2-ethylhexyl acrylate

Endpoint summary

Description of key information

see below

Additional information

1) Partition coefficient:An experimental log Pow of 4.64 (25 °C) was determined using the shake-flask method, but may represent an overestimation of the actual log Pow due to methological deficiencies. Log Pow values calculated by Q(SAR), i.e. Epi Suite SRC KOWWIN v1.67, and regression analysis, were 4.09 (BASF SE, 2008) and 3.67 (Fujisawa & Masuhara, 1981), respectively. Using a weight of evidence approach, the log Pow was estimated to be 4 indicating a potential for bioaccumulation.

2) OECD Test Guideline 305 study in Cyprinus carpio: In a study conducted with 2-Ethylhexyl Acrylate (2EHA) according to the OECD Guideline for Testing of Chemicals, No. 305, 2012, the ability of the test substance to accumulate in tissues of carp (Cyprinus carpio) was tested during an uptake phase of 28 days and a depuration phase of 56 days. The kinetic bioconcentration factor (BCF_k) was determined since no steady state was reached over the test duration. A sequential determination model was applied in addition to a normalization for the standard lipid content of 5%, however, based on a poor fit of the lipid-normalized data in both the simultaneous and sequential models, along with the understanding that the parent substance is likely readily metabolised, lipid-normalization of the kinetic BCF was not further pursued with this dataset. The BCF_k was determinded based on total radioactivity which includes the sum of the parent compound, possible metabolites and assimilated carbon, whereas GC-FID analysis of the extracts of the fish tissues showed no parent 2EHA. The BCF_kbased on total radioactivity was 347 L/kg and the half-life (DT₅₀) value of the total radioactivity was 19 days indicating slow depuration. The experimentally determined BCF is much lower than the cut off criterion of 2000 L/kg.

3)  Empirical results and QSAR models that predict significant metabolism of 2-EHA: Significant intrinsic clearance is predicted (via multiple QSAR models) for 2-EHA indicating that the material will be rapidly metabolized and not bioaccumulated (Table 1). Support for this comes from combined evidence of metabolism observed for 2-EHA in rodent toxicokinetic studies. Briefly, metabolism rates 2-EHA in rat liver microsomes and whole rat blood were determined. 2-EHA was hydrolyzed to acrylic acid with a half-life of 2.26 minutes in rat liver microsomes with an intrinsic clearance rate of 306 µL/min/mg (Table 1). Additionally, in whole rat blood, 2-EHA was rapidly metabolized with a half-life of 3.85 minutes and an intrinsic clearance rate of 180 µL/min (The Dow Chemical Company, 2018; Table 1). Thisin vitrometabolism result indicates that 2-EHA can be quickly metabolized primarily through hydrolysis to acrylic acid and/or glutathione conjugationin vivo.

4) PBT criteria:The registered substance and its relevant degradation products are not persistent(readily biodegradable based on OECD 301 F)according to the criteria laid down under annex XIII of REACh regulation. The bioaccumulation study resulted in a BCF of 347 L/kg. Thus, none of them is PBT/vPvB.