Overview
- Researchers have documented widespread chemical mixtures in the Lerma‑Santiago, Atoyac, Tula and Tijuana basins linked to municipal and industrial wastewater discharges.
- A 2012 IMTA analysis publicized by Greenpeace identified 1,090 distinct chemical substances in the Río Santiago basin, highlighting the complexity of contamination.
- Air measurements near the Tijuana River area recorded extreme hydrogen sulfide spikes and hundreds of other gases that can move from polluted water into the atmosphere.
- A 2026 study using the comet assay reported DNA damage in residents of communities bordering the Río Santiago, while scientists note that detection alone does not prove disease causation.
- Experts and journalists call for sustained, transparent water and air monitoring, targeted wastewater treatment tailored to detected pollutants, and stricter enforcement to reduce risks to communities.