Hair Manganese and Hyperactive Behaviors - tap water exposure

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Hair Manganese and Hyperactive Behaviors: Pilot Study of School-Age

Children Exposed through Tap Water

se Bouchard,1 François Laforest,1 Louise Vandelac,1 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

http://www.ehponline.org/docs/2006/9504/abstract.html

whole text:

http://www.ehponline.org/members/2006/9504/9504.html

http://www.ehponline.org/members/2006/9504/9504.pdf

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 & #8805; 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.