Plastics, pesticides, and other POPs 

About Persistent Organic Pollutants (POPs)

(Note: The information in A.-C. below is adapted from the optional "Provisional Background Statement and POPS Elimination Platform," issued by the International POPs Elimination Network, October 1998.)

A.  What are POPs?

Persistent organic pollutants (POPs) are carbon-based chemical compounds and mixtures that include industrial chemicals like PCBs, pesticides like DDT and unwanted wastes like dioxins. POPs are primarily products and by-products of human industry that are of relatively recent origin.

B.  What important qualities do POPs have?

POPs released to the environment can travel through air and water to regions far distant from their original source. In these distant regions, POPs can concentrate in living organisms, including humans, to levels with the potential to injure human health and/or the environment. Most POPs have a number of common properties:

C.  How can POPs cause injury?

Some populations of humans and some wildlife species are known to suffer significant injury from certain POPs in polar and temperate regions. There are fewer studies that document health injury in tropical regions caused by POPs in the environment. It stands to reason, however, that if POPs can injure human health and ecosystems thousands of kilometers from their sources, POPs can cause similar and even greater injury in and near source areas. Absence of well-documented evidence does not mean absence of harm.

Interest and concern regarding POPs dates to the late 1960s, when scientists began compiling evidence of injury to fish, birds and mammals in or around the Great Lakes. In some of these cases, the predominant POPs sources were relatively nearby; in others, they were thousands of kilometers distant. Documented injuries were especially prevalent in high predator species and included: (a) reproductive failure and population decline; (b) abnormally functioning thyroids and other hormone system dysfunctions; (c) feminization of males and masculinization of females; (d) compromised immune systems; (e) behavioral abnormalities; (f) tumors and cancers; and (g) gross birth defects.

Alarmed by these findings, scientists investigated similar injury to humans, who, after all, can also be considered high predators. In the years that followed, good evidence was gathered associating human exposure to specific POPs or classes of POPs with: (a) cancers and tumors at multiple sites; (b) neurobehavioral impairment including learning disorders, reduced performance on standard tests and changes in temperament; (c) immune system changes; (d) reproductive deficits and sex-linked disorders; (e) a shortened period of lactation in nursing mothers; and (f) diseases such as endometriosis, increased incidence of diabetes, and others. Of particular concern is evidence suggesting that women, infants, and children are especially vulnerable to certain effects of POPs.

In people as in wildlife, injury caused by exposure to POPs is often expressed, not in the exposed adult population, but in the offspring generation. Maternal body burdens of POPs are transferred through the placenta to the developing fetus and through breast milk to the nursing infant, and can cause injury at vulnerable stages of development that may not be expressed until the infant reaches puberty or adulthood.

In the early decades of this century, POPs were virtually non-existent in the environment. Production and generation of POPs expanded dramatically following World War II. Today, ecosystems and ordinary food supplies in most regions of the world, especially fish, meat and dairy products, tend to be contaminated by POPs. Both people and wildlife, everywhere in the world, carry body burdens of POPs at or near levels that can-- and in some cases clearly do-- cause injury to human health and to entire ecosystems.

People are generally exposed to POPs through their food supply, although workers and residents of communities near POPs sources can also be exposed through inhalation and skin contact. POPs exposures are often great in peoples whose diets include large amounts of wild food and especially big fish, marine mammals and other aquatic resources. Some of the best-documented, highly exposed populations are aboriginal peoples living in polar regions far distant from most POPs sources, such as the Inuit who live in the circumpolar region. But ordinary domesticated meat and milk products can also be significantly contaminated by POPs in tropical and temperate areas. The same POPs that travel long distances on air currents, can also travel shorter distances, contaminating pastures where livestock graze.

