What are they and how are they regulated?
Environmental toxins are chemicals, minerals, metals, and ionizing radiation that can harm health. Of an estimated 85,000 known chemicals, only a few have been thoroughly tested to assess their impact on health. Over the past 50 years, production of industrial chemicals has risen rapidly, and the U.S. generates or imports some 42 billion pounds of them per day. We ingest pesticide residues with our food, cover our skin with potentially toxic cosmetics and insect repellents, breathe air that is polluted from vehicle exhaust, power plant and industrial emissions and are exposed to wide variety of chemicals that are in thousands of household products.

In the U.S., toxic substances are regulated by the 1976 Toxic Substances Control Act (TSCA), but the burden of proving that chemicals are dangerous is almost entirely up to the government. Industry confidentiality privileges built into the TSCA prevents federal regulators access to critical information about how substances are made and what their effects might be. In the years since the TSCA became law, the Environmental Protection Agency (EPA) has issued restrictions on only a few chemicals.

There are two classes of chemicals that do have stricter regulation. Drugs are regulated by the U.S. Food and Drug Administration (FDA). Pesticides are regulated by both the federal Environmental Protection Agency (EPA) and by the states, usually by the state's agriculture office. Manufacturers must register or license pesticides for use before distribution. The EPA receives its authority to register pesticides under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). States are authorized to regulate pesticides under FIFRA and under state pesticide laws, and they may place more restrictive requirements on pesticides than the EPA.

REACH
Many experts on environmental toxins believe that stricter regulation of other chemicals and other toxic health hazards is a long-overdue safety step. They look to the safety laws recently put into place in Europe as a model. In 2007, the European Union implemented a new regulatory framework for chemicals, Registration, Evaluation, and Authorization of Chemicals (REACH). REACH shifts the burden of proof to industry, requiring chemical companies to prove that their products don't harm human health or the environment and to obtain special authorization to manufacture and distribute any chemicals designated to be of very high concern.

The American chemical industry has reservations about adopting a REACH-style program for the U.S., citing the cost of additional regulations. Critics of additional regulation point out that humans are exposed not only to man-made toxins but also to a broad array of naturally occurring and potentially dangerous chemicals and substances found in our environment, including in the air and in our food. Furthermore, it us undeniable that many of the thousands of chemicals that have been synthesized and introduced into our environment serve good purposes that are important to human welfare.
Are the dangers of environmental toxins well established?


Are the Dangers of Environmental Toxins Well Established?
Although we may recognize the benefits of chemicals, minerals and metals, very few have been thoroughly tested for human health problems. An additional problem is that almost all of the testing that has been done has looked at individual chemicals and there is very little understanding of how they might act in various combinations. It is probable that many toxic effects are dose related, that is, they are essentially harmless if we are exposed to them in very small amounts or if they are present in our bodies in very small amounts. The theory is that toxic substances can be safe as long as the amount remains below a certain threshold. Unfortunately for many toxins, the level when subtle adverse effects begin to occur is not known or is poorly understood. Research strongly suggests that the recommended safe exposure levels of metals such as lead and mercury, that were once considered safe, were too high—the trend is to set lower levels for safe exposure to many environmental toxins.

It is known that we all have hundreds of chemicals in our bodies today, including many that didn't exist even a few decades ago. Many of these chemicals are stored in body fat so they are eliminated very slowly. A biomonitoring survey by the Centers for Disease Control and Prevention (CDC) found traces of 212 environmental chemicals in Americans—including toxic metals like arsenic and cadmium, pesticides, flame retardants and even perchlorate, an ingredient in rocket fuel. Although much research remains to be done, it has become clear that developing fetuses, infants, children, pre-teens and teenagers are far more vulnerable to toxins in the environment than adults. Exposure to even tiny amounts of some toxic substances, at particularly vulnerable developmental times, can lead to significant harm to human health. For example, there are reports that suggest that some children's congenital heart defects may be associated with their mothers' exposure to specific mixtures of environmental toxins during pregnancy.

