Date: 9/28/2007 8:39:15 AM ( 14 y ) ... viewed 6269 times
Substantial threats to health arise during plastic manufacturing, both from ethylene monomers, the basic building block for plastic, and from the problem chemicals added to give plastic products their desirable performance properties.
Dioxins, which are highly toxic even at low doses, are produced when plastics are manufactured and incinerated. While dioxin levels in the U.S. environment have been declining for the last 30 years, they break down so slowly that some of the dioxins from past releases will still be in the environment many years hence. In its 2000 final draft reassessment of the health effects of dioxins, the EPA concluded that dioxins have the potential to produce an array of adverse health effects in humans. The agency's report estimated that the average American's risk of contracting cancer from dioxin exposure may be as high as one in 1,000--1,000 times higher than the government's current "acceptable" standard of one in a million. Dioxins are also endocrine disruptors, substances that can interfere with the body's natural hormone signals. Dioxin exposure, moreover, can damage the immune system and may affect reproduction and childhood development. The most common health effect in people exposed to large amounts of dioxin is chloracne, a severe skin disease with acne-like lesions that occur mainly on the face and upper body. Other effects of exposure to large amounts of dioxin include skin rashes, skin discoloration, excessive body hair, and possibly mild liver damage.
Most cling-wrapped meats, cheeses and other foods sold in delis and grocery stores are wrapped in PVC. To soften #3 PVC plastic into its flexible form, manufacturers add various toxic chemicals known as "plasticizers" during production. Traces of these chemicals, known as adipates and phthalates, can leak out of PVC when it comes in contact with foods.
In a National Institutes of Health (NIH) report published in 2000, di-2-ehtylhexyl phthalate (DEHP), commonly found in PVC plastics, was found reasonably anticipated to be a human carcinogen. While DEHP is not expected to cause harmful health effects in humans at the levels found in the environment, harmful effects did occur in animals with prolonged exposure or in those that were administered high amounts of the chemical. These effects include reproductive problems, birth defects and damaged sperm and liver in mice.
The same year, however, the International Agency for Research on Cancer (IARC) reclassified DEHP as non-carcinogenic to humans. According to NIH, blood transfusions and other procedures requiring the use of disposable PVC medical devices expose infants to high levels of DEHP, but another 2004 study of adolescents exposed to significant levels of DEHP during infancy found that there was "no significant adverse effects of on their physical growth and pubertal maturity."
Many #7 polycarbonate bottles (including baby bottles), microwave ovenware, eating utensils and plastic coating for metal cans are made with bisphenol A (BPA), a chemical invented in the 1930s during the search for synthetic estrogens. BPA can leach into food from the epoxy linings in cans or from polycarbonate bottles as they age.
Many studies have evaluated BPA as a hormone disruptor, a chemical that alters the body's normal hormonal activity. A March 1998 study in Environmental Health Perspectives (EHP) found that BPA simulates the action of estrogen when tested in human breast cancer cells.
A more recent study published in EHP shows a significant decrease of testosterone in male rats exposed to low levels of BPA. The study concludes that the new data is significant enough to evaluate the risk of human exposure to BPA.
#1 PETE plastic water bottles have been shown to leach antimony into water. A recent study conducted by University of Heidelberg researcher Bill Shotyk, and published in the January 2006 Journal of Environmental Monitoring, found antimony levels in PETE water bottles were higher than levels found where the water was sourced. According to Shotyk, consumers should not be concerned about drinking water bottled in PETE plastic, as the levels found in water are below safe drinking standards. Nonetheless, it's important to remember that leaving water in any plastic bottle for a prolonged period of time allows for chemical leaching to occur.
While most industrial processes are associated with certain byproducts, manufacturing plastic resin creates more toxic emissions than manufacturing glass--producing a 16-oz. PET bottle generates more than 100 times the toxic emissions to air and water than making the same size bottle out of glass.
The Berkeley Plastics Task Force stated in a 1996 report that the plastic industry contributed 14 percent of the most toxic industrial releases--including styrene, benzene and trichloroethane--into the air. Other major emissions from plastic production processes include sulfur oxides, nitrous oxides, methanol, ethylene oxide and volatile organic compounds (VOCs).
Furthermore, plastic polymers never fully biodegrade. Instead they photo degrade into dust, and in bodies of water, that dust can absorb other toxins such as polychlorinated biphenyls (PCBs) and the pesticide DDT, which is banned in the U.S. but is still used in developing countries. The toxins are concentrated even more strongly in this toxic dust, which is consumed by the fish that humans eventually eat.
Petroleum--A Non-Renewable Resource
Plastics are made of petroleum, a non-renewable resource that requires new fossil reserves to be extracted all the time. Because fossil fuels take millions of years to form, they are a finite and, ultimately, an exhaustible energy resource. The U.S., the world's second largest oil extractor, has only four percent of the world's oil reserves but uses nearly 30 percent of all oil extracted each year. By choosing to use non-plastic packaging, we can conserve this valuable resource and reduce our dependence on oil.
According to the Environmental Protection Agency (EPA), plastics are the fourth largest category of municipal solid waste. In 2001, the U.S. disposed of just over 25 million tons of plastic. While plastic recycling continues to grow, increasing 580 percent from 1990 to 2001, with 1,591 million pounds recycled annually the reality is that recycling budgets for many state and local agencies have been significantly reduced. In addition, consumers often believe the coding symbols on plastic containers mean the item is recyclable when, in fact, the symbols only identify the resin base of the plastics, not all of which are accepted by all recycling programs. Companies need to be urged to use easily recycled plastics and citizens should encourage their states to pass and enforce bottle bills, since these have demonstrably increased recycling rates in the 11 states where they exist.
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