Aims: This study aimed to determine levels of trace metals in Qua Iboe river estuary (QIRE), Ibeno and estimate human health risk associated with water from the river via ingestion and dermal exposure.
Method: Trace metals in water from QIRE was measured using atomic absorption spectrophotometer and human health risk induced by the trace metals in dry and wet seasons was investigated using mathematical models recommended by United States Environmental Potential Agency (USEPA).
Results: The range for the different metals investigated in dry season were as follows: Pb (0.147 to 0.19mg/l), Cd (0.02 to 0.31mg/l), V(0.04 to 0.11mg/l), Cr (0.09 to 0.18mg/l), Ni (0.28 to 0.61mg/l), Fe (8.78 to 13.97mg/l), Zn (0.13 to 0.56mg/l). The results for wet season were: Pb (0.07 to 0.19mg/l), Cd (0.05 to 0.31mg/l), V (0.01 to 0.03mg/l), Cr (0.02 to 0.15mg/l), Ni (0.03 to 2.33mg/l), Fe (0.02 to 4.92mg/l), Zn (0.11 to 0.43mg/l). Concentrations of metals were above USEPA limits except Zn. The target hazard quotient (THQ) and hazard index (HI) values via ingestion of water were greater than one while the THQ values via dermal contact were greater than one for Cd only. The combined target hazard index (HI*) from ingestion and dermal contact of water was greater than unity for Cd, Cr and Pb for wet and dry seasons.
Conclusion: Findings in this study show that Pb, Cd and Cr may contribute to health risk from dermal and oral exposure to water from the QIRE systems. Constant monitoring and remediation processes of the QIRE are strongly recommended.
Key words: Risk assessment, trace metals, hazard index, Qua Iboe river estuary, Nigeria
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