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Ecotoxicological information

Endpoint summary

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Additional information

There are no data available for the aquatic toxicity of the target substance 2-[3-[(4-Amino-2-methylpyrimidin-5-yl)methyl]-4-methyl-1,3-thiazoniol-5-yl]ethyl dihydrogen diphosphate (CAS 136-09-4). Therefore, the aquatic hazard of the target substance was assessed by a read-across approach to the structurally and physico-chemically closely related source substance 2-{3-[(4-amino-2-methylpyrimidin-5-yl)methyl]-4-methyl-1,3-thiazol-3-ium-5-yl}ethyl hydrogen phosphate (CAS 10023-48-0) in order to fulfill the standard information requirements laid down in Annex XI, 1.5, of the REACH Regulation (EC) No 1907/2006.

According to Article 13 (1) of this regulation, "information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI are met.” In particular for aquatic toxicity, information shall be generated whenever possible by means other than vertebrate animal tests, which includes the use of information from structurally related substances (grouping or read-across). In regard to the general rules for grouping of substances and the read-across approach, the regulation specifies (Annex XI, Item 1.5) that substances may be predicted as similar provided that their physicochemical, toxicological and ecotoxicological properties are likely to be similar or follow a regular pattern as a result of structural similarity.

Based on the high degree of structural and chemical similarity of the target and source substance, the source substance is considered a suitable proxy for the assessment of the aquatic hazard of the target substance, which is expected to exhibit a similar environmental fate and ecotoxicological profile as the selected source substance. A detailed analogue approach justification is provided in IUCLID section 13 of the technical dossier.

By means of the read-across approach, data for the assessment of the aquatic hazard of the target substance (CAS 136-09-4) are available from guideline studies performed under GLP standards for the short-term toxicity to all three trophic levels (fish, aquatic invertebrates and algae), for the long-term toxicity to one single trophic level (aquatic algae), as well as for the toxicity to microorganisms.

The short-term toxicity studies for fish (OECD 203), aquatic invertebrates (OECD 202) and algae (OECD 201) showed no effects up to a nominal concentration of 100 mg/L. Likewise, the single reported chronic effect concentration for aquatic algae indicates no chronic effects either (ErC10 > 100 mg/L). The respiration inhibition study (OECD 209) resulted in a NOAEC (3 h) of ≥ 1000 mg/L, indicating that the substance is not toxic to aquatic microorganisms.