D.  Optional:   Information about "Taking action on POPs" and the proposed international "POPs Elimination Platform"

E.  Faults in U.S. chemical-use system include:

• U.S. Government typically does not screen chemicals for safety before they go on market;

• Chemicals are presumed innocent until public can prove them guilty of causing harm (reflects curative, not preventative approach; extension of English law to chemicals; violates the Precautionary Principle);

• Chemical industry bends "scientific" studies to serve their interests-– see above;

• After decades, EPA and OSHA have set limits on less than 200 chemicals; yet 2,000 new chemicals are commercially released each year, adding to the 70,000 types already in use! -- U.S. puts 6 trillion pounds into our environment each year. More than 80% have not been screened for human health effects.

• "Currently, about 99.5% of the commercially used chemicals in the U.S. are entirely unregulated by federal and state governments." --Miller, p. 221

Government approved dioxin...

F.  Some basic causes

Ignorance, attitude, and corporate capitalism are significant basic causes of chemical contamination of our environment:

• capitalist, profit orientation
• short time perspective-- e.g., lag effects and pesticide treadmill
• limited spatial and systems view-- e.g., the "circle of poison"
• narrow view of effects (extended, consequential damage)

G.  Four examples of POPs

1.  Trichloroethylene (TCE) [C₂HCl₃]

• Trichloroethylene is the chemical example used in the assigned video, Toxics and Human Health. TCE is used mainly as a solvent to remove grease from metal parts, but also as an ingredient in adhesives, paint removers, typewriter correction fluids, and spot removers.

• Breathing TCE for long periods may cause nerve, lung, kidney, and liver damage. Breathing small amounts for short periods may cause headaches, lung irritation, dizziness, poor coordination, and difficulty concentrating. High concentrations have caused numbness and facial pain, reduced eyesight, unconsciousness, irregular heartbeat and death. Ingestion of TCE may cause nausea, liver and kidney damage, impaired immune system function, and impaired fetal development in pregnant women, convulsions, impaired heart function, coma, or death.

• Unlike many other POPs, TCE easily dissolves in water, and remains there for a long time. TCE evaporates from surface water, so it is commonly found as a vapor in the air. Exposure comes from breathing contaminated air; drinking, swimming, or showering in TCE-polluted water; contact with TCE-polluted soil (such as near a hazardous waste site); and contact with the skin or breathing contaminated air while manufacturing TCE or using it at work to clean paint or grease from equipment.

• E.g.: Toxic waste dumping by Grace and Beatrice at Woburn, Massachusetts-- the subject of the film, A Civil Action

2.  Pentachlorophenol (PCP or penta) [C₆Cl₅OH]

• Used as a wood preservative and biocide. Was one of the most heavily used pesticides in the U.S.; now only certified applicators can buy and use PCP. Still used to preserve power line poles, railroad ties, and fence posts. Now prohibited in U.S. wood preserving solutions, insecticides and herbicides for home and garden use.

• PCP can harm the liver, kidneys, blood, lungs, nervous system, immune system, and gastrointestinal tract; it is a suspected carcinogen (blood & lymph cancers) with a lag period of many years between exposure and diagnosis.

• Afflicts workers in the forestry, lumber mill, window manufacturing, paint, and construction industries, and people who have lived in direct contact with treated wood (as in some log cabins).

3.  PCBs (polychlorinated biphenyls) [C₁₂H₂Cl₈]

• Were used in electrical transformers
• Bioconcentrate in food webs
• In 1979 U.S. banned new use (even though Monsanto, the only U.S. producer, said they were harmless)
• E.g., severe contamination of Fox R. and Green Bay, Wisconsin

4.  PBBs (polybrominated biphenyls) [C₁₂H₄Br₆]

• Chemical cousin of PCBs; a synthetic hydrocarbon in which another halogen-- bromine-- is substituted for chlorine in the molecule)

• Very stable; was used as fire retardant; not manufactured in the U.S. since 1977.

• E.g.: Accidental mixing of PBBs into livestock feed led to "the poisoning of Michigan" in early 1970s

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Last updated 13 March 2001