| Distribution of 2,4-D in Air and on Surfaces inside Residences after Lawn Applications: Comparing Exposure Estimates from Various Media for Young Children Marcia G. Nishioka,1 Robert G. Lewis,2 Marielle C. Brinkman,1 Hazel M. Burkholder,1 Charles E. Hines,1
and John R. Menkedick1 1Battelle Memorial Institute, Columbus, Ohio, USA; 2National Exposure Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA
Abstract
We collected indoor air, surface wipes (floors, table tops, and window sills) , and floor dust samples at multiple locations within 11 occupied and two unoccupied homes both before and after lawn application of the herbicide 2,4-D. We measured residues 1 week before and after application. We used collected samples to determine transport routes of 2,4-D from the lawn into the homes, its subsequent distribution between the indoor surfaces, and air concentration as a function of airborne particle size. We used residue measurements to estimate potential exposures within these homes. After lawn application, 2,4-D was detected in indoor air and on all surfaces throughout all homes. Track-in by an active dog and by the homeowner applicator were the most significant factors for intrusion. Resuspension of floor dust was the major source of 2,4-D in indoor air, with highest levels of 2,4-D found in the particle size range of 2.5-10 µm. Resuspended floor dust was also a major source of 2,4-D on tables and window sills. Estimated postapplication indoor exposure levels for young children from nondietary ingestion may be 1-10 µg/day from contact with floors, and 0.2-30 µg/day from contact with table tops. These are estimated to be about 10 times higher than the preapplication exposures. By comparison, dietary ingestion of 2,4-D is approximately 1.3 µg/day. Key words: 2, 4-D, indoor air, particle size, pesticide exposure, pesticide transport, residential exposure. Environ Health Perspect 109:1185-1191 (2001) . [Online 6 November 2001] http://ehpnet1.niehs.nih.gov/docs/2001/109p1185-1191nishioka/ abstract.html Address correspondence to M.G. Nishioka, Battelle Memorial Institute, 505 King Avenue, Columbus, OH 43201-2693 USA. Telephone: (614) 424-4964. Fax: (614) 424-3638. E-mail: nishiomg@battelle.org We acknowledge the participation of families in the Columbus area and consultation with R. Burton of the U.S. Environmental Protection Agency (U.S. EPA) on particle size sampling. The U.S. EPA, through its Office of Research and Development, funded and collaborated in the research described here under Cooperative Agreement CR-822082. It has been subjected to agency review and has been approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use. Received 24 April 2000 ; accepted 13 April 2001.
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