ASTM E1676-12(2021)

5.1?Soil toxicity tests provide information concerning the toxicity and bioavailability of chemicals associated with soils to terrestrial organisms. As important members of the soil fauna, lumbricid earthworms and enchytraeid potworms have a number of characteristics that make them appropriate organisms for use in the assessment of potentially hazardous soils. Earthworms may ingest large quantities of soil, have a close relationship with other soil biomasses (for example, invertebrates, roots, humus, litter, and microorganisms), constitute up to 92 % of the invertebrate biomass of soil, and are important in recycling nutrients (1, 2).4 Enchytraeids contribute up to 5.2 % of soil respiration, constitute the second-highest biomass in many soils (the highest in acid soils in which earthworms are lacking) and effect considerably nutrient cycling and community metabolism 5.2?A number of species of lumbricids and enchytraeid worms have been used in field and laboratory investigations in the United States and Europe. Although the sensitivity of various lumbricid species to specific chemicals may vary, from their study of four species of earthworms (including E. fetida) exposed to ten organic compounds representing six classes of chemicals, Neuhauser, et al (7) suggest that the selection of earthworm test species does not affect the assessment of a chemical's toxicity markedly. The sensitivity of various enchytraeid species has not been investigated in a comparable way so far, but ecological importance and practicability reasons favor strongly the selection of a species belonging to the genus 5.2.1?E. fetida?is a species whose natural habitats are those of very high organic matter such as composts and manure piles. It was selected as the test species because it (1) is bred in the laboratory easily; (5.2.2?The recommended enchytraeid test species is 5.3?Results from soil toxicity tests might be an important consideration when assessing the hazards of materials to terrestrial organisms.

5.4?Information might also be obtained on the bioaccumulation of chemicals associated with soil by analysis of animal tissues for the chemicals being monitored. These results are useful for studying the biological availability of chemicals.

5.5?The soil toxicity test might be used to determine the temporal or spatial distribution of soil toxicity. Test methods can be used to detect horizontal and vertical gradients in toxicity.

5.6?Results of soil toxicity tests could be used to compare the sensitivities of different species.

5.7?An understanding of the effect of these parameters on toxicity and bioaccumulation may be gained by varying soil characteristics such as pH, clay content, and organic material.

5.8?Results of soil toxicity tests may be useful in helping to predict the effects likely to occur with terrestrial organisms in field situations.

5.9?Soil toxicity and bioaccumulation tests can be an important tool for making decisions regarding the extent of remedial action necessary for contaminated terrestrial sites.

1.1?This guide covers procedures for obtaining laboratory data to evaluate the adverse effects of contaminants (for example, chemicals or biomolecules) associated with soil to earthworms (Family Lumbricidae) and potworms (Family Enchytraeidae) from soil toxicity or bioaccumulation tests. The methods are designed to assess lethal or sublethal toxic effects on earthworms or bioaccumulation of contaminants in short-term tests (7 to 28 days) or on potworms in short to long-term tests (14 to 42 days) in terrestrial systems. Soils to be tested may be (1) reference soils or potentially toxic site soils; 1.2?Modification of these procedures might be justified by special needs. The results of tests conducted using atypical procedures may not be comparable to results using this guide. Comparison of results obtained using modified and unmodified versions of these procedures might provide useful information concerning new concepts and procedures for conducting soil toxicity and bioaccumulation tests with terrestrial worms.

1.3?The results from field-collected soils used in toxicity tests to determine a spatial or temporal distribution of soil toxicity may be reported in terms of the biological effects on survival or sublethal endpoints (see Section 14). These procedures can be used with appropriate modifications to conduct soil toxicity tests when factors such as temperature, pH, and soil characteristics (for example, particle size, organic matter content, and clay content) are of interest or when there is a need to test such materials as sewage sludge and oils. These methods might also be useful for conducting bioaccumulation tests.

1.4?The results of toxicity tests with (1) materials (for example, chemicals or waste mixtures) added experimentally to artificial soil, reference soils, or site soils, (2) site soils diluted with reference soils, and 1.5?This guide is arranged as follows:

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

1.7?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. 1.8?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.