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Beauty Secrets: Phthalates

Beauty Secrets

Phthalates

Invented in the 1930's, the versatile group of common industrial chemicals called phthalates (pronounced tha-lates) are used as ingredients in a diverse range of consumer products from cosmetics to food wraps, toys and building materials. Currently the chemical industry produces billions of pounds of phthalates each year. They are used as plasticizers to soften plastic, as skin moisturizers and skin penetration enhancers in cosmetics, and as solvents in a wide range of applications. People are exposed to phthalates daily through their contact with consumer products and via food and indoor air.

In spite of their widespread presence in cosmetics and other common consumer products, industry has only partially studied the health effects of phthalates and has never tested for the presence of phthalates in human bodies. Finally, in April 1999, over six decades after phthalates were first marketed, the federal government's National Institute for Environmental Health Sciences (NIEHS) initiated a study of the effects of phthalates on the human reproductive system through their new Center for the Evaluation of Risk to Human Reproduction (CERHR).

At the same time, scientists at the Centers for Disease Control and Prevention (CDC) were achieving the first accurate measurements of phthalates in people. Researchers there were surprised to find that people have much higher levels of some phthalates in their bodies than predicted by previous estimates (Blount et al 2000). In October 2000, CDC scientists announced that levels of some phthalates in women of childbearing age, including dibutyl phthalate (DBP) and di(2-ethylhexyl) phthalate (DEHP), exceed the government's safe levels set to protect against birth defects. Estimates based on data from this study indicate that for more than 3 million heavily exposed women of childbearing age, exposures to DBP may be 20 times greater than the average exposures in the rest of the population (Kohn et al 2000).

This report focuses primarily on DBP, a widely used phthalate that produces serious reproductive and developmental effects in laboratory animals. But DBP is not the only toxic phthalate to which people are routinely exposed. Many other phthalates widely detected in human urine by the CDC cause the same birth and developmental defects to the male reproductive system as DBP. Absent evidence to the contrary, it is reasonable to assume that the health effects from exposures to multiple phthalates are additive.

Health effects of dibutyl phthalate

At least two decades ago, scientists began building a body of work indicating that DBP can be a powerful reproductive and developmental toxicant in laboratory animals, particularly for males. Early studies focused on DBP's ability to cause testicular atrophy (e.g., Gray et al 1980), but DBP is now known to cause a broad range of birth defects and lifelong reproductive impairment in male laboratory animals exposed in-utero and shortly after birth (Ema et al 1998, Marsman et al 1995, Mylchreest et al 1998, 1999, and 2000, Gray et al 1999, Wine et al 1997 ).

Scientists believe that the active toxicant of DBP exposure is its first breakdown product, monobutyl phthalate (MBuP), which has been shown to harm the male reproductive system. The precise mechanism of action is not known but the pattern of reproductive harm is consistent with other so-called anti-androgens or chemicals that interfere with the male hormones called androgens.

Effects in immature male animals: DBP exposure damages the testes, prostate gland, epididymus, penis, and seminal vesicles in laboratory animals (see, for example, Mylchreest et al, 1998). These effects persist throughout the animal's life, and include, specifically:

• Testicular atrophy (the testes produce sperm and male sex hormones)
• Hypospadias (a defect of the penis in which the opening occurs on the bottom of the penis instead of the tip)
• Undescended testicles Ð a condition in which the testes fail to descend into the scrotal sac during pregnancy.
• Ectopic testes Ð a condition in which testes are grown outside the scrotal sac
• Absent testes Ð testes are not formed at all
• Absent prostate gland (the prostate gland contributes liquid secretions to semen)
• Absent or small seminal vesicles (seminal vesicles, like the prostate gland, contribute liquid secretions to semen)
• Reduced sperm count (reduced fertility of offspring)
• Malformed or absent epididymus (the epididymus is the structure where sperm mature and are stored)

Potential health effects of DBP continue to be significant for newborn animals who can be exposed to DBP by breathing phthalate-contaminated air, by touching things that contain phthalates, or by drinking their mother's milk, which can contain phthalates as a result of her exposures. In young lab animals, DBP has been shown to cause permanent testicular atrophy and reduced sperm counts (Foster et al 1981, Marsman 1995).

