2-hexyldecan-1-ol

Endpoint summary

Additional information

There is sufficient information available to indicate that 2-hexyldecan-1-ol is likely to adsorb to sediments and soils, for example, McCall (1981) classified 2-octyldodecanol with a Koc >5,000. Measured adsorption values for hexadecanol (Koc of 143,000) and octadecanol (Koc of 471,000) are presented in the SIDS SIAR Long Chain Alcohols Report (2006). In this CSR, the study by Bodsch (2009) reported a Log Koc of 8.92 for 2-octyldodecanol in soil with a corresponding Koc value of 8.4x10E8. For sewage sludge the Log Koc was determined to be 9.79 with a corresponding Koc of 6.2x10E9.

From these data it is expected that 2-hexyldecanol will be immobile in soils and sediment. However, while a substance may adsorb readily to sediment, sludge and soil, when it rapidly degrades, the availability of the substance to bind to substrates will be limited by degradation. In addition, where a substance does sorb to sediment or soil, the substance will be readily degraded as it desorbs.

According to the OECD SIDS Iinital Assessment Report for Long Chain Alcohols (2006) reliable measured data (e.g. for hexanol, octanol, decanol, dodecanol, tetradecanol, hexadecanol and octadecanol) show that alcohols with chain lengths up to C18 are readily biodegradable. At carbon chain lengths up to C16, most tests showed that pass levels for ready biodegradation were reached within the 10-day window, with removal levels up to 100% over the timescale of the test. In additional studies conducted at environmentally realistic concentrations with radio-labelled substances (C12-16), very high rates of degradation have been measured (very rapid rate constants, with ca. 75-85% removed as CO2 and metabolites). These rates accord with field data for measured concentrations in waste-water treatment plant influent and effluent showing greater than 99% removal for carbon numbers 12 to 18. This summary of degradation is applicable to both linear and branched components of substances in the category. Therefore, the whole category is considered to show very high levels of biodegradability. Rapid degradation is also indicated by the removal rates in the chronic aquatic toxicity tests for the lower solubility substances (C10 to C15), where rapid removal of the substance from the test medium was observed, most likely due to biodegradation by micro-organisms.

Reliable measured data show that 2 -hexyldecan-1-ol and all Guerbet alcohols of chain lengths at least up to C24 are readily biodegradable. The OECD SIDS Initial Assessment Report for Long Chain Alcohols (2006) concludes that linear and essentially linear C6-22 alcohols are rapidly biodegradable especially at environmentally relevant concentrations.

Biodegradation of 2-hexyldecanol will not produce degradation products of concern. In a study by Federle and Itrich (2006) long chain alcohols rapidly decayed in water treatment processes. The sorption potential of hexadecanol did not significantly affect degradation (predicted to be 99.84% in the absences of solids and 99.76% in the presence of solids. The half-lives of all the long chain alcohols tested was less than one minute. Removal in activated sludge plants of long-chain alcohols, such as hexadecanol, is reported to be 99.46%. Biodegradation occurs by two pathways oxidation of the alcohol to a fatty acid is beta oxidised to form carbon dioxide, the other pathway is via omega oxidation of the methyl group yields dioic acids, which undergoes beta oxidation (Federle and Itrich, 2006).

The Guerbet Alcohol will be rapidly removed from the environment due to its ready biodegradability.