Atlas of Contaminated Sites

Notable case, Oruro, Huanuni, Pazña, Oruro, Bolivia

Lakes Poopó and Uru Uru (Oruro mining districts)

Lago Poopó / Lago Uru Uru

On the Bolivian Altiplano the mining districts at the foot of the Cordillera Oriental, worked since colonial times, discharge acid drainage and metals into the shallow lakes Uru Uru and Poopó. Here mining contamination adds to naturally occurring arsenic and to drought: Poopó, the country's second-largest lake, dried up in 2015.

Status
Not addressed
Area
100,000 ha in water1
Media
surface water, groundwater, sediment, soil, living organisms
Kind of site
mining
  1. Area. About 1,000 km² was the permanent part of Lake Poopó; at its largest, in 1986, the lake covered 3,500 km² (Wikipedia). By December 2015 it had dried up completely. There is no perimeter for the contaminated area.

Contaminants

Metals

Metalloids

Other inorganics

Status

Not addressed

The mines of the basin are active and partly unregulated. In the municipality of Pazña, 78% of the water points examined in 2013–2014 had levels of natural and mining-related contamination such that, according to the authors, effective remediation would be difficult and costly (French et al. 2017). Lake Poopó dried up in 2015 and in 2016 its recovery was considered unlikely (Wikipedia).

Story

The Poopó basin has a long mining tradition, which grew in scale after Spanish colonisation; the districts, among them the Huanuni tin district, lie along the eastern edge of the basin. Lake Uru Uru, near the city of Oruro, receives acid mine drainage and urban discharges (Aucour et al. 2026; Agramont et al. 2020). In Poopó's water, arsenic, lead and cadmium exceeded Bolivian and WHO guideline values for drinking water (Wikipedia).

Not everything comes from the mines. Arsenic in the basin is also geological in origin: water from shallow wells exceeds the 10 µg/L limit, and even the rainwater tanks installed as an alternative held arsenic at about twice the limit, released by mineral dust settled on the roofs (Quaghebeur et al. 2019). Low rainfall, high evaporation and salinisation complete the picture (French et al. 2017).

By December 2015 Lake Poopó was completely dry; the causes put forward include drought, the retreat of Andean glaciers and the diversion of water for mining and irrigation. On 20 January 2016 the area was declared a disaster zone (Wikipedia).

Totora (Schoenoplectus californicus subsp. tatora) grows on the shores of Uru Uru. Isotope measurements show that the plant tolerates zinc by excluding it: sediment-to-shoot transfer is only 0.01 where zinc is high (Aucour et al. 2026). This is an observation on wild plants, not a remediation trial.

Timeline

  1. 1986Lake Poopó reaches its greatest extent, 3,500 km².
  2. 2002Lake Poopó is designated a Ramsar wetland.
  3. 2015December: the lake is completely dry.
  4. 201620 January: the government declares the area a disaster zone.

Health

In 230 women from villages around Lake Poopó the geometric mean of urinary arsenic was 68 µg/L, with lithium and boron also high (897 and 3,972 µg/L); the study found no correlation between urinary arsenic and DNA strand breaks measured with the comet assay (Tirado et al. 2024).

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, Bolivia

Cerro Rico, Potosí

184 km

  • Mercury

Sources

  1. French M. et al. Community exposure and vulnerability to water quality and availability: a case study in the mining-affected Pazña Municipality, Lake Poopó Basin, Bolivian Altiplano. Environmental Management, Springer, 2017
  2. Quaghebeur W. et al. Arsenic contamination in rainwater harvesting tanks around Lake Poopó in Oruro, Bolivia: An unrecognized health risk. Science of the Total Environment, Elsevier, 2019
  3. Aucour A.M. et al. Zn behavior and isotope fractionation in high altitude Andean lakes. Environmental Pollution, Elsevier, 2026
  4. Agramont J. et al. Fecal Pollution Drives Antibiotic Resistance and Class 1 Integron Abundance in Aquatic Environments of the Bolivian Andes Impacted by Mining and Wastewater. Microorganisms, MDPI, 2020
  5. Tirado N. et al. Genotoxicity in humans exposed to arsenic, lithium, and boron in drinking water in the Bolivian Andes – A cross sectional study. Environmental and Molecular Mutagenesis, Wiley, 2024
  6. Lake Poopó, Wikipedia (en), 2026

Draft compiled from public sources, not yet reviewed.