An expert in electromagnetic fields at Hydro-Québec advises against the use of certain radiant electric floors which could increase the risk of infant leukemia. <<As children are often laying and sitting on the floor, it is to be avoided, not recommended due to the doubts we have on this>>, declared Jan Erik Deadman, labour hygiene counsellor at the company. <<It would surprise me if Hydro-Québec recommended (these systems) in daycares.>>
This labour health doctor was reacting to the fact that certain of these heating systems, composed of an electric wire typically installed under a ceramic floor, emit a magnetic field measuring up to 100 milli gauss (mG0) at ground level. According to nine epidemiological studies, a chronic exposure to an average field of more than 4 mG doubles the risk of child leukemia. In 2002, this is what incited the International Center for Cancer Research, along with the World Health Organization, to class magnetic fields of 50-60 Hertz in Group 2B as ‘potentially cancer-causing’. The Canadian Mortgage and Housing Corporation in its Mechanical Equipment Guide for a Clean Interior Environment, that radiant electric floors <<can emit significant electrical and magnetic fields.>>
Four Cancers Targeted
The most solid proofs of noxious effects of electromagnetic fields come from epidemiological studies, explains Health Canada: <<The studies have led to suppositions of the existence of a weak positive association between being exposed to fields of 50-60Hz and leukemia, brain cancer, breast cancer and lung cancer.>> But we cannot exclude that other statistical, environmental or socio-economic factors may be responsible.
Also a researcher at the McGill Faculty of Medicine, Jan Erik Deadman is co-author of a historical study published last July. It concluded that female workers, whose average weekly exposure was at least 4mG during or within two years preceding their pregnancy, doubled their risk of having a child who will develop this type of blood cancer. Other studies concluded that chronic exposure to a field of 2mG doubled the risk in children.
Should owners of electrically heated floors disable their system or turn it off before entering a room? <<The risk is considered too weak and too uncertain to change heated floors in houses and daycares, analyzes Denis Gauvin, biologist at the Institut nationale de santé publique du Québec (INSPQ) Must the population be informed? Yes. If people have the possibility of choosing a floor which exposes them less, all the better.>> Electromagnetic fields are composed of electrical fields produced by voltage (live wires) and magnetic fields from amperage (power consumed) They are measured with a multi meter which frequently acts as a voltmeter, gauss meter and radio frequency and microwave reader. The intensity of the field and the degree of human exposure diminish rapidly when moving away from the source, easy if the radiant system is in a ceiling but impossible in the case of a floor.
At one foot from a floor emitting 100mG at ground level, the field can measure 16mG, a level at which very brief daily exposures are, according to a recent California study (Li, 2002), associated with an increased risk of false labour. These fields are weaker in a house where electrical consumption is lower and if the wires are close together and laid out in parallel, their fields have a tendency to mutually cancel themselves out.
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