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Ecotoxicological information

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Experimental studies are available investigating the short-term effects of the test item on aquatic organisms from three different trophic levels. The studies were performed according to internationally accepted guidelines in accordance with GLP. All studies were performed with freshwater species.

One experimental study was conducted testing acute toxicity of the test item to fish according to OECD Guideline No. 203 (1992) using zebra fish (Lebertz, 2017a). In order to investigate the effect of the test item on fish, the animals were exposed in a semi-static test design to up to a nominal test substance concentration of 111 mg/L (equivalent to 100 mg a.i. /L). Under the conditions used for the test, no significant toxic effects of the test item on fish were observed at a nominal test substance concentration of 111 mg/L (equivalent to 100 mg a.i. /L) (main test, performed as a limit test). As a conclusion of the analytical part of this study, it can be stated that the concentrations of the test item remained sufficiently stable during incubation. Based on this, the reported effect concentrations should refer to the nominal concentrations tested. The LL50 was determined to be > 100 mg a.i./L and 111 mg test item/L.

One study is available, in which the short term toxicity to invertebrates was investigated according to GLP and OECD guideline 202 using the water flea species Daphnia magna (Lebertz, 2017b). The nominal concentrations were verified by analytical monitoring. Daphnia magna was exposed over a period of 48 h without feeding in a static system to nominal concentrations of 11.1, 22.2, 44.4, 88.8 and 111.1 mg test item/L (nominal). The nominal test item concentrations are equivalent to the concentrations based on active ingredient of 9.99, 20.0, 40.0, 88.8 and 100 mg active ingredient/L (nominal). Under the conditions used for the test, there was an immobilisation of the D.magna at concentrations ≥22 mg test item/L representing 20 mg/L of active substance/L. As a conclusion of the analytical part of this study, it can be stated that the concentrations of the test item remained sufficiently stable during incubation of 48 h. As a result of the supporting analyse it can be stated that the results of the biological part should be based on the nominal concentrations applied because the recoveries of the nominal concentrations were all >80%. The EL50 was determined to be at 80.8 mg test item/L after 48 h and the NOEL was observed to be at 22.2 mg test item/L. Based on the active ingredient the EL50 was determined to be at 72.7 mg a.i./L and the NOEL was observed to be at 20.0 mg a.i./L.

One experimental study is available investigating the toxicity of the substance to aquatic freshwater algae. The study was conducted according to OECD 201 (GLP) using the freshwater algae Desmodesmus subspicatus (Lebertz, 2017c). Analytical monitoring of the test item concentration was performed during the exposure period of 72 hours. The test was performed using five concentrations of "WAFs" (Water accommodated fractions) in the nominal range of 11.1 to 178.6 mg/L of the test item representing 10 to 160 mg/L of active matter (90% of the test item are representing the active matter). As a result of the supporting analyse it can be stated that minor concentrations of the test item were measured due to WAF-preparation. Nevertheless the measured concentrations remained stable during incubation and thus, the results of the biological part should be based on the nominal concentrations. The EL50 (72h) for growth rate was determined to be > 100 mg/L based on the active ingredient as well as on the test item. The EL10 (72h) for growth rate was determined to be at 95.43 mg test item/L and based on the active ingredient it was determined to be at 85.86 mg a.i./L. The validity criteria for the study as given by the OECD Guideline 201 were all met and the study is therefore considered to be valid.

There is one key GLP study available investigation the effects of the substance on microorganisms from activated sludge by measuring their respiration rate in the presence of the substance, according to the OECD guideline 209. The study was conducted in accordance with OECD Guideline 209 and under GLP conditions (Lebertz, 2017d). The activated sludge was exposed to test item concentrations of 0, 93.9, 207, 455, 1000 and 2200 mg/L (nominal) together with and without the specific nitrification inhibitor allylthiourea. After 3 hours of incubation period the inhibition of the respiration rates of the activated sludge were determined in comparison to the respective set of test solutions without any test item. All conditions of validity of the test were kept within this study. Under the conditions of the test the following EC-values were determined on basis of the mean active substance concentrations in the treatments. The EC50 based of the inhibition of total respiration was determined to be at 25410 mg/L. The EC50 based of the inhibition of the heterotrophic respiration was determined to be at 2873 mg/L. The EC50 based of the inhibition of the respiration based on nitrification was determined to be at 1935 mg/L.