Toxic heavy metals found in indigenous people living near oil fields of Peruvian Amazon: Study

High levels of mercury, cadmium & arsenic were found in the urine samples of people living river basins of Corrientes, Pastaza, Tigre & Maranon

By Madhumita Paul
Published: Monday 08 May 2023
Exposure to cadmium can cause cancer of the lung, prostate and kidney. Representative photo: istock.
Exposure to cadmium can cause cancer of the lung, prostate and kidney. Representative photo: istock. Exposure to cadmium can cause cancer of the lung, prostate and kidney. Representative photo: istock.

Indigenous people living near the oil exploration sites of the Peruvian Amazon have dangerous levels of toxic metal content in their bodies, according to a new study.

High levels of mercury, cadmium and arsenic were found in the urine samples of indigenous people living in four river basins — Corrientes, Pastaza, Tigre and Maranon — in the northern Peruvian Amazon, according to the study published in journal Environmental Health Perspectives on May 3, 2023. Oil extraction in these river basins, all major tributaries of the Marañón River, began in the 1970s.

The research was led by Cristina O'Callaghan Gordo from the Barcelona Institute for Global Health (ISGlobal). Another study by ISGlobal had reported high levels of lead in the blood samples of the local population here.

Also read: Brazil launches operation against mining mafia on Indigenous land

Indigenous communities — Achuar, Quechua, Kichwa and Kukama — of these four river basins rely on subsistence agriculture, hunting, and fishing for their daily protein requirements.

Since the arrival of the oil companies, the inhabitants here have raised concerns about the potential health effects of environmental contamination. And the analysis intended to respond to these concerns associated with oil extraction.

From May-June 2016, the researchers assessed the data regarding urinary concentrations of mercury, arsenic and cadmium in 824 people, of which 230 were children under 12 years and 594 were adults.

A significant proportion of the children and adults studied exceeded the established reference levels for mercury, arsenic and cadmium. These high levels of metals were associated with the water they consumed and bathed, particularly in the case of mercury, which can be absorbed through the skin.

Mercury levels were found to have increased with age in adults. They were higher in people living near the Maranon River, where fish consumption is higher than in other river basins, according to the study. The elevated levels of mercury in fish from the Amazon basin have been linked to oil pollution.

Some 48 per cent of the child population and 23 per cent of the adult population had arsenic levels above the reference value set by the Peruvian Ministry of Health.

Urinary cadmium levels above the reference value were found in two per cent of children and 13 per cent of adults. Cadmium concentrations increased with age in adults and were higher in women, the study noticed.

Read more: Win for indigenous rights: Ecuador court halts mining project in Amazon

The highest levels were found in people from the Achuar community and people living around Corrientes and Tigre, the two most oil-active basins of the four studied. Elevated cadmium levels were also associated with the proximity of houses or gardens to oil spills.

The high concentration of these heavy metals in these indigenous people has serious health implications, such as childhood neurodevelopment and chronic diseases. Exposure to cadmium can cause cancer of the lung, prostate and kidney.

Preventing these exposures by providing clean water and ensuring food security is a high priority for the indigenous populations living in these river basins, the document noted. The study results from an agreement between the indigenous associations of the four river basins and the Peruvian government.

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