Polychlorinated biphenyls (PCBs) are Persistent Organic Pollutants (POPs). The World Health Organization (WHO) defines POPs as "chemicals of global concern due to their potential for long-range transport, persistence in the environment, ability to bio-magnify and bio-accumulate in ecosystems, as well as their significant negative effects on human health and the environment" WHO
PCBs are so pervasive at this point that global biomonitoring has failed to find a person on the planet whose blood does not contain PCBs.
What do PCBs do in our bodies?
PCB's are classified as Endocrine Disruptive Chemicals (EDCs). EDCs are synthetic compounds that alter hormone systems and can cause adverse health effects. As EDC's they interfere in metabolic and gene expression processes. That is, they don't just metabolized in the body, do their harm, and leave. Instead, they recompose metabolism itself, which means we have all been materially altered by PCBs.
Again, PCBs are not only persistent pollutants, they are endocrine disruptive chemicals whose effects can persist across generations through epigenetic inheritance which effects the health of future children, grand children, and great grandchildren of bodies exposed.
For more information about EDCs go to The Endocrine Disruptors Action Group
The primary contaminant found in Massena was Aroclor 1248, the commercial mixture used by all three industries
However the more heavily chlorinated congeners characteristic of Aroclor 1260 was also found.