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Description of key information

Short-term toxicity

Fish: LC50 (96 h) > 100 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) < 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 3a-A(NaK) and 2 -A. 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 both inhibition of growth rate (ErC50) and yield (EyC50) after 72 hours were > 123 mg/l. The NOEC for growth rate and yield was 30.8 and 7.69 mg/l, respectively.

Regarding long term studies, a Daphnia magna reproductive study is available on the substance performed according to the OECD Guideline 211. The NOEC (21d, overall threshold effects and reproduction) was determined as 3.22 mg/l based on the time-weighted mean measured concentrations of the test item.

For the evaluation of the long-term toxicity to fish, two studies are available: one on the substance and one on similar substance 2 -A. Both studies were performed according to the OECD Guideline 210. Justification for Read Across is given in Section 13 of IUCLID.

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.

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).

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".