발연질산법에 의한 부산, 경남 지역 환경시료의 90Sr분석

Abstract

Radiometric analysis of 90Sr for environmental samples in Busan and Gyeongnam by the fuming nitric-acid method

Jaejeong Sim

Department of Interdisciplinary Program of Biomedical Engineering, The Graduate School, Pukyong National University

Abstract

Strontium-90 (90Sr) activities are determined in environmental materials such as soils, agricultural products, pine needles, sea water, bottom sediments, fishes, shellfishes and seaweeds collected in some area of Busan and Gyeongnam. The fuming nitric acid method was used to separate 90Sr from the samples. The accumulation trends of 90Sr are compared with those observed in the past 10 years. The concentration of 90Sr are estimated to be in the range of 0.133~0.854 Bq/kg-dry, 0.0147~0.0710 Bq/kg-fresh, 1.12~4.07 Bq/kg-fresh and 0.907~1.74 mBq/L in soil, cabbages, pine needles and sea water, respectively, collected in 2013 and 2014. The samples of rices, radishes and marine organisms show activity concentration of 90Sr with the values less than minumum detectable activity (MDA) similarly to those observed in average year. It has been known that the activity concentration of 90Sr was detected over MDA in the bottom sediments collected before 2012. However, in 2013 and 2014, no detectable activity was determined in the bottom sidments over MDA. This is likely to the disturbance of the seabed due to the typhoons developed in this period. In case of 90Sr of sea water, its gradual decrease is observed in radioactivity from years to years in last 10 years. This is well consistent with the tendency of decreasing radioactivity reported for the water in Pacific Ocean. In overall, no significant radioactivity levels of 90Sr in 2013 and 2014 was detected in the envirionmental samples in some area of Busan and Gyeongnam.