Tilapia from most of the sources in Bangladesh are safe for human consumption: A Hazard Index (HI) based study on heavy metals

The present study was conducted to determine the variations of heavy metal (Cu, Pb, Ni, Cr, Cd, and Zn) bioaccumulation in edible muscles among the wild, pond-, gher- and cage-cultured tilapia, followed by risk assessment in humans caused by consumption of the contaminated fish. A total of 120 fishes from four different aquatic environments were collected, and the heavy metal levels were analyzed using an atomic absorption spectrophotometer (AAS). The result found the highest Zn concentration in all tilapia samples; however, the Ni was below the detection limit. The average concentrations of metals were found as Zn > Pb > Cr > Cu in wild tilapia, Zn > Pb > Cr > Cu > Cd in pond-cultured tilapia, Zn > Pb > Cr > Cd in gher-cultured tilapia, and Zn > Cd > Cr > Pb > Cu in cage-cultured tilapia. The estimated daily intake (EDI) value was lower than the maximum tolerable daily intake value, and target hazard quotient (THQ) and hazard index (HI) for adults, adolescent, and children was < 1 for wild and cultured tilapia, indicating that tilapia is safe for human consumption. However, high HI of Pb and Cd might be alarming and need further investigation in the near future