Potential exposures of children and adults to cypermethrin and other pyrethroid insecticides following treatment and control of indoor pests

Chemical residues on surfaces resulting from resident or professional pyrethroid use may result in unintentional or unavoidable exposures of adults and children. Clarification and evaluation of determinants of exposure are necessary to conduct human exposure assessments following indoor pyrethroid applications. Three related studies evaluate indoor human exposure to cypermethrin and other pyrethroid insecticides.; Assessment of the magnitude and determinants of indoor exposure followed fogger cypermethrin applications in a test room and residences. Total carpet pesticide and surface residue (SR) remained for 32 days. Transferable surface residue (TSR) measured using the California Roller (Ross et al. 1991) and the Automatic Surface Wipe were not significantly different during 14 to 20 day test periods. Significant negative correlation was observed between room volume and SR. Tile, wood, and linoleum flooring increased TSR relative to carpet flooring.; Spray distribution and SR were also evaluated following fogger, perimeter, crack and crevice, and spot application of pyrethroid pesticides and chlorpyrifos. Foggers distributed cypermethrin relatively evenly on the floor (4.1 mug/cm 2). Compared to fogger applications, perimeter, crack and crevice, and spot applications resulted in less SR within 40 cm of the wall. Crack and crevice and spot applications had high insecticide SR within 8 cm of the baseboard (14-15 mug/cm2). SR between 8 and 16 cm from the baseboard was below 0.5 mug/cm2.; Family-based, situational exposure studies (opportunistic, observational research) were performed to develop exposure data from normal living conditions following fogger and crack and crevice application of cypermethrin. Twenty participating families included 49 children and 53 teens/adults (persons >12 years) in five states. Children and teens/adults eliminated an average of 1.5 +/- 1.6 and 0.4 +/- 0.4 mug PE/kg-day, respectively. No experimental support was obtained for the hypothesis that cypermethrin metabolite ratio could distinguish hand-to-mouth contact as an important route of exposure in children. Biomarker elimination was measurable for 20 to 90 days. Biomarker elimination following crack and crevice application never exceeded background levels. Conservative back-calculated exposure estimates assuming parent insecticide exposure were far below experimental low-observable-adverse-effect-levels and regulatory no-observable-adverse-effect-levels for children and teens/adults following either fogger or crack and crevice applications.