EXTRACTION EFFICIENCIES OF ORGANOCHLORINE COMPOUNDS FROM NIAGARA RIVER WATER

A chromic acid digestion extraction technique was compared to conventional solvent extraction for recovery of a series of organochlorine compounds (chlorinated benzenes, polychlorinated biphenyls, DDT, DDE, mirex, and photomirex) from centrifuged Niagara River water. The digestion technique was more efficient than conventional solvent extraction. Relative recovery (undigested/ digested) decreased exponentially with increasing log K(OW). This implies that digestion-extraction recovers both the fraction dissolved and the fraction bound to dissolved organic matter (DOM), while conventional solvent extraction only recovers the dissolved fraction. As the time compounds equilibrated with the DOM increased, the extraction efficiencies by conventional extraction decreased while the efficiencies by digestion extraction remained 100%. Results obtained with the digestion technique were also more reproducible than those with conventional solvent extraction.