appendix X1 Statistical Guidance

 Appendix X2 Food

1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.6 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 and health practices and determine the applicability of regulatory limitations prior to use. Specific hazard statements are given in Section 8.