EXPOSURE OF CHILDREN TO RESIDENTIAL MAGNETIC-FIELDS IN NORWAY - IS PROXIMITY TO POWER-LINES AN ADEQUATE PREDICTOR OF EXPOSURE

The aim of this work was to study the exposure to magnetic fields of c hildren living at different distances from a power Line and to evaluat e how well theoretical calculations compared with actual exposure. Per sonal exposure instruments were carried for 24 h by 65 schoolchildren living 28-325 m from a 300 kV transmission line; the current load was 200-700 A. About half of the children attended a school far from the p ower line, whereas the other half attended a school located about 25 m from the line. Exposure to magnetic fields was analyzed for three cat egories of location: at home, at school, and at all other places. Time spent in bed was analyzed separately. The results indicated that chil dren who lived close to a power line had a higher magnetic field expos ure than other children. The power line was the most important source of exposure when the magnetic field due to the line was greater than a bout 0.2 mu T. Exposure at school influenced the 24 h time-weighted av erage results considerably in those cases where the distance between h ome and power line was very different from the distance between school and power line. The calculated magnetic field, based on line configur ation, current load, and distance between home and power line, corresp onded reasonably well with the measured field. However, the correlatio n depends on whether home only or 24 h exposure is used in the analysi s and on which school the children attended. The calculated magnetic f ield seems to be a reasonably good predictor of actual exposure and co uld be used in epidemiological studies, at least in Norway, where the electrical system normally results in less ground current than in most other countries. (C) 1997 Wiley-Liss, Inc.