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Ecotoxicological information

Toxicity to soil macroorganisms except arthropods

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Description of key information

Diuron is not considered to be toxic to eathworms under test conditions

Key value for chemical safety assessment

Additional information

One chronic toxicity test was conducted in accordance with prevailing guidelines ( BBA Guideline Teil VI, 2-2 and ISO Guideline 11268-2) with GLP, however, the test concentrations were not confirmed by chemical analysis (Stäbler, 2001).The NOEC for effects on biomass and reproduction was determined to be 21.3 mg a.i./kg dry artificial soil corresponding to 10 kg Karmex 80 WG/ha. The LOEC for effects on biomass was determined to be 53.3 mg a.i./kg dry artificial soil corresponding to 25 kg Karmex 80 WG/ha. These results indicate that the test item is in all probability not harmful to earthworms following chronic exposure.Furthermore, an acute toxicity test was conducted in accordance with the prevailing OECD testing guidelines (OECD 207), with GLP. This derived a LC50(14 days) for Diuron WP 80 of > 800 mg Diuron/kg and a NOEC of 142.4 mg Diuron/kg (Heimbach, 1993).

Discussion on endocrine disruption:

As at the current stage there is still no agreed approach and guidance on how to evaluate endocrine disruption in various EU legislations the OECD Conceptual framework for Testing and Assessment of Endocrine Disruptors might be used. Comparing available data with the Framework`s level concept allowed to rank Stäbler (2001) in OECD level 1, which is the lowest level and such studies do not allow to conclude on endocrine properties of diuron. This study assessed effects of Diuron exposure on reproduction and growth of Eisenia foetida according to GLP standard and a BBA guideline part VI, 2-2 / ISO guideline 11268-2, which may be understood as a precursor to OECD test guideline 222. As there is no such study among those listed in level 2 to 5 this study may only be ranked as level 1. This study reports of a reduced number of juveniles when exposed to a test item concentration which is at least 5-fold higher than the field application rate and, thus, was performed under unrealistic test conditions. In conclusion the study result are not adequate for decision on endocrine properties of diuron. See also the document on the ad hoc assessment on endicrine disruption properties of diuron attached in chapter 13 of IUCLID.