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Environmental fate & pathways

Endpoint summary

Administrative data

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Additional information

Stability

The parent compound ethyl chloroformate hydrolyses fast (DT50 = 20 min at 25 °C and pH 7) to ethanol, HCl and CO2 (OECD TG 111; SafePharm, 2003). Ethanol, however, is hydrolytically stable (OECD, 2005).

In air, ethyl chloroformate is expected to be photodegraded by OH-radicals with a half-life of 9.66 d (US EPA, 2008). This estimation refers to dry air. In mist, rain, droplets and aerosols hydrolysis will be the major fate process in air due to the short half-life in aqueous solutions.

Hydrolysis product ethanol: Based on the selected value of 3.27E-12 cm³/(molecule*sec) for the measured OH radical rate constant at 25 °C (OECD, 2005) and assuming a 24-h day with a mean concentration of 0.5E06 OH/cm³, a half-life of 4.9 ± 1 d can be calculated.

Biodegradation

Ethyl chloroformate was shown to be readily biodegradable in the MITI-(I)-test following OECD TG 301C. However, ethyl chloroformate is rapidly hydrolysed (half-life = 20 min, pH 7, 25 °C) to ethanol, HCl and CO2. Therefore, the results are most likely related to the hydrolysate. In separate tests, the hydrolysis product ethanol was shown to be readily biodegradable ( Price et al., 1974; OECD, 2005). Regarding the hydrolysis products HCl and CO2, biodegradation is not applicable due to the inorganic character of these molecules.

Bioaccumulation

Due to the low log Kow of the parent compound and its hydrolysis products, significant accumulation in organisms is not to be expected (BASF SE, 2008; OECD, 2005).

Transport and distribution

The estimated low Koc values of the parent compound and the hydrolysis product indicate no significant potential for adsorption to soils or sediments (US EPA, 2008; OECD, 2005).

A high Henry's Law Constant (HLC) of 316 Pa m³/mol was estimated for ethyl chloroformate (US EPA, 2008). However, it is rapidly hydrolysed to ethanol, CO2 and HCl.

Based on a calculated HLC of 0.6 Pa m³/mol, ethanol will not evaporate into the atmosphere from the water surface (OECD, 2005).

Following the Mackay Level I calculations, the parent compound will preferentially distribute into the air (86.8%) and water (13.2%) (BASF SE, 2008). The hydrolysis product ethanol is expected to preferentially distribute into the compartments air (48.1%) and water (51.9%) (BASF SE, 2008). Mackay Level III calculations reveal that ethanol would predominantly distribute into water (45.8 %) and soil (45.6 %) (BASF SE, 2008).