Twelve factories in eastern China were closed down after children living nearby were found to have high levels of lead in their blood, state press reported Monday.

While local authorities sought to downplay the significance of the shutdown, it is the latest in a string of incidents to highlight the increasing environmental and health costs of rampant economic development across China.

"All 12 factories, related to metals, chemicals and recycled paper, have been halted for investigation," the government of Jian city said in a statement carried in the state-run press on Monday.

The controversy surfaced when a boy living near the industrial park containing the factories was found last month to have higher-than-normal levels of lead in his blood, the China Youth Daily reported.

After a further 15 children were discovered to have excess lead levels, worried parents lobbied local authorities to close the factories, according to the report.

Prolonged exposure to lead can cause nausea and pain within the body, and may damage the heart and kidneys and harm fertility, according to the US Center for Disease Control.

While the government bowed to community pressure in closing the factories, the Jian city government said there was no evidence to show lead had leached out of the industrial park.

It added that the factories had only been closed temporarily.

Grassroots environmental activism is growing in China, with protests against polluting industries occurring frequently across the country.

Violent protests last week by thousands of people in the southwestern city of Shifang forced authorities there to cancel plans for a $1.6 billion heavy metals plant.