Residents of Xingzi township in the southern Chinese province of Guangdong say that hundreds of local children have levels of lead in their blood that exceed permitted safety levels, pointing to pollution from a local power station as the possible culprit.
Following an angry protest last month outside the township office buildings by parents demanding the closure of the power station and compensation for the damage to their children's health, families in the area had continued to get their children's blood checked for lead, according to a resident of Xingzi surnamed Huang.
More than 700 children had been shown to have lead levels in their blood higher than the permitted level of 100 micrograms/liter.
"There could be even more than that number, because there are 2,000 people in my village alone, and more than 100 kids have higher-than-permitted [lead] levels," he said. "There are another few dozen in Tianxin village right next door to us, and a few dozen more sick kids in Taiyuan village a bit further away."
"There are more than 10 villages in the township, and they all have children with high lead levels, so I would estimate there are at least 700," said Huang, whose own two sons have also been affected.
He added: "Children with more than 400 micrograms/liter have to be admitted to hospital."
Brain development can be affected in children who have as little as 100 micrograms of lead per liter of blood.
Children are particularly vulnerable to lead poisoning, which can result in neurological, liver, and kidney impairment, as well as anemia, convulsions, coma, and death.
High levels of lead exposure can cause permanent intellectual and developmental disabilities, including reading and learning disabilities, behavioral problems, hearing loss, attention problems, and disruption in the development of visual and motor functioning.
Huang said his sons, aged 3 and 6, had both suffered mild lead poisoning, and that the authorities had handed out subsidies and free milk supplies to parents with lead-poisoned children.
"They make a one-off payment of 120 yuan (U.S. $18) per child, and everyone gets six cases of milk, as well as a two-week supply of medicine for expelling lead from the system."
"My two sons have been taking it for a while, and on Thursday we will go to the hospital for a repeat test, to see if their lead levels have come down, and whether there have been any side-effects."
A resident of Tianxin village surnamed Zhou said the authorities had only admitted to 18 cases of lead-poisoning among children in the township, but that local people were suspicious of official figures.
He said that half of the children in Tianxin village alone were affected.
"I heard some of the villagers saying that the sick children's cognition was very poor, and that their kids were a bit slow-witted and stupid, and didn't grow much," Zhou said.
"My own son was born prematurely and ... we are afraid that he will suffer the after-effects," he said. "We aren't educated people, and we don't have any experts to explain it for us."
Villagers say that pollution from a nearby power station has been worsening steadily over the past decade, and that they have already held protests on the issue outside the township government offices.
The authorities had responded with a temporary closure of the plant last months for repairs, and local residents said the air quality had improved greatly during that time.
However, they have yet to respond to calls among the local community for it to be relocated.
"The Xingzi township government and the [nearby] Lianzhou municipal government have both expressed their concern over this issue," Zhou said. "But they aren't all giving out the same message."
"One the one hand, the township government is telling us that the power station will be shut down, but the Lianzhou municipal government is a major shareholder, and the power plant is a major taxpayer," he said.
"They keep passing the buck around, and they do nothing about it."
An employee who answered the phone at the Xingzi township government offices said some children were still receiving treatment in hospital, so final figures for the number of affected children were unavailable.
"As for the figures, we have already made them public," the employee said. "You can find them for yourself online."
Repeated calls to the Lianzhou municpal government offices went unanswered during office hours on Wednesday.
Battery makers and lead and zinc smelting plants have been blamed for a wave of lead poisoning cases affecting thousands of children across China in recent years, sometimes sparking violent protests.
And Chinese children who suffer lead poisoning as a result of industrial pollution are frequently sent back to live in contaminated environments and refused treatment, according to a 2011 report by the New York-based Human Rights Watch (HRW).
Chinese officials have warned that the country is facing a "grave" environmental crisis, with more than half its cities affected by acid rain and one-sixth of its major rivers too polluted even to water crops with.
Three decades of breakneck economic growth have taken their toll on the country's natural resources, sparking a huge increase in public unrest linked to environmental degradation and health problems caused by pollution.
Reported by Fung Yat-yiu for RFA's Cantonese service. Translated and written in English by Luisetta Mudie.