The top environmental watchdog has rejected a request to publish findings of a high-profile national survey on soil pollution, citing "state secrecy".
Legal and environmental experts called the Ministry of Environmental Protection's decision irresponsible, and said it put public health at risk, as contaminated land could jeopardise food safety and cause cancer or other health problems in people living on it.
"The ministry's claim is rather ill-founded, because the regulations on disclosure of government information actually allow for the release of so-called 'national secrets' if they involve public interests," said Beijing-based lawyer Dong Zhengwei , who requested the findings from the environmental ministry on January 30.
Ma Jun, director of the Beijing-based Institute of Public and Environmental Affairs, said soil contamination might pose more risk than other forms of pollution because it was not as visible and people did not know how to take precautions against it.
"The government has a responsibility to warn the public about whether a piece of land is safe to grow crops or build a home," Ma said.
Dong said the rejection also betrayed a promise made in June by Wu Xiaoqing , vice-minister of the environment, to "publish findings at an appropriate time" following a five-year ground-pollution survey that started in 2006 and cost 1 billion yuan (HK$1.24 billion).
The survey tested 200,000 samples of soil, ground water and farm produce nationwide, resulting in about 5 million pieces of data, the ministry said in 2011.
"The environmental ministry has been releasing real-time information about air pollution even though the air in Beijing was so bad last month. In contrast, soil pollution is a 'state secret'," Dong said. "Does this suggest that the land is contaminated much worse than the air?"
Authorities have a poor record of transparency on pollution information. A five-year national plan to tackle heavy-metal pollution by 2015 has never been made public.
Ma said authorities deemed the soil-pollution findings "too sensitive", and he said there were likely questions about the accuracy of the findings, because the survey was met with strong resistance from local governments.
"But the ministry should not use that as an excuse not to come clean on pollution. At the very least it could start with less-sensitive findings and tackle the severe problems, and set a timetable to release all of the findings."
The ministry said in 2006 that more than 10 per cent of farmland on the mainland was polluted, and that about 12 million tonnes of grain was contaminated by heavy metals annually. Updated figures have not been released since then.