As a small fishing canoe darts across the still waters of the San Silvestre wetlands in central Colombia, Wilson Díaz leans over and dips his hands overboard. He cups some water and brings a palmful to his face, inhaling deeply. “It smells foul,” he says.
Díaz, president of a fishing union in his home town of Barrancabermeja, knows the waters intimately. He has worked in the San Silvestre wetlands his entire life; the water he now says is foul has long been his family’s sustenance.
For years, scientists, environmental groups, fishers and the wider population have denounced the pollution of San Silvestre’s waters caused by a large landfill on the outskirts of Barrancabermeja.
“This issue has been here since the landfill arrived,” Díaz says. “It has caused significant damage to the fishing community, and our quality of life has changed completely.”
Díaz and his fellow fishers have reported mass die-offs of fish and other wildlife in the area, which they attribute to the contamination of the wetlands caused by the landfill. Five years ago, Díaz says it was common to catch up to 200 fish a day on the lake. Nowadays, it’s a triumph if he manages to catch 15.
“Production is not what it once was. I am very concerned as a fisherman and as an environmentalist. We are practically being displaced due to the landfill; they are going to eradicate us, little by little,” he says.
The landfill, operated by the French waste management company Veolia, has faced numerous accusations of environmental wrongdoing and corporate negligence in its site management.
The 30-hectare (74,000-acre) landfill, managed by Veolia since 2019, is situated in the heart of the San Silvestre wetlands, an environmentally protected area in the department of Santander. It surrounded by an expanse of lush, green land, teeming with flora and fauna and interlaced with a network of streams and waterways.
A report published this week by the environmental NGO Global Witness has accused the company of deliberately dumping liquid toxic waste residue, known as leachate, directly into the streams and waterways of the wetlands – reportedly causing environmental damage and severe health effects.
The report says “high concentrations of heavy metals – including mercury 25 times over what is regarded as safe limits” were found in sediment samples taken in September 2024 from water sources near the landfill.
The findings are supported by a video by San Silvestre Green, a local environmental group, which allegedly shows Veolia improperly dumping untreated liquid pollutants. The footage was captured between August and September 2023.
Veolia’s landfill receives approximately 150 tonnes of waste daily from Barrancabermeja, including waste from the area’s numerous oil refineries, as the city is at the heart of Colombia’s oil production region.
The San Silvestre wetlands are about 12km (7.5 miles) from the Veolia landfill, with numerous streams and waterways encircling the site.
According to Global Witness and San Silvestre Green, leachate from Veolia’s plant flows into a nearby waterway called Caño Moncholo, which feeds into the El Zarzal stream. This is one of the main waterways linking the landfill area directly to San Silvestre, contaminating the entire body of water and its connected tributaries.
Leonardo Granados, a lawyer in Barrancabermeja and head of San Silvestre Green, says: “Veolia’s actions are those of an environmental criminal.
“The landfill must be closed … because studies have shown that continuing its operation jeopardises the future of the San Silvestre wetlands. This area is designated for environmental preservation, and we’re fighting for species at risk, the ecosystem and our biodiversity.”
Communities living close to the Veolia landfill have complained of health issues among newborns and children for a long time. Local doctors have reported an alarming rate of anencephaly cases – a severe congenital disability where a baby is born without parts of the brain and skull – which they claim is due to pollutants in local waterways.
A local paediatrician, Dr Yesid Blanco, says he documented 27 cases of a rare skin condition known as Job – which typically affects one in 100,000 newborns – in Barrancabermeja between 2016 and 2018.
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Veolia vehemently denies any wrongdoing and says that it “operates the site in full compliance with environmental regulations”. “We strongly deny the allegations made by Global Witness. These accusations are not true, and there is no credible evidence to support them,” the company said in a statement.
Veolia representatives stated that all leachate produced by the waste it accepts is treated onsite. Once the leachate is decontaminated, it is repurposed for irrigation and infrastructure within the plant.
The company asserts that the “reports of contamination in this wetland predate the park’s operation and are linked to regional activities such as oil extraction, livestock and buffalo farming, palm oil production, and untreated wastewater from human settlements”.
Veolia representatives stated that the company neither holds nor has any interest in obtaining the necessary licensing to merely dispose of the leachate. The company says it prefers to treat and process the liquid waste onsite.
The company said that the video evidence provided by Global Witness and San Silvestre Green “was created with the intention of contravening the company’s processes, practices, and instructions, deliberately manipulating operational equipment to tarnish the company’s reputation”.
It said in a statement: “We reject allegations that Veolia’s operations at San Silvestre cause a contamination of Barracanbermeja’s water sources, particularly the San Silvestre swamp, with mercury, iron or cyanide.
“There is no evidence linking the park’s activity to the presence of these heavy metals, as laboratory analyses of the raw leachate parameters show very minimal concentrations, far from the results obtained by the complainants.”
Veolia also stated that environmental authorities conducted six visits to the landfill between 2023 and 2024, “concluding that environmental obligations were fulfilled”.
The environmental authorities in Barrancabermeja did not respond to multiple requests for comment.
Global Witness sent the test results and video evidence of the leachate dumping, filmed between August and September 2023, to Source International, an independent group of scientists specialising in the impacts of industrial pollution on public health.
Flaviano Bianchini, director at Source International, described them as “clear evidence of egregious and shameless malpractice”.
Residents of Patio Bonito, a small community of about 120 people directly opposite the Veolia landfill, dismiss the company’s justifications.
People in the village have traditionally relied on local water sources for fishing and household use, but say they can no longer do so due to contamination and health concerns. They have long complainted about pungent smells, an excess of insects, skin problems, and other medical issues they attribute to the presence of the landfill.
“Years ago, this place was wonderful,” says Himelda Arias, who has lived in Patio Bonito for nearly 40 years. “There was a healthy atmosphere and you could breathe freely. Since they built that landfill, everything has become increasingly difficult. The stench of rubbish is just dreadful. The landfill is slowly killing us.”
Arias says the odour of waste frequently wakes her at night and causes her skin and throat to sting. Her grandchildren often have to sleep with face masks to keep the smell at bay.
“I love nature. I’m fascinated by the trees and the animals, but this has damaged our ecosystem; it has affected everything,” she says, swatting flies away from her face as she speaks. “You no longer wake up with that same joy or enthusiasm. I feel like leaving; the smells are just too much.”