Risk Assessment of Some Heavy Metals in Nile Tilapia (Oreochromis niloticus) Cultured in the Biofloc System

The purpose of this research is to evaluate the risk of metals (lead, chromium, mercury, arsenic and nickel) on the health of children and adults through the consumption of Nile Tilapia cultured in the Biofloc breeding system. The number of 30 pieces of Tilapia grown in the Biofloc system was caught and analyzed by an atomic absorption device equipped with a graphite furnace system. The average concentration of metals, the daily intake (DI) of metals through the frequency of consumption of Tilapia for different groups (adults and children with an average age of 10 years), the risk index(HQ), the number of allowed servings of Tilapia per month(CRmm) was calculated for people in different groups. The highest and lowest daily absorption rates in the adult group are related to arsenic (2.08×10-3 µg/kg/d) and mercury (2.49×10-6 µg/kg/d) in the children group, respectively in the case of lead (4.93×10-5 µg/kg/d) and mercury (3.28×10-9 µg/kg/d). The hazard index (HQ) for both study groups was lower than one in all elements. The HI rate was 0.83 for adults and 0.02 for children, which was lower than one. For adults, the HI index was close to 1, which according to the HQ values of each element, the greatest increase in the HI value can be due to the higher HQ value for arsenic.