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Ecotoxicological information

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Description of key information

Short term toxicity

Fish: LC50 (96 h) > 1000 mg/l

Aquatic invertebrates: EC50 (48h) > 100 mg/l

Algae: ErC50 (72h) > 123 mg/l (nominal); NOEC (72h, growth rate) = 30.8 mg/l (nominal)

Long-term toxicity

Fish: NOEC (fry length, fry weight) = 4.41 mg/l (TWA, mean measured)

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

Additional information

The toxic potential of the substance to aquatic algae was evaluated considering data on the substance itself and on analogous substances. Justification for Read Across is given in Section 13 of IUCLID. The toxicity to fish and to aquatic invertebrates was entirely based on data on the substance itself.

Acute toxicity for Zebra fish was evaluated in the 96 hours screening test, according to the OECD guideline 203. Two concentrations were administrated at 562 and 1000 mg/l with no effect (Ciba - Geigy Ltd., 1992).

The study result is supported by other studies performed between 1973 and 1999 on Zebra fish at 96h for which only a summary is available indicating LC50 all greater than 1000 mg/l. Furthermore, a prolonged semistatic assay over 14 days was conducted with Brachydanio rerio. Endpoints were mortality, signs of intoxication, length and weight. The nominal concentrations were 100, 316 and 1000 mg/l. There was no mortality and no difference in body weight at nominal concentrations of 100 and 316 mg/l. Only at 316 mg/l one fish showed slackening in movement (Bayer AG., 1992).

Acute toxicity to Daphnia magna was evaluated in the 48 hours test, according to the EU method C2. A single dose was administrated at 100 mg/l (limit test). No dead occurred (Bayer AG., 2000). The result was confirmed by two supporting studies, one performed at just 24h (RCC Umweltchemie AG, 1988) and the other one at 48h, but just the summary is available (Solvias AG, 1999), with no effect up to 1000 mg/l.

The toxicity of the substance to aquatic algae was evaluated by considering data on similar substances obtained in studies conducted according to the OECD Guideline 201 and under GLP conditions. Supporting data from studies on the substance itself is also taken into consideration. The following results were obtained for the similar substances:

3a-A(Na): ErC50 (72h) > 123 mg/l (nominal); NOEC (72h, growth rate) = 30.8 mg/l (nominal).

3a-DSA: ErC50 (72hrs) > 110 mg/l (nominal); NOEC (72hrs, growth rate) = 110 mg/l (nominal)

The influence of 3a-MSA on the growth of the green alga Scenedesmus subspicatus chodat was also investigated. The study was performed according to the OECD Guideline 201. Based on the growth inhibition curve, the NOEC and the LOEC values were found to be 500 mg/l and 1000 mg/l, respectively. The EC50 values after 72 and 96 hours was >1000 mg/l (RCC Umweltchemie AG., 1990). The result is in agreement with a second study on the substance, for which just a summary is available (Solvias AG, 1999).

Following a conservative approach, the effect levels obtained in the study on 3a-A(Na) (lower NOEC) are considered for the chemical safety assessment considering the toxicity to aquatic algae.

Regarding long-term studies, a fish early-life stage toxicity study on the similar substance 1 -MSA was considered, performed according to OECD Guideline 210. Based on the results of a range finding test the test was conducted as a dose-response test with the nominal test item concentrations 0.301, 0.723, 1.74, 4.17 and 10.0 mg/l corresponding to 0.339, 0.796, 1.72, 4.41 and 10.8 mg/l (base on time-weighted arithmetic mean measured concentrations. For the parameters hatch, post-hatch survival and overall survival the NOEC was 10.8 mg/l. Therefore, the respective LOECs were determined to be > 10.8 mg/l. For the parameter fry growth (expressed as length and fresh weight) the NOEC was 4.41 mg/l. Therefore, the LOEC for this parameter was determined to be 10.8 mg/l.

Daphnia magna reproductive study is available on the substance conduected accorting to the OECD Guideline 211 in which the NOEC was determined as 6.59 mg/l.

The following results were obtained for the similar substances, obtained in studies conducted according to the OECD Guideline 211 and under GLP conditions:

3a-A(Na): NOEC (21d, overall threshold effects) = 3.22 mg/l; NOEC (21d, reproduction) = 3.22 mg/l

3a-DSA: NOEC (21d, overall threshold effects) = 2.0 mg/l; NOEC (21d, reproduction) = 4.0 mg/l

1 -MSA: NOEC (21d, overall threshold effects) = 1.10 mg/l; NOEC (21d, reproduction) = 2.53 mg/l

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.

Considering the available data on the three trophic levels, daphnia is considered to be the most sensitive species as the effect level during the long-term reproductive study was the lowest obtained.

Therefore, SELECTED NOEC for aquatic toxicity: 1.10 mg/l from the 21-days reproductive Daphnia study on the analogue substance 1 -MSA.

The study conducted on the similar substance 1 -MSA is used for the chemical safety assessment, following a conservative approach. More information on the results of the substances of the category are found on the document attached under "Ecotoxicological information".