Alcohols, C18-22, distn. residues

Endpoint summary

Additional information

Behenyl Bottoms are characterised as Alcohols, C18-22, distillation residues and the data requirement for bioaccumulation is waived. The REACH requirement in Annex IX for a study on bioaccumulation in aquatic species is not needed if the substance has a low potential for bioaccumulation and/or a low potential to cross biological membranes. The waiver argumentations are based on the technical difficulties associated with conducting bioaccumulation studies, the low toxicity in aquatic organisms and the low toxicity in mammals resulting in the unlikely potential for secondary poisoning, as presented in more detail below:

Study not technically feasible

The requirement to conduct bioaccumulation studies for Alcohols, C18-22, distillation residues is waived due to the technical difficulties in performing such a test. The water solubility of the substance is below the limit of quantification based on experimental evidence by Cartee and Schaefer (2009) where the limit of solubility was <1 mg/L. Further evidence provided in this dossier suggests that the maximum solubility for Alcohols, C18-22, distillation residues will be 0.007 mg/L, based on a conservative approach. The low solubility of the substance means that it is technically unfeasible to undertake a guideline (standard) study of bioaccumulation in fish where the test substance would need to be maintained in solution for 56 days to be available for uptake by fish.

Toxicity to Aquatic Organisms

Generally the short-term aquatic toxicity of the test substance is low and long-term toxicity is considered to be below the limit of solubility (LoS) for alcohols > C15 in chain length (OECD SIDS Long Chain Alcohols, 2006). In addition, the low solubility of the test substance means long-term exposure to aquatic organisms is unlikely.

Toxicity to Mammals

There is no requirement in REACH to conduct a secondary poisoning assessment in view of the lack of toxic effects in mammals. Evidence presented in this dossier demonstrates the low toxicity to mammals, for example, Kuhn (2009) reported LD50 in rats to be >2,000 mg/kg and in a reproduction study by Szucs (2010) a NOEL of 1,000 mg/kg/day in rats was reported. Additional evidence in the OECD SIDS report (2006) of long chain alcohols reported low toxicity in chronic and sub-chronic mammalian toxicity studies. Based on the combined experimental and published evidence, the test substance is not considered to be toxic (in PBT terms) to mammals and secondary poisoning is unlikely to occur in the environment.

In summary, the data requirement for bioaccumulation studies in aquatic and terrestrial organisms is waived on the evidence of technical difficulties and the absence of toxicity in aquatic organisms and mammals. A bioconcentration factor (BCF) for Alcohols, C18-22, distillation residues was calculated using EPISuite (BCFBAF v. 3) based on a range of SMILES notations for the constituent substances and the extrapolated log Kow of >7.17 (Schutt and Nixon, 2010). The resulting BCF was 2,780 (log BCF was >3.44). However, predicted BCFs for long chain alcohols have been shown to be overestimates (OECD SIDS, 2006; Veith et al., 1979 and Connell and Hawker, 1988).

References

SIDS Initial Assessment Report on Long Chain Alcohols (2006). Organisation for Economic Cooperation and Development (OECD).

Veith GD, Defoe DL and Bergstedt BV (1979). Measuring and estimating the bioconcentration factor of chemicals in fish. J. Fish. Board Can. 36: 1040-1048.

Connell DW and Hawker DW (1988). Use of polynomial expressions to describe the bioconcentration of hydrophobic chemicals by fish. Ecotox. Environ. Safety 16: 242-257.