## 4 Discussion
### Health Risk Assessment of Metals Accumulated in Plant Organs  
Metals with higher concentrations in wastewater, namely Fe, Zn, Mn, and Pb, were compared with permissible limits of metals set by different authorities. According to the Health Guidelines for the Use of Wastewater in Agriculture and Aquaculture [47], the concentrations of Fe, Zn, Mn, and Pb in the wastewater used at Chakera were found below the permissible limits. However, Zn and Pb concentrations when compared with the recommendations of the WWF [28] and USEPA [29] were found to be above the critical limit (Table 1). The increase in wastewater metal elements might have resulted from the discharge or metal-containing effluents from battery (Mn, Cd, Pb, and As), fabric (Zn, Cr, Cu, Ni, and Cd), and paint (Pb, Cu, Zn, and Cd) industries [51]. A continuous application of wastewater to the soil resulted in a high accumulation of metals in the soil. As compared to metal concentrations in wastewater, Fe was found to be the maximum, and Mn concentration was the minimum in the soil. When their concentration was compared with the safe limits of metals in soil, the concentrations of Zn and Pb were below the permissible limits [31]. However, their continuous addition to the soil through polluted effluents could result in the accumulation of trace elements in higher amounts, which may become phytotoxic [52]. The present results showed that soil macronutrients (N, P, and K) increased as a result of wastewater irrigation. A number of other studies also reported the accumulation of N, P, and K in polluted soil, which was attributed to the original content of these nutrients in wastewater used for irrigation [53]. It is documented that the amount of N, P, and K in wastewater in the soil can range up to 4, 10, and 8 times the fertilizers needed by forage crops [54]. The high accumulation of these macronutrients in wastewater and soil ultimately leads to an increase in plant mineral contents. The present findings agree with those already reported by different researchers [55], who found high P content in wastewater-irrigated plants. Relationship between Soil and Water Metal Concentrations and Tomato Fruit Parts Based on Multivariate Analysis  
Heatmap clustering for the control site irrigated with canal water mostly showed weak, negative interactions within roots and stems, indicating that plants mostly translocated essential minerals and metals towards leaves or developing fruits to meet the needs in physiological processes. In leaves, a weak, positive interaction was observed, as they are the final site of mineral metabolism [56]. Within fruit parts, the endocarp showed a weak, positive interaction with most minerals and metals, while the mesocarp and endocarp exhibited a weak, negative association. When compared with the original results of this study, these findings suggested that, in control conditions, fruits retained sufficient quantities of essential minerals and metal ions within permissible ranges [57]. In the \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Plant Organs** & **Mn** & **Fe** & **Zn** & **Pb** \\ \hline Roots & 16.5 & 137.32 & 26.13 & 28.5 \\ Stem & 7.7 & 65.03 & 12.78 & 22.7 \\ Leaves & 13.99 & 121.03 & 33.03 & 39.08 \\ Pericarp & 7.08 & 13.6 & 16.35 & 30.05 \\ Mesocarp & 7.75 & 32.3 & 12.98 & 29.42 \\ Endocarp & 4.6 & 63.43 & 23.85 & 34.95 \\ WHO limit [47] & 5 & 150 & 5 & 5 \\ Revised limit & 5 WHO/FAO & 1 WHO/FAO & 50 is & 0.1 ell, 2.5 is \\ \hline WHO = World Health Organization, FAO = Food and Agriculture Organization, is = Indian standards; ell = European legislation limit [11]. & & & \\ \end{tabular}
\end{table} 
Table 2: Mean levels of concentrations of heavy metals (mg kg\({}^{-1}\) DW) in different organs of tomato (_Lycopersion esculent_ L). wastewater of the contaminated site in Chakera, mineral nutrients (K, P, and N) and metals (Fe, Pb, Zn, and Mn) mostly showed strong, negative associations, and Pb had the most negative association.