| Rapid industrialization,urbanization,and agricultural advancements have led to the contamination of the fluvial ecosystem with various contaminants including heavy metals,which could pose several health problems in human beings.Long-term exposure to heavy metals,even at low concentrations,via different routes such as dermal and oral exposure could be detrimental to human health.In this regard,Atomic Absorption Spectrometer(ZEEnit 700p)was used to analyze the levels of toxic metals(lead and cadmium)and trace metals(zinc,Aluminum,Cobalt,Manganese,chromium,and copper)in the muscle(most edible part)of six most consumed fish species,(Hypophthalmichthys molitrix,Ctenopharyngodon idellus,Blicca bjoerkna,Mylopharyngodon piceus,Carassius carassius,and Pelteobagrus fulvidraco),and water samples(40)from the Yantze River.Health indices were used to estimate the noncarcinogenic and carcinogenic health risks associated with human utilization of resources(fish and water)from the Yantze River.Also,Water Quality Index model based on physicochemical characteristics was adopted in the study to appraise the water quality for human consumption according to the WHO and Chinese surface water quality criteria.Single-Factor Pollution index(Pi)and Nemerow’Multi-factor Pollution Index(NPI)were employed to estimate the level of pollution in the Yangtze river in Zhenjiang city.The mean physicochemical parameters of water from the Zhenjiang section of the Yangtze river were all within the WHO set limits except for those recorded for pH and alkalinity.Furthermore,the highest metal levels(wet weight)recorded among the examined fish species were as follows;Zn recorded the highest average concentration of 9.87 μg/g for Carassius carassius,Mn recorded 7.97 μg/g for Pelteobagrus fulvidraco,Cu recorded 2.07 μg/g for Mylopharyngodon piceus,Pb recorded 1.04 μg/g for Hypophthalmichthys molitrix,Cr recorded 0.63 μg/g for Hypophthalmichthys molitrix,Cd recorded 0.19 μg/g for Blicca bjoerkna,and Ni recorded 0.16 μg/g for Pelteobagrus fulvidraco.Health indices for noncarcinogenic and carcinogenic risks estimated for a child and adult exposure to analyzed metals indicated that humans could be at risk upon dermal and oral exposure to metals in water from the Yantze River.Pb and Cd recorded hazard quotient values of 1.27 and 1.54 for child whereas 1.09 and 1.32 for adults respectively which exceeds 1.The mean Target Hazard Quotient THQ value of each metal from the consumption of fish was generally less than 1,except for that recorded for Co,which suggests that individuals may not suffer noncarcinogenic health risks from their intakes of fish,which had THQ value exceeding the recommended value.Moreover,comparing the target cancer risk values with guideline values(1×10-4 to 1×106),it could be inferred that human consumption of fish from the Yangtze river may not pose carcinogenic threats to humans.Cancer risks of 2.30×10-2 and 3.57×10-6 were estimated for a child and an adult oral exposure respectively to dissolved Pb,suggesting a significant cancer effect observed in a child via oral exposure to dissolved Pb.The principal component analysis revealed that heavy metal pollution in the Zhenjiang section of the Yangtze river originated from anthropogenic activities and could subsequently affect the quality of the aquatic environment,hence proper monitoring and regulation are needed. |
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