Americans tested for toxic chemicals in blood, urine


A new US government study points to passive smoking as the chief culprit for the presence of toxic chemicals in people’s bodies. But environmentalists say the results are only the tip of the iceberg.

The Centre for Disease Control and Prevention (CDC), a US federal agency, on 21 July released the results of its third nation-wide biomonitoring report analysing Americans’ exposure to chemicals in the environment. One hundred and forty eight chemicals were tested for in the CDC report.

Samples of people’s blood and urine analysed in the study revealed the presence of dozens of man-made industrial chemicals. While the presence of the chemicals comes as no surprise in light of previous studies, there is still fierce debate over how scientists and policy-makers should interpret the data. 

The CDC itself was very cautious in communicating the results of the study in order to prevent unnecessary alarm in the US population, and placed the emphasis on the encouraging findings of the report:

  • The incidence of “elevated” levels of lead in children aged 1 to 5 years has decreased from 4.4% in the early nineties to 1.6% in 2002. But the CDC adds the problem remains “a major public health concern”. “There is no safe blood lead level in children. Children are best protected by controlling or eliminating lead sources before they are exposed,” commented the CDC’s Dr. Jim Pirkle.
  • Exposure to other people’s tobacco smoke (passive smoking) decreased by up to 75% for children, adolescents and adults between 1988 and 2002. But children’s levels are more than twice those of adults, the study adds, saying that the problem remains “a major public health concern”.
  • About 5% of the US population aged 20 years and older had urinary cadmium levels at or near to the CDC’s levels of concern. Cigarette smoking is the most likely source for these higher cadmium levels, it said. “We don’t know that there is a direct association but certainly finding cadmium of this level indicates a need for further research,” argues the CDC’s Dr. Gerberding.
  • Pesticides Aldrin, Endrin and Dieldrin were either not detectable or found at very low levels. All three were banned during the 70s and late 80s.
  • Dioxin-like compounds were found in lower limits than previously.
  • All women of childbearing age had mercury levels below concentrations associated with neurodevelopmental effects in the foetus. However, the CDC says the problem continues to merit close monitoring because 5.7% of those women had “levels within a factor of 10 of those associated with neurodevelopmental effects”. Defining safe levels of mercury in blood continues to be an active research area, the CDC notes. Mercury typically accumulates in seafood and fish.
  • Phtalates [a plastic softener used in toys and cosmetics which the EU recently banned] were found at levels where the CDC says health effects need to be further investigated.
  • Exposure to Pyrethroids, a chemical used in almost every insecticide used in homes, was found to be “widespread”. Likewise, the CDC indicates there is currently very limited information on potential health effects.

"Just because people have an environmental chemical in their blood or urine does not mean that the chemical causes disease," the CDC cautions in its introduction to the report.

The American Chemistry Council (ACC) said that the report indicates exposure to chemicals - whether man-made or natural - "remains extremely low". The ACC said it supported a balanced approach to biomonitoring and that the information in the report should not be cause for undue concern.

However, according to the World Wildlife Fund, the CDC study falls short of recognising the scale of chemical exposure to people and wildlife. "WWF's own biomonitoring studies document that people are broadly contaminated with a range of chemicals that are not measured in the new CDC report such as brominated flame retardants and perfluorinated chemicals," said Clif Curtis, director of WWF's Global Toxics Programme. 

According to Curtis, if the scope of the study had been widened, more chemicals would have been found. It said it hoped that future studies would include "the newly emerging, persistent and bioaccumulative industrial chemicals to which we are all exposed".

Curtis then praised the EU for charting a path toward safer chemicals with its proposed REACH regulation and invited the US to "follow Europe's lead".

The criticism was echoed by the North American chapter of the Pesticide Action Network (PAN). Margaret Reeves, Ph.D. - a senior scientist at PAN - said that the "CDC evaluated only a fraction of the total number of pesticides used every day," and pointed out that 90% of those tested carried a mixture of pesticides in their bodies. Reeves said the report measured 43 pesticides when 1,200 are registered for use in the US, saying children are particularly exposed.

"While the chemical industry will say this is the cost of doing business, we say risking our kids' health is not acceptable," said Reeves.

Earlier this month, the Environmental Working Group (EWG), a US NGO, published analyses of the blood from the umbilical cord of ten newborn babies. Performed by an independent laboratory, the tests revealed the presence of 287 industrial chemicals in the blood samples tested, leading the EWG to conclude that "industrial pollution begins in the womb" (see EURACTIV, 20 July 2005). Reacting to the new CDC report on 21 July, EWG called upon the US agency to perform tests on the umbilical cord of newborn babies. It invited 20 top chemical manufacturers to either conduct such tests or to give explanations why they did not do so.

Biomonitoring involves taking samples of human tissue (usually blood, urine or hair) to identify the presence of chemical substances in humans. It has been identified as one of the key policy tools in the Commission's health and environment action plan adopted in 2004. The plan was adopted as part of a broader strategy to reduce the negative health effects of environmental pollution on children - the SCALE strategy (see related LinksDossier).

Since then, the EU has approved plans to ban mercury exports in the 25-nation bloc, based on health concerns partly documented in various biomonitoring studies (see EURACTIV, 27 June 2005).

In 2003, Environment Commissioner Margot Wallström used blood tests to justify her controversial chemicals reform proposal, REACH. Blood tests are also used by the WWF as part of its campaign to strengthen chemicals regulation in Europe (see EURACTIV's LinksDossier on REACH).

The CDC report is likely to be used in the next stages of the legislative process of REACH, which is due for first reading in Parliament in late October.


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