Potential health risk consequences of heavy metal concentrations in surface water, shrimp (Macrobrachium macrobrachion) and fish (Brycinus longipinnis) from Benin River, Nigeria

Health risk consequences of consumption of heavy metal-contaminated water, shrimp (Macrobrachium macrobrachion) and fish (Brycinus longipinnis) from Benin River in Nigeria were evaluated. Three stations around Koko Community (Abialegbe, Ebenco/Optima and Total Facility) with known anthropogenic activities (industrial and petrochemical installations and loading) were studied. Samples of surface water, shrimp and fish were collected and analyzed using Buck scientific atomic absorption spectrophotometer, model 210VGP. Health risk indices were reported as Estimated Daily Intake (EDI), Target Hazard Quotient (THQ) and Total Target Hazard Quotient (TTHQ). Eight heavy metals were analyzed in water, shrimp and fish. Nickel (Ni) was observed to be the most dominant heavy metal in water, while Iron (Fe) was the most dominant in shrimp and fish. Heavy metal levels in water were below recommended limits set by World Health Organization (WHO) and Standard Organization of Nigeria (SON) except for cadmium (Cd), nickel (Ni) and lead (Pb). Assessment of non-carcinogenic health risk by target hazard quotient (THQ) indicated that THQ estimated for heavy metals in water (dermal exposure) and shrimp were below the threshold value of 1. However, THQ for heavy metals in water (oral exposure) and consumption of fish were above threshold value of 1 indicating potential health risk. Total Target Hazard Quotient (TTHQ) estimated for heavy metals in water (oral exposure) and consumption of fish were above 1 indicating potential non-carcinogenic health risk to consumers. The continuous monitoring of heavy metals in Benin River is of necessity in order to ensure the safety of aquatic organisms and humans who rely heavily on aquatic resources.