The Atoyac is now the river with the most chemical and organic pollution in all of Mexico, according to the latest report on the quality of the country’s tributaries by the National Water Commission (Conagua). The most critical point is within the borders of Puebla and Tlaxcala, where industrial and municipal waste from both entities is dumped, often illegally. According to Francisco Javier Sánchez Ruiz, an environmental researcher, the excessive pollution of the river is due to the permissiveness and unwillingness of the authorities.
According to the latest results of the National Water Quality Monitoring Network (RENAMECA), published annually by Conagua, in 2023 the Atoyac River had the highest levels of chemical oxygen demand (COD) and biochemical oxygen demand (BOD) – fundamental parameters for measuring water pollution – in Mexico.
Sánchez Ruiz, a researcher at the Faculty of Environmental Engineering at the Universidad Popular Autónoma del Estado de Puebla (UPAEP), explains that both criteria determine, among other things, the toxicity of water bodies, which is why their measurement plays a decisive role in their pollution. In addition, he explains that the two levels, COD and BOD, give an accurate picture of the damage done to ecosystems.
According to researcher Sánchez Ruiz, the Atoyac suffers the consequences of the historical lag in supervision, regulation and sanctioning that has characterised the Alto Atoyac sub-basin, a situation that depends directly on the Federal, Puebla and Tlaxcala governments.
There are at least three industrial estates in the area, two in Huejotzingo and one in San Martin Texmelucan, mainly dedicated to textile and food production. In Tlaxcala, the factories are concentrated in different areas, mainly in Panzacola and Nativitas.
Sánchez Ruiz points out that this area has become a “paradise of permissiveness”, as many companies located in this geographical strip have found various ways of circumventing national legislation, due to the lack of effective control procedures and severe sanctions, while the effluents exceed almost all pollution parameters.
The expert explains that the law in Tlaxcala is not aligned with the federal mechanism, which leads industries and users of waste discharges to essentially comply with the local regulation, which is much more permissive than the national one. In other words, since there are two sets of regulations, companies choose to comply with the local one, even though it is not necessarily the most demanding. Not to mention that the state government does not have the infrastructure to monitor all discharges.
According to Sánchez Ruiz, the lack of a coordinated legal mechanism with Tlaxcala exacerbates much of the backlog. For this reason, he stresses the need for the federal government to oblige the two states involved in the Atoyac to work on the basis of a single regulatory instrument that is efficient and regulates the responsibilities of each authority.
