A Heavy Legacy: lead contamination in San Antonio Oeste, Argentina

A Heavy Legacy: lead contamination in San Antonio Oeste, Argentina

10th October 2005

Summary by MAC Editor Luis Claps

Over twenty years after the closure of a mine and foundry which left thousands of tons of toxic waste in the place they live, the community of San Antonio Oeste has begun to realize the seriousness of their situation. "It would be better if the lead left spots on your face, because then the residents would be able to actually see the problem," says biologist Nuria Natalia Vázquez, whose thesis work has shown that marine organisms in the bay, notably mussels, accumulate lead and other toxic metals in their bodies.

Ten years ago, other professionals raised the alert about this cycle of contamination, but nobody did anything. Still today, the toxic waste pile has not been isolated nor is there a serious remediation plan. A multi-sectorial commission is coordinating education and informational activities as well as discussions as to what methods to take in the community. It has been proposed to carry out blood sample studies in children between six and nine years.

Summary of the work of Nuria Vázquez

Although the Patagonian coast has had practically no mining activities which release heavy metals in the environment, one exception is in the San Antonio Bay, in the province of Río Negro, where waste piles from an abandoned mine has over time leaked various metals, particularly lead, copper and zinc. The mine, known as "Gonzalito," is located some 107 km from the city of San Antonio Oeste, and was in operation between the 1960's through the 1980's, extracting lead, zinc, silver and vanidium for the company Geotécnica S.A.

In 1961 the company began construction of a foundry in San Antonio Oeste for the production of ingots. The lead ore excavated from the mines were smelted in the plant. Between 1953 and 1979 61,807 tons of lead and 12,725 tons of zinc concentrate were produced.

The wastes produced in this process were piled in the open air in different locations around the city, and on the edges of the bay, especially in the areas near the touristed beaches of Las Grutas. Some of the waste dumps are located within the city itself, and some of the piles have had houses constructed upon them.

In December 1994 and October of 1995, a local organization made an evaluation of heavy metal deposits in the area. They detected high levels of cadmium, copper, lead and zinc, levels much higher than in the rest of the coastal region of Patagonia. (Commendatore, 1996)

Ten years after these first studies showed high levels of heavy metals in the bay of San Antonio, the principal objective of study is to analyze the current level of contamination in sediments and in marine organisms, and compare changes and physiological reactions in bivalves affected by heavy metals.

Among other conclusions of the study, it was shown that mussels living in the San Antonio bay accumulate high levels of zinc, copper and cadmium, which constitutes a contamination risk throughout the food chain, proving a great threat to larger predators and therefore a potential risk for human health.

The results of this study clearly show that the magnitude of the problem described in the 1996 Commendatore study remains valid and that the evolution of the pollution needs to be studied on an ongoing basis for the potential problems presented both to the environment as well as the human population.

Mental disability and delayed mental development

María Isabel Díaz, director of the Special School 18, told the Diario de Río Negro that "in San Antonio there are high levels of mental disability and delayed mental development. There are people who worked for Geotécnica who have had have their children and now their grandchildren in our school for special students."

María Isabel says doubtfully, "in our family, the Díaz, we have chronic anemia. My sister doesn't know if she can have children... Because we lived in a house beside the plant. We lived there six or seven years, she says thoughtfully. "My father always worked in the offices of the company. The owners of Geotécnica were the engineer Juan Carlos Rega and Aldo Di Luciano. They were Argentine, lived in Buenos Aires. I think Rega is still alive, and Di Luciano, I believe, is dead".