Beijing (AsiaNews) - The level of lead in the Danjiangkou reservoir, which supplies water to Beijing and many cities in the north of the country, is 20 times higher than that recommended by the World Health Organization (WHO). This is revealed in a recent study conducted over many years - the data stops in 2010 - by some Chinese scientists and published in the Journal of Environmental Informatics.
The standard imposed by WHO for the presence of lead in water is 10 micrograms per liter. For the US Environmental Protection Agency (EPA) it should not exceed 15 micrograms, while China seeks to maintain levels below 50 micrograms. Chinese researchers have found that in Danjiangkou there are 200 micrograms of lead per liter of water, the level increased by 20 times from 2007 to 2010.
Prof. Zhang Quanfa, researcher at the Whuan Chinese Academy of Sciences and head of the research project, has declined all requests for interviews. On a request made by the South China Morning Post on whether water from the Danjiangkou is safe for drinking, he responded that "it is not a question that I can respond to."
According to the municipal government, the waters of Danjiangkou reservoir - located between the provinces of Henan and Hubei - supply 60% of taps in Beijing. According to the EPA, an excessive amount of lead in water can cause various health problems, especially in infants and children, such as delays in physical and mental development with attention and learning deficits. In adults the symptoms include kidney problems and high blood pressure.
The quality of water that reaches the homes of the capital is not known precisely, because it is treated in factories, the government ensures, with modern technology and strict regulations to ensure it is drinkable.
The study, which collected samples from eight different points of the Danjiangkou reservoir, shows that the levels of other pollutants such as arsenic and chromium (which can cause tumors and skin diseases) are beyond permitted levels.
Last month, the Minister of Water Resources had declared the Danjiangkou reservoir "grade 1", that is, with a lead level of less than 10 grams per liter. He also stated that since the government began its studies on its waters, the levels of this basin have never fallen below the "level 2" (between 10 and 50 micrograms).