Lead
The effect of lead on children's health is one of the harmful effects most clearly documented, but controversy remains about what is a "safe level." The dangers of lead have been found to be proportional to its concentration in a person's blood. Studies have conclusively shown that pre- and post-natal exposure to lead has toxic effects and leads to impaired cognitive development, reduced IQ and increased non-adaptive classroom behavior; and with heavier exposures to miscarriage, and even paralysis and blindness. Blood lead limit recommendations have been decreased progressively from 60 μg/dl in the 1960s to the current U.S. and WHO guidelines of a maximum level of 10 μg/dl. The banning of lead additives in paint and gasoline has reduced exposures from those sources, but industrial emissions remain an important contributor to environmental contamination with lead. For children, the primary route for lead exposure is from oral ingestion via food, water, soil, dust and flaking paint in older houses that were painted with lead-containing paint.

Mercury
Mercury, like lead, is toxic to the developing brain. Major sources are coal-fired power plants and waste incinerators. Methylmercury, the more toxic form of mercury, is produced by microorganisms acting on mercury in deposits in the sea and the soil. Since mercury accumulates through the food chain, the highest levels of methylmercury are found in large predatory fish that are at the top of the food chain. These fish are a major source of human exposure. Mercury exposure, especially during fetal brain development, can impair children's memory, attention, and language abilities and interfere with fine motor and visual spatial skills. The FDA and EPA advise pregnant women not to eat swordfish, shark, king mackerel and tilefish and limit consumption of albacore tuna to 6 ounces or less a week.

Air Pollution
Exposure to tobacco smoke and other forms of air pollution in pregnancy is associated with a wide range of behavioral, neurological, and physical difficulties including stillbirth, placental disruption, prematurity, lower mean birth weight, physical birth defects (e.g. cleft palate), reductions in lung function, and increased risk of infant mortality. Children should not be exposed to secondhand smoke. The effect of exposure to marijuana smoke is less well established but it may be similar to the risks of tobacco smoke.

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POPs
Persistent organic pollutants (POPs) are carbon-containing chemicals that are extremely stable, can be spread over long distances, accumulate in high concentrations in fat tissues, and are concentrated through the food chain. Some POPs, including DDT, are pesticides that because of their persistence and accumulation within the food chain have resulted in widespread human exposures. Exposure to DDT before the age of 14 is associated with increased risk of breast cancer. Dioxins (polychlorinated-p-dioxins), and polychlorinated-biphenols (PCBs) that are dioxin-like compounds, are examples of POPs that continue to cause human exposure. Exposure to dioxins in pregnancy has been associated with subtle developmental changes in the fetus. Effects on the child later in life include changes in liver function, thyroid hormone levels, and decreased performance in tests of learning and intelligence. PCBs were manufactured in large amounts until the 1970s and although the widespread use of PCBs is now banned, there is a damaging legacy of persistence. To date, human data do not provide a sufficiently accurate basis for establishing a tolerable intake of most POPs, both for the general population, and for children as a potentially vulnerable subgroup.

Developmental Neurotoxicity (DNT)
Some toxins, such as pesticides, affect the nervous system and there is thought to be a link between exposure to them and increases in learning and developmental disabilities such as autism and attention-deficit/hyperactivity disorder as well as many other chronic diseases. It is not clear if there are real increases in learning problems among children in recent years, or just better recognition and diagnosis, but currently, about one in six U.S. children under the age of 18 have some kind of learning, developmental, or behavioral disorder.

The developing fetus and young child is particularly vulnerable to certain environmental toxins because critical neurodevelopmental processes occur in the human central nervous system during fetal development and in the first three years of life. Protection of infants and children from exposure to environmental toxins is very difficult because they may enter a child's body transplacentally during fetal development or by direct ingestion of house dust, soil, breastmilk and other dietary sources during early childhood. Despite increased knowledge of the toxicity of environmental chemicals, testing for developmental neurotoxicity (DNT) and reproductive toxicity is rarely done. DNT testing uses animal experiments to provide information on the potential toxicity to the fetal nervous system that results from the mother's exposure to toxins during pregnancy and lactation. These studies make it clear that pesticides have the potential to cause serious damage to a developing fetus and analyses of infant cord blood shows that pesticides are transferred into the baby. For newer pesticides intended for use on food crops, regulations require only that DNT testing be evaluated for substances already known or suspected of being toxins. Even though more than 140 registered pesticides are neurotoxic (i.e., specifically designed to act against pests by interfering with neurotransmitters or other processes shared by mammals and insects), the EPA has received DNT testing using validated protocols for only nine pesticides.

