Environmental fate studies

This Test Guideline describes an experimental method using HPLC for the estimation of the adsorption coefficient (K_oc) in soil and in sewage sludge. The adsorption coefficient is defined as the ratio between the concentration of the substance in the soil/sludge and the concentration of the substance in the aqueous phase at adsorption equilibrium. The test item is injected in the column packed with cyanopropyl solid phase containing lipophilic and polar moieties. As a result of partitioning between mobile and stationary phases the test item is retarded. The retention time is determined in duplicate.

A test item is exposed to an inoculum in a closed environment as part of the OECD 301 aerobic biodegradation test, which analyses the substance's biodegradation by parameters such as DOC, BOD, or CO₂ measurements. This set of test identifies substances that do not require additional testing if they pass the OECD 301 test. A test item considered readily biodegradable if it achieves 60% of chemical breakdown within 28 day period according to OECD 301 D. When a sample is able to pass the test, it is considered that it has the ability to biodegrade rapidly and thoroughly in the environment, and therefore known to be readily biodegradable. Hence, more research is typically not needed to determine a substance's biodegradability, toxicity, or other environmental impacts.