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.