Ecological and Human Health Risk Assessment of Water, Sediment, Soil and Irrigated Vegetables’ Heavy Metals to Pankshin Community in Plateau State, Nigeria

Heavy metal contamination from parent material and/or anthropogenic activities is a major environmental health challenge and is potentially dangerous because of bioaccumulation through the food chain. The main objectives of this study are to estimate heavy metals pollution levels in water, sediment, soils and vegetables and also to estimate the dietary intakes and health risks of heavy metals to the consumers of the vegetables in Pankshin communities. Heavy metals in vegetable samples were analyzed by Inductively coupled plasma (ICP), water and the available fractions by Microwave Plasma Atomic        Emission Spectroscopy (MP-AES) while sediment and soil by Energy Dispersive X – Ray Florescence (ED-XRF). The soil and sediment were slightly acidic, none saline, low organic and carbon organic matter. Most of the concentrations of the metals in water were higher than the World Health Organization (WHO) and the Nigerian Agency for Food, Drug Administration and Control (NAFDAC) permissive levels. The heavy metals concentrations in sediment are mostly above threshold effect level (TEL) allowable limits. The study recoded high concentrations of metals (except As and Cd) increasing from surface soil to 21 – 30cm depth. The contamination factor (CF), degree of contamination (CD), pollution load indices (PLI) of all the soils and sediment indicated a state of deterioration with respect to the Department of Petroleum Resources (DPR) 2002 background. Ecological risks Factors, Enrichment factors and Geo Accumulation indices indicated moderate risks to biodiversity from soil contamination with metals. The ingestion pathway recoded the highest non-carcinogenic toxicity for soil and sediment in children while dermal and inhalation for the adults. The cancer risk was ranked in the order of As > Cr > Pb> Cd>Ni. The concentrations of most metals in the vegetables samples were within the FAO/WHO limits in edible parts. The HI ranges for adults and children through vegetable consumption were below one indicating no potential health risk consuming the vegetables. As and Cr were major contributors of contracting cancer from the vegetables. The obtained data can be a basis for implementing scientific and environmental pollution control measures in the irrigational areas.