title: Historical PCB fluxes in the Mexico City Metropolitan Zone as evidenced by a sedimentary record from the Espejo de los Lirios lake.
abstract: The accumulation of PCBs over time was studied in a sediment core collected from Espejo de los Lirios, an ecological reserve located within the heart of Cuatitlan Izcalli, in the Northern part of Mexico City Metropolitan Zone. A (210)Pb-derived chronology, was used to reconstruct the historical PCB fluxes to the site during approximately 84 yr (1911-95). The highest input fluxes occurred in the 1977, after a significant increase after the late 1940s. This trend is clearly the consequence of the increasing emissions that are related to the onset of industrial activities starting from early 1970s. A phase of decrease, after the ban of the use in open systems, ended in 1989 and in 1995, at the time of sampling, the trend was toward a new increase to the highest levels. A reconstruction of PCB atmospheric concentration from sedimentary fluxes is attempted; and the estimate suggests that PCBs concentrations in the air of the Cuautitlán Izcalli seem not of concern. Nonetheless, the contamination levels found in the sediments are relatively high, reaching values above the threshold effect level (TEL) guidelines and, in two cases, close to the probable effect level (PEL) which mean that some adverse effects on the fauna may have occurred all over the time interval represented by the core.
authors.affiliation: Dipartimento di Scienze Ambientali, Università di Venezia, Dorsoduro 2137, 30123 Venezia, Italy. piazza@unive.it
authors.forename: Rossano
authors.initials: R
authors.lastname: Piazza
authors.forename: Ana Carolina
authors.initials: AC
authors.lastname: Ruiz-Fernández
authors.forename: Mauro
authors.initials: M
authors.lastname: Frignani
authors.forename: Marco
authors.initials: M
authors.lastname: Vecchiato
authors.forename: Luca Giorgio
authors.initials: LG
authors.lastname: Bellucci
authors.forename: Andrea
authors.initials: A
authors.lastname: Gambaro
authors.forename: Libia Hascibe
authors.initials: LH
authors.lastname: Pérez-Bernal
authors.forename: Federico
authors.initials: F
authors.lastname: Páez-Osuna
mesh_terms: D002947:Cities; D019015:Geologic Sediments / Q000032:analysis*; D049673:History, 20th Century; D007856:Lead Radioisotopes / Q000737:chemistry; D008800:Mexico; D011078:Polychlorinated Biphenyls / Q000032:analysis* / Q000266:history; D012989:Soil Pollutants / Q000032:analysis* / Q000266:history
chemical_list: D007856:Lead Radioisotopes; D012989:Soil Pollutants; D011078:Polychlorinated Biphenyls