Evaluation and Health Risk Assessment of Five Toxic Metals Concentration in Soil, Water and Seasonal Vegetables and Fruits from Pakistan-Afghanistan Border, Torkham

Abstract

Heavy metals are of serious concern for human health and food security. The risk to human health is directly related to soil and water pollution, which enter the food chain (vegetables and fruits). The current study was designed to investigate the heavy metals (Cr, Pb, Ni, Cd, and Zn) concentrations in five vegetables (Potato, Tomato, Turnip, Onion & Taro) and five fruits (Banana, Apple, Grapes, Pomegranate, and Guava) samples. We also estimated metal concentrations in water and soil samples. Torkham, a border region between Afghanistan and Pakistan, was selected for the purpose. The analysis was performed on Atomic Absorption Spectroscopy (AAS, Perkin- Elmer 700). In vegetables, the highest Pb and Ni were recorded in Potatoes (0.34 ± 0.066) and Onions (0.278 ± 0.021). While in tomatoes, the highest concentrations of Cd (0.90± 0.115), Zn (0.726 ± 0.008), and Cr (1.761 ± 0.028) were noted. While, in fruits the highest levels of Pb (0.32± 0.03), Cd (0.61 ± 0.0119), Zn (0.357 ± 0.0047) and Ni (0.111 ± 0.0128), while in apples we noted the highest Cr levels (0.789 ± 0.0452). We compared the metal concentrations with permissible limits set by World Health Organization/Food and Agricultural Organization (WHO/FAO). In the majority of the samples, the metal levels exceeded the permissible limits, while few were found within the safe limits. Based on heavy metals concentrations in soil, water, vegetables, and fruit samples. We calculated the health risk assessment, i.e., daily intake of metals (DIM) estimated daily intake (EDI), target hazard quotient (THQ), total target hazard quotient (TTHQ), carcinogenic risk (CR), health risk index (HRI) and contamination factor (CF). The EDI for Ni and Zn was in the safest region. While for Cd and Pb, the highest EDI was recorded in tomatoes (0.394) and guava (0.303), respectively. Similarly, Cr poses’ serious risk with the highest EDI in tomatoes (0.771), apples (0.563), turnip (0.393), guava (0.282), and banana (0.263). If HRI, THQ THQ, and TTHQ are less than one (< 1), it means the exposed populations are not at risk. In the present HRI, THQ and TTHQ were found to be less than one. The contamination factor for Ni and Zn was found to be considerable (CF<6), while Pb, Cd, and Cr presented the highest contamination degree (CF>6). This study suggested that some samples may impose a certain degree of potential health risk. It is required that proper action should be taken to avoid chronic exposure and consequent adverse health effects.