PCBs(Polychlorinated biphenyls) is a pale liquid and extremely chemically stable under most conditions. Its destruction by any means is extremely difficult.
2. What was it used for?
It was widely used in electrical equipment as insulator and coolant fluids. It was also used as flame retardant,
3. Why it is bad? How bad it is?
PCBs is not very toxic acutely. You are unlikely to experience much adverse effect from immediate contact unless in extremely high dose. PCBs causes harm over a long period of time . PCBs is extremely stable and lasts for long time in the environment. Once inside the body, human and animals can only get rid of it very slowly. Given the continued presence in the environment and slow speed to exit body, it bio-accumulates over a long period of time and reaches an ever higher concentration. A few studies on pregnant women have shown that PCBs exposure adversely affect their baby’s neurological and cognitive development over a decade. Based on that, many states in northeast US have issued fish consumption advisory for pregnant woman as PCBs level in striped bass and bluefish reached dangerous level.
4. Is it still being used?
After people realizing its amazing persistence and threat to public health, PCBs production in US is banned in 1979 and worldwide production was halted in 2004. However, you will still encounter them as old equipment containing them are still operating and those in the environment still accumulate in human body.
5. What should I do to avoid it?
Ppb(parts per billion) is the most common concentration measure for PCB contamination. The higher the number, the more PCB is there. The most PCB contaminated food is certain types of fish from certain locations. Unlike mercury, there is a very large difference among the PCB levels found in the same kind of fish. EPA did a study of PCB levels found in New York City’s fish market. The highest level of PCBs are found in Yellow Croaker, Porgy and Strip bass with very large interspecies variation.
(courtesy of http://www.themysticbiscuit.com/roanoke-river-2010.html)(Courtesy of www.made-in-china.com)
(credit to http://www.sawyercharters.com/Sept1308.gif)
(Credit to www.21food.com)
Based on various published testing, I recommend two steps to limit PCB intake and buildup in your body:
A) avoid or eat no more than once every three month strip bass or bluefish caught of US east coast. Hudson River have the most severe PCB contamination problem historically, followed by Delaware Bay and Mid-Atlantic. Wild Strip bass and Blue fish collected along northern half of US east coast reached 400 ppb level. The picture to the right is EPA’s map for potential sources for PCBs on Lake Erie. The red squares indicate the pollution sources. No surprise that northern Atlantic coast produces fish with highest PCB levels.
B) Limit non organic butter. Its PCBs concentration is measured to be 70 ppb, the second highest among common food.