PCBs in Sport Fish:
Answers to Questions on Health Effects

This is Page 2 (go to page 1)

How do PCBs affect health?
Workers exposed on the job to PCBs at high levels have had irritation of their skin (acne, rashes, and coloring of the nails and skin) and eyes (redness, burning, irritation, and discharge). Rats that ate food containing large amounts of PCBs for a short period had mild liver damage, and some died. Animals that ate smaller amounts of PCBs in their food over several weeks or months had many serious health effects including liver, stomach and thyroid gland injuries; anemia; acne; and damaged reproduction. These effects have been seen in many different kinds of animals, including monkeys, as well as in the offspring of animals that ate PCBs. No birth defects have been reported.

At the PCB levels measured to date in fish in California, we would not expect you to become ill from any single large meal of fish or a few fish meals. Even if you ate PCB-contaminated sport fish frequently over a period of years, you might not develop any illness. This does not mean you should not be concerned. We do know that PCBs build up in the body over time, and that exposure to higher levels of PCBs in fish can cause measurable effects in children. There is also the potential for increased risk of cancer occurring after many years of exposure.

We do not have the tools to measure subtle effects, if any, that may be caused in people who are exposed to the levels of PCBs generally found in California. Sensitive medical tests may be able to detect physiological changes, but it would be hard to differentiate the changes caused by PCBs from those caused by other agents or illness. What we do is take the known effects from human and animal studies and estimate what would be a safe level of exposure to prevent those effects from happening. Our sport fish eating guidelines are designed to prevent PCBs from building up in your body above a safe level of exposure.

What is the main health concern from exposure to PCBs?
All PCB mixtures tested have caused adverse effects in the development of offspring of experimental animals, and several human studies have also suggested that PCB exposure may cause adverse effects in fetuses and children.

The results of human studies, while not consistent, are of particular concern. One of these studies examined pregnancy outcomes in women who had consumed PCB-contaminated fish from Lake Michigan over an average of 16 years, and who had exposure both before and during pregnancy. Children of the mothers who had eaten the contaminated fish had smaller heads, lower birth weights, and were more frequently born before their due date. They also had delayed neuromuscular development. When tested at seven months, the children were slower to recognize objects that they had been shown before. The women in this study were exposed to fish with estimated PCB levels between 168 and 3012 ppb. It was difficult, however, to determine how much PCBs the women in this study were exposed to because this information was based on their memory of how much they ate over many years. This study was further complicated because the women had exposures to other chemicals, and the exposed women, on average, drank more alcohol and caffeine before and during pregnancy, weighed more, and took more cold medications during pregnancy than the nonexposed women.

A recent study in North Carolina noted much more moderate effects of PCB exposure in the development of children whose mothers had been exposed. No changes in birth weight or head size were seen. Deficits seen in intellectual and muscle function in children up to two years of age were not detectable at ages three, four, and five. In this study, DDE (a product of the pesticide DDT) was also found in blood and milk samples from the mothers. PCBs measured in the mothers’ blood were used as a measure of exposure, rather than the mothers’ recall of their fish intake.

Evaluations of blood samples from women who aborted, miscarried or delivered prematurely showed associations between these effects and concentrations of PCBs. However, these effects were seen at higher levels of PCBs than typically found in California, and there was exposure to other chemicals beside PCBs.

Studies conducted in primates found neurological effects, including deficits in cognitive function in animals born to mothers exposed to PCBs when they were pregnant. Primates, which are similar to humans in neurological development, showed greater sensitivity than rodents did to PCBs.

The effects in these studies have mainly been from prenatal exposure of the fetus through the mother, but infant exposure through breast feeding is also of concern. Because the developing nervous system in the very young is more sensitive to PCBs, OEHHA recommends lower consumption limits for women who are pregnant or may become pregnant, or who are breastfeeding, and for children under 6.

What about cancer?
PCBs are considered likely to cause cancer in humans based on evidence that they cause cancer in laboratory animal studies. However, studies of humans exposed to PCBs have not yielded conclusive results. We do not know for certain whether PCBs cause cancer in humans. It is difficult to obtain conclusive results in such studies because of the long period between exposure and potential appearance of cancer 15 to 20 years later. Factors such as exposure to other chemicals and lifestyle differences also complicate the results. If the advisory guidelines are followed, the risk of developing cancer would be too low to be of health concern even if you eat sport-caught fish for many years.

Are all the health effects of PCBs known?
The health effects of PCBs are still under active evaluation. Immune system and hormone level effects are some of the more recent discoveries. The implications of some recent findings to humans are not yet known.

The U.S. EPA has identified a long list of studies needed to fill in areas of uncertainty. As new studies are reported, OEHHA scientists will continue to evaluate the results and update its fish consumption advisories.

Is there a way to reduce PCBs in fish to make them safer to eat?
As general advice, OEHHA recommends that you clean and gut the fish you catch before cooking it because some chemicals, including PCBs, tend to concentrate in the organs, particularly in the liver. PCBs are mainly stored in the fat and can be reduced by getting rid of the fat. You should also trim the fat, remove the skin, and fillet the fish before cooking. Fat is located along the back and the belly, and in the dark meat along the lateral line running along the side of the fish. Skinning fish will remove the thin layer of fat under the skin. You should use a cooking method such as baking or grilling that allows the juices to drain away, and then discard the cooking juices. Using these methods may eliminate about half or more of the PCBs in fish.

When properly prepared, fish provide protein that is low in saturated fats. Replacing high fat foods in the diet with low fat foods can provide real health benefits. You can get the health benefits of fish and reduce unwanted contaminants by following this advisory.

OEHHA also recommends fishing in different locations in case the location where you are accustomed to fishing is highly contaminated. Also, as a rule, eating a variety of fish species is likely to reduce your exposure to a species that has high contamination.

Where can I get more information?
The health advisories for sport fish in all parts of California are printed in the California Sport Fishing Regulations booklet, which is available wherever fishing licenses are sold. They are also available from the Office of Environmental Health Hazard Assessment, including new updates. OEHHA has additional educational materials and reports on fish contamination in the state.

Page 1

You will need the free program Adobe Acrobat Reader to view or print PDF files

For help with this web site please contact the Web Mistress