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Hello, my name is Sam and my presentation is on PCBs and how they effect human health.
So what are PCBs? PCBs are polychlorinated biphenyls, man-made organic chemicals consisting of carbon, hydrogen and chlorine atoms. They are classified as a Major Pollutant because (along w/ mercury) it is one of the most damaging pollutants in our environment. PCBs exist in 209 congeners. Congeners vary in the position and degree of chlorination. A general rule is that as the degree of chlorination increases so does its effect on the environment and human health. The more chlorinated the congener the longer it takes to degrade and the longer it persists in humans or the environment. Fat soluble, thus they accumulate in fatty tissuesPCBs have no known taste or smell, and range in consistency from an oil to a waxy solid.
PCBs were first manufactured in 1929. They were chosen because of their non-flammability, chemical stability, high boiling point and electrical insulating properties. By 1966 PCBs were detected in the Great Lakes. This was alarming and caused people to look at hazards associated with the use/disposal of PCBs. By 1977 there was concern over the impact PCBs have on the environment that led to a ban on the import, manufacturing, & sale of PCBs. By 1985 there was ban on PCB releases into the environment In 1988 storage of PCBs became regulated. Today, many are still concerned about the rate of removal of PCBs from existing equipment.
Any equipment containing PCBs is allowed to be used until the end of its service life. The PCB Waste Export Regulations (1996) prohibit the export of wastes containing PCB in a concentration of 50 mg/kg or more to any country other than the United States.
REMEMBER 4 PICTURES WILL POP UP!!
Where do PCBs come from? PCBs were used to manufacture all sorts of products before the ban in 1977.
Contamination occurs through accidental releases, careless disposal practices, leaks from industrial/chemical waste disposal sites, etc.
Poorly maintained hazardous waste sites that contain PCBs, illegal or improper dumping of PCB wastes, Leaks or releases from electrical transformers containing PCBs, Disposal of PCB-containing consumer products into municipal or other landfills not designed to handle hazardous waste, Burning some wastes in municipal and industrial incinerators
Farmers and municipalities commonly sprayed dirt roads with PCB oil as a dust suppressant.
The PCBs used in these products were chemical mixtures of PCB congeners. Most commercial PCB mixtures are known in the United States by their industrial trade names, the most common being Arochlor.
Aroclors are PCB mixtures manufactured by Monsanto until 1977. To make Aroclors biphenyls are chlorinated with anhydrous chlorine in the presence of a catalyst, such as iron filings or ferric chloride. In 1970s Monsanto's Aroclor production peaked at 85 million pounds.
Currently Monsanto is being sued by 6 United States cities for the environmental contamination with PCBs. The argument being made against Monsanto is that they continued to produce PCBs even though they were aware that their product containing PCBs was harmful to human & environmental health.
12 = number of carbon atoms in the biphenyl skeleton. Last two digits = percentage of chlorine by mass in the mixture.
Before the 1950s the main mixture used was Aroclor 1260 and 1254. Aroclor 1242 was the main mixture used in the 1950s 1971 - replaced by Aroclor 1016 Overall chlorine concentration going down steadily.
PCBs are extremely persistent. They last for many years because they do not break down easily on their own and they are difficult to destroy.
Trace levels of PCBs in the environment (air and water) are found all over the world, including remote areas of Canada. Some of this was caused by accidental releases and improper disposal practices in the past, but today, contamination is due primarily to the long-range transport of PCBs by global air currents. Once PCBs get into the environment, they accumulate in the cells of animals. The highest concentrations are found in animals at the top of the food chain, including humans.
PCB levels in aquatic organisms can be as much as one million times higher than the levels in the aquatic environment. Resistance of PCBs to biodegradation causes PCBs to become more concentrated as they move up the food chain. (ATSDR 2000)
Everyone has PCBs in their body, and consume less than 0.5 micrograms on a daily basis. Accidental exposure is the main way humans are exposed to PCBs.
Accidental Exposure Accidental Releases PCBs in liquid form contaminate soil and water, Uncontrolled fires (inhalation of aerosolized liquid PCBs) - do not burn treated/painted wood. Consumption of contaminated foods particularly fish, meat, and poultry – food high in animal fats. Living near incinerators or PCB disposal facilities
Workplace exposure Servicing old electrical equipment transporting PCBs to storage/destruction facilities working in storage/destruction facilities.
Health Effects Chloracne is a severe form of acne that covers the body Also causes cumulative liver damage, probable human carcinogen.
Target Organs skin, eyes, liver, reproductive system and other systems.
Mechanism of Toxicity PCBs bind to nucleophilic macromolcules (protein, DNA, RNA) and induce DNA strand breaks and DNA repair.
In Japan 1968, Kanemi company in Kyushu, Japana made rice bran oil. To deodorize the oil they heated it with PCBs circulating through pipes. Holes in the pipes allowed PCBs to leak into the rice bran oil. It was sold to poultry farmers for feed supplement and to consumers for cooking. A month later farmers reported their chickens were mysteriously dying due to difficulty breathing. Altogether around 400,000 chickens died, and 14,000 people were affected by the contaminated oil.
