New York: Young children are particularly vulnerable to the toxic effects of lead and even low exposure to it can give rise to emotional and behavioural problems, says a study.
As blood lead levels increase in children, so do the problems, the study added.
"This research focused on lower blood lead levels than most other studies and adds more evidence that there is no safe lead level," said Kimberly Gray, from National Institute of Environmental Health Sciences in the US.
"It is well-documented that lead exposure lowers the IQ of children," Gray added.
Blood lead concentrations measured in more than 1,300 preschool children in China were associated with increased risk of behavioural and emotional problems, such as being anxious, depressed, or aggressive.
The average blood lead level in the children was 6.4 micrograms per deciliter.
While many studies to date have examined health effects at or above 10 micrograms per deciliter, this study focused on lower levels.
"Young children are particularly vulnerable to the toxic effects of lead, because lead can affect children's developing nerves and brains," said Jianghong Liu from University of Pennsylvania School of Nursing in the US.
Lead is a naturally occurring toxic metal, but sources of lead exposure are often due to human activities, including burning fossil fuels, mining, and manufacturing.