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Arsenic present in the capital’s drinking water

By Talli Nauman*

Press conference

“The Mexican government has told us so many lies that we can’t believe them about the Río Sonora being clean”, says Mario Alberto Salcido, one of those affected by the 2014 spill, in a press conference 3 years after Grupo México’s Buenavista del Cobre mine disaster.


Recent test results of drinking water in the Sonoran capital show significant quantities of arsenic in all of the samples taken from the Rio Sonora basin while the heavy metal and carcinogen was absent in all samples collected from the Rio Yaqui basin.

Specialists from the University of Sonora conducted the study after the public expressed concern about the effects of the August 6, 2014 toxic chemical spill from the Buena Vista del Cobre Mine into the Río Sonora. It is considered the worst environmental mining disaster in Mexico's history.

Because both Grupo México (the mining company) and the Secretariat of the Environment and Natural Resources refused to provide data about the levels of contaminants released, even from the leach pools near the river, a US judge from Arizona ruled in favor of a public request for court assistance in obtaining the necessary information.

The US judicial ruling against Southern Copper Corp. was possible because while it is a subsidiary of Grupo México, which owns 75% of the company, it is based in Phoenix, Arizona.

Risk analysis and water quality tests were carried out immediately in response to the advocacy of 150 Hermosillo residents. Their municipality had originally been excluded from the compensation fund created by the federal government and the company.

The levels of aluminum, arsenic, copper, iron, manganese, mercury, and fluoride, all toxins reported to have been present in the spill, were tested.

Samples were taken from the following purification plants: Water Treatment Plant No. 2, located across from the Abelardo L. Rodríguez Dam; Water Treatment Plant No. 3 located near La Sauceda; and Water Treatment Plant No. 4, located in Las Lomas but fed directly from the Acueducto Independencia.

Water samples also were taken from the surface of the water behind the dam, collection points in the central neighborhood of El Mariachi, and well and tap outlets in the town of La Victoria north of Hermosillo.

Química Analítica del Noroeste, a certified laboratory in Hermosillo, analyzed the samples, according to Reyna Castro Longoria, researcher from the University of Sonora and author of the technical report Hermosillo Sonora City Water: the Study of Heavy Metals in Potable Water. (Agua de la ciudad de Hermosillo, Sonora: Estudio de metales pesados en agua de consumo humano).

The author thanks the citizens who made the analysis possible with their support.

With the exception of Treatment Plant No. 4, arsenic was the only heavy metal detected in all of the samples. The absence of any heavy metals in the samples from No. 4, which supplies the southern part of the city, was quite notable.

In one of the wells in La Victoria, the arsenic levels measured 60 µg/L (micro-grams per liter), far exceeding the 25 µg/L maximum value permitted by Mexican law, and marking it as the area of highest vulnerability.

International standards on the maximum values acceptable for human consumption are stricter than Mexican standards.

According to Canadian experts in this field, arsenic can cause lung, bladder, liver, and skin cancer. It can also cause neurological disorders, numbness, and tremors in the extremities.

At all sites where it was detected, arsenic levels exceeded the EPA and Canadian maximum allowable limits.

The study’s results and the toxin’s known associated health risks point to the need for remediation as well as the installation and modernization of water treatment plants across the city. Meanwhile, residents on the outskirts of Hermosillo also affected by the spill are demanding the same.

Los Comités de Cuenca Rio Sonora (CCRS), a coalition uniting spill victims in the Rio Sonora basin, won an amparo [1] related to the contamination of water in two other wells. They have also sued three agencies for their failure to help those harmed by the spill.

They point to another judgment, one made by the 1st District Court of Sonora, which recognizes that the Sinoquipe and La Labor wells have been contaminated by arsenic and manganese at levels that exceed those established by the World Health Organization.

Up until the ruling in mid 2017, Grupo México maintained that the Río Sonora was no longer contaminated, leading to the installation of drinking fountains to provide untreated river water in public schools.

