50 wells and cenotes in Yucatan, at a yellow traffic light with poor quality water: Conagua

Cenote Ik Kil

According to a Conagua study, 55 of 85 underground hydrological sites activate a yellow traffic light in water quality, while five are in red alert.

A water quality study carried out in 2020 at 109 hydrological sites in Yucatan (of which 85 are underground and 24 surface), revealed that less than half of the samples analyzed, which correspond to 48.62 percent, comply with all biochemical and physical safety standards for use in human activities, that is, they are at a green traffic light.

While 45.87 percent (percentage that represents groundwater sites) barely meet tolerable levels, so their indicator is yellow. And 5.50 percent of the places evaluated do not meet the tolerable levels of hygiene, that is, they are at a red light, according to the most current data available on the website of the National Water Commission (Conagua).

In this sense, in Yucatan, 50 underground hydrological sites (such as wells and cenotes) are at a yellow traffic light, 30 at green and five more at red. In the case of surface water, 23 points passed the green quality indicator and only one did not meet the minimum standards.

It must be taken into account that these measurements considered the characteristics of the water bodies, so different standards were used to check their level of contamination, and thus determine if they are safe to be used in various human tasks.

58.8% of groundwater sites at yellow light
When reviewing the data published by the federal water authority, it can be seen that the Yucatecan groundwater bodies that activated the red traffic light were five points (5.88 percent). These did not meet acceptable concentrations of dissolved compounds such as fluorides and nitrate nitrogen, fecal coliform bacteria, and heavy metals such as arsenic, cadmium, chromium, mercury, and lead.

There are five wells: one located in the municipality of Chemax (well one of the Potable Water System), one in Mérida (well six of the Temozón Norte plant of the Potable Water and Sewerage Board of Yucatán), one in Temozón and two in Valladolid (in Popolá and well 4).

In addition, the 45 yellow traffic light sites are located in the following municipalities: Acanceh, Cacalchén, Cansahcab, Celestún, Chemax (2), Chicxulub, Chocholá, Cuzamá, Dzan, Espita, Halachó, Hocabá, Homún, Hunucmá, Kanasín, Kinchil, Kopomá, Maní, Maxcanú Mérida (6) Muna, Opichén, Oxkuztcab, Progreso, Tahdziú, Teabo, Tecoh, Tekax, Tekit, Tetiz, Ticul, Tinum, Tixkokob (2), Tixpéhual (2) Tizimín, Tunkás, Tzucacab, Umán (3) Xocchel and Yaxkukul.

However, according to Conagua, the yellow traffic light for water quality indicates that these wells have this resource with standards for agricultural use or with the possibility of being made drinkable, since it has acceptable levels of alkalinity, conductivity, hardness, as well as sufficient quantities of manganese and iron.

Meanwhile, the 30 underground sites that passed the quality traffic light green correspond to three cenotes located in Chemax, Mérida, Tixcacalcupul, as well as 27 wells located in Akil, Cuzamá (2), Dzitás, Hoctún, Homún, Huhí, Izamal, Mérida (8), Motul, Sotuta, Tekantó, Telchac, Temax, Timucuy, Tixpéhual, Uayma, Umán and Yaxcabá (2).

Based on the concentration levels of contaminating particles, the water from these underground sources can be used for different activities, such as agricultural irrigation or be made drinkable for human consumption. In addition, CONAGUA specifies that the analyzed samples were collected directly at the hydrological supply site, in their natural condition, so they have not yet undergone a treatment phase.

Yalahau Lagoon, in Homún, is at a red light
On the other hand, the indicators corresponding to the water quality of surface sites show that the sample analyzed from Laguna Yalahau was the only one that did not pass the minimum standards. Also, there was no evidence that triggered the yellow traffic light.

In this sense, the red traffic light for surface water quality indicates that the samples do not meet the recommended concentrations of Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), fecal Enterococci and toxicity; and show concentrations of suspended solids, excremental bacteria (coliforms, Escherichia coli), or dissolved oxygen saturation.

The rest of the surface water samples from Yucatan that were evaluated by CONAGUA did meet the quality standards.

Although the agency does not specify what are the causes of contamination of the hydrological sites at a red light, it is worth putting in context that the pig farms that operate in municipalities such as Homún have been accused of not complying with environmental regulations, and of discharging their wastewater without any measures to prevent environmental disasters.

The Pork Food Production Company (PAPO) has even been blamed for contaminating the groundwater in the municipality of Homun and other Yucatecan municipalities.

The Yucatan Times



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