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MEXICO: Some Progress Made in Eliminating Toxic PCBs

Emilio Godoy

MEXICO CITY, Apr 21 2011 (IPS) - Mexico is carrying out a project to identify, decommission and eliminate polychlorinated biphenyls (PCBs) waste in order to reduce risks of human exposure and environmental damages.

But “more studies are needed, particularly about the effects on human health” in Mexico, Guillermo Román, national coordinator of the Environmentally Sound Management and Destruction of PCBs in Mexico project, told IPS.

The 2008-2012 4.6-billion dollar project is financed by the Global Environment Facility (GEF).

PCBs, which are persistent and toxic and accumulate in the food chain, are found in products like electrical transformers, hydraulic fluids, adhesives and paint. PCBs, along with other chemical compounds like organochlorine pesticides and herbicides, are Persistent Organic Pollutants (POPs).

Imports of PCBs have been banned by Mexico since 1988.

The first phase of the project covered 416 sites and 1,291 electrical transformers in 13 of Mexico’s 31 states, and reached the conclusion that 5.65 percent of the sample was contaminated. The Mexican government and the United Nations Development Programme (UNDP), which is running the project, evaluated 225 industrial sites, with 786 pieces of equipment, 43 of which showed levels above the legal limit.


They also inspected 191 sensitive sites like schools, hospitals and municipal wells powered by transformers located in close proximity to the water source, and 505 pieces of equipment, 30 of which were contaminated.

The sectors involved were the metallurgical, iron and steel, food, chemical, mining, sugar, paper and textile industries, and the sensitive sites included municipal wells, hospitals, schools and shopping centres.

PCBs are covered by the Stockholm Convention on Persistent Organic Pollutants, a global treaty signed in 2001 and in force since 2004, aimed at eliminating or restricting the production and use of 12 POPs like PCBs, dioxins, furans and pesticides.

Mexican authorities will present the data from the first stage of the project at the Fifth Meeting of the Conference of the Parties to the Stockholm Convention, to be held Apr. 25-29 in Geneva.

“Potential for worker exposure and exposure of sensitive site populations (school children, etc.) is heightened, because of low awareness and, as a consequence, low adherence to best practices for PCB management,” says a 91-page report from the project.

Mexico sets a limit of 50 parts per million of PCBs in transformers. The Comisión Federal de Electricidad (CFE), Mexico’s national electric power utility, has 1.1 million transformers, to which must be added the number of transformers in the hands of private companies.

Prolonged exposure to PCBs can cause health problems such as cancer, respiratory ailments, liver damage, immune and nervous system disorders, impotence, pregnancy problems and skin irritations.

The industrial use of PCBs is based on their resistance to high temperatures, high chemical stability and electrical insulating properties.

“They accumulate and have a toxic effect on invertebrate aquatic species, fish, birds, aquatic and land mammals, leading to changes in the structure of aquatic ecosystems,” Leonor Cedillo, director of Research on Chemical Substances and Ecological Risks at the National Institute of Ecology (INE), told IPS.

PCBs “affect behaviour, hormone levels, growth and reproduction of consumers” in the food chain, she said.

Monitoring carried out in 2004 and 2005 by INE, which falls under the Secretariat (ministry) of the Environment, found high concentrations of PCBs in fish at three locations in the southeast state of Yucatán, without determining the origin of the PCBs.

Four research studies conducted by Mexican scientists between 1989 and 2005 found PCBs and other toxic compounds in oysters, tilapia fish and sparrows at several different locations in Mexico, with no explanation of how the animals were contaminated with the chemicals. The authorities carried out no follow-up on the findings.

“The risk is that the contaminated transformers can affect transformers that are not contaminated. One industry that causes concern is electrical repair shops, which should be supervised,” said Román.

By 2005, Mexico had destroyed 14,587 tons of PCB waste material, including contaminated transformers and oils.

But the authorities estimate that some 28,000 tons of PCB-contaminated waste and waste equipment and materials must still be identified, decommissioned and eliminated.

Since the project began, 2.7 tons of PCB-contaminated materials have been eliminated.

The second phase of the project, currently underway, is to involve PCB-analysis and inspection at 284 sites, bringing the total number of states where inspections will have been carried out from 13 to 20. The results are to be released in December.

The Fifth Meeting of the Conference of the Parties to the Stockholm Convention will mark the fate of endosulfan, a highly toxic pesticide. In 2010 the Stockholm Convention’s Scientific Review Committee recommended a global ban on endosulfan.

Some 80 countries have already banned the pesticide, or are in the process of doing so.

Mauricio Limón, under-secretary of environmental management in the Secretariat of the Environment, told IPS that Mexico will support the international ban.

But he stressed that “It’s not enough just to declare a ban. A public policy is needed for its elimination, as well as a search for technical and economic alternatives.”

 
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