INDIVIDUAL PCBS AS PREDICTORS FOR CONCENTRATIONS OF NON AND MONO-ORTHO PCBS IN HUMAN-MILK

32 Dutch human milk samples were analyzed for PCBs with either HRGC-EC D or HRGC-LRMS in the NCI mode. Samples were collected from three diff erent locations in The Netherlands: Amsterdam, Rotterdam and Groningen . Quantitatively, no differences could be observed between the three l ocalities, while in addition the congener specific pattern showed a st riking similarity for all individual samples. Only principal component analysis revealed slight individual differences. Based on similaritie s in the PCB profiles, linear relationships were calculated between 2, 3'4,4',5-PnCB (#118) or 2,2'4,4'5,5'-HxCB (#153) and the most relevant non and mono-ortho PCBs exhibiting dioxinlike activity. These PCBs in cluded 2,3,3',4,4'-PnCB (#105), 3,3',4,4'5-PnCB (#126) 2,3,3',4,4',5-H xCB (#156), 2,3,3',4,4',5'-HxCB (#157), 2,3',4,4',5,5'-HxCB (#167) and 3,3',4,4',5'5-HxCB (#169). Good linear relationships were observed be tween individual PCBs. Based on the results of this study, PCB #118 ca n be used to predict concentrations of the PCBs #105 and #126. PCB #15 3 can be used as a predictor for the PCBs #156, #157, #167 and #169, b ut also for the total toxic equivalencies (TEQs) of non and mono-ortho PCBs present in human milk. This method using certain PCBs as predict ors for other toxicological relevant congeners, can be useful and cost effective, e.g. for epidemiological studies. However, before applied a number of conditions should be met. These are: 1) A stable compositi on of the PCB matrix should be established. 2) A possible time depende nt change in composition of the matrix should first be excluded when u sed over different time periods.