Tingkat Cemaran Unsur Radionuklida Alam 238U dan 232Th di Perairan Sekitar Kawasan PLTU-Batubara (Kajian di Perairan Pulau Panjang dan Pesisir Teluk Lada, Banten)

Abstract

Pengoperasian PLTU-batubara pada kondisi normal berpotensi melepaskan sejumlah radionuklida alam seperti 238U dan 232Th ke lingkungan perairan pesisir di sekitarnya melalui fly ash (abu terbang), bottom ash dan aktivitas pemasokan bahan bakar batubara ke PLTU dengan menggunakan kapal-kapal tongkang. Radionuklida alam dapat larut dalam kolom air dan terdeposit ke dalam sedimen, sehingga dengan adanya interaksi antara komponen biotik dengan abiotik dapat terjadi akumulasi dalam tubuh biota dan tumbuhan. Melalui jalur rantai makanan radionuklida alam tersebut akan sampai ke manusia sehingga dapat menimbulkan paparan radiasi interna dan pada tingkat konsentrasi tertentu menimbulkan kerusakan biologis misalnya kerusakan materi inti sel, khusunya pada DNA dan kromosom sehingga berpotensi menyebabkan kanker.

This study had been carried out by collecting sample of the surficial sediments, sea water, seaweeds, fishs (Stolephorus) and mussels (Codakia) from 4 locations in waters of Pulau Panjang and coastal of Lada Bay (as control/comparison site), Banten in June-July 2010. Natural radionuclide (238U and 232Th) concentrations in samples were measured using neutron activation analysis (NAA) method. The results showed that total radionuclide concentrations in sediment (238U: 18,6160– 35,0013 Bq/kg; 232Th: 11,2020-35,6685 Bq/kg), seawater (238U: undetected; 232Th: 0,0790-0,1299 Bq/l), cultivation seaweeds (238U: undetected; 232Th: 3,6735- 4,8345 Bq/kg), natural seaweeds (238U: 3,6851-48,0430 Bq/kg; 232Th: 3,9941- 9,0788 Bq/kg), Stolephorus (238U: undetected; 232Th: 3,3078 Bq/kg) and Codakia (238U: 6,8903 Bq/kg; 232Th: 3,6023 Bq/kg) in Pulau Panjang, Banten around Suralaya coal fired power plant (PLTU) higher than control site that were around the Labuan coal fired power plant, namely in sediments (238U: 10,4253 Bq/kg; 232Th: 16,5952 Bq/kg), seawater (238U: undetected; 232Th: 0,0671 Bq/l), cultivation seaweeds (238U: undetected; 232Th: 2,3005 Bq/kg), natural seaweeds (238U:19,5367 Bq/kg; 232Th: 2,6729 Bq/kg) and Stolephorus (238U: undetected; 232Th: 2,0603 Bq/kg). This means the coal fired power plant has an impact on natural radionuclides pollution in the waters. The internal radiation exposured (via consumed of Codakia and Stolephorus) that received by inhabitant who live in Kampung Peres, Pulau Panjang, Banten are between range 0,00047-0,01984 mSv/year. This value was considered less than limitation of effective doses that recomended by IAEA for public (1 mSv/year).