**6. Transportation via the food chain and occurrence in human food**

Anthropogenic and natural sources are major supply for heavy metals in the surroundings. Heavy metals contaminate land and leach out to waterbodies, show their effect by persisting in the food cycle, have antagonistic effects on biota since they are very responsive and toxic at low concentrations [104, 105]. Toxic metals gets accumulated by plants from roots. Heavy metal travels through the water stream by apoplast to the internal cells (endodermis). This endodermis function as a protective layer for Heavy metal movement. The casparian strip prevents water stream and the Heavy metal enters the symplastic phase. Heavy metal transportation (in low concentrations) through root to APP have accounted for of immobilization by contrarily charged gelatins inside the root cell divider [106, 107]. Insoluble Heavy metal salts hasten in intercellular spaces of root cells [107, 108]. Essentially, Heavy metal amassing in plasma layers of root cells [107, 109] or in rhizodermal vacuoles and cortical cells of roots. Significant segment of Heavy metal is discharged from internal cells (endodermis) during the detoxification process by the plant. Foundations of hyper accumulator species break up metals in soil [110], increment metal take-up and movement, and make hyper accumulator species to endure higher Heavy metal particles focuses. Other detoxifying components include specific metal take-up, discharge, ligand binding, all contribute to Heavy metal resistance. The transfer of Heavy metal from lower part of plant to upper (root-shoot) is aided by xylem, which is most likely supported by occurrence [111]. On mesquite plants [106], demonstrated X-beam planning and observed high Heavy metal statements in xylem and phloem cells. It was found that Heavy metal traveled to the leaf from the vascular stream via apoplastic pathway [75]. In xylem, Heavy metal can frame edifices with amino/natural acids [112]. In any case, inorganic Heavy metal can likewise be moved. Movement (i.e., Heavy metal present in aeronautical parts/driving roots) can be executed for understanding level of Heavy metal movement [110, 112–114]. Notwithstanding, the admission of Heavy metal tainted plants has been a significant openness to people and creature [113–115]. Consumable/wild plants developed/filled nearby phosphate businesses can be Heavy metal bio-pointers of harmful metals [113]. Occupants and laborers of these businesses/regions might be presented to Heavy metal tainting.

The degree of toxicity of TEs in people relies upon every day admission through utilization of different sorts of vegetables [41, 97, 116, 117]. To understand the human health vulnerabilities from TEs when they consume crops, existing data records, and boundaries are used. Target hazard quotient (THQ ), daily dietary intake of metals (DDI), hazard index (HI), daily intake of metals (DIM), and health risk index are among the items on the list (HRI). The THQ list is used to assess the health risks by toxic elements by giving a proper information on metal content from land (soil) and plants [118].
