Soman

CAS RN: 96-64-0

Soil Adsorption / Mobility

The Koc of soman is estimated as 103(SRC), using a log Kow of 1.78(1) and a regression-derived equation(2). According to a classification scheme(3), this estimated Koc value suggests that soman is expected to have high mobility in soil. Clay converted to a calcium form and dehydrated at 105 deg C adsorbed 30.0 mg soman(4). At 2.0, 2.3, 3.0 and 9.1 percent moisture, soman sorption in the clay was 91.2, 94.4, 91.3, and 43.1 mg/g(4). If soman is sorbed while soil is wet, desorption occurs quickly; if the soil is dry for 2 or 3 days after uptake, desorption is much more difficult. An increase in soil temperature generally leads to a decrease in adsorption of soman(5). Soil sorption studies using different soil types noted that soman applied to the surface can adsorb to soil with increasing resistance to desorption in the absence of sufficient moisture and water(6); simulated rainfall events were shown to desorb the soman resulting in volatilization to the atmosphere(6).
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