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Ecotoxicological information

Toxicity to soil microorganisms

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Description of key information

No effects at the highest test concentration. The 28 -d EC10 is >1000 mg/kg soil d.w. in soil microorganisms based on nitrate formation rate.

Key value for chemical safety assessment

Additional information

The toxicity to soil microorganisms was determined in a study according to OECD guideline No 216 and in compliance with GLP criteria (BASF, 2016). In this study the test substance was mixed with a natural soil containing an added nitrogen source at nominal concentrations of 0 (control), 62.5, 125, 250, 500 and 1000 mg/kg soil dry weight and incubated at ca. 20 °C for 28- days in the dark. Based on the limited water solubility the application of the test substance via an aqueous stock solution was not possible and the test substance was pulverized and the required amounts directly added to quartz sand and thoroughly mixed. Test concentrations were not analytically verified (not required). Two days before start of exposure the soil was mixed with deionized water to a water content corresponding to 40 % of the water holding capacity and the mixture stored until usage. Luzerne meal was used as nitrogen source at the start of exposure. The content of nitrate nitrogen (as mg/kg soil dry weight) in the test assays was determined at days 0, 7 and 28 and compared to the blank control. Throughout the test no significant inhibition of nitrate production was recorded at any of the concentrations tested. Based on these findings the 28 -d EC10 for soil microorganisms was determined at >1000 mg/kg soil d.w. The results in this study are consistent with all relevant validity criteria and the test is valid according to the guidelines of this study.