Milagros Salazar
LIMA, Nov 22 2007 (IPS) – The Mantaro river basin, one of the main water sources in Peru s central Andes mountains, is a dump for toxic substances, according to an independent scientific study. Lead levels, for instance, are 180 times higher than those accepted by the World Health Organisation (WHO).
The study shows that the river basin is a veritable sewer, containing cyanide, lead, arsenic, cadmium and mercury, used in mining, coliform bacteria from human waste, and nitrates from agrochemicals.
The pollution has multiple causes, Iván Lanegra, natural resources and environment manager for the regional government of Junín, told IPS. He has signed an agreement to implement urgent measures with the local social organisations that produced the report.
The study was carried out under the auspices of the Revive El Mantaro project. Lead was found throughout the basin, particularly in the Anticona river, where it was found at concentrations 180 times higher than the WHO reference levels and the quality baseline used in the study.
The local quality baseline was established by experts on the basis of analysis results from the water in nine rivers, sampled near their sources, where the water is regarded as the cleanest in the basin.
In the Yauli river, which forms part of the Mantaro basin, lead levels are three times higher than the Class III reference level, the Peruvian standard for agricultural and livestock use. After the tributary flows through La Oroya, its lead levels are 16 times higher than the water quality baseline adopted by the study.
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La Oroya is one of the 13 most polluted cities in the country, according to a government classification in 2001. It has also been ranked as one of the 10 most polluted cities in the world, according to the non-governmental Blacksmith Institute, based in New York.
Samples taken from the Mantaro river in La Oroya contained five times the permitted lead level for Class I water (fit for human consumption), and 23 times the baseline level.
The head of the Revive El Mantaro project, engineer Paula Meza, said that the highest levels of toxic substances were found in areas where, coincidentally, there is mining activity. The metal smelting plant of the U.S. firm Doe Run is located in La Oroya.
Samples taken at 53 locations along a 170-km stretch of the Mantaro basin showed that the Yauli river and the San Juan river, which flows into lake Chinchaycocha, have the highest concentrations of cyanide, lead, arsenic, cadmium and mercury.
In the San Juan river and the outflow from the Huascacocha lagoon, cyanide concentrations are up to 35 times higher than the baseline level.
Two irrigation channels are loaded with large amounts of heavy metals. The irrigation channel on the left margin of the Mantaro river (CIMIRM) receives 146.7 tons of copper, 388.9 tons of iron, 12.7 tons of lead and 10.2 tons of arsenic a year.
The Meris-Orcotuna irrigation channel, on the right-hand bank of the Mantaro, has 1.5 tons of copper, 3.2 tons of iron, 1.45 tons of lead and 1.4 tons of arsenic dumped into it every year.
The novel aspect of this study is that civil society organised itself to publicise scientific data that reflect the gravity of the problem, in an attempt to sensitise the authorities, the Catholic archbishop of Huancayo and coordinator of the Junín environmental negotiation group, Monsignor Pedro Barreto, told IPS.
In order to ensure the independence of the scientific report, 10 Peruvian experts and five researchers from the St. Louis University School of Public Health, in the U.S. state of Missouri, took part in monitoring the water and topsoil of the Mantaro basin.
The study was made more rigorous by collecting samples at hourly intervals throughout the day. Sequential monitoring of chemical compounds in multiple samples leads to greater precision in the results, and allows identification of peak pollution times.
The study also highlights environmental harm reflected in the total coliform bacteria counts, which are well above the standards set by Peruvian law and the quality baseline in the Yauli river where it flows through La Oroya, and in the Chilca and the Shulcas rivers.
Coliform bacteria are abundant in faecal matter, and their presence is an indicator of water polluted by human and animal waste, the report says.
As for nitrates, the concentrations found in the Anticona river are 56 times greater than the Class I levels, while in the Achamayo and Shulcas rivers, nitrates are present at 60 times the Class I reference concentration.
The report emphasises that the presence of nitrates is associated with the use of agrochemicals in the Mantaro river valley, an important farming region.
If we re all part of the problem, let s all be part of the solution, Barreto said in an attempt to awaken local people and the authorities to the urgent need to save the Mantaro basin.
Researcher Fernando Serrano at St. Louis University said that the principle of proportionality should apply when the costs of damage remediation are allocated. Those who pollute the most should pay most of the clean-up costs, he said.
For her part, Meza told IPS that these initial results are a big step forward. Next, the main sources of the toxic substances will be identified, she said, and it is hoped that the study s final report will include the principle of proportional cost-bearing along with the identities of the sources.
Junín s natural resources manager Lanegra said that from December, regional authorities will issue legislation to allow sanctions to be enforced against those responsible for environmental damages. The central government is to hand these powers over to the regions next month.
As a first step, Lanegra told IPS he would try to fill the legal vacuum in relation to water quality standards, because Peru has only one law to regulate water use, which dates back to the 1960s.
The same action would be taken to regulate soil quality, he said, an area in which Peru lacks national legislation.
In the absence of Peruvian standards, the Revive El Mantaro experts used WHO reference norms to determine water quality, and Canadian standards for soil quality.
In the historic quarter of the city of La Oroya, arsenic levels measured in topsoil are 393 times the Canadian standard of 12 micrograms per kilogram of soil, and cadmium levels are 138 times the Canadian maximum permitted levels.
In Orcotuna, an area of artichoke cultivation which is irrigated by water from the Mantaro river, significant amounts of cadmium, arsenic, zinc and copper have been detected in the soil.
Apart from these alarming findings, the authors of the study conclude that Peruvian legislation does not protect human health and environmental quality effectively, in comparison with the laws in other countries.
Mining companies should comply with international environmental standards, rather than our national ones which are beneath the dignity of the Peruvian people, Monsignor Barreto said.
