Olefines polymer, oxidized, hydrolyzed, distn. residues, from C20 alcohols manuf.

Bioaccumulation: terrestrial

Description of key information

The data requirement for bioaccumulation studies in aquatic and terrestrial organisms is waived on the evidence of technical difficulties, ready biodegradability and the absence of toxicity in aquatic organisms and mammals.

Additional information

Olefines polymer, oxidized, hydrolyzed, distillation residues is a by-product of the C20 alcohols manufacturing process. It is a UVCB substance that comprises several linear long chain alcohols, predominantly docosan-1-ol (C22), tetracosan-1-ol (C24), hexacosan-1-ol (C26) and eicosan-1-ol (C20). Together, these substances make up over 80% of the composition of olefines polymer, oxidized, hydrolyzed, distillation residues. 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.

The REACH requirement in Annex IX for a study on bioaccumulation in terrestrial 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 ready biodegradability of the test substance, 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 long chain alcohols, in particular the main constituents icosan-1-ol and docosan-1-ol, is waived due to technical difficulties in performing such a test. Guideline (standard) studies of bioaccumulation in fish would be confounded by the technical difficulties of maintaining the test alcohols (icosan-1-ol and docosan-1-ol) in solution, as was demonstrated in long-term invertebrate studies reported in the OECD SIDS Report for Long Chain Alcohols (2006). Severe difficulties were encountered when studies were conducted with ≥C15 alcohols, which are similar to constituents of Olefines polymer, oxidized, hydrolyzed, distillation residues

, as biodegradation in the test system was almost complete within the 24-hr test media renewal period.

 

Biodegradation

Long chain alcohols are readily biodegradable, as evidenced by biodegradation studies using icosan-1-ol, docosan-1-ol and 2-decyltetradecanol. In the most recent and reliable studies by Flach (2012), the degradation of 2-decyltetradecanol and docosan-1 -ol were 84.9% and 87.5%, respectively, after 28 days with the degradation rate reaching more than 60% within the 10-day window. As these constituents are readily biodegradable, olefines polymers, oxidized, hydrolyzed, distillation residues can also be regarded as readily biodegradable. Minor residual constituents which include ethers and esters are also expected to degrade rapidly. It should be noted that these minor residual constituent degradation products of olefines polymer, oxidized, hydrolyzed, distillation residues are unlikely to be chemicals that might be a cause for concern.

 

Toxicity to Aquatic Organisms

Generally the short-term aquatic toxicity of the primary constituent substances (icosan-1-ol and docosan-1-ol) is low. According to the OECD SIDS Report for Long Chain Alcohols (2006) long-term toxicity is also considered to be very low and greater than the limit of solubility for alcohols ≥ C15 in chain length.

 

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. Chronic and sub-chronic mammalian toxicity studies have shown that long chain alcohols (LCA) are of low toxicity. Furthermore, combined repeated-dose studies with developmental endpoints, as well as reproductive and developmental studies, showed no effects at the highest dose tested. This evidence indicates that the test substance is not considered to be toxic (in PBT terms) to mammals and secondary poisoning is unlikely to occur in the environment.

 

Summary

The data requirement for bioaccumulation studies in aquatic and terrestrial organisms is waived on the evidence of technical difficulties, ready biodegradability and the absence of toxicity in aquatic organisms and mammals.