Table 1.

Classification of HMs based on their impact on the human body.

HM Compounds	Impact HM on Human
Lead (Pb), mercury (Hg), arsenic (As), and cadmium (Cd)	High degree of toxicity, carcinogenic, and induce damage to multiple organs
Tin (Sn) and aluminum (Al)	Less toxic to human body
Barium (Ba) and lithium (Li)	Non-essential for physiological and biochemical functions
Copper (Cu), zinc (Zn), nickel (Ni), manganese (Mn), molybdenum (Mo), cobalt (Co), selenium (Se), chromium (Cr), and iron (Fe)	Essential for physiological and biochemical functions