In animal tests DBP is also "embryolethal" - causing loss of pregnancy - and prevents implantation of the fertilized egg. In lab animals it also causes "resorption" of some or all of the fetuses in a litter, where the mother's body essentially dissolves the fetus without miscarriage. DBP also causes a range of skeletal and external birth defects for male and female offspring of animals exposed during pregnancy Ð including deformity of vertebra and ribs, cleft palate, and fused breastbone (Ema et al 1994 and 1995).

Relevance to people

Broad and disturbing trends in human male reproductive health include many of the same effects seen in lab animals dosed with phthalates. Although a cause and effect relationship has not been established, the ubiquity of phthalates in the human population creates a biologically plausible presumption that phthalates may be contributing to these problems. Until proven safe, phthalates should be considered as potential contributors to the following human health effects:

• Declining sperm count: Recent analysis of 101 studies (1934-1996) by Shanna Swan of the University of Missouri confirms results of previous studies: average sperm counts in industrialized countries are declining at a rate of about 1 percent each year (Swan et al 2000).
• Hypospadias: Data from the Centers for Disease Control show that rates of hypospadias in the U.S. began climbing in about 1970, and continued this increase through the 1980s. This condition is a physical deformity of the penis in which the opening of the urethra occurs on the bottom of the penis instead of the tip. (Currently the occurrence of hypospadias appears to be stable, at about 30 to 40 cases per 10,000 births.) (Paulozzi 1999)
• Undescended testicles: This birth defect, where testicles fail to completely descend into the scrotum during pregnancy, occurs in 2-5 percent of full-term boys in Western countries. Rates of the defect increased greatly in the U.S. in the 1970s and 1980s. Men born with this defect are at higher risk for testicular cancer and breast cancer (Paulozzi 1999).
• Testicular cancer: This is the most common cancer of young men in many countries, including the U.S. Its incidence continues to increase at a rate of about 2 to 4 percent each year in industrialized countries, although rates appear to have stabilized in the U.S. after a 20-year increase. Men with hypospadias, infertility, and undescended testicles - the same constellation of conditions seen in lab animals exposed to DBP - are at greater risk for developing testicular cancer (Toppari et al 1996 and Moline 2000).

History of recent government studies of phthalates

In April 1999, CERHR initiated a review of the reproductive and developmental effects of phthalates in humans. The Center chose seven phthalates for examination, based on consideration of production volume, extent of human exposures, use in children's products, or published evidence of reproductive or developmental toxicity.

They addressed the following three questions for each phthalate based on their current understanding of levels of human exposure to phthalates:

1.Are young children at risk for harm to the reproductive system?

2.Is the fetus at risk for developmental effects when the mother is exposed?

3.Are adults at risk for effects to the reproductive system?

In their June 2000 report draft CERHR assigned low, minimal, or negligible concern to five phthalates, and higher concern for only one, DEHP. ("Concern" refers to whether CERHR believes the chemical is a reproductive or developmental toxicant in people at current levels of exposure.)

In September 2000, Dr. Brock and his team of CDC scientists published the results of the first human testing program for phthalates (Blount et al 2000). The results turned the CERHR conclusions of minimal concern on end. They found phthalates in every person tested, and at surprisingly high levels in some individuals for some phthalates. The scientists concluded that "from a public health perspective, these data provide evidence that phthalate exposure is both higher and more common than previously suspected, " adding that, "Exposure data for phthalates is (sic) critically important for human risk assessment, especially among potentially susceptible populations."

Brock and his team measured levels of seven phthalate metabolites in the urine of 289 adults. They found metabolites from two of these in 100 percent of those tested - dibutyl phthalate, or DBP, and benzylbutyl phthalate, or BzBP. A metabolite of DBP called monobutyl phthalate (MBuP), a potent reproductive toxin in lab animals, was found at significantly higher levels in women of childbearing age. Six of the eight highest measured levels were in this group. CDC postulates in their paper that high exposures to phthalates in women of childbearing age may arise from the use of cosmetics and beauty products. See Sidebar

These results caught both government and industry off guard. Now, government scientists are beginning a search for answers: Are normal body levels of phthalates safe for infants and pregnant women? How are people exposed to phthalates - through which consumer products and via what pathway?

