1. ^aCenter for Children's Environmental Health Research, School of Public Health, University of California, Berkeley, CA, USA
2. ^bUS Environmental Protection Agency, National Exposure Research Laboratory, Office of Research and Development, Research Triangle Park, NC, USA
3. ^cASPH Environmental Health Fellow, US Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, Office of Research and Development, Research Triangle Park, NC, USA
4. ^dBattelle Memorial Institute, Columbus, OH, USA
5. ^eUS Environmental Protection Agency, National Exposure Research Laboratory, Office of Research and Development, Cincinnati, OH, USA
6. ^fNational Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
7. ^gEnvironmental Health Investigations Branch, California Department of Health Services, Richmond, CA, USA
8. ^hOak Ridge Institute for Science and Technology, U.S. Environmental Protection Agency, National Exposure Research Laboratory, Cincinnati, OH, USA
9. ⁱLawrence Berkeley National Laboratory and University of California, Berkeley, CA, USA

Correspondence: Dr. Asa Bradman, Center for Children's Environmental Health Research, School of Public Health, University of California, Berkeley, 2150 Shattuck Avenue, Suite 600, Berkeley, CA 94720-7380, USA. Tel.: +1 510 643 3023; Fax: +1 510 642 9083; E-mail: abradman@socrates.berkeley.edu

Received 19 October 2005; Accepted 4 May 2006; Published online 31 May 2006.

Abstract

In support of planning efforts for the National Children's Study, we conducted a study to test field methods for characterizing pesticide exposures to 20 farmworker children aged 5–27 months old living in the Salinas Valley of Monterey County, California. We tested methods for collecting house dust, indoor and outdoor air, dislodgeable residues from surfaces and toys, residues on clothing (sock and union suits), food, as well as spot and overnight diaper urine samples. We measured 29 common agricultural and home use pesticides in multiple exposure media samples. A subset of organophosphorus (OP), organochlorine (OC) and pyrethroid pesticides were measured in food. We also analyzed urine samples for OP pesticide metabolites. Finally, we administered four field-based exposure assessment instruments: a questionnaire; food diary; home inspection; and a self-administered child activity timeline. Pesticides were detected more frequently in house dust, surface wipes, and clothing than other media, with chlorpyrifos, diazinon, chlorthal-dimethyl, and cis- and trans-permethrin detected in 90% to 100% of samples. Levels of four of these five pesticides were positively correlated among the house dust, sock, and union suit samples (Spearman's =0.18–0.76). Pesticide loading on socks and union suits was higher for the group of 10 toddlers compared to the 10 younger crawling children. Several OP pesticides, as well as 4,4'-DDE, atrazine, and dieldrin were detected in the food samples. The child activity timeline, a novel, low-literacy instrument based on pictures, was successfully used by our participants. Future uses of these data include the development of pesticide exposure models and risk assessment.