Initial results of 8-year soil pollution study not accurate enough, experts say
First findings of 8-year government soil analysis may not give accurate picture, experts warn
Experts have called for more detailed analysis of the extent of soil pollution on the mainland to gauge its seriousness, after the government released its first findings from an eight-year study.
The first nationwide survey to address soil pollution, conducted between April 2005 and last December, found the state of farmland soil pollution "worrying" and "hard to be optimistic about", the Ministry of Environmental Protection and Ministry of Land and Resources said on Thursday.
Of all the land surveyed, 16.1 per cent was polluted, the study found. For farmland, the pollution figure was 19.4 per cent. The authorities had previously kept under wraps the data collected in the survey, saying the information was a state secret.
An Environmental Protection Ministry spokesman said officials could not determine the exact amount of land polluted because they surveyed only one spot in every 6,400 hectares of farmland, Xinhua reported.
Chen Shibao , a member of the Agriculture Ministry's team of experts for treatment of heavy metal in soil, said the real situation could be worse. The figures released on Thursday were in line with researchers' previous estimates, he said, but this was only a "conservative finding".
Chen Nengchang , a researcher at the Guangdong Institute of Eco-Environment and Soil Sciences, said the authorities would have to conduct several rounds of detailed studies - involving surveys of plots smaller than 6,400 hectares - before they could tell just how bad the pollution really was.
"I believe the latest data is true, but we will not know the actual amount of polluted soil from this," he said. "The real extent could be bigger or smaller. But we will not know until more detailed research is done."
For the eight -year study, researchers divided 630 million hectares of land - two-thirds of the nation's total - into survey areas and took a sample from each survey area. These included farmland, forest, grassland, unused land and land for construction.
The study found that 83 per cent of the contaminated soil samples contained toxic inorganic pollutants, including cadmium, mercury, arsenic, chromium and lead.
The content of cadmium - which, if ingested, can reduce mineral density in bone - found in soil has risen sharply over the past decades. It rose more than 50 per cent in the southwest and coastal areas and up to 40 per cent in other areas, compared with that in the late 1980s, the Environment Ministry said.
The ministry blamed industrial and agricultural production as well as other "human activities" for the contamination, which it said had been accumulated over the years. It is working with other departments to conduct more detailed surveys.
Chen Shibao said the priority in tackling the soil pollution problem was to control the sources of pollution or to stop pollutants entering the environment. That could mean shutting down plants responsible for heavy pollution and imposing strict regulations on fertiliser contents and its use on farmland.
"The polluted soil will never be cured no matter how good our treatment methods are, if the polluting goes on even as we try to treat it," he said.