Metal contaminants dumped by Doe Run’s La Oroya smelter in Mantaro River, threaten Peru’s breadbasket

Mine waste dumped by Doe Run’s La Oroya poly-metallic smelter is spreading into neighboring provinces and threatening a chain of lakes and rivers that feed into the Mantaro River, one of the main water sources in Peru’s central Andes mountains, according to a scientific study carried out under the auspices of the “Revive El Mantaro” project.

The recently published study, financed by the Italian-Peruvian Fund, was carried out by a group of scientists from Missouri’s Saint-Louis University. It consisted in periodically and systematically collecting water, soil and air samples in various provinces of Peru’s highland department of Junín: Yauli, La Oroya, Jauja, Concepción, Chupaca and Huancayo.

Of 18 rivers, the Mantaro, whose course takes it through the giant smelting complex run by U.S.-based Doe Run in the town of La Oroya, was determined to be the most polluted.

According to the study, the Mantaro, which is one of the main sources of irrigation water and electric power in the fertile Mantaro river basin, or the breadbasket of Peru, carries in its headwaters 12.3 tons of copper, 313 tons of steel, 11.8 tons of lead and 9.9 tons of arsenic every year.

Basically a dump for toxic substances, the Mantaro has became a veritable sewer containing cyanide, lead, arsenic, copper, cadmium, mercury, and zinc and other metal contaminants that affect human health whose concentration threshold has exceeded limits set by the World Health Organization, or WHO.

Permitted WHO lead concentrations in water used for human consumption are set at a maximum of 1.3 milligrams per liter. But, in the Mantaro and the chain of lakes and rivers that flow into it, the study detected levels that exceeded this set limit by more than 228 times.

The Mantaro also contains coliform bacteria from untreated sewage and nitrates from agrochemicals.

And, an International Journal of Environment and Health semi-quantitative analysis of two algal samples from the Mantaro River taken few kilometres downstream from La Oroya determined that the river contained both organic-pollution tolerant and morphologically abnormal diatom, or microscopic algae.

In La Oroya, a central highland mining town dubbed “Slow Chernobyl” for the appalling environmental impact of contamination generated by the U.S.-run smelter, approximately 250,000 hectares of land have been burned bare of vegetation by acid rain.

Acid rain, which makes land less suitable for growing crops as it erodes away soils and nutrients in the ground, is a side effect of the sulfur dioxide being spewed from la Oroya’s smokestack. The smelter’s 1.5 tons of lead and 810 tons of sulfur dioxide daily emissions have been held responsible for widespread lung ailments and high numbers of premature deaths.

It is damaging our crops and polluting the air in the department of Junín, said Washington Mori, the Executive Secretary of the Environmental Dialogue Association of Junín.

According to Mori, sulfur dioxide, which among other things interferes with the process of photosynthesis, stays in atmosphere for five days before it pours down as acid rain.

On October 1, Doe Run Peru inaugurated a $50 million plant to treat sulfur dioxide emissions from its La Oroya poly-metallic smelter and refinery complex. The plant was constructed under the Peruvian government’s Environmental Suitableness and Management Program, or PAMA.

In 1997, soon after Peru passed its first national environmental laws, Doe Run, a subsidiary of the Renco Group owned by Ira Rennart, was privatized and acquired by the Missouri-based Doe Run for $125 million, plus $120 million in upgrades. At that time, the environmental damage in La Oroya was so severe that Rio Tinto, a large British mining company, decided it was not worth buying.

As part of the purchase agreement, Doe Run agreed to comply with a 10-year environmental cleanup plan.

But in August, the health and environmental crisis in La Oroya reached a new stage when record-breaking levels of sulfur dioxide were detected.

The sulfur dioxide levels rose from the former record benchmark of 22,000 parts per cubic meter registered by the El Sindicato monitoring station on Aug. 4 and 17,000 parts on July 21, according to the Peruvian environmental Web page Eco Portal.Net.

Peruvian law stipulates sulfur dioxide levels within a set legal limit of 364 micrograms or less per cubic meter of air.

Sulfur dioxide emissions from the U.S.-run Doe Run smelter sometimes reach 10 times the amount considered acceptable by the WHO, and the annual mean concentration exceeds this level by a factor of two or three.

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