Wednesday, July 23, 2008

Children's Sensitivity to EMF pollution


Quote From Microwave NewsJuly 22 2008

The brains of young children absorb twice as much as RF energy from a cell phone as those of adults, according to a set of new calculations carried out by Joe Wiart's research group at France Telecom in the suburbs of Paris.

"[Our] analysis confirms that peripheral brain tissues of children seem to be higher exposed than the peripheral brain tissue of adults," Wiart concludes in a paper that appears in the July 7 issue of Physics in Medicine and Biology. "Children are not simply small adults." Wiart explained in an interview with Microwave News. "Their skin and their skulls are thinner than those of adults, and their ears are smaller too," he said. "Given these differences, the higher SAR for children is not surprising,"

These new findings apply to children who are eight years old or younger. Above the age of eight, the SARs in children are much like those of adults, according to Wiart.

"I agree with Joe," said Niels Kuster, the director of the IT'IS Foundation in Zurich. A team led by Kuster and Andreas Christ recently completed a project for the German Federal Office of Radiation Protection (BfS), which like Wiart, found that regions of the brains of young children can have exposures that are twice those of adults —or even higher.

Even more striking, Kuster and Christ concluded that the "exposure of the bone marrow of children can exceed that of adults by about a factor of ten." They also report that children's eyes are more highly exposed that those of adults.

Whether or not children are at a greater health risk than adults has been debated since at least the year 2000, when a U.K. panel chaired by Sir William Stewart advised that parents limit their children's use of mobile phones. Since then, other government groups, especially those in France and Germany, have issued similar precautionary recommendations.

The mobile phone industry has long disputed the possibility that children are at any greater risk. For instance, earlier this year after the French Ministry of Health reiterated concerns over children's use of cell phones, the MMF, an industry lobby group, issued an advisory stating that cell phones do not present health risks to any users "regardless of age."

The MMF has relied heavily on statements issued by the WHO's EMF Project in Geneva, and the Health Council of the Netherlands. For instance, in a paper published in 2004, the Health Council concluded that: "There is no convincing scientific data to assume a difference in the absorption of electromagnetic energy in heads of children and adults."

July 3… Exposures to ambient magnetic fields may affect the quality of human sperm and may well explain its well-documented decline over the last few decades. De-Kun Li, an epidemiologist at Kaiser Permanente in Oakland, CA, has found that daily exposures of only 1.6mG or higher for at least two-and-a-half hours were associated with significantly poorer semen quality. Men who were exposed to over 1.6mG for over six hours a day were four times more likely to have substandard sperm.

"The longer you are exposed, the higher the risk," Li told Microwave News. He presented these new findings last week at the annual meeting of the Society for Epidemiologic Research, held in Chicago. He has submitted them for publication.

"If it holds up, this would be very important because magnetic field exposures are ubiquitous," Li said. "We know that sperm quality has been going down for a long time with the largest declines in urban areas. That would be consistent with EMF exposures which are highest in cities."

The quality of the semen was assessed according to WHO criteria for motility and morphology —that is, the ability of sperm to "swim" (to the egg) and their shape. "Sperm quality could turn out to be a sensitive endpoint to study the biological effects of EMFs," Li said.

Li is one of the few to explore new ways of defining what is a biologically significant dose of EMFs. An important implication of his new study is that while he might classify a man as being in a "high" exposure group, that same man could still have a time-weighted, 24-hour average exposure of less than 1mG, which would put him in the "unexposed" group in most past studies. Such a misclassification would reduce the chances of seeing this effect.

In a study published in 2002, Li showed that women exposed above a certain threshold (16mG) had higher rates of miscarriages (see MWN, J/F02, p.1). At the time, many considered that this new concept of EMF dose was worth pursuing. But, in fact, no one did —at least no one has yet published a follow-up study. "In that earlier study we saw higher miscarriage risks among women who had an exposure of more than 16mG at least once a day," Li said, "in our new study, men had poorer sperm quality if they were exposed to a much lower field but it had to be for at least 10% of the day."

The power-frequency fields implicated in this new study are extremely weak. They are approximately 1,000 times lower than the current ICNIRP guidelines and some three times lower than what many see as the threshold for increasing the risk of childhood leukemia (3-4mG). According to a large-scale survey carried out a decade ago, close to 15% of the U.S. population is exposed to an average of more than 2mG over a 24-hour period (see MWN, M/J98, p.4).