2-Propenoic acid, ethyl ester, reaction products with mixed substituted alkyl esters of phosphorodithioic acid and propylene oxide

Endpoint summary

Description of key information

The test substance is a UVCB substance with an overall high water solubility (305 mg/L)/ The log Pow of the majority of its constituents is very high (94.24% with log Pow > 4, 67.0% with log Pow > 10.) A toxicant can enter the body via the gastrointestinal tract, the lungs and the skin. In general, a substance needs to be dissolved before it can be taken up from the gastrointestinal tract after oral administration. The test substance is a liquid with a moderate to high water solubility (305 mg/L) and can therefore dissolve into GI fluids and hence make contact with the mucosal surface. Furthermore, as the substance is surface active, the absorption can be enhanced if the substance undergoes micellar sobulization or by bile salts. There, for risk assessment purposes oral obsorption of the test substance is set at 100%.

For Inhaled substances the process of deposition of the substance on the surface of the respiratory tracr and the actual absorption have to be differentiated. The vapour pressure for the test substance is low (0.036 Pa at 20C), indicating a low volatility. It is not likely that the test substance will rach the nasopharyngeal region or subsequently the tracheo/bronchial/pulmonary region via inhaltion of vapour.

The test substance is a liquid which can potentially be taken up across the skin. According to the criteria given in the REACH Guidance, a default value of 100% dermal absorption should be used unless MW > 500 and log Pow <-1 or > 4, in which case a value of 10% skin absorption should be chosen. These criteria are fulfilled for the majority of constituents of the test substance (94.2% with log Pow >4, MW of all constituents > 500 g/mol.) The substance was not irritating to skin inthe available skin irritation study, but signs of dermal irritation were noted in the available acute dermal toxicity study.

Once absorbed, the substance can be distributed throughout the body, based on irs moderate to high water solubility (305 g/L). Considering very high low Pow of the majority of the constituents, the test substance is expected to accumulate in adipose tissue. Metabolism of the substance is epected to involve oxidative desulfuration, ester hydrolysis, aliphatic C-oxidation, and phosphate ester hydrolysis. The parent substance is expected to be completley metabolised..

Biliary and foecal excretion may be expected to occur based on the molecular weight of the substance (as well as several of the metabolites) and its high apolarity. Based on moderate to high water solubility, some degree of urinary excretion cannot be excluded for the test substance as well as its metabolites although the high molecular weight of the parent substance may limit urinary excretion.

Key value for chemical safety assessment

Bioaccumulation potential:

low bioaccumulation potential

Absorption rate - oral (%):

100

Absorption rate - dermal (%):

10

Absorption rate - inhalation (%):

100

Additional information

Based on the physical/chemical properties of the substance, absorption factors for this substance are derived to be 100% oral, 100% inhalation and 10% dermal for risk assessment purposes. Based on the metabolism model, the parent is expected to be completley metabolized, but there are several stable metabolites. Fecal and urinary excretion are expected based on the molecular weight and water solubility of the substance and its metabolites.