Chinese scientists have gradually refined the technique of cultivating the bracken fern (Pteris vittata L.) to “absorb” heavy metal elements in the soil such as arsenic, copper, and zinc. With this technique, they hope to fundamentally address the heavy metal pollution issue in the downstream regions of China caused by mining activities.
In a recent interview, researcher Chen Tong Bin from the Institute of Resource and Geographic Science, part of the Chinese Academy of Sciences, stated that they cultivate plants capable of absorbing heavy metals beyond normal levels, such as the fern species, in contaminated soil so that they can draw in these metals. They then plan to “recover” the heavy metals from these plants to extract pure metals for industrial use.
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Cultivating ferns can rehabilitate heavy metal-contaminated soil. |
Chen Tong Bin’s research team conducted a large-scale rehabilitation project for over 5,000 agricultural land samples contaminated in Huanjiang County, Hechi City, Guangxi Province. After each flood, the farmland and river basins in Guangxi and Yunnan provinces are heavily contaminated due to high concentrations of heavy metals leaching from mining areas, directly impacting production yields.
According to data from Chinese authorities, there are currently nearly 20 million hectares of arable land contaminated with heavy metals in the country, accounting for nearly 20% of the total arable land area, leading to an annual loss of 10 million tons of food, resulting in direct economic losses exceeding 10 billion yuan.
Chen Tong Bin’s heavy metal soil restoration team began surveying the heavy metal contamination of soil nationwide in 1997. By 1999, they discovered the fern—which is the first known plant in the world with the ability to hyper-accumulate arsenic.
To date, they have developed three patented techniques for soil restoration and contamination assessment and have identified 16 other plant species capable of absorbing heavy metals in China.
The fern species is widely distributed in southern China, with arsenic concentrations on the leaves reaching 0.8%, vastly exceeding the nitrogen and phosphorus content found in the stem, all while the plant continues to thrive. The ability of this plant to absorb arsenic significantly increases as it grows, and it can even pass this trait on to subsequent generations.
Currently, the research team is using synchronous radiation techniques and scanning electron microscopy to analyze the mechanisms of arsenic tolerance in this plant on living stems.
The team’s research has also discovered that the fine root hairs on the fern have a unique ability to aggregate arsenic, and the water within these hairs serves as the primary storage location for arsenic. This creates a clear barrier against arsenic, effectively “trapping” this toxin in a safe area within the plant’s body, thereby not affecting the plant’s growth.
Tuyết Nhung