Endocrine Disruptors
An endocrine disruptor is a substance or mixture of chemicals from external sources that alters functions of the endocrine system and consequently causes adverse health effects in an intact organism, or its progeny. Chemicals that are endocrine disruptors can exert their effects through a number of different mechanisms: They may mimic the biological activity of a hormone, usually estrogen, prevent or alter the normal effects of a naturally occurring hormone, or affect the synthesis or breakdown rates of natural hormones.

Although the hormonal activity of these chemicals is many times weaker than the body's own naturally present hormones, there is evidence that certain man-made chemicals may be able to cause endocrine changes. These include some pesticides (e.g. DDT and other chlorinated compounds), chemicals in some consumer and medical products (e.g. some plastic additives), and a number of industrial chemicals (e.g. polychlorinated biphenols, PCBs), and dioxins.
Suspected effects of endocrine disruptors include male genital organ abnormalities, low sperm counts, female precocious puberty, lowered female fecundity (fertility), polycystic ovary syndrome, endometriosis, uterine fibroids, breast cancer, prostate cancer, testis cancer, thyroid cancer, developmental neurotoxicity, metabolic syndrome and effects on wildlife including invertebrates, fish, amphibians, reptiles, birds and mammals.

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Chemicals of concern as endocrine disruptors
Chemicals of concern as endocrine disruptors include:
PCBs, PCDDs, PCDFs
Polybrominated biphenylethers (PBDEs)
Perfluorinated compounds (PFCs)
DDT/DDE
Pesticides
Heavy metals
Alkylphenols, bisphenol A (BPA), parabens
Phthalates
Pharmaceutical estrogens
Phytoestrogens (estrogen-like chemicals naturally occurring in plants)

Among the chemicals suspected of being endocrine disruptors, bisphenol A (BPA) and phthalates (key ingredients in modern plastics)are probably the best studied and the research is indicative that they can disrupt the developing endocrine system.

Bisphenol A (BPA)
BPA is widely used, with some 6 billion pounds produced globally each year. BPA is used to harden polycarbonate plastics and make the epoxy resin used in the lining of food and beverage containers. Polycarbonates can be identified in some plastics by the resin identification code or recycling number 7.
BPA is a useful and pervasive industrial chemical but it is also a synthetic estrogen. When heated, worn or washed, plastics containing BPA can break down, allowing the chemical to leach into food and water and then enter the human body. The CDC has found BPA in the urine of 93% surveyed Americans over the age of 6. Unlike many other chemicals we are exposed to, BPA is readily excreted, so if ingestion of BPA stops, the body eliminates it quickly.

The scientific consensus has been moving away from the idea that BPA is completely safe. Animal studies link low-level fetal BPA exposure to a wide spectrum of developmental and reproductive effects, including breast cancer, early-onset puberty, male genital defects, decreased testosterone levels and sperm counts and neurobehavioral problems. In the Bush Administration years, the FDA reviewed the chemical and ruled it safe. But that report was criticized for relying almost exclusively on industry-funded studies. In 2008, Canada deemed infant exposure to BPA potentially unsafe and banned the sale of baby bottles that use the chemical — a step later taken by a number of American states and major retailers, including Walmart. Although European regulators declared BPA safe in a 2008 assessment, Denmark has enacted a ban on BPA in baby bottles.

In 2009, the International Endocrine Society released a statement declaring that endocrine disrupters were a significant concern for public health and called for regulation to reduce human exposure. The FDA has recently expressed "some concern" over BPA as the Obama Administration launched a $30-million study of the chemical.

