Scientists Calling for Urgent Study of Phthalates

The National Research Council is calling upon the EPA to study the cumulative effects of exposure to phthalates, a class of hormone-mimicking chemicals found in items like cosmetics, toys, air fresheners, plastic containers and other household products.

Humans are being exposed to hormone-disrupting chemicals at a far greater rate than ever before, and we don’t yet know what the long-term effects might be. Research has already shown that phthalates can affect the reproductive organs of young boys, causing smaller penis size. It’s been theorized that such exposure could lead to fertility problems later in life.

A new law will ban several types of phthalates from children’s products starting in February, and the EPA will soon require cosmetics manufacturers to report whether their products contain phthalates, but you still won’t be able to tell by reading the ingredients – and phthalates are in plenty of other products.

From the NRC report, via The Daily Green:

Recent animal studies have increased understanding of the potential risks from phthalates, although few human studies on the health effects of phthalates are available … To decide whether a cumulative risk assessment is warranted, two factors needed to be determined: whether humans are exposed to multiple phthalates at any given time, and whether sufficient evidence exists linking exposures to similar adverse health effects. The committee established that recent studies have shown widespread human exposure to multiple phthalates, including in utero exposure.

Then, the committee reviewed animal research and found that exposure to various phthalates in lab animals produced similar health outcomes, including a range of effects on the development of the male reproductive system. The most notable effects in male rats are infertility, undescended testes, malformation of the penis, and other reproductive tract malformations. However, the severity of effects differs among phthalates; some exhibit less severe or no effects. Furthermore, the age of the animals at the time of exposure is critical to the severity of the effects. For example, the fetus is most sensitive. Given that multiple human exposures to phthalates occur and that research shows exposure to different phthalates leads to similar outcomes in lab animals, a cumulative risk assessment is called for, the committee said.

The animal studies reviewed by the committee also indicated that some phthalates reduce testosterone concentrations. Depending on when this drop occurs, it can cause a variety of effects in animals that are critical for male reproductive development. Other chemicals known as antiandrogens, which prevent or inhibit male hormones from working, can produce similar effects in lab animals. The committee recommended that phthalates and other chemicals that affect male reproductive development in animals, including antiandrogens, be considered in the cumulative risk assessment. A focus solely on phthalates to the exclusion of other chemicals would be artificial and could seriously underestimate risk, the committee emphasized.

Currently when conducting cumulative risk assessments, EPA often considers only chemicals that are structurally related, on the assumption that they have the same chain of reactions that lead to a final health outcome. That practice ignores how exposures to different chemicals may result in the same health effects. The conceptual approach taken for phthalates — to consider chemicals that cause similar health effects — should also be applied when completing any cumulative risk assessment, the committee said. For instance, EPA could evaluate the risk of combined exposures to lead, methylmercury, and polychlorinated biphenyls because all contribute to cognitive deficits consistent with IQ reduction in children.

It’s about time phthalates were given in-depth study. When you think about it, as consumers we really don’t have any idea what is in most of the products we buy. Manufacturers can get away with putting all kinds of chemicals in their products because the chemicals haven’t proven to be dangerous. But if no one has ever checked to see whether they’re dangerous, we could go on using them unaware for years. Scary.

Link [The Daily Green]
Photo credit: Flickr user Gaetan Lee