According to a new report cited by the Chinese government, 19.4 percent of the country's arable land has been polluted due to years of rapid industrialization, raising concerns over the safety of the homegrown food for that nation's 1 billion people.

Toxins from factories, mining, and agriculture have seeped into the soil of the farmland, and 16.1 percent of China's soil overall. About three percent of the arable land affected is either moderately or seriously polluted, and the areas hit most severely were listed as the Yangtze River Delta, the Pearl River Delta, and industrial areas in the northeast. The figures are gleaned from a comprehensive soil survey, which looked at samples taken throughout the nation from 2005 to 2013.

The report (written in Chinese) was posted to the Ministry of Environmental Protection's website. Per a Wall Street Journal Marketwatch translation, it notes that: 

The national soil situation overall does not offer cause for optimism... In some areas, soil pollution is relatively severe. The condition of arable land is troubling, with the problem of pollution from industry and mining particularly worrisome.

The Associated Press reports that about 80 percent of the toxins are inorganic, and that the most prevalent ones are cadmium, nickel and arsenic. Cadmium, a carcinogen, is especially concerning. The toxin can cause damage to kidneys and is absorbed by rice. 

Though China's air pollution has received much public attention, farmland pollution could pose a greater risk to citizens. In 2012, China said it only had 334 million acres of usable farmland, a number dangerously close to the minimum needed to feed the population. Recently, news outlets have focused more attention on this problem. In 2013, a local paper reported that tens of thousands of tons of cadmium-tainted rice had been sold to Chinese noodle makers since 2009. But the issue of arable land pollution has long been kept under wraps. The Guardian reported last year that a Chinese science journal refused to publish a 2010 investigation into the country's soil for fear of divulging state secrets. It's not clear whether that study is related to this one.