Nearly a third of the soil in the Pearl River Delta, one of China's most developed areas, contains excessive levels of heavy metals, Guangzhou Daily reported on Thursday.

The main metals that exceed the standards are mercury, cadmium and arsenic, according to Zeng Sijian, an agricultural official of Guangdong province.

In places such as Foshan and Nanhai, both in Guangdong province, more than half the soil contains an excessive level of heavy metals, according to the report.