Atlas of Contaminated Sites

Notable case, Huanjiang (Hechi), Guangxi, China

Huanjiang (farmland polluted by mine tailings)

环江毛南族自治县

In June 2001 a flood breached the tailings ponds of three lead-zinc ore-dressing plants upstream on the Huanjiang river in Guangxi, and the tailings settled on the fields along its banks. It is one of China's most often cited cases of large-scale farmland remediation with plants.

Phytoremediation

Status
Remediation under way
Area
600 ha on land1
Media
soil, sediment, living organisms
Kind of site
mining, accident
  1. Area. More than 9,000 mu (about 600 hectares, at 15 mu per hectare) of farmland contaminated to varying degrees in 2001, according to the Xinhua agency (2013).

Contaminants

Metals

Metalloids

Other inorganics

Status

Remediation under way

The county remediation project, started in March 2011 with phytoextraction and chemical treatment, had substantially completed the first of three phases by June 2013 (Xinhua). The state of the later phases was not checked for this record.

Story

Huanjiang Maonan Autonomous County, in northern Guangxi, is a karst area with lead and zinc mines. In June 2001 exceptional rain breached the tailings ponds of three ore-dressing companies upstream on the Huanjiang river. When the flood receded, tailings and waste slag were left on the submerged fields of Luoyang, Da'an and Si'en townships: more than 9,000 mu of farmland was contaminated to varying degrees (Xinhua, 2013).

Crops died over large areas and would not grow the following year. Testing found strongly acid soil, from the oxidation of sulphides, and lead, zinc, sulphur and arsenic above the limits. Later studies of the fields along the river describe soil contaminated with arsenic, lead, cadmium, copper and zinc.

In March 2011 the county started a remediation project based on phytoextraction and chemical amendment, with quicklime against the acidity. The first phase, costing 24.5 million yuan (about 20,000 yuan per mu), was substantially complete by June 2013. The Institute of Geographic Sciences of the Chinese Academy of Sciences (the group of Chen Tongbin and Lei Mei), Guilin University of Technology and the Guangxi Environmental Monitoring Centre have all worked on the site.

Timeline

  1. 2001June: a flood breaches the tailings ponds of three plants upstream; more than 9,000 mu of fields are contaminated.
  2. 2011March: the county starts the remediation project with phytoextraction and chemical treatment.
  3. 2013June: the first phase (24.5 million yuan) is substantially complete.
  4. 2016Publication of the survey on the compensation farmers expect during remediation: about 16,980 yuan per hectare per year.

Remediation

  1. 2011soil amendmentQuicklime to correct soil acidity, alongside phytoextraction, in the county project (first phase 2011–2013).

Plants and fungi at this site

PhytoremediationField scale, 2011–2013

First phase of the county project: phytoextraction combined with chemical soil amendment. The Xinhua article does not name the extracting species; it mentions mulberry, sugarcane and rice as the crops measured on the treated land. The technical publications of Chen Tongbin's group on the project were not read for this record.

Outcome After two years of treatment the mulberry leaf yield was still 15 kg below that of uncontaminated land, while sugarcane and rice yields exceeded the average of unpolluted land (Xinhua, 2013). Soil metal concentrations before and after are not reported.

PhytoremediationField scale

Saccharum officinarum

A 12-month trial on a contaminated field along the Huanjiang river with a low-accumulating sugarcane variety, meant as productive phytostabilisation: total and available metal concentrations measured before and after, with and without cane.

Outcome With cane, soil metal concentrations were lower than without and trace-element availability fell. Metals in the juice were all below the food limits; in the bagasse they reached the limit. Copper and zinc were the most mobile elements (Wang and colleagues, 2017, conference proceedings).

From the literature

Species that acted on one of this site's contaminants in at least one study. The list is automatic and takes no account of this site's soil, concentrations or climate.

Plants

Fungi

The rest are on the contaminant pages.

Nearby

Notable case, Wanshan (Tongren), China

Wanshan mercury mining district

314 km

  • Mercury

Phytoremediation

Sources

  1. 广西环江土壤重金属污染修复首期项目完成, Xinhua (xinhua08 / cnfin.com), 2013
  2. Wang X. et al. Short-term phytoremediation effect of sugarcane for contaminated farmland on heavy metal accumulation ability along the Huanjiang River in Guangxi, China, Atlantis Press, 2017
  3. Zeng W.Q. et al. Effects of Remedies on the Remediation of Typical Pb and Zn-contaminated soil in Huanjiang, Guangxi. Huanjing Kexue (abstract via Europe PMC), Huanjing Kexue, 2015
  4. Li H., Zhang X., Yan J., Ji M., Chen T. Farmers acceptance investigation of ecological compensation for heavy metals polluted farmland remediation: a case study from Huanjiang, Guangxi. Journal of Guilin University of Technology (abstract), Guilin University of Technology, 2016
  5. Qiao P. et al. Quantitative analysis of the factors influencing spatial distribution of soil heavy metals based on geographical detector. Science of the Total Environment (abstract), Elsevier, 2019
  6. Huanjiang Maonan Autonomous County (coordinates), Wikipedia, 2026

Draft compiled from public sources, not yet reviewed.