Quantitative analysis of polychlorinated biphenyls (PCBs) and hydroxylated PCBs

Polychlorinated biphenyls (PCBs) are a set of toxic environmental pollutants. PCBs can be transformed to even more toxic breakdown products. Our understanding of the contemporary prevalence, sources, exposures, and toxicities of these chemicals is limited by our ability to measure them accurately and precisely. This dissertation is therefore focused on the development of measurement techniques and the determination of contamination levels.

The PCB levels in foods that are normally consumed by mothers and children from two Midwestern communities are accurately and precisely measured. Although PCB levels is highest in fish, these people ingest PCBs from meat more than other kind of foods. PCB levels in food is found to be decreasing over the last 20 years. Still, these people are exposed to PCBs from diet but at a lower level comparable to inhalation exposure.

Hydroxylated polychlorinated biphenyls (OH-PCBs) are ones of toxic PCB breakdown products. However, they have never been fully studied due to the limitation of measurement methods. Therefore, this dissertation developed a new technique that can accurately, precisely, and fully measure OH-PCBs. The new technique was then used in the determination of OH-PCBs in sediments. OH-PCBs were found in all sediments that are contaminated with PCBs. This study found evidence that these OH-PCBs were/are produced in the environment and produced site-specifically by where the sediments come from. Some predominant OH-PCBs that are more likely to possess concern for humans and ecosystems are also identified for future studies.