title: Chronicling a century of lead pollution in Mexico: stable lead isotopic composition analyses of dated sediment cores.
abstract: Analyses of lead isotopic compositions (204Pb, 206Pb, 207Pb, and 208Pb) of dated sediment cores from two coastal estuaries and two inland lakes chronicle the predominance of industrial lead emissions in Mexico over the past century. These isotopic ratios exhibit a shift in composition from the turn of the previous century (1900) that corresponds with measurable increases (from 2- to 10-fold) in lead concentrations in the cores above their baseline values (3-22 microg/g)--both changes are consistent with the development of Mexican lead production for export and the manufacture of tetraethyl lead additives for Mexican gasolines. While subsequent changes in lead concentrations in the cores correspond with calculated emissions from the combustion of leaded gasoline in Mexico, isotopic compositions of the cores remain relatively constant throughout most of the 1900s (e.g., 206Pb/207Pb = 1.200 +/- 0.003; 208Pb/207Pb = 2.463 +/- 0.004). That isotopic constancy is attributed to the widespread pollution from lead production in Mexico and the dispersion of some of that lead used as an additive in Mexican gasolines.
authors.affiliation: Department of Environmental Toxicology, WIGS, University of California at Santa Cruz, Santa Cruz, California 95064, USA. martin.@ola.icmyl.unam.mx
authors.forename: Martin F
authors.initials: MF
authors.lastname: Soto-Jimenez
authors.forename: Sharon A
authors.initials: SA
authors.lastname: Hibdon
authors.forename: Charley W
authors.initials: CW
authors.lastname: Rankin
authors.forename: Jugdeep
authors.initials: J
authors.lastname: Aggarawl
authors.forename: A Carolina
authors.initials: AC
authors.lastname: Ruiz-Fernandez
authors.forename: Federico
authors.initials: F
authors.lastname: Paez-Osuna
authors.forename: A Russell
authors.initials: AR
authors.lastname: Flegal
mesh_terms: D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000032:analysis* / Q000266:history*; D019015:Geologic Sediments / Q000737:chemistry; D049673:History, 20th Century; D007554:Isotopes; D007854:Lead / Q000032:analysis* / Q000266:history*; D008800:Mexico; D001335:Vehicle Emissions / Q000032:analysis
chemical_list: D004785:Environmental Pollutants; D007554:Isotopes; D001335:Vehicle Emissions; D007854:Lead