Environmental Group Accuses Cozumel Wastewater Plant of Polluting Laguna Ciega

Cozumel, Quintana Roo — Environmental group Sélvame MX has intensified its allegations of ecological damage at Laguna Ciega, calling on federal, state and local authorities to investigate possible contamination from the San Miguelito wastewater treatment plant.

The organization released satellite images that it says show progressive deterioration of the lagoon and surrounding mangroves. According to Sélvame MX, the changes coincide with earlier complaints about possible wastewater discharges from the island’s main sanitation facility.

The accusations come after a major public investment in the plant. In 2025, San Miguelito was expanded through a project worth more than 113 million pesos (about US$2.2 million), financed under the federal Wastewater Sanitation Program. The upgrade doubled treatment capacity from 110 to 230 liters per second and added new pretreatment areas, biological reactors, regulation tanks and infiltration wells, making it one of the most significant sanitation projects on the island in recent decades.

Despite those improvements, Sélvame MX says recent field tests detected high concentrations of fecal coliforms, E. coli, nitrogen and phosphates — indicators that could be linked to wastewater contamination and processes that harm coastal ecosystems.

The group also criticized authorities for downplaying the problem despite what it says is visible damage to the lagoon. It called for transparency in environmental monitoring results, independent studies and urgent ecological restoration measures.

Laguna Ciega is part of a high-value environmental system connected to wetlands and mangroves that serve as natural barriers against storms, wildlife habitat and biological filters for water quality. Specialists have warned that degradation of these ecosystems could have direct consequences for the island’s biodiversity and environmental balance.

As the allegations continue, public demand is growing for environmental authorities to determine whether there is a link between the San Miguelito plant’s operations and the reported damage to Laguna Ciega.