Notable case, Tongling, Anhui, China
Tongling copper mine tailings ponds
铜陵铜尾矿库
Tongling, on the Yangtze in Anhui, is one of China's copper cities: ore dressing has left large tailings ponds rich in sulphides, acid and poor in nutrients. For more than twenty years they have been an open-air laboratory for revegetating tailings with grasses such as Imperata cylindrica and vetiver.
At a glance
- Status
- Remediation under way
- Area
- 44 ha on land1
- Media
- soil, surface water
- Kind of site
- mining
- Area. 44 hectares is the surface of the Shuimuchong pond alone (Li and colleagues 2016), to which the coordinates also refer. In Tongling the copper tailings are spread over five main areas (Yang and colleagues 2004); the total surface is not in the sources read.
Contaminants
Status
Remediation under way
The disused ponds are partly revegetated, by natural colonisation and by planting, with or without a soil cover; studies from 2025 still find an average of 1,226 mg/kg of copper in soils around the Shuimuchong pond (Cai and colleagues). No official overview of the state of all the ponds was found.
Story
Tongling means "copper hill", and copper is abundant there. The tailings from ore flotation have been stored in ponds around the city: a 2004 survey identified five main areas. Among the most studied are the Shuimuchong pond, built in 1990 and covering 44 hectares, and the Yangshanchong pond.
The tailings contain polymetallic sulphides which, as they oxidise, acidify the substrate and release metals. Plants struggle to establish because of the acidity, the toxicity of the metals, copper above all, and because freshly deposited tailings hold no nitrogen or organic matter. Around the Shuimuchong pond soils contain on average 1,226 mg/kg of copper, with zinc, arsenic, cadmium, lead and mercury above background values (Cai and colleagues 2025); copper isotopes have been used to trace migration from the pond to the nearby soils.
Plant cover increases with time: 40 plant species, spontaneous or introduced, were counted on the older ponds. On Shuimuchong grow Imperata cylindrica, which arrived by itself, and vetiver, which was planted; on Yangshanchong, Imperata cylindrica and Miscanthus floridulus, on areas with and without a soil cover.
Timeline
- 1990The Shuimuchong tailings pond is built.
- 2004Publication of the survey of Tongling's tailings ponds and their plant colonisation.
- 2016Study of microbial communities along the profile of the revegetated Shuimuchong tailings.
- 2025Copper isotopes trace contamination from the Shuimuchong pond to the surrounding soils.
Remediation
- —soil coverSoil cover on part of the Yangshanchong pond before revegetation (Chen and colleagues 2026).
Plants and fungi at this site
PhytoremediationField scale
Imperata cylindrica, Chrysopogon zizanioides
Revegetation of the Shuimuchong pond (44 ha): Imperata cylindrica that established spontaneously and planted vetiver (Chrysopogon zizanioides). Li and colleagues compared the two covers with bare tailings along a 60 cm profile, measuring substrate chemistry and microbial communities.
Outcome Both covers slowed the degradation of the tailings, raising pH in the top 30 cm, and changed the bacterial communities in the top 20 cm; according to the authors revegetation, especially with Imperata, helps the microbial community develop and hinders sulphide oxidation. The study does not measure a fall in total metals.
PhytoremediationField scale
Imperata cylindrica, Miscanthus floridulus
Yangshanchong pond: comparison of areas with and without a soil cover, both vegetated by the two dominant species, at depths of 0–20, 20–40 and 40–60 cm; substrate properties, bacterial communities and carbon and nitrogen functional genes were measured.
Outcome The soil cover changed pH, raised organic matter, organic carbon and ammonium nitrogen and lowered surface total nitrogen, total phosphorus and some heavy metals (abstract of Chen and colleagues 2026; numerical values not read).
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
- Agrostis capillarisCommon bentEvidence: field
- Arabidopsis halleriHaller's rockcressEvidence: field
- Cannabis sativaIndustrial hempEvidence: field
- Festuca rubraRed fescueEvidence: field
- Noccaea caerulescensAlpine pennycressEvidence: field
- Populus albaWhite poplarEvidence: field
Fungi
- Funneliformis mosseaeEvidence: greenhouse
- Rhizophagus irregularisEvidence: greenhouse
- Paxillus involutusBrown roll-rimEvidence: greenhouse
- Aspergillus nigerBlack mouldEvidence: laboratory
- Mucor circinelloidesEvidence: laboratory
- Suillus luteusSlippery jackEvidence: laboratory
The rest are on the contaminant pages.
Nearby
Sources
- Li Y. et al. Ecological restoration alters microbial communities in mine tailings profiles. Scientific Reports 6: 25193 (full text via Europe PMC, PMC4850430), Nature Portfolio, 2016
- Yang S., Xie J., Liu D. Reclamation and plant colonization in copper mine tailings in Tongling, Anhui Province. Resources and Environment in the Yangtze Valley (abstract via Europe PMC), Resources and Environment in the Yangtze Valley, 2004
- Cai Q., Chen X., Xie F., Li G. Source apportionment and risk assessment of heavy metal contamination in soils surrounding the tailings based on copper isotopes. Ecotoxicology and Environmental Safety (abstract), Elsevier, 2025
- Ren M. et al. Tracing copper pollution migration mechanisms in mine tailings pond and surrounding soils using isotopes: a case study of the Shuimuchong tailings pond, Tongling, China. Environmental Pollution (abstract), Elsevier, 2025
- Chen Y. et al. Effects of soil covering on bacterial communities and C/N functional genes during phytoremediation of copper tailings (abstract), Elsevier, 2026
- Tongling, Wikipedia, 2026
Draft compiled from public sources, not yet reviewed.