A Chinese government official who blamed lead poisoning in more than 300 children on the possible chewing of school pencils was excoriated in state-run media and ridiculed online Monday.

Lead levels as high as three times national standards were found in the blood of children in a village in the central province of Hunan, with the contamination blamed on pollution from a local chemical plant, the official news agency Xinhua reported.

The factory has been closed down for investigation, Xinhua said citing local officials.

But Su Genlin, the chief of Dapu township, told the told state broadcaster CCTV that "Kids use pencils in school, and chewing pencils could also cause the excessive (lead) levels."

In Chinese, the character for the heavy metal is also used in the word for pencil, in the same way that "lead" has a double meaning in English.

The online mouthpiece of China's ruling Communist party, the People's Daily, blasted the official in an op-ed published on Monday.

"It is scientific knowledge that pencils are made from graphite," the article by commentator Zhang Yusheng said. "Does this official's statement show ignorance, or just disregard for the people's welfare?"

Chinese Internet users also mocked the official. "How can such low IQ cadres appear in public?" asked author Cui Chenghao on Sina Weibo, a Chinese equivalent of Twitter.

China's rapid industrialisation over the past 30 years has left the country with widespread environmental damage that has taken a heavy toll on public health.

Recent studies have shown that roughly two-thirds of China's soil is estimated to be polluted and that 60 percent of underground water is too contaminated to drink.

In 2011 authorities in the eastern province of Zhejiang detained 74 people and suspended work at hundreds of factories after 172 people -- including 53 children -- fell ill with lead poisoning.

US battery maker Johnson Controls was in 2012 blamed for lead pollution in the commercial hub of Shanghai, after 49 children were diagnosed with lead poisoning.