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Tuesday, March 11, 2014
- Scientific uncertainty about the health impacts of electromagnetic fields is fueling worries among people in the Argentine capital who are demanding that energy power transformers be located far from their neighborhoods.
The World Health Organisation (WHO) does not rule out the possibility that exposure to extremely low frequency electromagnetic fields could pose a risk to human health, even possibly being linked to childhood leukemia. But it says there is not enough evidence to warrant strict recommendations.
Since 2004, local residents living near the Rigolleau substation in the district of Berazategui, on the southeast side of Buenos Aires, have been demanding that the plant be moved, for fear of possible health effects.
And according to charges brought in court, another substation, operating since 1978 in the neighboring city of Ezpeleta, has driven up the rate of cancer among the people living near the transformer.
In 2000, a chemical company asked for an expansion of electricity supplies for its factory, and Edesur, the company that runs the substation, doubled its output.
But the local residents protested that the move also increased electromagnetic pollution.
The courts upheld the precautionary principle – which states that even if a cause-effect relationship has not been fully established scientifically, precautionary measures should be taken if the product or activity may pose a threat to health or the environment – and ordered that the transformer stop operating until the possible link to the increase in cancer cases was clarified.
But the substation is still generating electricity.
Based on the court precedent, residents of Berazategui are demanding that Rigolleau be relocated before it begins operating.
But their efforts have so far been unsuccessful, and there are suspicions that the transformer is already running.
“They tell us we have to prove that Rigolleau pollutes. But it is the other way around: it is the state and the company that have to give us scientific certainty that there will be no long-term health impacts,” Vanesa Salgado told Tierramérica*.
Salgado is a member of the Forum for the Rights of Children, Adolescents and Young People of Berazategui. Her two children attend a school located 150 metres from the plant, whose underground cable runs underneath that building as well as another school.
In 2004, when Edesur decided to install the plant there, the neighborhood began to mobilise. Local residents had been warned by people from Ezpeleta about the imperceptible danger posed by exposure to electromagnetic radiation, which varies in intensity depending on demand for energy throughout the day.
Edesur did not respond to their requests for information. According to Salgado, “they say they are within the legal limits” for emissions.
The national electricity regulatory agency, ENRE, backs the position taken by the company. And if it is taking the regular measurements that it is required to take, it has not informed the community of the results.
Edesur and ENRE cite Energy Secretariat Resolution 77/98, signed in 1998, which established an upper limit of 25 microteslas (µT) – the unit used to measure magnetic fields – for this kind of radiation.
“But that resolution is a technical norm, and doesn’t take into account health impacts on the population living around the substation,” Salgado said.
The Forum for the Rights of Children and the Asamblea de Vecinos Autoconvocados por la Vida de Berazategui – an assembly of local residents – have turned to the courts.
Meanwhile, they are calling for approval of a health bill that would set preventive standards with respect to electromagnetic fields, which is being studied by several legislators.
In 2011, a protest by local residents was the target of a police crackdown that left 12 people injured. In February 2012, when a fence was put up around the plant and a heavy police guard set, further incidents and clashes occurred.
According to Salgado, the station is already running. But no one knows for sure – and no one has answered the letters sent to Edesur and ENRE.
In 1996, the WHO launched the International Electromagnetic Fields Project to investigate possible health risks.
In 2005, it established a Task Group that two years later produced a report on extremely low frequency (ELF) electromagnetic fields, which reviewed the scientific evidence of different health effects.
The study did not find substantive health issues related to general public exposure to ELF electric fields.
But it did find short- and long-term effects from exposure to ELF magnetic fields.
In the short-term, it states, “There are established biological effects from acute exposure at high levels (well above 100 µT) that are explained by recognised biophysical mechanisms. External ELF magnetic fields induce electric fields and currents in the body which, at very high field strengths, cause nerve and muscle stimulation and changes in nerve cell excitability in the central nervous system.”
With respect to the long term, the study ratified the WHO classification in 2002 of ELF magnetic fields as “possibly carcinogenic to humans”.
The WHO goes on to say, “This classification is used to denote an agent for which there is limited evidence of carcinogenicity in humans and less than sufficient evidence for carcinogenicity in experimental animals.”
“This classification was based on pooled analyses of epidemiological studies demonstrating a consistent pattern of a two-fold increase in childhood leukemia associated with average exposure to residential power-frequency magnetic field above 0.3 to 0.4 µT,” it adds.
But the epidemiological evidence is weakened by methodological problems, and there are no accepted biophysical mechanisms that would suggest that low-level exposure is involved in cancer development, it says, adding that animal studies have been largely negative.
With regard to other adverse health effects studied for possible association with ELF magnetic field exposure, such as other kinds of cancer in children or adults, depression, suicide, cardiovascular disorders, reproductive dysfunction, developmental disorders or immunological modifications, the WHO Task Group concluded that scientific evidence of a link between exposure to ELF magnetic fields “is much weaker than for childhood leukemia.”
In an interview with Tierramérica, engineer Jorge Sinderman, director of electronic engineering studies at the National University of San Martín, said “the data on possible harmful effects to human health are inconclusive.”
“For electromagnetic radiation, which includes frequencies of electrical distribution, it cannot be categorically stated that it is either harmless or dangerous. The normal practice is to employ the precautionary principle, and establish upper limits on exposure,” he added.
Dr. Guillermo Sentón at the same university’s School of Science and Technology explained to Tierramérica that the data on cancer among individuals living near power lines “is consistent in indicating a slightly higher risk of childhood leukemia.”
Nevertheless, he said, “more recent studies question the weak association previously observed.” And he added that “without a foundation of laboratory studies, the epidemiological data is too scarce to establish recommendations.” The uncertainty continues.
* This story was originally published by Latin American newspapers that are part of the Tierramérica network. Tierramérica is a specialised news service produced by IPS with the backing of the United Nations Development Programme, United Nations Environment Programme and the World Bank.