Childhood lead poisoning from the smelter in Torreo ´ n, Me ´ xico Martin F. Soto-Jime ´ nez a,n , Arthur R. Flegal b a Unidad Acade ´mica Mazatla ´n, Instituto de Ciencias del Mar y Limnologı ´a, Universidad Nacional Auto ´noma de Me´xico (UAM-ICMyL-UNAM), Apdo. Postal 811, Mazatla ´n 82040, Sinaloa,Me´xico b WIGS, Microbiology & Environmental Toxicology, University of California at Santa Cruz, Santa Cruz, CA 95064, USA article info Article history: Received 21 September 2010 Received in revised form 24 January 2011 Accepted 26 January 2011 Keywords: Children Lead Isotopes Smelter Urban dust PbB abstract Lead concentrations and isotopic compositions in blood samples of 34 children (ages 2–17 years) living within a 113 km 2 area of a silver–zinc–lead smelter plant in Torreo ´ n, Me ´ xico were compared to those of associated environmental samples (soil, aerosols, and outdoor and indoor dust) to identify the principal source(s) of environmental and human lead contamination in the area. Lead concentrations of soil and outdoor dust ranged 130–12,050 and 150–14,365 mgg 1 , respectively. Concentrations were greatest near the smelter, with the highest levels corresponding with the prevailing wind direction, and orders of magnitude above background concentrations of 7.3–33.3 mgg 1 . Atmospheric lead depositions in the city varied between 130 and 1350 mgm 2 d 1 , again with highest rates o1 km from the smelter. Blood lead (PbB) concentrations (11.0 75.3 mg dl 1 ) levels in the children ranged 5.0–25.8 mg dl 1 , which is 3–14 times higher than the current average (1.9 mg dl 1 ) of children (ages 1–5 years) in the US. Lead isotopic ratios ( 206 Pb/ 207 Pb, 208 Pb/ 207 Pb) of the urban dust and soil (1.200 70.009, 2.467 70.003), aerosols (1.200 70.002, 2.466 70.002), and PbB (1.199 70.001, 2.468 70.002) were indistinguishable from each other, as well as those of the lead ores processed at the smelter (1.199 70.007, 2.473 70.007). Consequently, an elevated PbB concentrations of the children in Torreo ´ n, as well as in their environment, are still dominated by industrial emissions from the smelter located within the city, in spite of new controls on atmospheric releases from the facility. & 2011 Elsevier Inc. All rights reserved. 1. Introduction Although great strides have been made in reducing environ- mental lead pollution over the past several decades, the metal is still ranked second on the US Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Priority List of Hazardous Substances (http://www.atsdr.cdc.gov/cercla/). Moreover acute environmental lead pollution continues to be a global problem, particularly around mining and smelting opera- tions (Banza et al., 2009; Bao et al., 2009; Fraser, 2009; Gulson et al., 2009; Munksgaard et al., 2010). This is especially true for children in those areas because of their proclivity to ingest lead through pica and to assimilate a relatively greater amount of inhaled and ingested lead than older individuals (NRC, 1993; Moodie et al., 2010). Moreover the global emission of lead from primary smelting operations is still substantial, in spite of marked reductions in the use of lead in gasoline additives, paint, and many other industrial uses. Based on reports of emission factors (Skeaff and Dubreuil, 1997) and global production for 2003–2008 (USGS, 2010), we estimate the current global atmospheric flux of lead from smelting and refining non-ferrous metals (primary production of Cu, Ni, Pb, and Zn) alone ranges 25,830–30,800 ton y 1 (mean ¼ 28,100 ton y 1 ). The greatest percentage (  30%) of those emis- sions is in China, where the emission controls of smelters are relatively limited or non-existent as in the case of the infamous secondary smelting of e-waste in Guiyu (Huo et al., 2007). Lead emissions from mining and smelting in Me ´ xico are an order of magnitude smaller (  3% of global emissions) than those of China, but they are still substantial (832–1012 ton y 1 ) and most are from one facility, Met-Mex Pen ˜oles S.A. de C.V. (‘‘Met- Mex’’) in Torreo ´ n. That smelter went into production in 1902 and was operated with little or no environmental controls for a century, measurably elevating blood lead (PbB) concentrations of the children within the city (Albert and Badillo, 1991; Benin et al., 1999; Valde ´ s-Pe ´ rezgasga and Cabrera, 1999; Garcı ´a-Vargas et al., 2001; Albalak et al., 2003). In 1999, Me ´ xico’s Environmental Protection Agency (Procuradurı ´a Federal de Proteccio ´ n al Medio Ambiente, PROFEPA) mandated corporate efforts to reduce that lead pollution, clean-up the area, and monitor the adjacent environment (Metals and Minerals Latin America, 2000). This study, therefore, was designed to assess the efficacy of those efforts and to characterize the current level and source of lead contamination in Torreo ´ n. We employed both lead concentration Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/envres Environmental Research 0013-9351/$ - see front matter & 2011 Elsevier Inc. All rights reserved. doi:10.1016/j.envres.2011.01.020 n Corresponding author. Fax: + 52 669 9826133. E-mail address: martin@ola.icmyl.unam.mx (M.F. Soto-Jime ´ nez). Environmental Research 111 (2011) 590–596