Ecotoxicological investigation of arsenic contamination within the water-soil-fruit-human continuum

Arsenic (As) contamination of water, soil, and plants has become a global critical concern owing to its ecological consequences and human health risks. This study investigated As contamination in soil-irrigation water-fruit plant systems from previously unexplored fruit orchards in Vehari District, Pakistan. A total of 193 samples, comprising irrigation water, soil, and plants, were collected from three tehsils of district Vehari: Mailsi, Vehari, and Burewala. Results showed As concentrations ranging from 0.2 to 69.9 µg/L (mean: 16.2 µg/L) in water, 0.1-83.6 µg/L (mean: 44.6 µg/L) in soil, and 0-50.6 µg/L (mean: 9.18 µg/L) in plants. Notably, the world of water, 91.6% of soil, 28.3% of plant leaves, and 15.28% of fruit samples exceeded the permissible limit of 10 µg/L set by the World Health Organization (WHO). Moreover, 11.6% of irrigation water, 45% of soil, and 1.67% of plant leaf samples surpassed the hazardous threshold of 50 µg/L. To evaluate health risks, target hazard quotients, estimated daily intake, and cancer risk values for As were calculated as 1.54E-03, 4.63E-04, and 6.94E-07, respectively. Principal component analysis (PCA) revealed a strong correlation among water quality parameters including As carbonate (CO₃^2-), bicarbonate (HCO₃^-), and pH, which significantly influenced As uptake by plants. A triangular heatmap indicated associations of water and soil As with pH, CO₃^2- (r²: 0.08, 0.17, 0.46), and plant As (r²: - 0.04), supporting the concept of reduced As absorption in high-carbonate soils. This study underscores widespread As contamination in groundwater, soil, and vegetation in Vehari District, Pakistan. The findings highlight the urgent need to improve irrigation water quality or implement systematic evaluations to mitigate risks to human health.