Experimental animals that inhaled very high levels of PCBs had liver and kidney damage. PCBs have been classified as probably carcinogenic by the U. There are a few studies in workers exposed to PCBs that show associations with cancer of the liver and biliary tract. Rats exposed to high levels of PCBs in their food developed liver cancer. In a long-term study, PCBs caused cancer of the liver in animals that ate certain PCB mixtures throughout their lives.
It is not known if the effects seen in animals would occur in people. Babies can be exposed to PCBs through breast milk or through the placenta. Babies born to women with high dietary PCB exposure were smaller and showed abnormal responses to tests of infant behavior.
Some of those behaviors lasted several years. Mutation Res ;— Environ Toxicol ;— Toxicol Sci ;— Metabolic activation of PCBs to carcinogens in vivo — a review. Environ Toxicol Pharmacol ;—6. Ortho-substituted PCBs kill cells by altering membrane structure. Toxicol Sci ;—9. Comparative carcinogenicity in Sprague-Dawley rats of the polychlorinated biphenyl mixtures Aroclors , , , and A case-control study of cancer mortality at a transformer-assembly facility.
Int Arch Occup Environ Health ;— Effect of PCBs on mouse lung tumorigenesis induced by 1-nitorpyrene: a preliminary report. Robertson LW, Ludewig G. Gefahrst Reinhalt Luft ;— Hospitalization rates for coronary heart disease in relation to residence near areas contaminated with persistent organic pollutants and other pollutants.
Hazardous waste sites and stroke in New York State. BMC Environ Health ; High serum PCBs are associated with elevation of serum lipids and cardiovascular disease in a Native American population.
Analysis of the effects of exposure to polychlorinated biphenyls and chlorinated pesticides on serum lipid levels in residents of Anniston, Alabama. Proinflammatory properties of coplanar PCBs: in vitro and in vivo evidence. Association between serum concentrations of persistent organic pollutants and self-reported cardiovascular disease prevalence: results from the national health and nutrition examination survey, — Environ Health Perspect ;—9.
Exposure to persistent organic pollutants and hypertensive disease. Environ Res ;—6. Blood pressure and hypertension in relation to levels of serum polychlorinated biphenyls in residents of Anniston, Alabama.
J Hypertens ;— Blood pressure in relation to concentrations of PCB congeners and chlorinated pesticides. Association of polychlorinated biphenyls with hypertension in the — national health and nutrition examination survey.
Environ Res ;—7. Association between serum concentrations of persistent organic pollutants and prevalence of newly diagnosed hypertention: results from the national health and nutrition examination survey — J Hum Hypertens ;— Increased rate of hospitalization for diabetes and residential proximity of hazardous waste sites.
Diabetes in relation to serum levels of polychlorinated biphenyls and chlorinated pesticides in adult Native Americans. Environ Health Perspect ;—7. Low chlorinated, non-dioxin-like polychlorinated biphenyls are strongly associated with elevated prevalence of diabetes in a Native American population.
PCBs and cognitive functioning of Mohawk adolescents. Neurotoxicol Teratol ;— Evidence of an age-related threshold effect of polychlorinated biphenyls PCBs on neuropsychological functioning in a Native American population. Seegal RF. In humans, a recent study found that individuals infected with Epstein-Barr virus had a greater association of increased exposures to PCBs. It also increased the risk of non-Hodgkins lymphoma more than for those who had no Epstein-Barr infection. This finding is consistent with increases in infection with Epstein Barr virus in animals exposed to PCBs.
Since PCBs suppress the immune system and immune system suppression has been demonstrated as a risk factor for non-Hodgkin's lymphoma, suppression of the immune system is a possible mechanism for PCB-induced cancer.
Immune effects were also noted in humans who experienced exposure to rice oil contaminated with PCBs, dibenzofurans and dioxins. Taken together, the studies in animals and humans suggest that PCBs may have serious potential effects on the immune systems of exposed individuals. Reproductive effects of PCBs have been studied in a variety of animal species, including Rhesus monkeys, rats, mice and mink. Rhesus monkeys are generally regarded as the best laboratory species for predicting adverse reproductive effects in humans.
