Consequences of health risk assessment of wastewater irrigation in Pakistan

Accumulation of heavy metals in food crops as a result of wastewater irrigation practices, especially from industrial effluents might exert a potential threat for public health. The aim of this study was to investigate the uptake and accumulation of heavy metals including cadmium (Cd), chromium (Cr), iron (Fe), nickel (Ni), and lead (Pb) in eight food crops irrigated with industrial wastewater, and correlate the levels with potential human health risk. Data demonstrated high concentrations of metals in the food crops irrigated with wastewater in decreasing order: Fe> Cr> Cd> Ni> Pb. In all cases, metallic content in vegetable parts exceeded the safe limits recommended by FAO/WHO. The highest bioaccumulation factor (BAF) was recorded for cadmium (Cd). Further, the health risk index HRI of Cd and Pb was greater than one for seven food crops. The Ni HRI value was exceeded only for Pisum sativum and Solanum tuberosum. The HRI for various food crops were in a decreasing order: Cd> Pb> Ni> Cr> Fe. Out of eight food crops, only C. antiquorum showed lower risk (HRI < 1) for all heavy metals. Data demonstrated that the food crops irrigated with wastewater in this study area are highly metal contaminated and may constitute a serious health risk to the local human and animal populations. Therefore, urgent preventive measures are required to reduce metallic contamination and regular monitoring of irrigation water quality is necessary in the study area.