Measurement and Determination of Emission Levels of Ionizing Radiation from High Tension Lines around Kaduna Metropolis, North West, Nigeria

Gamma radiation dose rate was measured at the base of 11 KV, 33 KV, 132 KV and 330 KV high tension lines (power lines) from different locations in Kaduna including Mando transmission sub-station using Radex 1503+ model. A total of about 187 measurements were taken and calculated. Radiation dose rate was also measured from a control site, an area that has no power line for comparison. Results show that the highest radiation dose rate from power lines within the city and the control site were about 1.46 mSv and 1.52 mSv respectively, which are greater than the ICRP guideline of 1mSv for public exposure by about 46% and 52% respectively. The results also show inconsistent relationship between the radiation dose rate and distance from the base of the power line. Results from the power sub-station was a little above that from the control site, about 0.84 mSv which comparing to ICRP guideline of 20 mSv for occupational exposure, the measured data is about 4.2% of ICRP guideline. Though the power lines show no significant evidence of emitting ionizing radiation, the high radiation dose rate (above the guidance level for the public), including the control site may probably result from beta radiation from 40K, a known beta radiation emitter constituent of fertilizer use in farming that is very common in the area, since Radex radiation meter also measures beta radiation.