Determination of PCBs and LABs in sewage, sludge from a wastewater treatment plant

The results from a study of the presence and temporal variability of linear alkylbenzenes (LABs) and polychlorinated biphenyls (PCBs) in sewage sludge are presented in this work. The sewage sludges, with anaerobic treatment, were originated in the Arazuri (Pamplona, Spain) wastewater primary treatment plant, which receives urban and industrial wastewaters. The organic pollutants extracted from the sewage sludge by a Soxhlet apparatus. Then, PCBs and LABs were separated from the rest of the pollutants on a chromatographic column. Some different detectors were flame ionization (FID), electron capture (ECD) and mass spectroscopy (MS). The results showed that LABs concentration varied between 1.4 and 73.0 mg kg(-1) dry matter (d.m.). PCBs appear in smaller quantity, between 0.050 and 0.929 mg kg(-1) (d.m.). The factor analysis of the results allowed verification of the different origin of PCBs and LABs.