DETERMINATION OF COPLANAR AND ORTHO-SUBSTITUTED PCBS IN SOME SEWAGE SLUDGES OF SWITZERLAND USING HRGC ECD AND HRGC/MSD/

The three most toxic coplanar PCB congeners PCB 77, 126 and 169 as wel l as 7 mono-and di-ortho-PCBs (PCB 28, 52, 101, 118, 153, 138, 180) we re measured in 19 sewage sludges. Concentrations of the coplanar PCBs ranged between 231 - 5050 ng/kg dw for PCB 77, 43 - 1511 ng/kg dw for PCB 126 and 29 - 273 ng/kg dw for PCB 169. Comparable results were obt ained with mass selective detection in the single ion monitoring mode (MSD-SIM) except for PCB 169, where MSD-SIM was less sensitive than EC D. The sum of the 7 mono-and di-ortho-PCBs, which are routinely measur ed as representatives of the PCB fraction, reached levels between 43 - 550 mu g/kg dw and agreed well with results previously obtained in ou r laboratory. Based on our data, a selective accumulation of the copla nar PCBs could not be observed. Sludges that received industrial efflu ents clearly showed higher PCB levels than rural ones. Finally, calcul ation of TEQ equivalents of the coplanar PCBs in the sewage sludges re vealed that, based on application rates normally used in Switzerland, the contribution of the sludges to sail pollution seems to be of minor importance. Copyright (C) 1996 Elsevier Science Ltd