Hair manganese and hyperactive behaviors: pilot study of school-age children exposed through tap water.
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 Quebec (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: WI: mean 610 microg/L; W2: mean 160 microg/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 WI had higher hair Mn (MnH) than those supplied by W2 (mean 6.2+/-4.7 microg/g vs. 3.3+/-3.0 microg/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 microg/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.
Bouchard
Maryse
M
Centre de recherche interdisciplinaire sur la biologie, la santé, la société et I'environnement (CINBIOSE), Université du Québec à Montréal, Montréal, Québec, Canada.
Laforest
François
F
Vandelac
Louise
L
Bellinger
David
D
Mergler
Donna
D
D000293:Adolescent; D019958:Attention Deficit and Disruptive Behavior Disorders / Q000453:epidemiology* / Q000209:etiology; D015415:Biomarkers / Q000032:analysis; D002648:Child; D004784:Environmental Monitoring; D062665:Epidemiological Monitoring; D005260:Female; D006197:Hair / Q000737:chemistry*; D006801:Humans; D008297:Male; D008345:Manganese / Q000032:analysis*; D011569:Psychiatric Status Rating Scales; D011595:Psychomotor Agitation / Q000453:epidemiology / Q000209:etiology; D011792:Quebec / Q000453:epidemiology; D012574:Schools; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014881:Water Supply / Q000032:analysis*
D015415:Biomarkers; D014874:Water Pollutants, Chemical; D008345:Manganese