Phthalates
Phthalates are a widely used class of industrial chemicals that may affect the endocrine system. They are found in polyvinyl chloride plastics and many consumer products, including nail polish, hair spray, deodorant and shampoo. When pregnant women have been exposed to phthalates, they have been shown to adversely affect genital development in male children. In animal studies, phthalates have also been shown to disrupt hormones and have been linked to reduced sperm counts and other signs of feminization in male rodents. Similar effects are caused by a class of long-lived chemical fire retardants known as polybrominated diphenyl ethers (PBDEs), used in electronics, polyurethane foam and other plastics. These chemicals can leak out of polyurethane cushions in car seats or changing table pads and can be inhaled or absorbed through a baby's skin. Although they're being phased out, unlike BPA and phthalates that are excreted within a few days, PBDEs can remain in the body for years.

Higher levels of phthalates and other endocrine disrupters have been linked to earlier breast development in girls and male genital abnormalities like undescended testicles and smaller penises. However, the science around endocrine disrupters is not settled and some peer-reviewed studies fail to show a link between endocrine disrupters and health effects. Although human exposure to BPA and phthalates is still well below safety levels set by most governments, and most health agencies around the world say the chemicals are safe for humans, the precautionary principle suggests that minimizing exposure, especially for pregnant women, infants and children is a good idea.

Pharmaceuticals
When outdated and unused drugs are put into trash or flushed, they may end up in our water system and may not be eliminated by water-treatment techniques. New programs to encourage proper disposal of drugs would address just 10% of the source of the problem, because 90% comes from pharmaceuticals passing through the body largely unaltered and into the sewage system. There are about 3,000 prescription pharmaceuticals in use in the U.S. and thousands more over-the-counter drugs, as well as the creams and ointments we apply to our skin and then shower off. Pharmaceutical pollutants are worrisome because they are specifically designed to be metabolically active in humans.

In the 1990s, pharmaceutical estrogens, principally from birth control pills, began showing up in the water, leading to male fish with androgynous sex organs. It did not take much estrogen to affect the fish — just 5 or 6 nanograms, or billionths of a gram, per liter of lake water.

Even though very tiny amounts of many classes of drugs are found in many water supplies, they are in such low concentrations that they do not appear to have an impact on human health. Among those drugs identified are antidepressants, anticonvulsants, tranquilizers, antibacterials, antipsychotics, ACE inhibitors (for hypertension), steroids, analgesics (like ibuprofen), and caffeine. While short-term exposure to these drugs at thousandths of their effective dose levels does not seem to entail a risk, there is essentially no data on long-term low-level exposures and interactions between drugs.

Exposure to pharmaceuticals in water is largely dependent on the source of municipal water, and bottled water provides no guarantee of freedom from pharmaceuticals. Many water systems start with pure water and their wastewater flows away. But for other water systems that take water form the Mississippi or Colorado rivers, their cleaned-up wastewater can end up in the water supply of another city or town.

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Environmental Toxins: A Listing
The following are toxins that can affect health:
Acetone
Ammonia
Artificial Turf
Arsenic
Asbestos
Benzene
Bisphenol-A
Carbon Monoxide
Chlorine
Dioxins
Drinking Water Contaminants
Endocrine Disruptors (BPA and Phthalates)
Environmental Tobacco Smoke
Ethylene Glycol
Flame Retardants (PBDEs or BFRs)
Formaldehyde
Gasoline
Lead
Mercury
Mold
Nitrogen Oxides
Ozone
Particulate Matter
Perchloroethylene
Perfluorooctanoic Acid (PFOA)
Pesticides
Phthalates
Polychlorinated Biphenyls (PCBs)
Polycyclic Aromatic Hydrocarbons (PAHs)
Radon
Solvents
Sulfur Dioxides
Sun Exposure
Toluene
Volatile Organic Compounds (VOCs)

The Top Ten Toxins
According to Dr. Joseph Mercola, among the thousands of toxins in our environment, the following top 10 toxins are among the most prevalent in our air, water and/or food supply:

1. PCBs (polychlorinated biphenyls): This industrial chemical has been banned in the United States for decades, yet is a persistent organic pollutant that's still present in our environment.
   Risks: Cancer, impaired fetal brain development.
   Major Source: Farm-raised salmon. Most farm-raised salmon, which accounts for most of the supply in the United States, are fed meals of ground-up fish that have absorbed PCBs in the environment.
   
