You are here:
DISTRIBUTION OF 2,4-D IN AIR AND ON SURFACES INSIDE RESIDENCES FOLLOWING LAWN APPLICATIONS: COMPARING EXPOSURE ESTIMATES FOR YOUNG CHILDREN FROM VARIOUS MEDIA
Citation:
Nishioka, M. G., R G. Lewis, M. C. Brinkman, H. M. Burkholder, C. E. Hines, AND J. R. Menkedick. DISTRIBUTION OF 2,4-D IN AIR AND ON SURFACES INSIDE RESIDENCES FOLLOWING LAWN APPLICATIONS: COMPARING EXPOSURE ESTIMATES FOR YOUNG CHILDREN FROM VARIOUS MEDIA. ENVIRONMENTAL HEALTH PERSPECTIVES 109(11):1185-1191, (2001).
Impact/Purpose:
The goal of this task is to contribute to a better understanding of human exposure to pesticides, especially for small children by developing methods to characterize sources and pathways in and around the residential environment. We will support the science behind FQPA and assist the Office of Pesticide Programs (OPP) in the development of guidelines for the assessment of residential exposure to pesticides. Specific research objectives include: (i) to evaluate and develop methods for measuring pesticides in air using passive/diffusive samplers. Assess and refine devices for the collection of surface transferable pesticide residues and to establish transfer efficiencies; (ii) to develop and apply analytical methods for new and emerging pesticides using both gas and liquid chromatographic methods in support of the National Exposure Research Laboratory's (NERL) Human Exposure Measurement Project; and, (iii) to conduct pilot studies investigating chiral chromatographic methods.
Description:
Indoor air, surface wipes (floors, table tops and window sills) and floor dust samples were collected at multiple locations within 11 occupied and 2 unoccupied homes both prior to and following lawn application of the herbicide 2,4-D. Residue measurements were made over periods of 1 week pre- and post-application. Collected samples were used 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. Residue measurements were used to estimate potential exposures within these homes. Following the lawn application, 2,4-D was detected in indoor air and on all surfaces throughout all homes. Track-in by an active dog and 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 um to10 um. Resuspended floor dust was also a major source of 2,4-D on tables and window sills. Estimated post-application indoor exposure levels for young children from non-dietary ingestion may be 1-10 ug/day from contact with floors, and 0.2-30 ug/day from contact with table tops. These are estimated to be about 10 times higher than the pre-application exposures. By comparison, dietary ingestion of 2,4-D is approximately 1.3 ug/day.
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.