Determination of 210Po levels and annual committed effective dose in crustaceans from an oil-contaminated Mangrove Ecosystem in Niger Delta, Nigeria

Abstract

This study examined the levels of 210Po and the annual effective dose in edible crustaceans from the Santa Barbara River, Nembe. The crustaceans analyzed included Crab (Cardisoma crassum), Prawn (Macrobrachium rosenbergii), Shrimp (Penaeus notalis), and Crayfish (Decapoda reptania). The concentration of 210Po in the crustaceans was measured using an alpha spectrometric procedure, with 209Po tracer used as a yield monitor after acidified HNO3 digestion. The results indicated trace amounts of 210Po in the different crustaceans, with a concentration of 24.17 Bq kg−1 fresh weight in Crab, 0.01 Bq kg−1 fresh weight in Prawn, 50.89 Bq kg−1 fresh weight in Shrimp, and 40.71 Bq kg−1 fresh weight in Crayfish. The doses of 210Po concentration from the crustaceans were calculated using ingestion dose coefficients of 1.2 μSv Bq−1 for adults, as provided by the regulatory framework that protects humans from exposure to ionizing radiation. The calculated annual effective doses suggested low levels of exposure to crustacean consumers, with values below the recommended limit of 1000 μSv y−1 set by the ICRP for effective dose. The crustaceans with the highest annual committed effective doses of 210Po were Penaeus notalis and Decapoda reptania. However, even small amounts of 210Po in crustaceans can lead to contamination that may be harmful to human health.