Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

If released to air, a vapor pressure of 3.40 mm Hg at 23°C indicates that allyl isothiocycanate will exist solely as a vapor in the atmosphere. Vapor-phase allyl isothiocycanate will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 4.7 hours. Allyl isothiocycanate does not contain chromophores that absorb at wavelengths >290 nm, and therefore is not expected to be susceptible to direct photolysis by sunlight.

 

If released to soil, allyl isothiocyanate is expected to have moderate mobility based upon an estimated Log Koc of 2.24 -2.41. Volatilization from moist soil surfaces is expected to be an important fate process based upon a Henry's Law constant of 2.4X10-4 atm-cu m/mole. Allyl isothiocyanate may volatilize from dry soil surfaces based upon its vapor pressure. A mean half-life of 2 days in 6 different soils maintained at 75% moisture capacity and 20 deg C was reported for allyl isothiocycanate. When maintained under aerobic conditions, transformation rates were not affected, suggesting that biodegradation is not an important environmental fate process in soil or water.

 

If released into water, allyl isothiocyanate is expected to adsorb to suspended solids and sediment based upon the estimated Koc. Volatilization from water surfaces is expected to be an important fate process based upon this compound's Henry's Law constant. Estimated volatilization half-lives for a model river and model lake are 3.4 hours and 5 days, respectively. However, volatilization from water surfaces is expected to be attenuated by adsorption to suspended solids and sediment in the water column. The estimated volatilization half-life from a model pond is 30 days if adsorption is considered.

In aqueous solution, allyl isothiocyanate is gradually decomposed. The decomposition is not based on hydrolysis of R-NCS, but on the addition reaction on -N=C=S.

An estimated BCF of 7.5 L/Kg suggests that the potential for bioconcentration in aquatic organisms is low.

Additional information