Consequently, CCRS and the civil organization Project on Organizing Development, Education and Research (PODER) lodged a complaint against the Sonoran Institute for Security and Social Services of State Workers (ISSSTESON), the Secretary of Health (which runs the public health insurance program, Seguro Popular), and the Mexican Social Security Institute (IMSS) for not having responded to the many requests for information about the health of residents, and for not having dealt with their complaints.

The complaint points out that in the current state of uncertainty resulting when the well contamination was confirmed, "it has become urgent to adequately assess our state of health. This should include at a minimum the appropriate and necessary tests to confirm if we are suffering from exposure to, or poisoning by, heavy metals".

It is estimated that up until now, three years after the disaster that also contaminated the Rio Bacánuchi, at least 22,000 people have been directly affected, and another 250,000 indirectly impacted in the seven municipalities along the shores of the Río Sonora which include: Arizpe, Banámichi, Huepac, Aconchi, San Felipe, Baviácora, Ures, as well as Hermosillo.

In April 2017, Grupo México announced that it would be building nine water treatment plants, and had so far installed one. PODER complained that the company had promised to build thirty-six.

When questioned by the United Nations Working Group on Business and Human Rights about the lack of water purification plants, company officials argued that "it would be irresponsible to build them" because the municipal authorities "did not have the capacity to make use of them."

According to PODER, Grupo México’s cleanup and remediation work has also been inadequate. The majority of the leach ponds that should have been relocated remain, and many continue to be used in spite of their location just a few meters from the river bank.

A series of independent analyses of drinking water has shown, year after year, the presence of heavy metals in quantities well above international standards. These toxins are bioaccumulative and, as such, the effects on health can take months or even years to manifest.

Grupo México committed to building a medical center and while it had not yet completed the work, the Epidemiological and Environmental Monitoring Unit (Uveas, for its acronym in Spanish) said in July 2017 that 381 residents of the Rio Sonora basin require treatment because blood and urine tests showed toxic residues.

Compensation for losses to growers and ranchers has been another point of contention and criticism. The technical committee of the Río Sonora Trust did not study how best to distribute the 2 million pesos earmarked for compensation of economic losses caused by the spill. According to PODER, this has resulted in negligible amounts being dispersed compared to the degree of damages suffered.

The amount in the trust equaled 0.013% of the gross income of Grupo México in 2014, and the 24 million peso fine (US$1.26 million) that was imposed by the Federal Attorney General’s Office for Environmental Protection (PROFEPA) equaled 0.00016% of that year’s gross income.

"The Mexican government has demonstrated little or no interest in seeing that Grupo Mexico fulfills its commitment to remediating the damages caused. It has abandoned the legal actions it had initiated against the business, an attitude that was highlighted by the United Nations Work Group in their final report released in June 2017," said PODER.

The CCRS, along with PODER, has sought protection and taken legal actions more than 12 times against the company and a variety of governmental agencies, "but this still has not been sufficient to achieve justice and the restitution for damages", commented PODER in a document released in August.

"Access to justice begins with assuring that this type of disaster doesn't occur in the first place, and having laws that focus on safety is the only way to avoid unfortunate accidents like the spill in Sonora and the consequent effects on people and the environment," maintains PODER.

"At the same time we must strive to have adequate standards as well as monitoring systems and sufficiently strong penalties in order to better control spills into waterways," they added.

The CCRS unites those who live in the municipalities of Arizpe, Banámichi, Huepac, San Felipe de Jesús, Aconchi, Baviácora y Ures and were affected by the copper sulfate acid spill from the Buenavista del Cobre mine.

PODER is a regional nonprofit, nongovernmental organization. It works to improve corporate transparency and accountability in Latin America, from the perspective of protecting human rights and strengthening civil society stakeholders.

[1] A Mexican legal proceeding that serves to guarantee constitutional rights.

**Codirector of Journalism to Raise Environmental Awareness