Environmental Fate
A summary of the environmental fate properties of the category members is presented in the table below. For all the substances in the category, there is data available for all the required environmental fate endpoints. The conducted studies are of appropriate quality to warrant a high degree of reliability (Klimisch score 1 or 2). QSAR estimations addressed the endpoints of hydrolysis (t-BA, i-BA) and phototransformation in air and supported the assessment of bioaccumulation. Read-across was not applied to any of the environmental fate endpoints.
The available data provides evidence that abiotic degradation by hydrolysis is only expected to play an important role in the degradation of acrylate esters in alkaline environment, with the exception of 2EHA which hydrolyses slowly in contact with water.
All substances within the category are readily biodegradable in water, except for tert-butyl acrylate which is moderately biodegradable (59% by 28-d, ISO 14593). All the substances were concluded as “not P” according to the PBT assessment criteria.
Additionally, none of the substances present potential for bioaccumulation considering logKow and BCF values, with all category members concluded as “not B” according to the PBT assessment criteria.
Adsorption of acrylic acid and the acrylate esters to soil, sediments and suspended solids is not anticipated, which supports no need to perform studies to assess toxicity to sediment and terrestrial organisms.
The acrylate esters are expected to evaporate slowly but to an increasing extent with increasing chain length and molecular weight. Considering the physico-chemical properties of the acrylate esters, distribution modeling indicates that the atmosphere is the main target compartment for partitioning and only small amounts will remain in the hydrosphere and geosphere.
Overall, the available data demonstrates clear similarities and trends in the environmental fate properties of the members of the category and supports the hypothesis that read-across between category members is justified for ecotoxicity endpoints.