Industrial chemicals in mothers and daughters: The pollution we share and inherit
Across Generations: About the Chemicals
In this study two major laboratories tested blood and urine from 22 people, including four mothers and their daughters, for 70 common consumer product chemicals, including plasticizers known as phthalates, perfluorochemicals (PFCs) in the family of Teflon and Scotchgard chemicals, brominated flame retardants called PBDEs, lead, and methylmercury. Below is information on exposure sources, safety standards, and health concerns for each of these chemicals or chemical families.
Teflon chemicals (Perfluorochemicals, or PFCs). PFCs are ubiquitous stain- and grease-proof coatings on furniture, carpet, clothing and food packaging. They include Teflon, Scotchgard, Gore-Tex, and coatings on microwave popcorn bags, butter boxes, and fast food containers. They never break down in the environment, and can build up in the body over time. Some chemicals in this family move through the atmosphere easily, and contaminate wildlife globally, from polar bears to cormorants. In laboratory studies they have been linked to multiple types of cancer (breast, liver, testicular, and pancreas) and birth defects. In studies of workers they are associated with prostate cancer and elevated risk of stroke. Safe levels of exposure have not yet been set.
The level of total PFCs (the sum of 13 individual chemicals) in serum, averaged 1.5 times higher in mothers than their daughters, and ranged from 6.7 to 42.5 parts per billion (nanograms per milliliter of serum).
One PFC chemical accounted for an average of 62 percent of the total PFC exposures among mothers and daughters: 3M's Scotchgard chemical (PFOS), which the company used from the 1950's until its phaseout over health concerns in 2000 (Scotchgard has since been reformulated). The PFOS in women and girls from this study is likely from past exposures.
Most PFCs are difficult to excrete, and remain in the body for a long time. The body burden levels in this study reflect exposures over a period ranging from decades to months prior to blood sampling, depending on the particular PFC chemical.
PFC manufacturers are facing a barrage of legal and regulatory pressure over the toxicity of these compounds and their near universal presence in human blood. The Environmental Protection Agency (EPA) forced 3M to take Scotchgard off the market in 2000 when company tests revealed widespread human blood pollution and birth defects in laboratory studies. 3M has since reformulated the product. Under pressure from EPA, in February 2006 DuPont, 3M and other major manufacturers agreed to dramatically reduce their environmental pollution for PFCs. For at least $120 million DuPont recently settled two cases over drinking water pollution and the company's suppression of data on birth defects and human blood pollution. Two chemicals in the PFC family and in the blood of all eight mothers and daughters tested are proposed for global phase-out under the terms of the Persistent Organic Pollutants (POPs) treaty known as the Stockholm Convention. These are PFOS (pre-2000 Scotchgard) and PFOA, a Teflon manufacturing aid and breakdown product of PFC coatings that is linked to birth defects and cancer.
EPA is currently conducting an assessment to estimate health risks from consumers' exposures to PFCs, but in the meantime, the chemicals are still the standard in stain- and grease-proof coatings in everything from blue jeans to French fry boxes.
To minimize exposures to PFCs and their impacts on the environment, we recommend that consumers phase out their use of Teflon and other non-stick pans; decline optional stain-proof coatings on furniture and carpet; avoid buying clothing advertised as stain-proof; and eat fewer greasy, pre-packaged foods, which tend to be held in containers coated with PFCs.
Mercury. In blood samples we tested for methylmercury, the form of mercury associated with seafood contamination, not dental fillings or vaccine preservatives. In general, levels reflect the contamination in seafood eaten over the several months prior to blood sampling.
The level of methylmercury averaged 5.3 times higher in mothers than their daughters, and ranged from 0.9 to 9.8 parts per billion (nanograms per gram of serum). For 3 mothers, methylmercury levels were higher than the federal safety standard of 5.8 ppb set for pregnant or nursing women and young children to protect against brain damage. While the government has not yet set a safe level to protect non-pregnant adults, the National Academy of Sciences found that mercury-driven risks for immune disorders and cardiovascular disease may occur at even lower levels than those associated with brain impairment.
People can lower their mercury exposures by changing the types of seafood they eat. Body burden levels will decline over time: on average, the human body can excrete half of its mercury load over a period of about two months. We recommend avoiding fish high in mercury, including swordfish, red snapper, tuna, and halibut, and eating fish known to be low in mercury.
Bisphenol A (BPA) and Bisphenol A diglycidyl ether metabolite (BADGE-40H). BPA is used to make polycarbonate plastics, and is also used to make a chemical called BADGE that forms epoxy resins lining metal food cans. We tested blood for BPA as well as BADGE, in the form in which it is found in the body (BADGE-40H). Recent studies have linked BPA to many adverse health effects in mice and rats at doses that overlap typical human exposures. These effects include early puberty, breast cancer, diabetes, and low sperm count. Safe levels of exposure for BPA and BADGE have not been set.
BPA was detected in the blood of 1 daughter in this study, at 2.6 parts per billion (nanograms per milliliter of serum). BADGE-40H was detected in 3 mothers and 3 daughters, at levels ranging from 0 to 174 parts per billion (nanograms per milliliter of serum). National exposure levels are not available: the Centers for Disease Control and Prevention is expected to publish the first national study of BPA body burden levels in 2007.
