title: Organochlorine pesticides in the ambient air of Chiapas, Mexico.
abstract: Organochlorine (OC) pesticides were measured in the ambient air of Chiapas, Mexico during 2000-2001. Concentrations of some OC pesticides (DDTs, chlordanes, toxaphene) were elevated compared with levels in the Great Lakes region, while those of other pesticides were not (hexachlorocyclohexanes, dieldrin). While this suggests southern Mexico as a source region for the former group of chemicals, comparably high levels have also been reported in parts of the southern United States, where their suspected sources are soil emissions (DDTs, toxaphene) and termiticide usage (chlordane). Ratios of p,p'-DDT/p,p'-DDE and trans-chlordane/cis-chlordane/trans-nonachlor (TC/CC/TN) in Chiapas suggest a mixture of fresh and weathered sources, while congener profiles of toxaphene suggest emission of old residues from soils. This is supported by air parcel back trajectory analysis, which indicated that air masses over Chiapas at the time of sampling had previously passed over areas of continuing or recent use of some OC pesticides as well as areas of past use.
authors.affiliation: Chemistry Department, California Lutheran University, 60 West Olsen Road, Thousand Oaks, CA 91360, USA. halegria@clunet.edu
authors.forename: Henry
authors.initials: H
authors.lastname: Alegria
authors.forename: Terry F
authors.initials: TF
authors.lastname: Bidleman
authors.forename: Miguel Salvador
authors.initials: MS
authors.lastname: Figueroa
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000452:Aldrin / Q000032:analysis; D002706:Chlordan / Q000032:analysis; D003634:DDT / Q000032:analysis; D004026:Dieldrin / Q000032:analysis; D004726:Endosulfan / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods; D001556:Hexachlorocyclohexane / Q000032:analysis; D006843:Hydrocarbons, Chlorinated / Q000032:analysis*; D007306:Insecticides / Q000032:analysis*; D008800:Mexico; D014112:Toxaphene / Q000032:analysis
chemical_list: D000393:Air Pollutants; D006843:Hydrocarbons, Chlorinated; D007306:Insecticides; D002706:Chlordan; D001556:Hexachlorocyclohexane; D014112:Toxaphene; D003634:DDT; D004026:Dieldrin; D004726:Endosulfan; D000452:Aldrin