Registration Dossier

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Short-term

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

Aquatic invertebrates: EC50 48h > 113 mg/l

Algae: ErC50 (72hrs) = 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 (nominal)

Additional information

All three acute trophic levels were assessed either with study on the substance itself or with reliable Read Across studies on analogous substances. Justification for Read Across is given in Section 13 of IUCLID. EC50 was always measured as higher than 100 mg/l.

For the short-term toxicity to fish, some summary reports are available, for which the original complete reports were not recovered. The summaries are old, but they contain enough details to well identify the studies. They are all consistent and indicate a LC50 on Zebrafish at 96h higher than 500 - 1000 mg/l. A test (with a good reliability) on the toxicity to fish at 14 -days with Brachydanio rerio is available on the similar substance 3a-MSA. The nominal concentrations of 100, 316, 1000 mg /l were tested and the NOEC was identified at the concentration of 859 mg/l (nominal) (Bayer, 1992).

For the short-term toxicity to aquatic invertebrates, one test was performed on the substance under registration 3c-MSA (Ciba-Geigy Ltd in 1996), according to OECD guideline 202 on Daphnia magna; at the nominal concentration of 100 mg/l tested, no effects were observed. Nevertheless, the measured concentrations after 48h were less than 20 % of the nominal and geometric mean will result in EC 50 > 53 mg/l.

Acute toxicity for Daphnia magna was evaluated for the analogue substance 3a-MSA in a 48 hours screening test, according to the OECD guideline 202. A single dose was administrated at 100 mg/l (limit test) with no effect. The result was confirmed by two supporting studies: one performed at just 24h (RCC Umweltchemie AG., 1988) and the other one at 48, but just the summary is available (Solvias AG., 1999), with no effect up to 1000 mg/l.

No short-term toxicity to aquatic invertebrate is expected also for 3c-MSA. The result of the key study for 3a-MSA is taken as a reference for risk assessment.

The toxicity of the substance to aquatic algae was evaluated by considering data on similar substances. Supporting data from studies on the substance itself is also taken into consideration.

The substance is part of the group 3, but it has a difference in the organic substitution moiety: it has just one functionality hydroxyethyl, instead then two, as amino substituent.

It is a medium sulfonated, and the performed supporting study on the same substance indicate a NOEC < 100 mg/l. It has also to be noticed that water solubility is much less than the water solubility of the analogue 3a-MSA. In this respect the most similar and representative substance cannot be identified in the same group as 3a-MSA, but in group 2 (2-MSA) and 4 (4-MSA).

Regarding long-term studies, a long-term toxicity study on fish and on aquatic invertebrates are present for the similar substance 1 -MSA, performed according to the OECD Guideline 210 and 211, respectively and under GLP conditions.

The test item caused significant effects on Zebrafish in an early life stage test, 30 days post hatch. For the parameter hatch, the NOEC was 10.0 mg/l. Therefore, the respective LOEC was determined to be > 10.0 mg/l. For the parameters post hatch survival and overall survival, the NOECs were 1.25 and 2.50 mg/l, respectively. Therefore, the respective LOECs were determined to be 2.50 and 5.00 mg/l. For the parameter fry growth (expressed as length and fresh weight) the NOECs were < 0.625 mg/l (length) and 0.625 mg/l (weight). Therefore, the LOECs for length and weight were determined to be 0.625 and 1.25 mg/l, respectively.

The effects on reproduction of daphnia 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 11.3 mg/l (NOEC) and 22.5 mg/l (LOEC) based on the nominal concentrations of the test item.

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 similar 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".