Scientists find ways to clean polluted soil

BEIJING - There are ways to clean heavy-metal-polluted soil, according scientists that attended a two-day forum in Beijing that ended Thursday.

A total of 300 soil scientists and ecology experts attended the 2012 Forum on Heavy Metal Soil Remediation and Ecological Restoration.

Chen Tongbin, researcher with Institute of Geographic Sciences and Natural Resources research under Chinese Academy of Sciences told Xinhua, "Heavy metals, different from organic pollutants, are non-biodegradable and can't be separated from the polluted soil."

"They can cause serious pollution to farmland and drinking water."

Chen's team is running a project to clean polluted soil in Guangxi Zhuang autonomous region by using the Chinese fern, Pteris vittata L that has a strong capacity to extract arsenic from the soil.

They also cultivated a dozen more pollution-extracting plants, called "hyper-accumulators" that can ensure "soil recovery with lower costs and lower risks of secondary pollution," said Chen.

By inter-cropping with sugarcane and mulberry, Chen said his solution could bring a certain degree of profits for farmers.

Researchers from South China University of Technology have found new applications for maize straw aside from using it to make biomass energy.

"Agricultural castoff, like stalks, have many pores. It can be used to effectively absorb soil cadmium after modification," said Yang Chen, associate professor of environment sciences.

However, Wang Qi, a solid waste specialist from China Research Academy of Environmental Sciences, said the heavy metal cleansing was a systematic project, requiring a combination of technologies covering all industry process.

"A single technology can be promising, but the after-treatment is always neglected by enterprises. The material absorbed with heavy metals tend to be simply buried, causing some potential risks," said Wang.

Chen's brake fern project has taken heavy metals recovery into account. "The fern reaped are to be incinerated to solidify the arsenic that can be recycled into industrial materials," Chen said.

China's 12th Five-Year Plan on environmental protection has urged efforts to carry out the cleansing of heavy-metal-polluted soil.

"The growing public awareness and the national policy over heavy metals could also bring a considerable market potential in soil repair," Chen said.