About one tenth of China's farmland is polluted by lead, zinc and other heavy metals to “striking” levels exceeding official limits, a government expert said according to reports Monday. Wan Bentai, the chief engineer for China's Ministry of Environmental Protection, said a survey of soil pollutants this year found heavy metal from smelter chimneys, water run-off and tailings meant “in total about 10 percent of farmland has striking problems of heavy metal levels exceeding (government) limits,” the Southern Metropolitan Daily reported. “In recent years, there have constantly been outbreaks of heavy metal pollution, and from January to February alone there were 11 incidents, nine involving lead,” Wan told a meeting in Guangzhou, the capital of Guangdong province in south China, according to the report. China's voracious appetite for the metals has turned heavy metal pollution into a source of widespread public worry and occasional protest. Exposure to lead and other heavy metals can damage nerves, reproductive systems and kidneys, among other health complications, especially among children. The Chinese government estimates the country has 1.22 million square kilometers of farmland, and says protecting that land is a priority. But many rural areas support smelters and foundries that spill pollution into soil and water supplies. China is the world's biggest consumer of refined lead, and battery making accounts for 70 percent of that consumption, which is likely to grow to 4.1 million tons in 2011. China's environment ministry has called for urgent measures to tackle heavy metal poisoning. Meanwhile, China's total imports are expected to almost equal its exports over the next five-year period, the nation's commerce minister said in comments published Friday. Chen Deming said total imports were expected to reach $10 trillion in that period, which would be “on a par with our exports.”