Seasonal variation in terrestrial gamma radiation in the hilly region of Manipur, India

Abstract

The aim of this study is to assess effective dose rates due to terrestrial gamma radiation of certain specific area and analyses its variation with seasons using statistical tools. The study area consists of two southern hilly districts of Manipur namely Churchandpur and Chandel district. The present study suggested that effective dose rates of certain specific area follow normal distribution. Seasonal variation of effective dose rate is observed in the two districts especially among summer (May and June), rainy (July – September) and winter (December –January). The maximum and minimum gamma dose rate for Churchandpur district is observed in summer season (0.879 ± 0.074 mSvy−1) and in rainy season (0.792 ± 0.056 mSvy−1). Whereas for Chandel maximum and minimum dose rate is observed in summer season (0.972 ± 0.122 mSvy−1) and in winter season (0.884 ± 0.112 mSvy−1) respectively. Inter-district study of effective dose rates for same season observed that terrestrial gamma radiation dose relationship between the two districts is extremely poor.