Significance and Use
4.1 This guide provides a test procedure for evaluating the potential ecological impacts and environmental transport of a chemical in an agricultural (tilled, low-till, or no-till) or natural field soil ecosystem that may be released or spilled into the environment. The suggested test procedures are designed to supply site-specific information for a chemical without having to perform field testing. (See EPA 560/6-82-002 and EPA 560/6-82-003.)
4.2 This guide is not specifically designed to address fate of chemicals in soils of forested ecosystems. However, with some modifications, it may be adapted for that purpose by the individual investigator.
4.3 Specifically, this guide is used to determine the effect of a chemical on (1) growth and reproduction of either natural grassland vegetation or crops, and (2) nutrient uptake and cycling within the soil/plant system. Additionally, the soil-core microcosm will provide information on (1) potential for bioaccumulation (enrichment) of the chemical into plant tissues, and ( 2) the potential for and rate of transport of the chemical through soil to groundwater.
4.4 The results of this test should be used in conjunction with information on the chemical and biological activity of the test substance to assess the relative environmental hazard and the potential for environmental movement once released.
4.5 The test methods described in this guide are designed specifically for liquid or solid materials. Significant modifications of the exposure system would be necessary to accommodate chemicals that are volatile or that may be released in a gaseous or aerosolized form. For methods that could be adapted for use with volatile or gaseous test substances see Refs (3, 4, 5, 6).
Scope
1.1 This guide defines the requirements and procedures for using soil-core microcosms to test the environmental fate, ecological effects, and environmental transport of chemicals that may enter terrestrial ecosystems. The approach and the materials suggested for use in the microcosm test are also described.
1.2 This guide details a procedure designed to supply site-specific or possibly regional information on the probable chemical fate and ecological effects in a soil system resulting from the release or spillage of chemicals into the environment in either liquid or solid form.
1.3 Experience has shown that microcosms are most helpful in the assessment process after preliminary knowledge about the chemical properties and biological activity have been obtained. Data generated from the test can then be used to compare the potential terrestrial environmental hazards of a chemical.
