Sonora water supply contaminated?


According to a sampling carried out by the Federal Commission for the protection of sanitary risks of Mexico (Сofepris), 48 of the 60 wells of the Sonora River, in the north of the country, have lead and arsenic.

The area was affected six years ago by the toxic spill from Grupo México’s Buenavista del Cobre mine – the largest mining company in the country and the third-largest copper producer in the world. However, so far the authorities have not linked this catastrophe with the high levels of heavy metals in the measurements of the wells or have not given another explanation for this drastic situation in the area.

Some of the samplings were carried out by Cofepris in Hermosillo, capital of the state of Sonora. 

According to the measurement it was found that: 

  • 90% of the samples had arsenic concentrations above the tolerance level established by the World Health Organization (WHO) of 0.01mg per liter; 
  • They measured that the arsenic concentration in 80% of the samples exceeds that established by the official Mexican Standard NOM-127-SSA1-1994 regarding the limits of permissibility in water for human consumption. 
  • The 10% of wells that are contaminated with arsenic also have elevated lead data.
  • In a few wells, other heavy metals were found, such as iron, manganese, and sulfates. 

The information was released through requests for public information made by the Sonora River Basin Committees and the civil organization Poder, which is accompanying the case. Although they have requested more information in this regard, they said from Power, they have not obtained an official response on the origin of this contamination and the measures to prevent its presence in the vital liquid from causing damage to the health of the local population.

The organization Poder systematized the Cofepris measurement data and made it available on the web for download.

However, the researcher Samantha Camacho pointed out, they have no longer obtained new information through official channels throughout the year 2020, which she pointed out as a lack of the right to public information. 

Health risks

Both arsenic and lead are considered a risk to public health, since they are bioaccumulative in the body and are not easily eliminated, in addition to being linked to chronic non-communicable diseases, such as cancer. 

For this reason, the organizations that disseminated this information claim that the official government bodies that have an impact on the material – the Ministry of Health, the Commission for the protection of sanitary risks, the National Water Commission, the Ministry of the Environment, the Attorney for the protection of the environment, the State Government and the Municipality of Sonora— determine the source of the contamination of the water of the Sonora River.

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Once it is identified, they stress from the organization, a policy can be proposed that mitigates the damage and allows constant access to information on the situation of the river water through a monitoring program. 

They also require coverage of specialized medical care for diseases that may afflict the population of the area, caused by the ingestion of heavy metals for prolonged periods


The Sonora Post