PT05 Atmospheric Transport and Fate
Exhibit Hall
8:00 AM - Tuesday
(PT078) Ambient Air Levels of Organochlorine Pesticides in Southern Mexico.
Alegria, H1, Wong, F2, Harner, T2, Bidleman, T3, Salvador Figueroa, M4, 1 California Lutheran University, Thousand Oaks, CA, USA2 Meteorological Service of Canada, Downsview, On, Canada3 Centre for Atmospheric Research Experiments, Egbert, On, Canada4 Universidad Autonoma de Chiapas, Tapachula, Chiapas, Mexico
ABSTRACT- We have carried out two air sampling campaigns in southern Mexico (2000-2001 and 2002-2003) to determine if ambient air levels of organochlorine pesticides (OCPs) are significant enough to support the hypothesis that the region is a source region of OCPs to North America. Biweekly high volume air samples were collected at a suburban site in Tapachula, Chiapas (93 m elev) during 2000-2001, and at the same suburban site as well as a mountain site (1300 m elev) in 2002-2003. Passive air samplers using polyurethane foam disks were also deployed in the second campaign. During the first campaign, levels of some OCPs at the suburban site were elevated (e.g. SDDTs - 1000 pg/m3, toxaphene - 500 pg/m3, endosulfan I - 367 pg/m3) or moderate (e.g. Schlordanes - 135 pg/m3). In the second year, levels were generally lower at the suburban site compared to the first year, although still elevated or moderately elevated for some OCPs (e.g. SDDTs > 600 pg/m3, endosulfan I - 255 pg/m3, toxaphene - 166 pg/m3). Levels of most OCPs were lower at the mountain site compared to the suburban site in 2002-2003, with the exception of DDTs (e.g. SDDTs > 2000 pg/m3, endosulfan I - 182 pg/m3, toxaphene - 70 pg/m3). Discussion will focus on the interpretation of the results, including comparison of passive and active air samplers, relationships with air trajectories, and comparison with other suspected source regions and receptor regions.
Key words: Mexico, pesticides, air, mountain