Guidelines on the determination of chlorinated hydrocarbons in sediment.

Abstract

These guidelines are based on the review from Smedes and de Boer (1994, 1998) and Eljarrat and Barceló (2009). The analysis of chlorinated hydrocarbons in sediments generally involves extraction with organic solvents, clean-up, removal of sulphur, column fractionation and gas chromatographic separation, mostly with electron capture or mass-spectrometric detection. All steps of the procedure are susceptible to insufficient recovery and contamination. Quality control measures are recommended in order to regularly monitor the performance of the method. These guidelines are intended to encourage and assist analytical chemists to critically review their methods and to improve their procedures and quality assurance measures, if necessary. These guidelines can be applied for the determination of several types of chlorinated hydrocarbons, e.g., chlorinated biphenyls (CB), chlorobenzenes, DDT and its metabolites and hexachlorocyclohexanes. It should be noted that these guidelines do not cover the determination of non-ortho substituted CB. Due to the low concentrations of non-ortho CB in sediments comparing to those of other CB, their determination requires an additional separation and concentration step similar to the analysis of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F). These guidelines are not intended as complete laboratory manual. If necessary, guidance should be sought from specialized laboratories. Laboratories should demonstrate validity of each methodological step. Moreover, use of an alternative method, carried out concurrently to the routine procedure, is recommended for validation. Contracting parties should follow the HELCOM monitoring guideline but minor deviations from this are acceptable if the method achieves comparable results. Validation of the adopted method needs to be performed on the relevant matrix and concentration range e.g. by taking part in intercomparison studies or proficiency testing schemes.