HUMAN HEALTH RISK ASSESSMENT OF HEAVY METALS IN WATER, FISH FEED AND THREE CULTURED CATFISH OF RAJSHAHI CITY, BANGLADESH

Heavy metals are very common contaminants to the environment through natural and anthropogenic sources and contamination depends on the type of contaminant, species, sampling location, trophic level, and rearing practices. The assessment of heavy metals (Co, Zn, Mn, Cu, Cd, Cr, Pb and Ni) in water, fish feed and three carnivorous catfish species (Heteropneustes fossilis, Mystus tengara, and Ompok pabda) from Rajshahi City, Bangladesh were analyzed using a flame atomic absorption spectrophotometer (AAS). The results were expressed as μg.g−1 wet weight. Results indicated that the metals in water and fish feed were found to be below the safe limit of the drinking water standard and fish feed. The concentration of heavy metals was detected as highest in fish organs (skin, gills and muscle) followed by pond water and lowest in fish feed. In the accumulation of heavy metals in different organs in three catfishes from four sampling ponds, no significant difference was found between the species and organs (p > 0.05). The value of the bioaccumulation factor (BAF) from both water and fish feed was lower than 100, indicating potential heavy metal accumulation. The estimated daily intake (EDI) in three catfish species was below the tolerable daily intake (TDI). The mean target hazard quotient (THQ) and hazard index (HI) based on studied metals in three fish species were below 1 indicating that consumption of these fish can be safe for human health.