GUANGZHOU - Dozens of children living near a lead refinery plant in South China's Guangdong province have been diagnosed with excessive lead in their blood, a local government statement said.

Environmental protection authorities have begun investigating the plant in Dongtang township of Renhua, a county-level city in Guangdong province, the statement said on Thursday.

The statement did not identify the company's name, but said its waste gas and water and industrial residue will be closely monitored.

As of Tuesday, 37 residents in Dongtang, mostly children, have been diagnosed with excessive lead in their blood, the statement said.

Excessive amounts of lead can harm the digestive, nervous and reproductive systems and cause stomachaches, anemia and convulsions, doctors said.

Samples of the surface and ground water in the township have not tested positive for excessive lead, the statement said.

Tests on samples of soil and air near the plant are still under way, the statement added.

"The company will be severely punished if it is found to be emitting excessive pollutants," said Huang Renfeng, an official with the Renhua government.

Liu Hongdai, a resident of Dongtang township, holds up a body check sheet of one of his granddaughters who had been diagnosed with excessive lead in blood on Wednesday. Provided to China Daily