1,4-Dithiane

TERRESTRIAL FATE: Based on a classification scheme(1), a Koc value of 63(2), indicates that 1,4-dithiane is expected to have high mobility in soil(SRC). Volatilization of 1,4-dithiane from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 4.2X10-5 atm-cu m/mole(SRC), derived from its vapor pressure, 0.8 mm Hg(3), and water solubility, 3,000 mg/l(3). 1,4-Dithiane is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(3). No biodegradation data were located for 1,4-dithiane(SRC,2006); however, its detection in environmental samples long after the release of mustard gas suggests it may persist in the environment(3).

AQUATIC FATE: Based on a classification scheme(1), a Koc value of 63(2), indicates that 1,4-dithiane is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(3) based upon an estimated Henry's Law constant of 4.2X10-5 atm-cu m/mole(SRC), derived from its vapor pressure, 0.8 mm Hg(4), and water solubility, 3,000 mg/l(4). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 16 hours and 11 days, respectively(SRC). According to a classification scheme(5), an estimated BCF of 3(SRC), from a log Kow of 0.77(4) and a regression-derived equation(6), suggests the potential for bioconcentration in aquatic organisms is low(SRC). No biodegradation data were located for 1,4-dithiane(SRC,2006); however, its detection in environmental samples long after the release of mustard gas suggests it may persist in the environment(4).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 1,4-dithiane, which has a vapor pressure of 0.80 mm Hg at 25 °C (2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase 1,4-dithiane is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 10 hours(SRC), calculated from its rate constant of 3.9X10-11 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3).

1,4-Dithiane

Nervous

1 x 10 ^-2 mg/kg-day

1,4-Dithiane's production and use as an organic synthesis reagent(1) may result in its release to the environment through various waste streams(SRC). 1,4-Dithiane has also been identified as an impurity and thermal decomposition product of mustard gas(2).

SOIL: 1,4-Dithiane was identified, not quantified, in soil samples, sheep wool, and a bomb casing in November 1988, from a region of Iraq near the Turkish and Iranian border(1). 1,4-Dithiane was identified, not quantified, in soil samples from Fort McClellan, Alabama(2).

An estimated BCF of 3 was calculated for 1,4-dithiane (SRC), using a log Kow of 0.77(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is low(SRC).

The Henry's Law constant for 1,4-dithiane is estimated as 4.2X10-5 atm-cu m/mole(SRC), from its vapor pressure of 0.80 mm Hg and water solubility of 3,000 mg/L(1). This Henry's Law constant indicates that 1,4-dithiane is expected to volatilize from water surfaces(2). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(2) is estimated as 16 hours(SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec)(2) is estimated as 11 days(SRC). 1,4-Dithiane is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(1).