Greenpeace Report: Faecal Contamination Threatens Yucatan's Vital Drinking Water Sources

Faecal bacteria are contaminating wells and sinkholes across Mexico’s Yucatan state, posing a significant threat to the region's primary drinking water sources, according to a new report by the global environmental organization Greenpeace. The report, released on Tuesday, points to nearby pig farms and municipal wastewater as the probable culprits behind the pollution in the southeastern coastal state.

"A range of chemical and microbiological indicators reveal a complex mosaic of severe, localised organic pollution," the report stated. Greenpeace is urging an immediate halt to new industrial livestock operations and farm expansions in the peninsular state, an area historically significant as the heartland of the ancient Maya civilization.

Given that the Yucatan lacks above-ground rivers, its groundwater serves as the sole source of freshwater. The region's porous limestone bedrock facilitates the rapid seepage of pollutants into the aquifer.

Laboratory Results Highlight Widespread Contamination

In August, Greenpeace commissioned an independent laboratory to conduct tests on water samples from 17 locations near Merida, the state capital. These sites included household wells, farm wells, community water points, and cenotes—natural sinkholes characteristic of the Yucatan Peninsula, a popular tourist destination.

The findings indicated that every sample exhibited some level of contamination, likely originating from faecal waste, with several sites showing heavy pollution. Total coliform bacteria exceeded the test's upper limit in 16 out of 17 samples, and faecal coliforms did so in 13 samples. While these tests cannot definitively determine the source of the waste (human or animal), leaking septic tanks and municipal sewage systems are also considered potential contributors to the contamination.

However, Greenpeace highlighted separate testing that utilized Pig2Bac, a pig-specific DNA marker method. This method detected pig faecal matter in samples analyzed by laboratories at Johns Hopkins University in the United States and Mexico’s National Autonomous University (UNAM). Greenpeace asserts that these results raise "critical accountability questions" for nearby pig farms.

Maya communities have joined Greenpeace in their call for environmental authorities to take action against the contamination.

Industrial Pig Farms Under Scrutiny

A United Nations report from July identified over 500 industrial pig farms in Yucatan state, housing more than 50,000 animals, many situated close to the lands and territories of Indigenous Peoples. Marcos Orellana, who authored the UN report and previously served as a UN special rapporteur, stated that waste and chemicals from these industrial farms rapidly enter the water used by communities for daily needs, including bathing, cooking, and drinking.

Orellana noted that most farms operate without the required permits and that regional government efforts have been inadequate. "The contamination of the waters that have sustained Mayan culture for millennia is predominantly coming from the industrial operations of the growth of animals," he said.

Conversely, Antonio Zumarraga, vice president of the Yucatan Citizen Scientific Water Observatory, defended the local pork industry, citing its investments in water treatment and support for conservation programs. He attributed the inaction to local authorities, suggesting, "It’s an issue that, as long as it doesn’t carry political weight for the government, they won’t do anything about it."

The Yucatan state government and Mexico’s national water commission, CONAGUA, were unavailable for comment at the time of reporting. The Merida Association of Pig Farmers also did not respond to a request for comment from Reuters.