Potentially serious effects on the reproductive system were seen in monkeys and a number of other animal species following exposures to PCB mixtures. Most significantly, PCB exposures were found to reduce the birth weight, conception rates and live birth rates of monkeys and other species; and PCB exposure reduced sperm counts in rats.
Effects in monkeys were long lasting and were observed long after the dosing with PCBs occurred. Studies of reproductive effects have also been carried out in human populations exposed to PCBs. Children born to women who worked with PCBs in factories showed decreased birth weight and a significant decrease in gestational age with increasing exposures to PCBs.
Studies in fishing populations believed to have high exposures to PCBs also suggest similar decreases. This same effect was seen in multiple species of animals exposed to PCBs, and suggests that reproductive effects may be important in humans following exposures to PCBs.
Proper development of the nervous system is critical for early learning and can have potentially significant implications for the health of individuals throughout their lives.
Effects of PCBs on nervous system development have been studied in monkeys and a variety of other animal species. Newborn monkeys exposed to PCBs showed persistent and significant deficits in neurological development, including visual recognition, short-term memory and learning. Some of these studies were conducted using the types of PCBs most commonly found in human breast milk.
Studies in humans have suggested effects similar to those observed in monkeys exposed to PCBs, including learning deficits and changes in activity associated with exposures to PCBs. The similarity in effects observed in humans and animals provide additional support for the potential neurobehavioral effects of PCBs. There has been significant discussion and research on the effects of environmental contaminants on the endocrine system "endocrine disruption".
While the significance of endocrine disruption as a widespread issue in humans and animals is a subject of ongoing study, PCBs have been demonstrated to exert effects on thyroid hormone levels in animals and humans. Thyroid hormone levels are critical for normal growth and development, and alterations in thyroid hormone levels may have significant implications. It has been shown that PCBs decrease thyroid hormone levels in rodents.
Research has also shown that these decreases result in developmental deficits in rodents, including deficits in hearing. PCB exposures have been associated with changes in thyroid hormone levels in infants in studies conducted in the Netherlands and Japan.
Additional research will be required to determine the significance of these effects in the human population. Each IRIS assessment can cover a chemical, a group of related chemicals, or a complex mixture. Some substances are generally excluded from TSCA, including but not limited to, food, drugs, cosmetics and pesticides. TSCA addresses the production, importation, use and disposal of specific chemicals including polychlorinated biphenyls PCBs , asbestos, radon and lead-based paint.
The Federal Register Notices listed below include PCB-related rules proposed and final , notices of public meetings, responses to official comments, etc. This is not a comprehensive list of current regulations. Petition for Exemption. However, it is possible that PCBs may be incidental contaminants in listed hazardous waste e. In these cases, wastes that otherwise meet a listing criteria or are characteristically hazardous are still subject to RCRA regulation regardless of PCB content.
Section States may also have a regulatory program which is more stringent or broader in scope than the Federal program. Many state have expanded their universe of regulated wastes to cover additional waste e.
More information is available here. PCBs have been used as coolants and lubricants in electrical equipment such as transformers and capacitors , hydraulic fluids, additives in paint, carbonless copy paper, plasticisers and dye carriers.
PCBs were used as they do not burn easily and are good insulators. PCBs range in appearance from colourless, oily liquids to more viscous and increasingly darker liquids, to yellow to black resins.
The appearance depends on the chlorine content of the PCB. Some PCBs can exist as a vapour in air. They have no known smell or taste.
PCBs are chemically stable, have good insulating properties and do not degrade appreciably over time or with exposure to high temperatures. They are very soluble in organic solvents. Symptoms experienced by people exposed to large amounts of PCBs are skin conditions such as acne or rashes also known as chloracne and irritation and burning in the eyes.
Blood and urine tests indicate damage to the liver for affected people. Other symptoms include nausea, lethargy, brown pigmentation of skin and nails, swelling of the face, distinctive hair follicles, excessive eye discharge, swelling of the eyelids, visual disturbances, gastrointestinal disturbances, jaundice and decreased lung function.
These are only likely to be evident in those who work with PCBs and who do not wear appropriate protective clothing. Women exposed to relatively high levels of PCBs either in the workplace, or from consuming contaminated fish, may have babies that weigh slightly less at birth, and have an effect on the gestational period and head circumference.
The babies may also have abnormal responses in tests of infant behaviour, such as motor skills and short term memory.
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