Forty-one people have been detained for storing and dumping thousands of tons of solid waste in areas close to the Yangtze River in Anhui province, local authorities announced recently.

Media reports said the people were responsible for five cases of storing and dumping waste in the riverside cities of Wuhu, Tongling and Chizhou.

A joint investigation launched by Xinhua News Agency and the provincial environmental protection department in late March found 60,500 metric tons of solid waste in Qianjiang Industrial Park in Chizhou. The park lies on the southern bank of the Yangtze.

Sharp odors rose from the site, and water polluted by the waste runs directly into the river, according to Xinhua.

Investigators concluded that multiple enterprises failed to meet pollution control requirements for storing industrial waste and should be held responsible for the pollution.

One of the companies, Chizhou Xinmao Fine Mineral Technology, was ordered by environmental authorities in August to suspend production, but later it continued business by receiving industrial waste transported from other provinces along the river, according to Xinhua's March report.

Unnamed companies in Shanghai were suspected of being responsible for transporting waste to the industrial park and a team was sent for further investigation, according to the Anhui provincial government.

The investigations will cover all of the more than 20 enterprises in the park, whose industrial output was valued at 12.75 billion yuan ($2 billion) in 2017, one-sixth of Chizhou's total for the year, according to the March report.

In another case, 62.9 tons of industrial waste were transported by boat from neighboring Jiangsu and Zhejiang provinces and dumped on a riverbank in Tongling in May last year.

After the dumping was discovered in October, Anhui police detained seven boats carrying industrial waste and another one carrying household refuse from Jiangsu and Zhejiang to Anhui.

The eight boats were carrying nearly 7,000 tons of solid waste when they were found, officials said on Wednesday at a conference addressing protection of the river.

Three of the boats' owners confessed that in November they dumped more than 2,400 tons of solid waste into marshland close to the Yangtze in Tongling.

"The serious pollution cases revealed that there are loopholes in our work," said Li Jinbin, Party secretary of Anhui province.

After the conference, provincial authorities decided to launch a monthlong systematic investigation into illegal practices that are polluting the Yangtze but have yet to be discovered.