According to Taiwan’s “Inclusion Criteria for Construction Works Required for Environmental Impact Assessment (ICCWREIA)”, it is necessary for a transmission line with a voltage of 345 kilo voltages (kv) and a length of 100 kilo meters (km) to go through an EIA procedure before construction can be initiated. As the length of nearly all newly constructed transmission lines has been far less than 100 km in recent years; and there has been growing public concern over the potential health risks from exposure to power frequency electromagnetic fields, the above inclusion criteria for the construction of transmission line to be assessed need to be revised. The purpose of this study was to make suggestions, particularly from health risk perspectives, regarding the elements that need to be considered when the revision is eventually made necessary.
This study explored the information on the background of Taiwan’s ICCWREIA, which was thereafter compared to the relevant information (including act, regulation, case study, etc.) of numerous nations/organizations/areas such as European Union, Hong Kong, Canada, Japan, World Health Organization, and United States.
In order to estimate the additional health risks associated with exposure to high-voltage (69/161/345 kv) generated power frequency magnetic field in Taiwan, we took on-site measurements of magnetic field, using EMDEX II dosimeters, at seven locations in Taipei and Taoyuan areas. Measurements were made within 100 meters of high-voltage transmission lines at a one-meter high location. The magnetic field strength ranged from 0.8-114 mili-Gauss (mG) for 345 kv power lines. The range was 0.6-57 mG and 0.3-46 mG for 161 kv and 69 kv power lines, respectively. Based on the assumption that the population is homogeneously distributed in each township, we estimated, using the Geographic Information System (GIS) (Arc View 8.2), that 469,801 out of 4,975,970 (or 9.4%) children (aged under 15) were residing within 100 meters away from 161 or 345 kV power lines in 2000. With the information on on-site measurement data, percentage of exposed (within 100 m of high-voltage power lines) child population, and magnetic filed strength specific relative risk estimates (ranging from 0.84 to 3.44) derived from previous epidemiological data, and the assumption of causal link between power frequency magnetic field and childhood leukemia, we estimated that 8.9 cases and 7.1 cases childhood (<15 years) leukemia can be attributable to exposure to elevated magnetic field emitted from 345 kv and 161 kv power lines.
We made, based on the above information and the conclusions from two sessions of expert meeting, the following suggestions regarding the possible revision of ICCWREIA.
“A construction of 345/161 kv power lines should go through an environmental impact assessment procedure if the construction work is less than 100 meters away from residences, school, or hospitals, or the planned power lines may pass over the sky of national parks or reserved/protected areas for wild animals”
With respect to the potential health risks of 69 kv power lines and underground cables, we need to collect more data before any recommendations or conclusions that can be made.
