Ethanol

Toxicity to soil microorganisms

Description of key information

Toxicity testing on soil micro-organisms is considered unnecessary. Therefore no data is provided for PNEC-derivation (see also discussion below).

Additional information

 This substance (S-Ethanol, composition 2) has degree of ethanol purity between 76 - 82%. Methanol is the main impurity of the target substance (conc. 13-14 %), and considered the major driver for adverse effects based on its properties and relative quantity in the substance. These secondary constituents and relevant impurities trigger the need to carry out a separate chemical safety assessment for S-ethanol (beyond ethanol).Testing of the substance itself was considered unnecessary. Instead the available REACH registration data for ethanol and methanol is used in order to update the chemical safety assessment of this substance. Other minor constituents of secondary ethanol were taken into account in the chemical safety assessment and risk characterization as far as possible. Exposure assessment and quantitative exposure scenario building of S-ethanol takes primarily into account ethanol, methanol and acetaldehyde. These constituents are regarded as the most hazardous and relevant chemical constituents in the environmental risk based evaluation. Some minor constituents (ethoxyethers, ethyl acetate and sulphur dioxide) are dealt at least in qualitative way (see also section 9 and 10 in CSR).

In accordance with column 2 of REACH annex IX testing for degradation in sediment and soil is not required if the substance is readily biodegradable. Based in the existing data on the main constituents of this substance, this substance (S-ethanol) is considered to be readily biodegradable, and the degradation in soil and sediment can confidently be expected. Based on the theoretical partitioning of S-ethanol constituents between main environmental compartments (water, soil, air) has been given in chapter 9 in CSR (chapter of environmental fate). At static equilibrium calculations also indicate that the alcohols will be distributed mainly to water and air compartments and adsorption to soil and sediment is not strong.

Based on the use pattern for this substance as a biofuel for energy production, direct and indirect exposure of soil is unlikely. Fugacity level 3 modelling of the main constituent (ethanol) using realistic mass flow splits (see chapter 5.4.3) predicts that concentrations in soil would be less than 2% of that in the water compartment. Based on this low exposure and the fact that good data is available for the aquatic compartment, the equilibrium partitioning method is considered adequate to estimate the toxicity to soil micro-organisms based using the existing aquatic toxicity hazard data as a starting point and this end point is considered complete.