   
2. Pesticides: According to the Environmental Protection Agency (EPA), 60 percent of herbicides, 90 percent of fungicides and 30 percent of insecticides are known to be carcinogenic. Pesticide residues have been detected in 50-95 percent of U.S. foods.
   Risks: Cancer, Parkinson's disease, miscarriage, nerve damage, birth defects, blocking the absorption of food nutrients.
   Major Sources: Food (fruits, vegetables and commercially raised meats), bug sprays.
   
   
3. Mold and other Fungal Toxins: One in three people have had an allergic reaction to mold. Mycotoxins (fungal toxins) can cause a range of health problems with exposure to only a small amount.
   Risks: Cancer, heart disease, asthma, multiple sclerosis, diabetes.
   Major Sources: Contaminated buildings, food like peanuts, wheat, corn and alcoholic beverages.
   
   
4. Phthalates: These chemicals are used to lengthen the life of fragrances and soften plastics.
   Risks: Endocrine system damage (phthalates chemically mimic hormones and are particularly dangerous to children).
   Major Sources: Plastic wrap, plastic bottles, plastic food storage containers. All of these can leach phthalates into our food.
   
   
5. VOCs (Volatile Organic Compounds): VOCs are a major contributing factor to ozone, an air pollutant. According to the EPA, VOCs tend to be even higher (two to five times) in indoor air than outdoor air, likely because they are present in so many household products.
   Risks: Cancer, eye and respiratory tract irritation, headaches, dizziness, visual disorders, and memory impairment.
   Major Sources: Drinking water, carpet, paints, deodorants, cleaning fluids, varnishes, cosmetics, dry-cleaned clothing, moth repellants, air fresheners.
   
   
6. Dioxins: Chemical compounds formed as a result of combustion processes such as commercial or municipal waste incineration and from burning fuels (like wood, coal or oil).
   Risks: Cancer, reproductive and developmental disorders, chloracne (a severe skin disease with acne-like lesions), skin rashes, skin discoloration, excessive body hair, mild liver damage.
   Major Sources: Animal fats: Over 95 percent of exposure comes from eating commercial animal fats.
   
   
7. Asbestos: This insulating material was widely used from the 1950s to 1970s. Problems arise when the material becomes old and crumbling, releasing fibers into the air.
   Risks: Cancer, scarring of the lung tissue, mesothelioma (a rare form of cancer).
   Major Sources: Insulation on floors, ceilings, water pipes and heating ducts from the 1950s to 1970s.
   
   
8. Heavy Metals: Metals like arsenic, mercury, lead, aluminum and cadmium, which are prevalent in many areas of our environment, can accumulate in soft tissues of the body.
   Risks: Cancer, neurological disorders, Alzheimer's disease, foggy head, fatigue, nausea and vomiting, decreased production of red and white blood cells, abnormal heart rhythm, damage to blood vessels.
   Major Sources: Drinking water, fish, vaccines, pesticides, preserved wood, antiperspirant, building materials, dental amalgams, chlorine plants.
   
   
9. Chloroform: This colorless liquid has a pleasant, nonirritating odor and a slightly sweet taste, and is used to make other chemicals. It's also formed when chlorine is added to water.
   Risks: Cancer, potential reproductive damage, birth defects, dizziness, fatigue, headache, liver and kidney damage.
   Major Sources: Air, drinking water and food can contain chloroform.
   
