Environmental protection authorities in Shandong province on Sunday cleared 25 enterprises of allegations that they disposed of polluted water by pumping it deep underground, while simultaneously vowing quicker responses to future concerns raised online.

The Shandong provincial environmental protection department said on its micro blog that it had concluded a half-year probe into more than 5,400 enterprises with water discharges in six cities in the province, including Weifang, Dong-ying and Rizhao, and that it did not uncover evidence of waste water being pumped underground.

The provincial authority published details of investigations into the 25 factories alleged to have committed the crimes, showing no evidence of their guilt.

However, three of the 25 enterprises reported were found guilty of other forms of pollution and have received penalties and orders to correct their practices.

Allegations first appeared on Sina Weibo in February claiming that chemical plants and paper mills in Weifang had been pumping waste water 1,000 meters under the ground through high-pressure wells, causing severe pollution to groundwater.

The posts attracted public concern and media attention soon after they were forwarded by Deng Fei, a member of the Phoenix Weekly editorial board. Deng is known as a philanthropist and now has more than 3.94 million followers online.

The environmental protection department took to Sina Weibo last week and required Deng Fei, who reposted messages by whistleblowers, to make an apology to the enterprises on the list. The two parties later exchanged views on Weibo and agreed that a mechanism is needed to enhance the interaction between the public and government departments.

Deng told the Beijing News last week that it is impossible to rely on reports made by netizens to be 100 percent accurate.

Deng, who earlier demanded that the authority publish details of the investigation, said the efforts of the authority in communicating with the public over issues of public concern set an example for other government micro blogs.

"Faced with numerous reports by netizens, the authority tried to present the truth rather than simply labeling them as rumors. That's why I agree with the move," he said.

Meanwhile, he called for an independent third-party investigation into the claims of underground water pollution problems in the province. "An investigation into just 25 enterprises does not sound convincing enough," he said.

He hopes the authority will encourage netizens to report their concerns and continue to respond to them in a timely manner.

"More communication and cooperation with netizens can only benefit the cause of environmental protection," he said.