Adsorption of chlordane onto humic acids from soils and pig slurry

Adsorption of trans- and cis-chlordane onto humic acids (HAs) isolated from soils and a pig slurry was measured using a batch equilibrium method followed by gas chromatographic analysis. Experimental data for adsorption of either chlordane isomers onto any HA examined were best fitted by a Langmuir-type isotherm. The adsorption capacity of pig slurry HA for chlordane was slightly lower than that of soil HAs. FT-IR, fluorescence and ESR spectroscopic data excluded the formation of strong chemical bonds between chlordane and HA, thus suggesting that chlordane can be adsorbed to HA only by physical (hydrophobic) mechanisms, involving to some extent fluorophore groups of the HAs.