BIOACCUMULATION OF HEAVY METAL IN FARMED TILAPIA AND SHRIMP IN SATKHIRA DISTRICT, SOUTHWEST BANGLADESH

Abstract

Fish farmers in the Satkhira district, southwest Bangladesh, are progressively moving towards intensive aquaculture, and heavy metal contamination of the feed may frequently occur. This study explores the bioaccumulation of heavy metal in farmed tilapia (Oreochromis mossambicus) and shrimp species such as bagda (Penaeus monodon), golda (Macrobrachium rosenbergii), randomly collected from 3 gheer at Assasuni and Debhata Upazilla in Satkhira, Bangladesh from December 2020 to March 2021. The levels of elements including Fe, Mn, Zn, Cu, Cr, Cd, Pb, and As were evaluated using the flame-AAS and HG-AAS methods followed by Nitric Acid (HNO3)-Perchloric Acid (HClO4) digestion. The results revealed that the concentrations of Fe, Mn, Cr, and As were higher than the WHO and FAO recommended levels. Maximum concentrations (mg/kg) of Fe, Mn, Cr, and As were observed as 104.00 ± 8.30 in Tilapia (O. mossambicus) from gheer #3, 3.40  ± 1.71 in Tilapia (O. mossambicus) of gheer #3, 12.80 ± 1.45 in golda (M. rosenbergii) of gheer #1, and 1.96 ± 0.09 in Tilapia (O. mossambicus) from gheer #3, respectively. But on average, M. rosenbergii was discovered to contribute more to the maximum level of almost every metal compared to the other two species, whereas species from gheer #3 were found to be more contaminated. Overall, tilapia and shrimp from all three gheer were considered unsafe for consumption. More research is recommended for estimating the levels of heavy metal accumulation in fish and shrimp over a longer time period and across a wider geographic range.