By Janet Raloff
From Minneapolis, at the Second International Conference on Pharmaceuticals and Endocrine Disrupting Chemicals in Water.
Preschoolers ingest traces of atrazine, a herbicide used widely on corn, soybeans, and other major row crops, a new federal study finds. Though concentrations measured in the tots’ drinking water were tiny, this preliminary phase of the analysis identified just one of several potential routes by which small children could be exposed to this and other toxic agents.
Simply because they’re little, young children have a larger surface area per unit volume than do adults. They also have a tendency to put many nonfood items in their mouths and to eat a less varied diet than their parents do. For such reasons, toxicologists have worried that children might incur higher exposures to certain toxic chemicals than adults do. To begin evaluating this quantitatively, the Food Quality Protection Act of 1996 directed the Environmental Protection Agency to undertake special pollutant-exposure assessments for young children.
As part of that program, Marsha K. Morgan of EPA in Research Triangle Park, N.C., and her colleagues have been measuring preschoolers’ exposures in two states to atrazine and other suspected hormone mimics, such as insecticides and phthalates used in plastics. The researchers’ goal is to sum up probable exposures from ingestion, inhalation, and absorption through the skin. To do this, the researchers are measuring the chemicals in air, soil, food, drinks, and on other potential environmental sources, such as carpets and kitchen counters.
So far, the only complete set of data comes from water-sampling efforts in North Carolina. Although limited, the data reveal traces of atrazine in drinking water available to 130 children. For the 63 who attended daycare centers, measurements were made at home and in the center. For the rest, the researchers sampled water only at home.
The good news, Morgan reported, is that in this portion of the study, concentrations of atrazine–which animal data show can impair development–averaged only 0.02 parts per billion (ppb). Under current law, EPA permits up to 3 ppb of this pollutant in drinking water.
Within a year, Morgan says, her agency hopes to post data for all of the compounds–identified by route of exposure–on an Internet site available to the public.
