United States Children's Environmental Exposure Research Study Delayed Due to Ethical Concerns

The United States Environmental Protection agency's proposed study, which is partially funded by the American Chemistry Council, to assess children's exposure to residential pesticides has been temporarily suspended due to ethical concerns.

Pesticides have been implicated in a variety of adverse health outcomes and children are expected to be especially at risk. The increased susceptibility of children is a result of many factors including; increased burden of pesticide exposure based on body weight, specific play behaviours and differences in the metabolism and excretion of chemicals as compared to adults. Critical information needed to assess children's exposure to the wide array of chemicals they encounter in their homes and other environments is currently very limited. Toxicological assessment of pesticides may not be sensitive enough to detect compounds that pose a carcinogenic risk to humans, and it is not possible for these tests to obtain accurate information about the hazards of exposure to mixtures of commercial pesticides. Epidemiological studies have been conducted in an attempt to fill some of these gaps, however these investigations are limited as many did not consider critical windows of exposure to pesticides, and biological samples following exposure were rarely collected.

The United States Environmental Protection Agency has designed a 2 year long prospective study to collect data that is expected to improve the understanding of exposures of very young children to pesticides commonly found in homes. The Children's Environmental Exposure Research Study (CHEERS) is intended to gather information regarding the most important pathways of exposure for young children, exposure factors specific to age/developmental stage, and the relationship between biomarker concentrations and exposure estimates. This study will be conducted in Jacksonville, Florida and will follow sixty children for 2 years who reside in households which regularly use pesticides. The parents will maintain a log of pesticide use in and around the home, as well as a log of their child's activities. Regular samples of floors and other surfaces will be taken and urine samples will be collected to analyze metabolism of the pesticides. It is proposed that this data will reduce the number of assumptions made in human exposure assessments, ultimately reducing the uncertainty in exposure and risk assessments for children.

Participants will be eligible for recruitment into the study if they report that they have high pesticide use in their residence. A screening visit will confirm the reported level of pesticide use based on the results of floor surface wipe samples. In exchange for participating in the two year study the EPA will give each family a video camera and a VCR. Monetary compensation will also be provided. To ensure retention of the participants in the study, this compensation will be distributed in a tiered approach. Six Duval county health department clinics and three local hospitals will serve as the sites of participant recruitment. These centres primarily serve individuals with lower incomes, in the year 2000, 75% of the users of these centres for pregnancy issues were at or below the poverty level.

This study has generated a great deal of controversy surrounding the ethical nature of this research. These concerns stem from the fear that families from the primarily low income population base from which subjects will be recruited will be enticed to expose their children to pesticides in exchange for the monetary compensation the study offers. Concerns have also been raised about the lack of explicit information parents will receive about the potential danger of continued pesticide use in the home. The involvement of industry funding is also a source of controversy, as some believe that this may interfere with the EPA's independence of research to regulate chemicals.

It is clear that there is a need for more accurate data to assess children's exposures to pesticides and that the proposed study may generate very useful information for conducting pesticide risk assessments. However the ethical shortcomings may outweigh the potential benefits of this research. The design of this study requires further consideration to ensure that children are not being unnecessarily exposed to potentially hazardous pesticide levels. One possible option may be to attempt recruitment of subjects without a monetary incentive. This may require more time and resources to enlist an adequate number of participants, however it would eliminate the enticement for low-income families to begin using pesticides in exchange for the compensation they would receive.