A fuel slick that polluted a Chinese river has reached a southern Russian city, where experts have been battling to minimise the risks. Millions of litres of fresh drinking water have been trucked in to Khabarovsk. The slick of benzene, caused after a factory explosion in China, spread along the Songhua river and into the Amur river. Dams near Khabarovsk have been reinforced, while containers and sacks full of sand and special charcoal are being dumped into the water to try to neutralise the pollution.Meanwhile, China’s southern province of Guangdong is rushing to protect water supplies after a second toxic spill, this time from a zinc smelter. A river near the city of Yingde has been polluted, and levels of cadmium have been found to be 10 times higher than normal. The leak apparently happened during maintenance work last week. China had already been forced to apologise to Russia over the benzene spill and the environment minister in Beijing resigned over the affair.