Wikipedia. 2016. Yusho disease. Web. 28 March 2016. Retrieved from https://en.wikipedia.org/wiki/Yush%C5%8D_disease
Polychlorinated biphenyls (PCBs) and human health
PCBs and human health
UNIVERSITY OF WINNIPEG, FACULTY OF BIOLOGY.
What are PCBs?
Persistent organic pollutant
209 PCB congeners
No known taste/smell
Figure 1. Chemical structure of PCBs.
1929: PCBs first
1966: PCBs first
detected in the
sale banned in
1985: Illegal to
release PCBs to
1988: Storage of
Where do PCBs come from?
Transformers and capacitors
Electrical equipment (voltage regulators, switches,
re-closers, bushings, electromagnets)
Oil used in motors and hydraulic systems
Oil based paint
Fluorescent light ballasts
Adhesives and tapes
Old electrical devices or appliances containing PCB
Thermal insulation material including fiberglass, felt,
foam, and cork
Carbonless copy paper
Contamination from PCBs has been caused by accidental releases, careless disposal
practices and leaks from industrial facilities or chemical waste-water disposal sites.
Commercial PCBs: Aroclor
Lower chlorinated biphenyls (Aroclor 1242) has a half life of 2.6 years.
Higher chlorinated biphenyls (Aroclor 1254) has a half life of 4.6 years.
Less-chlorinated congeners more readily metabolized then highly chlorinated congeners.
Highly chlorinated congeners remain in body longer than low-chlorinated PCBs.
Thus, highly chlorinated congeners bioconcentrate in adipose tissue.
The only North American producer of PCBs was Monsanto until it was banned in
1977. Currently dealing with 6 lawsuits.
PCBs in the environment.
Highly chlorinated PCBs more resistant to
Does not readily break down in the environment.
Found around the world and contaminates food, air,
soil and water.
Incorporated into plant material and food crops.
Bioaccumulates in fish and animal tissues.
Distributed to remote locations by air currents.
Figure 2. Biomagnification of PCBs in Great Lakes
EPA DW Guideline: 0.0005 ppm
FDA Food Guideline: 0.2-3 ppm (2 ppm in fish).
Human Exposure to PCBs
All humans have PCBs in their body.
Average Daily Consumption is <0.5 micrograms.
PCBs are absorbed through ingestion, inhalation, and dermal exposure, after which they
are transported through the circulation.
Primary Exposure Route: Accidental exposure
Accidental releases, consumption of contaminated foods, living near incinerators or
PCB disposal facilities
Servicing old electrical equipment, transporting PCBs to storage/destruction facilities,
working in storage/destruction facilities.
Adverse Health Effects of PCBs
Mechanism of Toxicity
PCBs bind to nucleophilic macromolecules (protein, DNA, RNA) and induce DNA strand breaks
and DNA repair.
Skin, eyes, liver, reproductive systems, other.
Chloracne, cumulative liver damage, probable human carcinogen
Eye irritation, chloracne, liver damage, reproductive effects, dry skin, redness, headache,
Adverse Health Effects of PCBs
Every commercial PCB mixture tested caused cancer.
Increases in rare liver cancers and malignant melanoma
Significant decrease in size of thymus gland
Reduced immune system response.
Decreased IgA and IgM antibody levels
Decreased monocyte, granulocyte, and natural killer cell
Deficits in neurological development (effected visual
recognition, short and long term memory and
Reduced birth weight, conception rates, and live birth
Accumulation in breast milk
Neurobehavioral/developmental deficits in newborns
exposed to PCBs in utero.
Reduced sperm counts
Decreased thyroid hormone levels (thyroxine and
triiodothyronine) (EPA, 2016).
Adverse Health Effects of PCBs
Mass PCB poisoning caused by consumption of PCB contaminated
Western Japan 1968 - Yushō disease – average PCB intake: 633 mg
Taiwan 1979 – Yu-cheng disease – average PCB intake : 973 mg
Increased eye discharge, pigmentation of nails, skin and mucous membranes,
acneform eruptions, weakness (Masuda, 1985).
How to Protect Yourself?
• Choose plain food packaging that uses less inks
• Install activated carbon filter
• Don’t rinse chemicals, solvents, oil, paints, etc.
down your home drains or storm-water drains.
• Be aware of fish consumption advisories since
PCBs can bio-accumulate in them. Allow fatty
tissue to drip away when grilling/cooking.
Environment and Climate Change Canada. 2014. Polychlorinated biphenyls (PCBs). Web. 29 March 2015. Retrieved from
Environmental Protection Agency. 2016. Polychlorinated biphenyls (PCBs). Web. 29 March 2015. Retrieved from
Health Canada. 2005. PCBs – It’s your health. Web. 29 March 2015. Retrieved from http://www.hc-sc.gc.ca/hl-vs/alt_formats/pacrb-
Masuda, Y. (1985). Health status of Japanese and Taiwanese after exposure to contaminated rice oil. Environmental Health
Perspectives, 60, 321–325.
US Department of Health and Human Services, 2014. Agency for toxic substances and disease registry. Case studies in environmental
medicine: Polychlorinated biphenyls (PCBs) toxicity.