Alcohols, C20-30 (even numbered)

Short-term toxicity to fish

Description of key information

The short-term toxicity in fish of components of Alcohols, C20-30 (even numbered), has been documented within this dossier.  Adequate reliable measured data exists for short-term toxicity to fish to substances that are themselves constituents of as well as analogous to the primary components of Alcohols, C20-30 (even numbered). The most sensitive study result from across these substances was a reliable study with octadecan-1-ol (Wetton 1996), with read-across applied to icosan-1-ol, which reports an LC50 for short term toxicity in fish of >0.0011 mg/L, which is at the limit of solubility. Adequate reliable tests with long chain alcohols category, show no acute toxicity to fish at levels greater than the limit of solubility.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

0.4 mg/L

Additional information

Alcohols, C20-30 (even numbered), is a UVCB substance that comprises several linear long chain alcohols, predominantly tetracosan-1-ol (C24), hexacosan-1-ol (C26), and octacosan-1-ol (C28). Together, these substances make up approximately 70% of the composition of Alcohols, C20-30 (even numbered). Other constituents include, to a much lesser extent, secondary long chain alcohols and complex mixtures of long chain carboxylate esters. On this basis, study data, where available, for each of the long chain alcohol constituents has been evaluated and considered together; this is consistent with the Category approach applied for Long Chain Alcohols (LCA) under REACH.  In a conservative approach the most sensitive study result from the constituents of the LCA category have been identified and used to address the endpoint in question.

 

Several reliable (Klimisch 1 or 2) short-term toxicity studies in fish are available for substances that are themselves constituents of as well as analogous to the primary constituents of Alcohols, C20-30 (even numbered), and are included in this dossier. The reliable studies included for each constituents briefly described below. In a conservative approach the most relevant and reliable study result from these substances will be used to address the hazard endpoint in question.

 

Fisk et al. (2009) provided predicted results for the short-term toxicity of icosan-1-ol to fish using a validated QSAR based on measured data available across the alcohols category and the Log Kow of the substance. Fisk et al. (2009) predicted a 96hr LC50 of >100 mg/L for short–term toxicity to fish when exposed to icosan-1-ol. The result was compared to the limit of solubility (LoS) and for this substance the predicted LC50 is greater than the limit of solubility (>LoS, which is 0.1 mg/L). It is concluded that under circumstances when the predicted LC50 is greater than the LoS, the substance is not considered to be toxic.

Wetton (1996) conducted an OECD 203 compliant test exposing Rainbow trout, Oncorhynchus mykiss, to octadecan-1-ol for 96 hours. A 96 h LC50 value of >0.4 mg/L was determined for the effect of the test substance on mortality of the fish Oncorhynchus mykiss. The water solubility of octadecanol is 0.0011 mg/L at 25˚C (SIDS dossier on 1-octadecanol, 1993b; Budavari, 1996), therefore the LC50 value was attributed to be >0.0011 mg/L, (greater than the limit of solubility); that is, the test substance was not toxic at the limit of solubility.

 

Fisk et al. (2009) provided reliable (Klimisch 2) predicted results for the short-term toxicity of docosan-1-ol to fish using a validated QSAR based on measured data available across the alcohols category and the Log Kow of the substance. Fisk et al. (2009) predicted a 96hr LC50 of >100 mg/L for short-term toxicity to fish when exposed to docosan-1-ol. The result was compared to the limit of solubility and for this substance the predicted LC50 is greater than the limit of solubility. It is concluded that under circumstances when the predicted LC50 is greater than the limit of solubility, the substance is not considered to be toxic.

Wetton (2000) conducted an OECD 203 and GLP exposing Rainbow trout, Oncorhynchus mykiss, to docosan-1-ol for 96 hours resulting in a 96hr LL50 of >1000 mg/L WAF (water accommodated fraction). Experimental values are preferred over predicted values and therefore, the Wetton (2000) study is designated as key for assessment purposes.

 

The short-term toxicity in fish of components of Alcohols, C20-30 (even numbered), has been documented within this dossier. Adequate reliable experimental data exists for short-term toxicity to fish to substances that are themselves constituents of as well as analogous to the primary components of Alcohols, C20-30 (even numbered). In a conservative approach the most sensitive study result from the experimental studies has been identified and used to address the hazard endpoint in question. The most sensitive experimental study result from across the three substances is a reliable study with octadecan-1-ol (Wetton 1996), with read-across applied to icosan-1-ol, which reports an LC50 for short term toxicity in fish of >0.4 mg/L, which is greater than the limit of solubility for icosan-1-ol. Consequently this value will be taken as the short-term toxicity in fish endpoint for Alcohols, C20-30 (even numbered).