Down the Drain: » Phthalates
Invented in the 1930s, the 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, especially PVC plastic, and to make nail polish flexible and chip-resistant; as skin moisturizers and skin penetration enhancers in cosmetics; as an ingredient of fragrance in cosmetics and cleansing products; as components of a broad array of consumer products, from adhesives to inks; and as solvents in a wide range of applications. People are exposed to phthalates daily through their contact with consumer products, via food packaged in plastic, and from indoor air (CDC 2005).
In September 2000, scientists from the Centers for Disease Control and Prevention (CDC) conducted the first accurate measurements of human phthalate exposures, and reported finding phthalates in every one of 289 people tested, at surprisingly high levels (Blount 2000). Levels of some phthalates in U.S. women of childbearing age have been found to exceed the government's safe levels set to protect against birth defects, according to another CDC study (Kohn 2000). Results of phthalate testing in more than 2,500 people ages 6 and above confirmed the CDC's original findings: phthalate exposures are widespread across the population, and women are exposed at higher levels than men (CDC 2003). In a recent study of girls age 6 to 8 spearheaded by Mount Sinai School of Medicine, phthalates were found in every one of 90 girls tested (Wolff 2007). Phthalates are widespread contaminants in the environment as well (Kolpin 2002; Rudel 2003).
Epidemiological studies of ordinary people have linked high phthalate levels to reduced sperm motility and concentration, increased damage to sperm DNA, and alterations in hormone levels in adult men (Duty 2003, 2004, 2005; Hauser 2007). A recent study of 134 births found marked differences in the reproductive systems of baby boys whose mothers had the highest phthalate measurements during pregnancy (Swan 2005). A second study indicated that these mothers' exposures were not extreme, but rather were typical for about one-quarter of all U.S. women (Marsee 2006). Further research documented decreased testosterone levels among baby boys exposed to phthalates in their mother's breast milk (Main 2006).
New epidemiological studies indicate phthalates may produce non-reproductive health effects in men as well. Results from one study suggest that breakdown products of one particular phthalate, DEHP, may be associated with alterations in thyroid hormone levels (Meeker 2007). In another study, increased levels of certain phthalates were associated with increased waist circumference and insulin resistance in adult men in the United States (Stahlhut 2007). According to the American Heart Association (2007), over 60 million Americans have insulin resistance; 1 in 4 of these people develop Type 2 diabetes.
In addition to this epidemiological research on humans, laboratory studies indicate phthalates cause a broad range of birth defects and reproductive impairments in animals exposed in utero and shortly after birth (e.g. Marsman 1995; Wine 1997; Ema 1998; Mylchreest 1998, 1999, 2000; Gray 1999; CERHR 2000). Phthalate exposures damage the testes, prostate gland, epididymis, penis, and seminal vesicles in laboratory animals (e.g. Mylchreest 1998); most of these effects persist throughout the animal's life. Phthalates have also been shown to bioaccumulate in fish tissue and to affect estrogen levels in fish (Jobling 1995).
Phthalates are considered a hazardous waste and are regulated as pollutants when industry releases them into the environment. In contrast, phthalates are essentially unregulated in food, cosmetics, and consumer products. One phthalate, DEHP, is regulated in drinking water. In addition, this phthalate was removed voluntarily from children's toys more than a decade ago. The European Union has banned use of some phthalates in cosmetics and other consumer products, in response to concerns about exposure and toxicity.