Spectroscopic Quantification of Heavy Metal Bioaccumulation, Soil-to-Plant Partitioning, and Dietary Toxicity in Four Economic Crops Irrigated with Textile Industrial Wastewater in Bhilwara, Semi-Arid Rajasthan

In the semi-arid industrial basin of Bhilwara, Rajasthan, effluent discharge from textile wet-processing, dyeing, and finishing units contaminates ephemeral drainage channels and unconfined aquifers. This investigation quantifies toxic trace heavy metal concentrations (Cd, Cr, Pb) across the irrigation water–soil–crop continuum under a factorial field design () comparing an unamended groundwater control (C1–C4), vermicompost-amended organic management (OS1–OS4), and composite textile effluent irrigation (TS1–TS4) across four contrasting economic taxa: Wheatgrass (Triticum aestivum L.), Fenugreek (Trigonella foenum-graecum L.), Spinach (Spinacia oleracea L.), and Spearmint (Mentha spicata L.). Flame atomic absorption spectroscopy (AAS) following matrix-specific wet acid digestions revealed high contaminant loadings in composite textile wastewater: Pb (), Cr (), and Cd (), exceeding permissible national irrigation thresholds (CPCB/BIS) by -, -, and -fold, respectively. In harvested foliar biomass, trace metal bioaccumulation followed the species-dependent hierarchy: . Foliar lead levels in S. oleracea and M. spicata reached and dry weight, substantially exceeding the international WHO/FAO benchmark () and the national Indian FSSAI statutory threshold (). Cadmium exhibited high soil-to-plant transfer efficiency, yielding Bioaccumulation Factors () greater than unity () in all effluent-irrigated crops. In contrast, foliar metal levels in organic control treatments remained below the solid-phase Limit of Quantification for Cd () and within safe baselines for Pb and Cr. Human dietary risk assessments yielded Target Hazard Quotients () of for Pb and for Cd in S. oleracea, demonstrating serious non-carcinogenic health hazards through the food chain. These findings confirm that untreated textile wastewater serves as a potent vector for heavy metal accumulation in leafy produce, while vermicompost-based organic management mitigates toxic metal entry into the agricultural food chain.