| Hair Manganese and Hyperactive Behaviors: Pilot Study of School-Age Children Exposed through Tap Water Maryse Bouchard,1 François Laforest,1 Louise Vandelac,1 David Bellinger,2 and Donna Mergler1 1Centre de recherche interdisciplinaire sur la biologie, la santé, la société et l'environnement (CINBIOSE), Université du Québec à Montréal, Montréal, Québec, Canada; 2Department of Neurology, Children's Hospital Boston, and Harvard Medical School, Boston, Massachusetts, USA Abstract
Background: Neurotoxic effects are known to occur with inhalation of manganese particulates, but very few data are available on exposure to Mn in water. We undertook a pilot study in a community in Québec (Canada) where naturally occurring high Mn levels were present in the public water system. Our objective was to test the hypothesis that greater exposure to Mn via drinking water would be reflected in higher Mn content in hair which, in turn, would be associated with increased level of hyperactive behaviors. Methods: Forty-six children participated in the study, 24 boys and 22 girls, 6–15 years of age (median, 11 years) . Their homes received water from one of two wells (W) with different Mn concentrations: W1: mean 610 µg/L ; W2: mean 160 µg/L. The Revised Conners' Rating Scale for parents (CPRS-R) and for teachers (CTRS-R) were administered, providing T-scores on the following subscales: Oppositional, Hyperactivity, Cognitive Problems/Inattention, and ADHD Index. Results: Children whose houses were supplied by W1 had higher hair Mn (MnH) than those supplied by W2 (mean 6.2 ± 4.7 µg/g vs. 3.3 ± 3.0 µg/g, p = 0.025) . MnH was significantly associated with T-scores on the CTRS-R Oppositional (p = 0.020) and Hyperactivity (p = 0.002) subscales, after adjustment for age, sex, and income. All children with Oppositional and Hyperactivity T-scores ? 65 had MnH > 3.0 µg/g. Conclusions: The findings of this pilot study are sufficiently compelling to warrant more extensive investigations into the risks of Mn exposure in drinking water. Key words: children, CPRS-R, CTRS-R, hair, hyperactive behaviors, manganese, well water. Environ Health Perspect 115: 122–127 (2007) . doi:10.1289/ehp.9504 available via http://dx.doi.org/ [Online 3 October 2006]
Address correspondence to D. Mergler, CINBIOSE (SB-1983) , 141 av. Président-Kennedy, Montréal, Québec H2X 3Y7 Canada. Telephone: 1-514-987-3000 (ext. 3355#) . Fax: 1-514-987-6183. E-mail: mergler.donna@uqam.ca We acknowledge all the children, parents, and teachers who kindly participated in the study, as well as the school's principals. The Canadian Institutes for Health Research provided a scholarship (M.B.) . The authors declare they have no competing financial interests. Received 11 July 2006 ; accepted 3 October 2006.
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