How a sinking gold town in Ecuador is contaminating a Peruvian river

“They are searching for dynamites, you know, illegal gold miners like to use them.” says Tito Castillo, a local tour guide, nonchalantly. “Last December, a sinkhole swallowed three houses just below the main plaza," said Señora Paola, who works at Restaurante Chamizal in the town’s centre. “And a few years before, the primary school was damaged. It still remains closed,” she added. Zaruma was founded thanks to gold mining, she explained, and if things continue the way they are, it will be the death of it.

Zaruma is a tiny mountaintop town of slightly over 24,000 inhabitants, perched on the western side of the Andes in the southern province of El Oro. The depths of the mountains in the area hold an unusually high level of gold. Normally, you can find three to five grams of gold per tonne of dirt and rock in your average commercial gold mine. The earth below Zaruma can yield as much as 180 grams per tonne, and in some veins, it can even reach 500 grams. 

This rush of gold has long attracted people to the area. The locals like to boast that their mines have been there since the time of the Incas, about 500 years ago. At the beginning of the 19th century, multinational companies, like the British-backed Great Zaruma Gold Mining Company and the South American Development Company, established some of the biggest mines in the area without any state regulations or restrictions. Unsurprisingly, this means that Zaruma’s mountains have been running out of gold for some time now. 

A Reckless Gold Rush

While there was long an unspoken rule, which became law in the 1990s, that the ground below the town is untouchable, it was only a matter of time before some dissidents, unable to resist the temptation of literally striking gold, would start mining there as well.

“The ground underneath Zaruma is like Swiss cheese now. There are hundreds of tunnels,” says Rodrigo Zambrano Toro, historian and Secretary of the Committee for the Bicentennial of the Independence of Zaruma. In April 2022, Interpol published a statement about the recent worrying spike in illegal mining worldwide, especially in Latin America. It also noted that illegal gold mining has acted as a ‘pull factor’ for other branches of organised crime, like human trafficking, human rights abuses, and financial crimes. Although the figures have not been updated since 2016, an Interpol report estimates that illegal mining accounts for about $48 billion per year in criminal proceeds.

Zambrano Toro adds that the Ecuadorian government has been trying to address the situation, periodically sending groups of soldiers to crack down on illegal miners. Between 2017 and 2021, authorities arrested at least 89 people and confiscated 680 explosive devices and 9600 kg of mined materials. Engineers from Ecuador’s Geological and Energy Research Institute have also been working in Zaruma since 2017, trying to survey the exact extent of the illegal tunnels using everything from historic maps to 3D laser scanners. 

At the beginning of 2022, even one of the country’s top engineers, Iván Núñez Pérez, was sent to Zaruma to devise a plan that would both stop the town from sinking and halt illegal miners. According to an interview with Bloomberg, Núñez Pérez’s scheme is to drill large wells and fill them up with cement, rock, and sand. He believes this would help stabilise the ground and close off some of the key tunnels illegal miners depend on. 

Zambrano Toro, who was born in Zaruma, remains sceptical about the government’s attempts. “There is still too much gold under Zaruma, and too much corruption among authorities,” he says.

CROSS-BORDER POLLUTION

The world’s unsatisfiable thirst for gold, however, does not only undermine Zaruma - its disastrous impact has been reaching as far as Peru. Two rivers around Zaruma, the Calera and Amarillo, that both legal and illegal mines use for their operations, are among the main tributaries of the river Puyango-Tumbes, which after running a few hundred kilometres in Ecuador crosses the border into Peru. This river supplies over 471,000 Ecuadorians with water along the way, and is one of the main water sources for the nearly 240,000 people living in the Peruvian department of Tumbes. 

Various studies have shown that in recent years the waste from mining activities in the Zaruma area in Ecuador has contaminated the entire Puyango-Tumbes river basin in both countries. The analysis found toxic levels of lead, arsenic, cyanide and mercury, among other chemicals and heavy metals, in the water. In an interview for Periodistas Sin Cadenas, Sonina Gonzaga Vallejo, a civil engineer and researcher of Hydrology and Water Resources Management at the Private Technical University of Loja, Ecuador says that the contamination levels in the Puyango-Tumbes river contribute to the development of various diseases like acute diarrhoea, anaemia and various forms of cancer. The water, he warns, should not be used in any agricultural or other food production processes. 

In November 2018, the Peruvian National Federation of Farmers of Peru filed a lawsuit against Ecuador over the contamination of the Puyango-Tumbes river at the Inter-American Commission on Human Rights (IACHR). In July 2020, the IACHR admitted the claim, but apart from a series of meetings between Ecuador and Peru, concrete actions to address the contamination in either country are yet to take place. Meanwhile, in 2022, the Regional Health Directory of Tumbes in Peru declared a health emergency in the Tumbes Department and called on local authorities to survey not only how people’s health has been affected but also to pinpoint the remaining water sources that are suitable for human consumption. 

Less than two weeks after FairPlanet’s visit, on the morning of 27 December, another sinkhole - 6 metres wide and 4 metres deep - opened in the middle of Zaruma, just outside of the town’s market. The Ecuadorian Army Corps of Engineers rushed to cover the hole. Preliminary examinations found that this latest hole was not caused by illegal mining but likely, and ironically, by the failure of some early attempts in 2017 to fill a previous sinkhole in the area.