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Long-term toxicity to aquatic invertebrates

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Description of key information

NOEC (21d, overall threshold effects) = 1.10 mg/l

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates
Effect concentration:
1.1 mg/L

Additional information

The long-term toxicity to aquatic invertebrates is evaluated in a reproduction test on Daphnia magna conducted on the substane itself. Additional data on the analogue substance 1 -MSA are considered. Justification for Read Across is given in Section 13 of IUCLID.

A reproduction test on Daphnia magna (semi-static, 21 days) was carried out to assess the effect of the test item on the reproductive output of Daphnia magna, according to the OECD Guideline 211. Ten daphnids, held individually, were used per concentration level and control. Nominal concentrations of the test item were selected based on the results of a preliminary range finding test (non-GLP) as follows: 0.625 - 1.38 - 3.03 - 6.66 - 14.6 mg/l (separation factor 2.2). The effects on the reproduction capacity and other test item-related effects or parameters such as the intrinsic rate of the natural increase, first appearance of living juveniles, occurrence of aborted eggs and stillborn juveniles, adult mortality, body length and dry weight of the parental daphnids, were assessed. The test item concentrations were analytically verified via HPLC-DAD in the fresh media at the start of the exposure-renewal intervals on days 0, 9, 14 (0 hours) and in the old media at the end of the exposure intervals on days 2, 12, 16 (48 or 72 hours, respectively) in all concentration levels (with surviving daphnids) and in the control. The measured concentrations of the test item in fresh media at the start of the respective exposure renewal intervals (0 hours) were in the range of 93 to 111% of the nominal concentrations. At the end of the respective exposure-renewal intervals (48 and 72 hours), the measured test item concentrations in the old media were in the range of 92 to 104% of the nominal concentrations. The environmental conditions were within the acceptable limits. The validity criteria of the test guideline were met. The Cochran-Armitage trend-test revealed a significant trend in mortality. The effects on reproduction were evaluated based on the reproduction per introduced parent animal, since this parameter is the ecologically most relevant response variable and is required by the OECD test guideline 211 (2012), when a significant trend in mortality is detected. The overall effect threshold for effects of the test item on daphnid reproduction under the test conditions was 6.66 mg/l (NOEC) and 14.6 mg/l (LOEC) based on the nominal concentrations of the test item.

A reproduction test on Daphnia magna (semi-static, 21 days) was carried out to assess the effect of the similar substance 1 -MSA on the reproductive output of Daphnia magna, according to the OECD Guideline 211. Ten daphnids, held individually, were used per concentration level and control. Nominal concentrations of the test item were selected based on the results of a preliminary range finding test (non-GLP) as follows: 0.478 - 1.10 - 2.53 - 5.82 - 13.4 mg/l (separation factor 2.3). The effects on reproduction were evaluated based on the reproduction per introduced parent animal, since this parameter is the ecologically most relevant response variable and is required by the OECD test guideline 211 (2012), when a significant trend in mortality is detected. The overall effect threshold for effects of the test item under the test conditions was 1.10 mg/l (NOEC) and 2.53 mg/l (LOEC) based on the nominal concentrations.

The choice to include also data on the analogue substance is due to the fact that the study conducted on 1 -MSA showed the lowest effect levels regarding the toxic potential to long-term aquatic invertebrates.

Following a conservative approach, the results obtained in the long-term toxicity study on acquatic invertebrates on the Similar Substance 1 -MSA will be used for the chemical safety assessment.

More details on the results of the other substances in the Category will be provided in the attached document under "Ecotoxicological Information"