NANNING -?Ten people have been arrested over industrial waste discharges that polluted a river in South China's Guangxi Zhuang autonomous region, according to local officials Wednesday.

The ten people, stakeholders or executives of Guangxi Jinhe Mining Co Ltd and Jinchengjiang Hongquan Lithopone Material Co Ltd in Hechi city, were arrested on the charge of polluting the environment, said a statement of the People's Procuratorate of Jinchengjiang district of Hechi.

Procurators found that both companies were not up to standard in terms of waste discharge and the arrested executives should be held responsible for the cadmium contamination in the Longjiang River.

Cadmium pollution was first detected in the Longjiang River on January 15 in Hechi, and it later spread to the downstream Liujiang River, threatening water security in Liuzhou, a city with 1.5 million permanent residents.

Cleanup efforts have managed to bring pollution levels down to near or within the official limit. The contamination has killed many fish and triggered panic buying of bottled water.

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 chemical mostly used in industrial effluents.