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Ecotoxicological information

Toxicity to soil microorganisms

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Reference
Endpoint:
toxicity to soil microorganisms
Data waiving:
exposure considerations
Justification for data waiving:
the study does not need to be conducted because direct and indirect exposure of the soil compartment is unlikely

Description of key information

In accordance with Section 3 of REACh annex XI, a test on toxicity towards soil microorganisms does not need to be conducted as exposure of the terrestrial compartment is unlikely to occur. In the case of hydrazine, exposure to the terrestrial compartment will only result from indirect pathways via emissions to air or to waste water. Any waste air possibly containing hydrazine is either transferred to an incineration plant, to a gas scrubber or cleaned by the means of an activated char coal filter. Based on the efficiency of these processes and the fact that hydrazine will rapidly be degraded in the atmosphere, soil exposure via wet deposition of hydrazine from the atmosphere can be neglected. Emissions to waste water might result in an indirect exposure of the terrestrial compartment via the application of sludge originating from sewage treatment plants (STPs). Only sludge originating from municipal STPs is allowed to be used for agriculture, whereas the use of sludge from industrial STPs is prohibited. The entry of relevant amounts of hydrazine on soil via the application of sewage sludge can be excluded as hydrazine is not assumed to sorb on sewage sludge to a significant extent. Hydrazine is characterized by a logPow of -0.16, is highly soluble in water and rapidly degrades in the overlying water phase due to the presence of organic matter and ions. Concluding, sorption to sewage sludge is unlikely due to the substance partitioning behaviour and physico-chemical properties.  

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