title: Historical trends of polychlorinated dibenzo-p-dioxins and dibenzofurans in three dated sediment cores from Mexico.
abstract: This paper describes the first report of dioxins and furans (PCDDs/Fs) in sediment cores from Mexico. Sedimentation rates and vertical fluxes were estimated using (210)Pb dating. Two cores correspond to marine sediments and one to an endorheic lake. Concentrations of PCDDs/Fs found in the three sites are typical of non-impacted areas with low concentrations when compared to reference values. However the PCDDs/Fs sediment profiles show an increasing concentration trend in the upper core sections. This behavior is different from that found at many sites around the globe where diminishing concentrations have been reported. A strong predominance of OCDD was observed, and a comparison to typical composition profiles of industrial and other sources did not result in clear origin assignments for these measured compounds. We suggest that local sources may be responsible for the increase in concentration and, because these undetermined sources have not been curtailed, their importance is still growing.
authors.affiliation: Postgrado en Oceanografía Costera, Facultad de Ciencias Marinas/Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California, Apartado postal 453, Ensenada, CP 22860, Baja California, Mexico.
authors.forename: Canedo-López
authors.initials: CL
authors.lastname: Yunuén
authors.forename: Macías-Zamora J
authors.initials: MZ
authors.lastname: Vinicio
authors.forename: Huerta-Diaz
authors.initials: HD
authors.lastname: Miguel Angel
authors.forename: Laval Liong
authors.initials: LL
authors.lastname: Wee Kwong
authors.forename: Joan Albert
authors.initials: JA
authors.lastname: Sanchez-Cabeza
mesh_terms: D001572:Benzofurans / Q000032:analysis* / Q000266:history; D019015:Geologic Sediments / Q000032:analysis*; D049673:History, 20th Century; D049674:History, 21st Century; D008800:Mexico; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000032:analysis / Q000266:history; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000266:history
chemical_list: D001572:Benzofurans; D000072317:Polychlorinated Dibenzodioxins; D014874:Water Pollutants, Chemical; C023614:dibenzofuran