Government scientists published a letter in the October issue of Environmental Health Perspectives outlining the significance of the CDC urine study. Their analyses showed that the highest exposures measured, in women of childbearing age, were above federal safety levels set to protect against birth defects. Estimates based on these data indicate that DBP exposures for up to 3 million women of childbearing age may be 20 times higher than for the rest of the population.

In an effort to determine key routes of exposure, CDC is beginning work on an extensive survey to find which products are causing the high DBP levels in women of childbearing age.

Phthalates: regulated as toxic pollutants - but OK in consumer products

Phthalates are considered a hazardous waste and are regulated as pollutants in air and water. In contrast, phthalates are essentially unregulated in food and cosmetics. (One phthalate, DEHP, which was removed from children's toys more than a decade ago, is regulated in drinking water.)

Under various environmental laws, individual companies are limited with regards to how much DBP they can release to the environment as pollution each year. For example, industries must report any spill or release of DBP over 10 pounds, and industries using phthalates must keep records of their location and transportation. But FDA does not limit the amount of DBP that can be used in cosmetics and other beauty products. And the FD&C Act does not require that cosmetic manufacturers or marketers test their products for safety.

So, by design from the chemical industry, the federal government treats phthalates with a bipolar approach. Phthalates are recognized as toxic substances under environmental law, but companies are free to use unlimited amounts in cosmetics. Moreover, the labeling requirements for cosmetics are riddled with loopholes. If a woman reads the fine print on the back of every cosmetic bottle she purchases, she might discover whether the product contains phthalates. However, she won't know the quantiy of phthalates in the product, or what health effects her use of the product could possibly have on her fetus.

Specifically, FDA's labeling requirements state that all cosmetics produced or distributed for retail sale to consumers for their personal care bear a list of ingredients, ordered by prevalence (21 CFR 701.3). Cosmetic labeling requirements apply to all cosmetics marketed in the U.S., whether manufactured here or abroad. But it's simple for industry to hide phthalates in consumer products, as components of fragrances, flavorings - or chemical mixtures that are considered "trade secrets" - all of which are exempt from labeling requirements.

Remarkably, women who work in nail and hair salons and presumably get the highest exposures, are not protected even by labeling regulations. Ingredient labeling requirements do not apply to products used only by beauty professionals in the workplace. The 1997 U.S. Economic Census shows that over 407,000 people are employed in the more than 81,000 beauty salons across the country. These employees, primarily women including what is likely a large percentage of women of childbearing age, are exposed to DBP in beauty products daily, with no knowledge of it and no option for choosing alternate products.

The federal government has "low" confidence in their safe daily dose value for DBP

Ten years ago, using a study published in 1953, the Environmental Protection Agency (EPA) established a "safe" daily dose of DBP, called the Reference Dose, or RfD. Even then, the EPA characterized this pivotal study as weak, and their confidence in the RfD as "low." Ten years later the agency has not revised the safe dose, nor required new studies to strengthen its knowledge of DBP toxicity.

The CDC found that high-end DBP exposures in women of childbearing age are above the federal safe daily dose (Kohn et al 2000). If the safe daily dose value were brought up to modern standards, even more women in the CDC study group would fall into the zone of concern.

The study supporting the RfD is archaic in design and does not provide any information on the health effects that concern scientists today - birth defects in male offspring. The study included only adult male rats, and death was the only health effect studied. Irrespective of the fact that the study examined only the most crude endpoint, the results are of marginal relevance to real world human exposures, and do not provide a sufficient scientific basis to establish a safe exposure level under contemporary standards applied to pesticides or food additives regulated under federal law. EPA admits that the study has many deficiencies. In their documentation of the RfD the agency states "The Oral RfD for dibutyl phthalate may change in the near future pending the outcome of a further review now being conducted by the Oral RfD Work Group" (EPA 1990).

Nonetheless, the current RfD is derived from a "safe" dose in this study of 125 mg of chemical ingested per kilogram of body weight (mg/kg) - the dose that was shown to induce no additional deaths relative to the control group. A study published this year (2000) found that exposures at this level, thought previously to produce no effects, in fact cause birth defects in male pups, including extra nipples in a third of the pups (Mylchresst et al 2000). This study found a "safe" dose, called a no observed adverse effect level, or NOAEL, of 50 mg/kg - 60 percent lower than the dose that is currently the basis for the RfD.