   
10. Chlorine: This highly toxic, yellow-green gas is one of the most heavily used chemical agents.
    Risks: Sore throat, coughing, eye and skin irritation, rapid breathing, narrowing of the bronchi, wheezing, blue coloring of the skin, accumulation of fluid in the lungs, pain in the lung region, severe eye and skin burns, lung collapse, reactive airways dysfunction syndrome (RADS) (a type of asthma).
    Major Sources: Household cleaners, drinking water (in small amounts), air when living near an industry (such as a paper manufacturing plant) that uses chlorine in industrial processes.
    Source: Mercola.com, © (c) CanWest MediaWorks Publications Inc.

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Avoiding Environmental Toxins
Given the great uncertainty regarding what exactly is toxic in our environment, the levels that are harmful and the health effects of environmental toxins, it is best limit exposure as much as possible. It should be recognized that it is impossible to avoid all environmental toxins. What can be done is to minimize exposure by adhering to following recommendations:
The University of California, San Francisco Program on Reproductive Health and the Environment offers the following advice reproduced from their publication: "Toxic Matters Protecting Our Families from Toxic Substances" available online at: www.prhe.ucsf.edu/prhe/toxicmatters.html

Prevent Exposure At Home

• Don't smoke.
  Talk to your doctor if you need help quitting.
  Don't let people smoke around you and stay away from public places where people are smoking.
  
• Use non-toxic personal care products. Many of these products have ingredients that can harm reproductive health.
  Find safer products at:
  www.prhe.ucsf.edu/prhe/tmlinks.html#personalcare.

Become A Smart Consumer

• Use non-toxic products
  
Many of the products you use everyday may contain toxic substances. Some consumer guides can help you find non-toxic products. Find links to some of these guides at:
www.prhe.ucsf.edu/prhe/tmlinks.html#consumerguide.

Become a Smart Consumer: Consumer Guides
Healthy Stuff.org is a project of the Ecology Center (a Michigan-based nonprofit), and has basic information and rankings on a range of consumer products based on research conducted by environmental health organizations and other researchers around the country.
Environmental Working Group's Skin Deep Cosmetics Database displays online safety profiles for cosmetics and personal care products; it allows you to search products and rank them according to their health hazard.

United States Department of Health and Human Services' Household Products Database is sponsored by the National Institutes of Health and National Library of Medicine. It contains searchable information on household products, manufacturers, ingredients and health effects for everyday items.
Good Guide provides searchable rankings for companies and products. Products are ranked according to health hazard, environment and social responsibility. Good Guide also offers a mobile app.

The National Geographic Green Guide website includes buying guides and information on sustainable choices for food, travel, home and garden. The Green Guide publishes a monthly magazine, weekly newsletter, product reports and reviews focused on practical everyday, environmentally responsible and health-minded product choices and actions.

Natural Resources Defense Council (NRDC) publishes a variety of reports and policy papers on environmental health topics such as: children's health; health threats and effects; farming and pesticides; chemicals at home, school and work; and science and public policy. They also produce Smart Shopper's Guides and NRDC's Smarter Living site has factsheets for chemical safety and sustainability in the home, school or workplace. The site also has convenient shopping guides that you can download and bring to the store to help you make more informed choices.

The California Department of Public Health's Safe Cosmetics Program has begun collecting information from manufacturers on ingredients in products sold in California that cause cancer or reproductive harm such as birth defects. Currently, the website has information on emerging issues related to cosmetic toxicity and a list of chemicals for which the state is requesting information from manufacturers. Eventually, a database will be created to allow people to find out if personal care products they use contain harmful chemicals.

Magee-Women's Hospital at University of Pittsburgh Medical Center video series called "UPMC's Guide to Green Parenting" is available on YouTube: http://www.youtube.com/user/upmc#g/c/03646D128774A6BB

Prevent Exposure In Your Community
You can also help reduce pollution in your community. Learn more at: www.prhe.ucsf.edu/prhe/tmlinks.html#community.

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Help create a better environment for your family and everyone around you:

Don't spray bugs.
Pesticides are toxic chemicals for killing insects, rodents, weeds, bacteria and mold. Keep insects and rodents out of your home.

Links