(ECNS) -- Severe soil contamination threatens agricultural safety in some parts of China, the Economic Information Daily reports, citing experts at the 4th China Forum on Environmental Remediation Development Strategy.

Some areas face heavy soil contamination, especially where heavy polluting enterprises, derelict industrial land, industrial parks, centralized disposal sites for solid waste, oil producing regions, mining areas, sewage-irrigated areas and arterial highways are located.

The main pollutants are cadmium, arsenic, lead, mercury, chromium and copper, said Wei Fusheng, an academic from the Chinese Academy of Engineering.

The China National Environmental Monitoring Centre (CNEMC) recently sampled 4,910 point locations in vegetable cultivation areas, 1,188 of which were polluted, accounting for 24.3% of the sampled locations. Of all pollutants, heavy metal pollution accounted for 17.5%.

A 2011 investigation of soil around 284 factories, mines and enterprises conducted by the CNEMC showed that the quantity of clean land, mildly polluted land, moderately polluted land and heavily polluted land were 68.1%, 13.1%, 3.3% and 13.5%, respectively.

The Ministry of Agriculture, also in 2011, made a survey of 2.372 million mu of paddy fields in 88 counties of four heavily polluted regions in Hunan, Hubei, Jiangxi and Sichuan provinces. The results showed that polluted land accounted for 67.8%, or 1.608 million mu. The top six pollutants were cadmium, arsenic, nickel, copper, mercury and chromium.

Experts say that soil remediation should be achieved through tougher laws and higher environmental standards.