Radiological Risk Assessment to Marine Biota Along Manora Channel Karachi Coast Pakistan

Abstract

A B S T R A C TSources of radioactivity in the aquatic environment include naturally occurring radionuclides, fallout from the atmospheric and radioactive effluent from nuclear facilities that was released either accidentally or routinely. Depending upon the element and the chemical form, radionuclides may accumulate in bottom sediment or remain in the water column in the dissolved state. Marine organisms receive external radiation exposure from radionuclides in water and sediment. Radiological risk assessment was made for marine fish that are exposed to 137 Cs, 226 Ra, 228 Ra and 40 K along Manora channel Karachi coast of Pakistan using ERICA tool software. The ERICA tool is a software system that has a structure based upon the tiered ERICA integrated approach to assessing the radiological risk to terrestrial, freshwater and marine biota. The results were calculated using Tier 1 and Tier II assessments which are based on media concentration and use pre-calculated environmental media concentration limits to estimate risk quotients. If the sum of the risk quotients is <1, then it can be assured that there is a very low probability that the assessment dose rate to any organism exceeds the incremental screening dose rate and therefore the risk to non-human biota can be considered negligible. Risk quotient in this study is far below 1 which reveals that there is no evidence of deleterious effect of radionuclide for marine biota of the area under study.