According to a report in BBC News, about 20% of the soil in China is contaminated. Cadmium, nickel, and arsenic are the main pollutants.
Foods grown in China and exported to the U.S. in large amounts include apple juice (70%), mushrooms (43%), and spinach (22%). Dr. Oz reported about the high amount of arsenic in apple juice so this shouldn't be a surprise. Eat organic apples instead of drinking apple juice. Don't buy mushrooms that don't state where they come from because it is likely they come from China. Same with spinach. You could also grow spinach. Spinach is easy to grow in the city and in the country.
Another large import from China is the fish tilapia. 78% of tilapia consumed in the U.S. comes from China. It may look like a good deal but tilapia is anything but as it contains PCBs and heavy metals. Tilapia is farm raised. There is a rumor that about 50% of tilapia are fed animal feces making them highly susceptible to E. coli and salmonella. Also, because tilapia are farm raised, just like cows, they are given large amounts of antibiotics to keep infections at bay. You might want to stay away from tilapia and all farm raised fish. Wild caught salmon is still your best choice for fish consumption.
Report: One Fifth of China's Soil Contaminated
A decade of Dangerous Food Imports from China
Rumor: Imported Chinese Tilapia are Often Raised on Feces