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Long-term toxicity to aquatic invertebrates

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Description of key information

The long-term toxicity in invertebrates of Alcohols, C20-30 (even numbered), constituents has been documented within this dossier.  In accordance with REACH Annex XI, section 1, testing does not appear scientifically necessary for Annex endpoint 9.1.6.  Sufficient information is available to predict an absence of toxicity at the limit of solubility for linear alcohols with carbon chain lengths >C15 (Schaefers, 2005).  Moreover, from experience gained in tests that have been conducted with substances in this category, considerable technical difficulties would be expected in the conduct of such a test, due to the very rapid biotic removal of the substance from the test system.  Therefore, long-term toxicity to invertebrates requirements are waived based on technical testing difficulties, ready biodegradation and no short-term toxicity to aquatic organisms at the limit of solubility.  No reliable measured or predicted long-term toxicity data to invertebrates for constituents of Alcohols, C20-30 (even numbered), is available.

Key value for chemical safety assessment

Additional information

In accordance with REACH Annex XI, section 1, testing does not appear scientifically necessary for Annex endpoint 9.1.6. Sufficient information is available to predict an absence of toxicity at the limit of solubility for linear alcohols with carbon chain lengths ≥C15. Moreover, from experience gained in tests that have been conducted with substances in this category, considerable technical difficulties would be expected in conducting such a test, due to the low solubility of the test substance and its very rapid biotic removal from the test system. Therefore, long-term toxicity to invertebrates requirements are waived based on technical testing difficulties, ready biodegradation and low to no short-term toxicity to aquatic organisms at the limit of solubility. No reliable measured or predicted long-term toxicity data to invertebrates for constituents of Alcohols, C20-30 (even numbered), is available.

 

Study not technically feasible

The requirement to conduct long-term toxicity studies for Alcohols, C20-30 (even numbered) and its primary constituents tetracosan-1-ol, hexacosan-1-ol, and octacosan-1-ol is waived due to anticipated technical difficulties in performing such a test. Guideline (standard) studies for long-term toxicity testing would be confounded by the technical difficulties of maintaining the constituent alcohols 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 Alcohols, C20-30 (even numbered), as biodegradation in the test system was almost complete within the 24-hr test media renewal period.

 

Biodegradation

Reliable experimental studies (Klimisch scores 1 and 2) were performed in accordance with OECD Guidelines on eicosan-1-ol (C20), docosan-1-ol (C22), 2-decyltetradecanol (C24) and tetradecyloctadecan-1-ol (C32) that are constituents of and analogous to primary constituents of Alcohols, C20-30 (even numbered) and the LCA Category. The key study by Flach (2014) reported 90% biodegradation of tetradecyloctadecan-1-ol in an OECD 301B CO2-evolution test over 28 days. More than 60% of tetradecyloctadecan-1-ol had degraded within the 10-day study window. The key study demonstrates that tetradecyloctadecan-1-ol, a C32 long chain alcohol, is readily biodegradable. Supporting studies also confirmed the ready biodegradability of LCAs including constituents and analogue constituents of Alcohols, C20-30 (even numbered).

 

Toxicity to Aquatic Organisms

Generally the short-term aquatic toxicity of the primary constituent substances (tetracosan-1-ol, hexacosan-1-ol, and octacosan-1-ol) is low and long-term toxicity is considered to be greater than the limit of solubility (LoS) for alcohols ≥ C15 in chain length. In addition, the ready biodegradability of the test substance means long-term exposure to aquatic organisms is unlikely. Therefore, long-term toxicity to invertebrates requirements are waived based on technical testing difficulties, ready biodegradation and no short-term toxicity to aquatic organisms at the limit of solubility.