Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

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 VII, this study does not need to be conducted if the substance can be expected to have low potential for adsorption (e. g. log Kow<=3). Based on the properties of the main constituents, S-ethanol can be considered to have low potential for adsorption (log Kow< 3) and this study is not required. Adsorption on soil is not to be expected due to the high solubility of ethanol and methanol as well as their low octanol-water partition coefficient log Kow of -0.35 and -0.77, respectively.

In addition, as supportive information the adsorption coefficients between 0.13 and 1 for methanol were measured and calculated, respectively (Lokke 1984, BASF 2004). These coefficients indicate that methanol has a low adsorptive capacity on soils. A value of 0.461 Pa m³/mol for the Henry’s Law constant indicates that volatilization is not a significant removal process from the aquatic compartment. Based on the Mackay Level I fugacity model the majority of Methanol is calculated to partition into the water phase. In addition a distribution calculation with the Mackay Level III fugacity model (BASF, 2003) was performed. This is a comprehensive multimedia model in which chemical emission, advection, reaction, intermedia transport and residence time or persistence are taken into account and therefore provides a more realistic representation of the fate of methanol in the environment. Using emission rates derived from total releases into water, air and soil (79658, 1531 and 658 tonnes, respectively) reported in the U. S. Toxics Release Inventory for 2001 the model predicts that the air is the target environmental compartment for methanol.

Based on the theoretical partitioning of S-ethanol constituents between main environmental compartments (water, soil, air) has also 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. In dynamic situation (level III) the equilibrium is dependent also on target compartment of release, but still the alcohols will stay strongly in the water compartment if released to water. If released to soil, the alcohols will be still distributed mainly to the water and soil compartment. If released simultaneously to air, soil and water, the alcohols will be distributed mainly to water and soil compartment. Theoretical partitioning of S-ethanol constituents in static equilibrium Fugacity level I and level III to distribution is presented in table below.

 

Level III equilibrium results are in brackets if calculated. The Level III results expect that the same mass emission level (e.g. kg/day) is targeted to air, water and soil. Theoretical partitioning of S-ethanol constituents in static equilibrium, Fugacity level I/III (III results in brackets) are the following:

 

·        Ethanol : 92 % water; <1% sediment; <1% soil, 8% air

·        Methanol : 90 % water; <1% sediment; <1% soil, 9.5 % air

·        Acetaldehyde: 42(49) % water; <1(1) % sediment; <1(46) % soil; 57(4) % air

·        Ethyl acetate: (44) % water; (<1) % sediment; (40) % soil; (16) % air

·        Ethers:  (ca. 50) % water; (<1) % sediment; (ca. 50) % soil; (<1) % air

·        SO2: Oxidises/hydrolyses to H2SO4and partitions primarily to the aquatic phase