There seems to be a direct relationship between higher levels of the neurotoxin manganese in drinking water and poorer neurobehavioral outcomes in children, according to research in Environmental Health Perspectives. Significant impacts were found even at levels commonly found in some North American water supplies.
The Quebec-based researchers recruited 375 children and measured manganese levels in their home tap water and their hair, and estimated their manganese intake from the water ingestion. They then examined associations with memory, attention, motor function, and parent- and teacher-reported hyperactive behaviors.
After adjusting for potential confounders, the researchers found that there was a “linear” relationship between increasing levels of manganese exposure in the water with poorer memory and attention. They also found declines in performance and motor function. “There was no significant association between manganese exposure and hyperactivity,” they wrote.
“Exposure to manganese in water was associated with poorer neurobehavioral performances in children,” the researchers concluded, “even at low levels commonly encountered in North America.”
(Full text) Neurobehavioral Function in School-Age Children Exposed to Manganese in Drinking Water (Oulhote, Youssef et al. Environmental Health Perspectives. December 2014. DOI: 10.1289/ehp.1307918)