CAS RN: 67-66-3

Soil Adsorption / Mobility

Kocs for chloroform of 153-196 were calculated(1) based upon Kd values of 1.763-2.133 mg/g and % organic matter in tested soil (1.6-2.4)(2). Chloroform is adsorbed most strongly to peat moss, less strongly to clay, very slightly to dolomite limestone and not at all to sand(3). The Koc values measured for 2 soils was 34; 3 other soils with the lowest organic carbon content in the same study gave no appreciable adsorption(4). Field experiments in which chloroform was injected into an aquifer and the concentration in a series of observation wells determined, demonstrated that chloroform is very poorly retained by aquifer material (retardation factor 2-4), less so than other C1- and C2-halogenated compounds studied(4-5). Laboratory percolation studies with a sandy soil gave similar results (retardation factor <1.5)(6). Chloroform was reported to have a Koc of 65(7), 55(8), 47(9) and 34(10). According to a classification scheme(11), these Koc values suggest that chloroform is expected to have very high to moderate mobility in soil.
The Kd of chloroform was measured in three soil types (Missouri, California, Florida)(1).
Parameter Missouri California Florida
% Sand 11.4 45.1 91.7
% Silt 52.7 35.2 6.3
% Clay 33.4 21.7 2.0
Organic Matter 2.4 1.7 1.6
pH 6.9 8.1 4.7
Kd (ug/g) 2.133 1.941 1.763
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