Mercury speciation in the hair of pre-school children living near a chlor-alkali plant Paolo Montuori a , Eric Jover b , Sergi Díez b, ⁎ , Núria Ribas-Fitó c , Jordi Sunyer c , Maria Triassi a , Josep M. Bayona b a Department of Preventive Medical Sciences, University of Naples “Federico II”, C/ Sergio Pansini, 5, Naples, E-80131, Italy b Environmental Chemistry Department, I.I.Q.A.B.-C.S.I.C., C/ Jordi Girona, 18–26, Barcelona, E-08034, Spain c Respiratory and Environmental Health Research Unit, Institut Municipal d'Investigació Mèdica, C/ Doctor Aiguader, 80, Barcelona E-08003, Spain Received 8 July 2005; received in revised form 6 April 2006; accepted 14 April 2006 Available online 12 June 2006 Abstract Exposure to mercury species was assessed in the hair of 130 Spanish children (age 4) from the general population in two areas. Both areas are exposed to different sources of mercury: a point source in Ribera d'Ebre (northeastern Spain) and a diffuse source on the island of Menorca (northwestern Mediterranean). The median MeHg values in the hair of children from Ribera d'Ebre (RE) were nearly twice (0.631 μg/g vs. 0.370 μg/g) those of children from Menorca (MC) (p b 0.05). Total Hg showed a similar trend (RE median : 0.720 μg/g vs. MC median : 0.476 μg/g). Nevertheless, inorganic mercury levels were similar in the two groups of children (RE median : 0.186 μg/g vs. MC median : 0.210 μg/g). Two subgroups of the Ribera d'Ebre group were defined: children living in Flix (a village near a chlor-alkali plant) (RE1) and children living on the outskirts of Flix with no clear, direct influence of the plant (RE2). The mercury concentrations in RE1 were also significantly higher than those in Menorca, but no significant differences were found between Menorca and the RE2 subgroup. We evaluated the fish consumption of RE1, RE2 and MC and found that the Menorcan children consumed significantly less fish (p b 0.05) than the other two subgroups. Children who consumed fish more than three times a week had higher MeHg concentrations (β (SE) = 0.991 (0.279) than those who ate it less than once a week. Nevertheless, the differences in MeHg levels between children from Ribera d'Ebre and Menorca remained statistically significant after adjustment for fish intake and other variables (β (SE) = 0.779 (0.203) for children from RE1). In conclusion, local sources other than seafood contribute significantly to MeHg content in hair in the two Ribera d'Ebre subgroups. © 2006 Elsevier B.V. All rights reserved. Keywords: Mercury exposure; Mercury speciation; Methylmercury; Children's hair; Routes of mercury intake; Sex effect 1. Introduction Mercury is a naturally occurring element that is wide- spread in the environment (Schuster et al., 2002; Gustin, 2003; Mather and Pyle, 2004). Human activity has increased its release, mobilization and distribution into the environment (Yokoyama et al., 2000; Heebink and Hassett, 2002). Once released into the environment, inorganic mercury (I-Hg) undergoes biotic and abiotic transformations to become methylmercury (MeHg), a more toxic organic form (Wood et al., 1968; Greenwood, 1985; Palheta and Taylor, 1995; Kinjo et al., 1996). MeHg Science of the Total Environment 369 (2006) 51 – 58 www.elsevier.com/locate/scitotenv ⁎ Corresponding author. Tel.: +34 93 400 61 00; fax: +34 93 204 59 04. E-mail address: sdsqam@cid.csic.es (S. Díez). 0048-9697/$ - see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.scitotenv.2006.04.003