Gas chromatographic determination of organic micropollutants in samples of sewage sludge and compost: Behaviour of PCB and PAH during composting

A simple method for a simultaneous gas chromatographic determination of polyclorobiphenyls and polycyclic aromatic hydrocarbons in samples of sewage sludge and compost is described. Certified materials were used for the evaluation of the method. Organic micropollutants were extracted from freeze-dried samples through a mixture of organic solvents - n-hexane/dichloromethane, 4:1 v:v-in a sonification bath. A multilayer clean-up/ separation column was used to remove interfering organic compounds and to divide PCBs and PAHs into two distinct fractions; and additional purification with metallic mercury was necessary to eliminate sulphur. Fractions are quantifiable with GC-ECD and GC-MS-SIM. The method was applied to determine the concentrations of both PCBs and PAHs during the composting process; a characteristic time profile was traced.