Sodium p-chloro-m-cresolate

Endpoint summary

Additional information

There are no aquatic toxicity data available for sodium p-chloro-m-cresolate (CAS 15733-22-9).Therefore, a read-across approach was conducted to compile relevant data from a structurally and chemically related source substance in order to fulfill the standard information requirements laid down in Annex VIII of REACH Regulation (EC) No 1907/2006. The read-across was conducted in accordance with Regulation (EC) No 1907/2006 Annex XI, 1.5.

This read-across is based on the hypothesis that the source substance (p-chloro-m-cresol, CAS 59-50-7) and the target substance (sodium p-chloro-m-cresolate) have similar respectively the same toxicological and eco-toxicological properties. The target substance is transformed by hydrolysis into the source substance and sodium cation. The source substancep-chloro-m-cresolis the common compound in this analogue approach and is solely responsible for the (absence of) effects.Thus, the source substance is considered a suitable representative for the evaluation of the toxicity of the target substance to aquatic organisms. The read-across approach is justified in detail within the analogue justification in IUCLID section 13.

Acute and chronic tests evaluating the toxicity of the source substance p-chloro-m-cresol (CAS 59-50-7) to aquatic organisms from three different trophic levels are available. The assessment of short-term toxicity to fish is based on a key study according to EPA OPP 72-1 (GLP). A LC50 of 0.92 mg/L (measured arithmetic mean) for Oncorhynchus mykiss was determined. In addition to the short-term study two additional studies investigated the long-term toxicity to rainbow trout. These studies were prerformed according to OECD 215 and equivalent to OECD 204, respectively. The NOEC (28 d) in the key study was determined to be 0.15 mg/L (measured) based on growth rate. In the supporting study a NOEC (14 d) of 1 mg/L (nominal) based on mortality was determined. The toxicity of p-chloro-m-cresol to Daphnia magna was investigated in one short (EPA OPP 72-2) and one long-term study (OECD 211). The EC50 (48 h) was 2.29 mg/L (arithmetic mean measured) and the NOEC (21 d) based on reproduction 0.32 mg/L (nominal).
The assessment of toxicity to algae is based on one key study. Based on growth rate an EC50 (72 h) of 30.62 mg/L for Desmodesmus subspicatus was determined (corresponding NOEC (72 h) = 9.8 mg/L) based on nominal concentrations. One study investigated the toxicity on aquatic microorganisms according to OECD 209. An EC50 (3 h) of 41.4 mg/L (nominal) was derived. The EC10 (3 h) was determined to be 5.7 mg/L (nominal).

Based on the available results from a structurally similar source substance (in accordance to Regulation (EC) No 1907/2006 Annex XI, 1.5) which is the main transformation product of the target substance and is characterized by a similar ecotoxicological profile and comparable structure, it can be concluded thatsodium p-chloro-m-cresolatehas effects in the same range as the target substance.