Metanalytical assessment of reference values for polychlorinated biphenyl in human blood

Due to their physico-chemical characteristics, polychlorinated biphenyls (PCBs) are highly persistent in the environment and therefore easily measured in the biological matrices of more and more large groups of general population. For these reasons it would be useful to determine suitable Reference Values (RVs) for these xenobiotics. In this paper, a metanalysis to the published data on PCBs values in human blood is presented. This investigation was carried out in order to reach adequate information on their RVs and to focus some specific topics to be taken into account when producing directly RVs for PCBs. The PCBs RVs resulted between 1.2 e 8.28 microg/L for males and between 2.69 e 5.17 microg/L for females the general range varied from 0.9 to 56 microg/L. The main criticisms in the assessment of RVs for PCBs resulted: the number of examined subjects; the inclusion and stratification criteria; the analytical method adopted and their quality assurance; the type and number of congeners to be determined and their specific quantification; the calculation of blood PCBs concentration (weight/volume or weight/lipids); the statistical analysis and in particular the treatment of not detectable data.