Pollutants remain in Americans’ blood despite bans
ISTOCKPHOTO
example, DDT was banned by the changed during the years of the surResearchers have found that levels of U.S. EPA in 1973, but its breakvey, which makes data from different some of the most troublesome condown product DDE was detected in years difficult to compare statistitaminants for human health are 99.7% of people in the 2003-2004 cally, he notes. Patterson says that lower than in previous years but persamples. Likewise, the fungicide more statistical tests may be possible sist in most Americans’ blood, even hexachlorobenzene was detected in after the next set of data, collected in decades after being banned. 99.9% of people tested despite a 2005-2006, is analyzed and released The new data in ES&T (DOI 1984 ban. This continuing occurin late 2009 or early 2010. 10.1021/es801966w) provide the rence in blood may result most recent and compreat least in part from conhensive picture to date of sumption of foods that exposure to persistent orwere imported from counganic pollutants (POPs) in tries that still use these the U.S. chemicals, the authors say. Blood samples were colThe new study provides lected in 2003-2004 from valuable information to approximately 1800 Amerievaluate the effectiveness of cans aged 12 years and older international bans, says as part of the National Heidelore Fiedler of the UN Health and Nutrition ExamiEnvironment Programme’s nation Survey (NHANES), Chemicals Branch, which which is administered by the helps to manage Stockholm National Center for Health Convention programs. HowStatistics at the Centers for ever, she notes that NHANES Disease Control and PrevenResearchers measured levels of dozens of chemicals in blood uses different protocols than tion (CDC). Previous CDC from a representative sample of about 1800 Americans. the Stockholm Convention studies reported levels in and therefore not all of the 1999-2000 and 2001-2002. U.S. results can be compared with Despite the statistical shortResearchers at the CDC, led by other countries’. comings, researchers are able to Donald Patterson (now heading EnFurther studies by epidemiologists, make some cautious comparisons viroSolutions Consulting, Inc.), meatoxicologists, and risk assessors are over time. For example, levels of sured levels of 21 types of POPs in needed to interpret how POPs levels dioxins and furans, both of which blood serum. The survey focused on in the new study relate to human are carcinogenic, have declined in chemicals that have been banned, health. With the new data, researchthe overall U.S. population, says including PCBs and some agriculers can better understand how and risk-assessment specialist Judy tural chemicals, or that are being why POPs levels vary in certain LaKind, president of the consultconsidered for bans, such as polypopulations, says epidemiologist ing firm LaKind Associates and brominated flame retardants and Russ Hauser of Harvard University. associate professor at the Univerperfluorinated compounds, under For example, the study found signifisity of Maryland School of Meditwo international treaties, the Stockcantly lower total toxicity levels cine. Her analysis of NHANES holm Convention on POPs and the among Mexican Americans comdata is published in the Journal of POPs Protocol to the 1979 Geneva pared with other ethnic groups, but Exposure Science and EnvironConvention on Long-Range Transacross all groups, levels were genermental Epidemiology (DOI boundary Air Pollution. By definition, ally higher in women than in men. 10.1038/jes.2008.63). “Levels [of all POPs are persistent in the envi“It’s that sort of finding that dedioxins] have decreased over time ronment, bioaccumulate up the food mands additional research to figure in the younger part of the populachain, and have toxic effects in huout what’s going on,” says epidemition, but have held steady in mans and the environment. ologist David Garabrant, who leads older people,” LaKind says. “As Levels of all of the POPs tested in a study of dioxin exposure at the pointed out by CDC, this is conAmericans’ blood were lower than in University of Michigan. “These are sistent with today’s younger the previous NHANES surveys. “This clues to important factors that depeople being exposed to lower is good and it’s important to point termine your levels of these chemilevels in the environment.” out,” Patterson notes, “but whether cals.” Many persistent compounds can that’s a trend that will continue in still be detected in Americans’ the same direction, we cannot say.” —ERIKA ENGELHAUPT blood decades after U.S. bans. For Some of the analytical methods 974 9 ENVIRONMENTAL SCIENCE & TECHNOLOGY / February 15, 2009
10.1021/es803694d
2009 American Chemical Society
Published on Web 01/14/2009
