Registration Dossier

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Short-term

Fish: LC50 (96 h) > 100 mg/l

Aquatic invertebrates: EC50 48h > 100 mg/l

Algae: ErC50 (72h) = 208 mg/l (nominal); NOEC (growth rate, 72h) = 12 mg/l (nominal)

Long-term toxicity

Fish: NOEC (fry weight) = 0.625 mg/l (nominal)

Aquatic invertebrates: NOEC (21d, overall threshold effects and reproduction) = 3.22 mg/l (twa)

Additional information

The toxic potential of the substance to aquatic invertebrates and fish after a short-term exposure was evaluated considering data on the substance itself and on analogous substances. Justification for Read Across is given in section 13 of IUCLID.EC50 was always measured as higher than 100 mg/l.

The toxicity to aquatic algae was entirely based on data on the substance itself. The toxicity of the substance to the unicellular freshwater green alga Pseudokirchneriella subcapitata was determined according to the principles of OECD 201 and Council Regulation (EC) No. 266/2016/Method C.3 for the determination of the effects on growth rate and yield over a period of 72 hours. The study was conducted under static conditions. The effect values of the substance on the growth of the freshwater green alga Pseudokirchneriella subcapitata after 72 hours were determined as follows (based on nominal test item concentrations): The EC50-values for inhibition of growth rate (ErC50) after 72 hours was 208 mg/l. The NOEC for growth rate was 12 mg/l.

Regarding long term studies, a Daphnia magna reproductive study is available on the similar substance 3a-A(Na) (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 as follows: 0.480 - 1.20 - 3.00 - 7.50 - 18.8 mg/l (separation factor 2.5), corresponding to the time-weighted mean measured test item concentrations 0.540 – 1.29 – 3.22 – 7.78 – 19.3 mg/l. The NOEC for orverall threshold effects and for effects on reproduction was found as 3.22 mg/l.

For the evaluation of the long-term toxicity to fish, two studies on similar substances are available. Both studies were performed according to the OECD Guideline 210.

2 -A 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. For the parameters post hatch survival and overall survival, the NOECs were 1.25 and 2.50 mg/l, respectively. 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).

3a-A(Na) partly caused significant effects on Zebrafish in an early life stage test, 30 days post hatch when tested with time-weighted arithmetic mean measured concentrations of 1.09 and 11.2 mg/l. For the parameters hatch, post-hatch survival, overall survival and fry growth (expressed as length) the NOEC was 11.2 mg/l. For the parameter fry growth (expressed as fresh weight) the NOEC was < 1.09 mg/l.

Considering the available data on the three trophic levels, fish is considered to be the most sensitive species as the effect level during the fish early-life stage toxicity study on 2 -A was the lowest obtained.

Therefore, SELECTED NOEC for aquatic toxicity: 0.625 mg/l from the fish early-life stage toxicity on the similar substance 2 -A.

The study conducted on the similar substance 2 -A 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".