oil experienced deficits in developmental testing and abnormalities in behavioral assessment (Rogan et al., 1988). This study did not include good body burden measures, but sample sizes were large, permitting elucidation of more subtle effects.

Data on most compounds are not as extensive as those on PBBs, PCBs, and lead. Nevertheless, the pattern shown in the data on those compounds generate concern about the vulnerability of the developing human brain to any neurotoxic pesticides.

Levels of Pesticides Affecting Children

Although the vulnerability of the developing brain to neurotoxic exposure is of serious concern, it is entirely unclear from the data available whether exposures at levels consistent with usual dietary exposures would pose a substantial risk to the long-term neurologic development of children in general or to particular subgroups of children that are neurologically vulnerable.

It is theoretically possible that certain children with preexisting neurologic conditions such as hyperactivity might be more vulnerable to certain low-level neurotoxic exposures. There has been a scientific controversy surrounding the effects of "food additives" (i.e., dyes, flavors, and sugar) on children diagnosed as hyperactive. Responses vary with the study methodology, but even studies that do show effects do not show that all children in the hyperactive subpopulation are affected. These studies do not quantify effects of trace pesticide exposures, but they do raise the question, What would the dose curve for neurodevelopmental toxicants look like, and would all children be similarly vulnerable?

Comparability of Neurotoxicity Effects in Laboratory Animals

An evaluation of the accuracy with which adverse effects are detected across species (Stanton and Spear, 1990) was included in the proceedings of a workshop on "Similarities and Differences Between Children and Adults: Implications for Risk Assessment," sponsored by the International Life Sciences Institute (Kimmel et al., 1990). Species were subdivided into rodents, nonhuman primates, and humans and compared across several categories of neurobehavioral function (sensory, motivational/arousal, cognitive, motor, social). Such an analysis is extremely complex, and required a meticulously detailed comparison of hundreds of research reports for the seven toxicants considered. Overall, the investigators concluded that despite wide species differences in neurobehavioral functional categories, there was close agreement across species for the neurotoxic agents reviewed. Agents that produced cognitive, motor, and sensory

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