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Ecotoxicological information

Toxicity to soil microorganisms

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A dateline on the mineralisation of organic N by soil microorganism is available in a review. However, no NOEC was mentioned. Graphically, we can estimate it to be probably between 0.1 and 10 mg/kg soil. It is not clear whether the results were expressed in kg wet soil or dry soil. The exact NOEC is also unclear as the experimental design and statistics were not presented. Therefore, this result cannot be used to derive a PNEC

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Ammonification and nitrification are the most important processes of the nitrogen cycle. Usually tests for effects of pesticides are carried out with nitrogen-containing amendments like lucerne meal. In soils with a low carbon content such amendments may result in disturbance of soil populations. The ammonium ions released by nitrification are converted by nitrifying bacteria via nitrite in nitrate. Nitrification can also be studied by addition of ammonium directly to the soil. In this way, a NOEC (inhibition of nitrification in soil) for ETU, a conversion product in soil of ethylenebisdithiocarbamate fungicides (e.g. maneb, zineb) was graphically estimated between 0.1 and 10 mg/kg soil.