|Persistent organic pollutants (POPs) comprise several classes of halogenated compounds that are long-lived, both in the environment and in wildlife and humans. These include: polychlorinated biphenyls (PCBs); polychlorinated dibenzodioxins and furans (PCDDs/PCDFs); organochlorine pesticides (OCPs); polybrominated diphenyl ethers (PBDEs), and other brominated flame retardants (BFRs). These chemicals are known to cause a variety of adverse health effects in both wildlife and humans. Biomonitoring is an increasingly important tool in gauging the effectiveness of legislation that restricts or bans the use of certain chemicals, and in examining the relationship between chemical exposure and the presence of disease. Gas chromatography-mass spectrometry (GC/MS) is one important tool in the biomonitoring of these chemicals. This presentation describes two biomonitoring studies in which the levels of PBDEs and PCBs were measured in breast adipose tissue. In a study of 32 Brazilian women BDEs-47, -99, -100, -153, and-154; and PCBs-118, -138, -153, and -180 were measured using GC/NCI-MS (negative chemical ionization) detection. The median sum PBDEs was 1.36 ng/g lipid weight, with the concentrations in the order of 47>99>153>100>154. The median sum PCBs was 125 ng/g lipid weight, with concentrations in the order of 153>138>180>118. In a study of 155 California women, the same PBDE and PCB congeners were measured using GC/EI-MS/MS (electron impact tandem mass spectrometer) detection. The median sum PBDEs was 27 ng/g lipid weight. The median sum PCBs was 783 ng/ lipid weight. For both chemical classes, the order of concentration was the same for both populations. The results from these studies are consistent with other studies showing that the levels of PBDEs in Californians are among the highest in the world. These two studies also use two different types of gas chromatography with low resolution mass spectrometric detection. GC/NCI-MS can be carried out easily on most single or tandem quadrupole mass spectrometers, and offers very high sensitivity. However, it lacks specificity for PBDEs and other BFRs, and is a relatively dirty ionization technique. GC/EI-MS/MS can only be carried out on a more expensive tandem quadrupole mass spectrometer, but has the advantages of a very clean baseline, is a relatively clean ionization technique, and offers very high specificity, even for PBDEs and other BFRs.|
Both studies were funded in part by the California Breast Cancer Research Program. The ideas and opinions expressed are those of the authors and do not necessarily reflect the views of the California Department of Toxic Substances Control.