diethyl 1-(2,4-dichlorophenyl)-5-methyl-4,5-dihydro-1H-pyrazole-3,5-dicarboxylate

Endpoint summary

Additional information

The substance is not expected to pose a risk to terrestrial organisms. There is no indication for high adsorption or high persistence of the substance in soil. The determined log Pow of the substance is 4 and the adsorption potential is low (Koc range 486 – 823). Available tests on the biodegradation of the substance in soil determined half-lives of 7-13 days. Thus a long-term exposure of terrestrial organisms to substance is not likely. The substance is not acutely very toxic to aquatic organisms. All available effect concentrations (EC/LC50) are > 1 mg/L . Furthermore the available acute toxicity test conducted with earthworms determined no toxic effects of the substance. The study was conducted according to OECD guideline 207 (1991) using artificial soil as substrate. Earthworms of the species Eisenia fetida were exposed to a limit concentration of 1000 mg/kg. The artificial soil, prepared from a mixture of dried sphagnum peat, kaolin clay and industrial sand, was mixed with the test substance. No mortalities or symptoms of intoxication were observed. The determined 14-day LC50 was > 1000 mg/kg soil dw was no death occurred at this limit dose. In the absence of any sublethal findings (intoxication symptoms, weight gain and intoxication symptoms) the NOEC (14 d) was 1000 mg/kg soil dw. The available studies on toxicity of the substance to soil microorganisms determined no adverse effects. The studies were conducted according to OECD 217 ( Soil Microorganisms: Carbon Transformation Test, 2006a) and OECD 216 (Soil Microorganisms: Nitrogen Transformation Test, 2006b). The study was performed in a field soil at concentrations equivalent up to a field application rate of 525 g test item/ha. A NOEC (28 d) of 0.7 mg/kg soil dw (nominal) was determined for respiration rate and nitrate formation rate respectively.

According to Annex IX, column 2 of Regulation (EC) No 1907/2006, chronic toxicity testing with soil macroorganisms does not need to be conducted as the Chemical Safety Assessment does not indicate a need for further investigations. According to Annex XI, Section 3 of Regulation (EC) No 1907/2006 toxicity tests on soil macroorganisms are considered not necessary. The exposure concentrations for the terrestrial compartment during the lifecycle of the substance are low. The environmental exposure assessment for the substance indicates no risk for the terrestrial compartment (all RCR< 1; please refer to Chapter 9 and 10 of the Chemical Safety Report for detailed information).