POLYCHLORINATED-BIPHENYLS IN DIGESTED UK SEWAGE SLUDGES

Twelve sewage sludges from rural, urban and industrial waste water treatment works in north west England were analysed for polychlorinated biphenyls by capillary GC-ECD. The total polychlorinated biphenyl content ranged between 106 to 712 mug/kg, with a mean of 292 mug/kg. Di- and penta-chlorinated congeners made the greatest contribution to SIGMAPCB concentrations at most sites. The 6 IUPAC congeners were found in the following order of abundance, 101>180>153>138>52>28. Industrial inputs would appear to influence levels of SIGMAPCB in the sludge. If these sludges were ploughed into arable land at typical rates only a slight elevation in soil SIGMAPCB levels would result. Alternatively, if the same quantity of sludge were applied to the surface of pasture grassland, significant elevations in the potential transfer of PCBs to grazing livestock may result.