Climatic variations of beryllium-7 activity in the atmosphere of Peshawar basin, Pakistan, during 2001-2006

摘要

In the present study, the climatic variations of 7Be in the Peshawar basin (longitude 71°15' and 72°45' E and latitude 33°45' and 34°30' N) of Pakistan was observed during the period of 2001-2006. Under the domain of environmental surveillance programme, air particulate samples were collected from Peshawar basin on fiberglass filters and analyzed for gamma emitting radionuclides using the gamma spectrometry system. The results of the last six years (2001-2006) range between 3.6 to 5 mBq/m3, while the composite average concentration of this radionuclide for the whole period is 4.5 mBq/m3. The measured values were significantly lower than the world average value of 12.5 mBq/m3. The climatic variations in the concentrations of 7Be were also checked by classifying the whole year into four seasons (winter, spring, summer, and fall) and a positive correlation between 7Be activity and change in temperature was obtained.