Biomonitoring fallout 137Cs in resident and migratory fishes collected along the southern coast of India and assessment of dose.

The globally distributed fallout radionuclide (137)Cs was monitored in 25 resident and 22 migratory fish species collected from some regions of west and east coast of southern India to establish a baseline data. The samples were collected during June 2008 to June 2009. Higher level of (137)Cs was noted in planktivorous fishes and lower level in herbivores. A significant variation in (137)Cs was observed between fishes with different feeding habits and different migratory pattern. Oceanodromic migratory fishes displayed higher cesium levels than other migratory types. Similarly, migratory fishes displayed higher (137)Cs concentration compared to resident fishes. The overall range of (137)Cs varied from 0.06 to 0.3 Bq/kg in fishes. The biological concentration varied from 55 to 250. The average external dose rate to fishes was calculated to be 2.7 × 10(-7) μGy/h, while the internal dose rate varied from 8.50 × 10(-6) to 5.27 × 10(-5) μGy/h. The hazard quotient for fishes was found to be less than 1. The average intake of (137)Cs via fishes to the public was calculated to be 3.5 Bq/year and subsequently the committed effective dose was 0.05 μSv/year. The data obtained were less than global average and comparable to those of many regions.