2-decyltetradecanol

Endpoint summary

Additional information

There are no toxicity data for terrestrial organisms relating to 2-decyltetradecanol or other long chain alcohols ≥ C16 in length. In Annex X of Regulation (EC) No 1907/2006, it is laid down that long-term toxicity to terrestrial organisms shall be proposed by the registrant if the chemical safety assessment indicates the need to investigate further the effects of the substance and/or relevant degradation products on terrestrial organisms. Column 2 of Annex X states that studies do not need to be conducted if direct and indirect exposure of the soil compartment is unlikely. This endpoint is waived on the basis of the following arguments (i) ready biodegradability within the STP process and the environment means that direct and indirect exposure is not expected, (ii) the physico-chemical data indicate that the substance is not bioaccumulative, (iii) based on read-across from other long chain alcohols 2-decyltetradecanol is unlikely to be toxic to terrestrial organisms. 2-Decyltetradecanol is a member of the Guerbet Alcohols, which comprises a range of branched long chain alcohols C12-32. It is also structurally related to the substances of the OECD SIDS Long Chain Alcohols (LCA) categories, comprising a range of straight and branched long chain alcohols C6-22. As defined in the ‘Read Across Justification Document’ section 13, data provided for these categories is representative of 2-decyltetradecanol and suitable for assessment purposes. Experimental data for the Guerbet and LCA categories has been evaluated and trends in the environmental fate of long chain alcohols was used to extrapolate to the C24 alcohol, 2-decyltetradecanol for some endpoints. Unlikely Direct and Indirect Exposure Reliable measured data demonstrate that Guerbet Alcohols of chain lengths at least up to C24 are readily biodegradable. A ready biodegradation study by Federle (2009) tested 10 linear primary alcohols from butanol (C4) to docosanol (C22) and concluded that all 10 LCAs are readily biodegradable and satisfy the 10-day criterion. When the biodegradation data are considered in more detail, it is clear that longer chain LCAs degrade more rapidly than the intermediate chain lengths; docosanol achieved a mineralisation level of 88% at the end of the 28-day study and 83% mineralisation within the 10-day window. Other studies by Richterich (1998a and b), Belangeret al(2009) and Federle and Itrich (2006) all reported rapid biodegradation in LCAs from C16 to C22 linear and Guerbet alcohols. Indirect exposure is not expected as rapid biodegradability means 2-decyltetradecanol will be biodegraded within the STP process and as a consequence a transfer to the soil compartment via STP effluent is not expected. 2-decyltetradecanol will not be directly applied to soils and as such, direct exposure to soil organisms is not expected. Low Bioaccumulation Potential The evidence seen in the literature (e. g. SIDS LCA Report, 2006) and in the estimated BCFs indicates that 2-decyltetradecanol is unlikely to bioaccumulate in the aquatic environment. As described above, LCAs have low solubility in water making for technically challenging test conditions but they are also unavailable for uptake and bioconcentration. This was confirmed by de Wolf and Parkerton (1999) who demonstrated that LCAs do not bioconcentrate because they are rapidly metabolised. On the basis of this evidence, bioaccumulation in terrestrial organisms is considered to also be unlikely and the endpoint was waived. Low Aquatic Toxicity Short-term fish studies for 2-hexyldecanol, 2- octyldodecanol and C32/36 branched alcohols provide evidence of the low toxicity to fish with lethal concentrations (LC50) greater than 5, 500 to >10,000 mg/L. For invertebrates, effect concentrations in 48-hour immobilisation tests usingDaphnia magnarange from >0.035 to 100 mg/L. The SIDS report identified several Daphnia magna studies for long chain alcohols with carbon numbers C8 to C15. Toxicity increased with increasing chain length up to C14, but then the trend reversed between C14 and C15 and for longer chain length alcohols. In conclusion, LCA’s with increasing chain length result in lower availability and low or no acute toxicity to aquatic organisms. In summary, the low solubility and ready biodegradability of 2-decyltetradecanol in the environment means that it is unlikely that terrestrial life will be exposed to 2-decyltetradecanol with potential to exert long-term toxic effects over extended periods. It is possible to qualitatively conclude based on low solubility and available effects data using freshwater aquatic species that 2-decyltetradecanol does not pose a risk to the terrestrial compartment. In the environment, ready biodegradability means it can be assumed that 2-decyltetradecanol will be biodegraded within the STP process and as a consequence a transfer to the soil compartment via STP effluent (indirect exposure) is not expected. Furthermore, for substances not passing the STP-process but being readily biodegradable, it can be assumed that they will be also biological degraded in the surface water within a short time. 2-Decyltetradecanol will not be directly applied to soils and as such, direct exposure to soil organisms is not expected. Therefore, no tests on terrestrial organisms are provided.