OECD Guidelines for the Testing of Chemicals, Section 2
Effects on Biotic Systems
- 2074-5761 (online)
The OECD Guidelines for the Testing of Chemicals is a collection of about 150 of the most relevant internationally agreed testing methods used by government, industry and independent laboratories to identify and characterise potential hazards of chemicals. They are a set of tools for professionals, used primarily in regulatory safety testing and subsequent chemical and chemical product notification, chemical registration and in chemical evaluation. They can also be used for the selection and ranking of candidate chemicals during the development of new chemicals and products and in toxicology research. This group of tests covers effects on biotic systems.
Test No. 216: Soil Microorganisms: Nitrogen Transformation Test
- 21 Jan 2000
- 9789264070226 (PDF)
This Test Guideline describes a laboratory test method designed to investigate the long-term effects of chemicals, after a single exposure, on nitrogen transformation activity of soil microorganisms.
Sieved soil is amended with powdered plant meal and either treated with the test substance or left untreated. For agrochemicals, a minimum of two test concentrations are recommended (five for non agrochemicals) and these should be chosen in relation to the highest concentration anticipated in the field. The soil is divided into three portions of equal weight (six for non agrochemicals). Two portions are mixed with the carrier containing the product (five for non agrochemicals), and the other is mixed with the carrier without the product (control). A minimum of three replicates for both treated and untreated soils is recommended. After 0, 7, 14 days and 28 days of incubation, samples of treated and control soils are extracted with an appropriate solvent, and the quantities of nitrate in the extracts are determined. All tests run for at least 28 days. If, on the 28th day, differences between treated and untreated soils are equal to or greater than 25%, measurements are continued to a maximum of 100 days. Results from tests with multiple concentrations are analysed using a regression model, and the ECx values are calculated.