BPA is currently under intense scientific and regulatory debate because of concerns that it might pose risks to human reproduction. A major government safety panel is due to convene on the subject in the fall of 2006. Seven prior government reviews outside the U.S. have deemed current BPA exposures within safe limits, but none has assessed the reproductive risks demonstrated in what are now more than 100 low-dose studies.
To reduce exposures to BPA and its epoxy resin (BADGE), we recommend avoiding drinking water from hard, transparent plastic bottles (including water cooler bottles, and Nalgene), and avoiding regularly consuming foods from metal cans.
Lead. Lead was found in the blood of all mothers and daughters tested, at levels below the current action level of 10 ug/dL, set to protect children against the well-established brain damage associated with this neurotoxic metal. While an action level has not been set for adults, lead is thought to pose risks at any level, and scientists are beginning to question the role that a lifetime of lead exposure may play in degenerative diseases of aging.
The level of lead in blood averaged 2.1 times higher in mothers than their daughters, and ranged from 5 to 36 parts per billion (nanograms per milliliter of serum). Mothers' higher levels were expected, since lead builds up in the body over time.
In general, Americans' lead exposures are much lower now than they were before about 1980, when the use of leaded gasoline and lead-based house paint was restricted. Now, most people are exposed to lead through their drinking water (it leaches from lead pipes, pipe solder, and brass fixtures in the home) or through dust from chipping paint in older homes.
Lead stays in the body for a long time: on average people excrete half of any lead exposure over a period of 30 years. The levels measured in blood reflect both childhood exposures and more recent exposures. While it is not possible to significantly reduce your current body burden of lead, it is a good idea to minimize future exposures.
We recommend that people test their tap water for lead with a simple home test kit and install a water filter if needed. Since lead can accumulate in water pipes overnight, we recommend that running the tap water for at least 60 seconds, until it runs cold, before drinking it. And we recommend keeping paint in older homes in good repair, having chipped surfaces repaired using wet sanding methods to minimize dust formation.
Phthalates. Phthalates were found in all eight mothers and daughters tested. These chemicals are common plastic softeners and solvents in a wide variety of consumer products, including cosmetics, paint, food packaging, and plastics including children's toys. In many laboratory studies phthalates are linked to birth defects of the male reproductive system, including a penis deformity called hypospadias, and undescended testicles, a condition linked to infertility and testicular cancer. Studies of phthalates in people have been few, but tentatively link the chemicals to impaired sperm motility, demasculinization of baby boys, asthma, and alteration of reproductive hormone levels in breast-fed boys.
In general, people excrete phthalates from the body fairly rapidly, so body burden levels reflect exposures in the day or two prior to sampling. Because of their ubiquity in consumer products and the human body, phthalates are the subject of much recent scientific and regulatory action and debate. Of the seven phthalates found in this study, the EU has banned DEHP from children's toys, and DBP and DEHP from cosmetics. None are banned in the U.S., but some manufacturers have removed them from toys and personal care products because of public pressure.
To reduce exposures to phthalates, we recommend avoiding nail care products containing "dibutyl phthalate" (read the ingredient label); avoiding products with "fragrance" noted on the label, which commonly contains the phthalate DEP; avoiding cooking in plastic; buying a non-plastic shower curtain; and using paints and other hobby products in well-ventilated areas. Also, don't let children chew on soft plastic toys.
Brominated flame retardants (PBDEs). PBDEs, or polybrominated diphenyl ethers, are brominated flame retardants used in foam furniture and plastics for electronics like televisions and computers for the past 25 years. These chemicals interfere with the thyroid gland, which controls metabolism and growth. They may jeopardize brain development in children, and they raise concerns with respect to thyroid disease in adults. Safe exposure levels have not yet been established.
The level of total PBDEs (the sum of all individual chemicals) in serum averaged 1.6 times higher in mothers than their daughters, and ranged from 9.4 to 41 parts per billion (nanograms per milliliter of serum). National exposure levels are not available; the Centers for Disease Control and Prevention is expected to publish the first national study of PBDE body burden levels in 2007.
Many PBDEs are difficult to excrete, and remain in the body for a long time. Your body burden levels reflect your exposures over a period ranging from years to weeks prior to your blood draw, depending on the particular PBDE chemical.
In 2005 manufacturers stopped selling two of the most toxic PBDE commercial mixtures because of concerns over its ubiquity in human blood and breast milk: "Penta," (predominantly containing chemicals called PBDE-99 and PBDE-47 chemicals) and "Octa," (predominantly comprising PBDE-183). These same mixtures were banned in Europe two years earlier, although European manufacturers had never used them widely. Penta and Octa chemicals remain in many U.S. homes, primarily in foam furniture, and they commonly contaminate house dust.
Penta and Octa chemicals may continue to build up in people's bodies even after their phase-out: laboratory data shows that the common "Deca" form of PBDEs (PBDE-209) used in electronics, including computer and television casings, may break down into Penta and Octa in the environment and the body. Many states are considering banning Deca as well as Penta and Octa formulations.
Despite the potential health risks and the ability of these chemicals to accumulate in the human body, the Consumer Product Safety Commission has issued national fire-proof mattress standards effective July 2007 that could increase the use of flame retardants. Developed primarily to protect against cigarette fires, these standards would result in the widespread use of brominated flame retardants in mattresses. Because such standards have long been in place in California, several companies offer mattresses free of flame retardants as an alternative for concerned consumers.