Analysis and occurrence of toxic planar PCBs, PCDDs and PCDFs in milk by use of carbosphere activated carbon

Abstract

A method is described for the determination of the toxicologically related planar PCB-congeners 3,3′,4,4′-tetra, 3,3′,4,4′,5-penta and 3,3′,4,4′,5,5′-hexachloro-biphenyl, based on the former Carbosphere methodology for the isomer-specific analysis of the seventeen toxic 2,3,7,8- chlorine substituted PCDD and PCDF congeners. The method proved to be rapid, accurate and reproducible (SD 8 %) for the analysis of low ppt levels of planar PCBs in cow's milk. The method has been applied to the analysis of planar PCBs, PCDDs and PCDFs in cow's milk from the vicinity of several sources and in human milk. A level of planar PCBs in human milk in the Netherlands was found of 9.2 pg TEQ/g fat. In samples of cow's milk from the vicinity of municipal waste incinerators and a metal reclamation plant, planar PCB levels ranged between 1.1 and 6.1 pg TEQ/g fat, whereas PCDD/Fs levels ranged between 1.3 and 12.9 pg TEQ/g fat. The factors that may be involved in the occurrence of planar PCBs in cow's milk are discussed in view of the presence of different sources in combination with the influence of kinetics of the individual PCB congeners in the cow.