Characterization of organohalogen matter in sediments from the receiving water of a bleach plant

A sediment collected 1 km from the discharge of a kraft mill was characterized for organochlorine sum parameters and specific organochlorine compounds. The sediment was found to contain 1100 μg extractable organically bound chlorine (EOCl) per g dry weight material. To help identifying other tracer substances, different extraction techniques, purification and derivatization were utilized in combination with chlorine specific detection using electron capture- (ECD), atomic emission- (AED) and mass spectrometric detection (MS). Supercritical fluid extraction (SFE) was found to give extracts containing mainly nonpolar organochlorine compounds. This extraction method gave higher chlorine to carbon ratio than a nonpolar solvent extraction method. A characteristic gas chromatographic pattern of organochlorine compounds was obtained. Some of these compounds were tentatively identified as methyl esters of chlorinated resin acids. Derivatization experiments did not result in any new identified compounds. Low levels of chlorinated phenols, both free and bound, were found by analysing sediments collected up to 16 km from the discharge point. Steep declining gradients were found for the organochlorine sum parameter, the chlorinated phenols and the compounds giving the characteristic gas chromatographic pattern mentioned above.