Taps have been turned back on for 80,000 residents of China's Hunan province...four days [after] leaks from chemical plants in Yueyang county contaminated the Xinqiang river...Senior managers at the factories, which officials said had not passed any environmental assessments and had no pollution treatment facilities, have been detained...The factories had been discharging arsenide, which can damage the liver and kidney and cause lung and skin cancer, directly into the river.