Seven people have been prosecuted over industrial waste discharges that polluted a river in south China's Guangxi Zhuang Autonomous Region earlier this year, local officials said Monday.

The seven people, all stakeholders and executives of Jinchengjiang Hongquan Lithopone Material Co., Ltd. in the city of Hechi, are being sued for polluting the environment, according to the People's Prosecutorate of the Jinchengjiang district of Hechi.

Prosecutors said the company has not conformed to relevant standards when discharging waste, adding that the arrested executives should be held responsible for cadmium contamination that occurred on the Longjiang River in early 2012.

Cadmium pollution was detected on the Longjiang River from Jan. 12 to 15. It later spread to the downstream Liujiang River, threatening water security in Liuzhou, a city with 1.5 million residents.

As the downstream city of Liuzhou completely relies on the Liujiang River for tap water, its officials announced earlier this month that they plan to build a reservoir on the Guchang River as a backup water source.

Cadmium is a carcinogenic industrial chemical.