**2.4 Lead**

Pb(II) ion has been discovered to be one of the most dangerous heavy metals, with the ability to cause harmful consequences in animals and plants. Drinking water is the primary route for Pb(II) ions to enter the food chain, and aquatic creatures' bioaccumulate them [39]. Lead poisoning and chelation therapy: The general public is exposed and its compounds through industries like automobile and battery manufacture, refining, and smelting. Lead disrupts several biological processes and is toxic to the nervous system, heart, kidneys, and gastrointestinal tract, with the neurological system being the most vulnerable. Lead also causes cognitive issues in children by interfering with brain growth [40]. Heavy metals, including Pb, are produced by the combustion of fossil fuels in automobiles. Pollution is also thought to be caused by the wear of motor tires and the corrosion of parts. As a result, heavy metal pollution caused by automobiles continues to be a severe problem around the world [41].

Many strategies have been used to remove heavy metals from contaminated liquid effluents to reduce the negative impact. Chemical precipitation is a popular industrial procedure that takes multiple phases before the water can be considered drinkable [42]. The majority of adsorption research was done in a batch setting. Various lowcost adsorbents, such as bagasse pith sulphurised activated carbon, blast furnace sludge, biogas residual slurry, olive mill products, and peanut shell carbon, have been used in the search for effective and cheap removal of Pb(II) from wastewater [43].

#### **2.5 Copper**

Copper is common metal contamination that, by definition, is essential for organism functioning, but it is also potentially dangerous copper may in the soil be either static or migratory. Immobile copper that is not bioavailable can be absorbed or precipitated into the soil matrix. Because copper is usually cationic, it forms complexes with negatively charged clay minerals, anionic salts, organic materials, hydroxides, phosphorus, and sulfate [44]. Copper is a versatile metal with many uses due to its excellent qualities. It's utilized in electronics, as well as the manufacture of wires, sheets, and tubes, as well as the formation of alloys. Copper is resistant to the effects of the atmosphere and many chemicals; yet, it is known that metal is prone to corrosion in aggressive media. Copper corrosion inhibitors are required in such situations since no protective passive layer may be envisaged. Copper corrosion is a possibility [45]. Even though copper is required for human metabolism, it is hardly used. Excessive copper use, on the other hand, can cause major health problems including high cholesterol, rapid breathing, kidney and liver damage, convulsions, cramps, vomiting, and even death [46].

The disposal of precipitated cupric hydroxide is a major issue with this form of treatment. Ion exchange treatment, which is the second most extensively used approach for copper removal, does not have a sludge disposal issue and has the advantage of Cu(II) reclamation [47].

#### **2.6 Zinc**

Zinc belongs to the periodic table's group IIB and is a beautiful bluish-white metal. When heated between 110°C and 150°C, it transforms from brittle and crystalline to ductile and pliable. It's a moderately reactive metal that reacts with oxygen and other non-metals to form hydrogen, as well as dilute acids. The majority of zinc is added through industrial processes such as mining, coal and waste combustion, and steel processing [48]. Zinc is an important trace element for human health. It regulates various metabolic processes and is necessary for the physiological functioning of living tissue. Too much zinc, on the other hand, can cause serious health problems such as stomach pains, rashes, vomiting, nausea, and anemia [10]. Vomiting, diarrhea, bloody urine, icterus (yellow mucus membrane), liver failure, renal failure, and *Heavy Metal's Environmental Impact DOI: http://dx.doi.org/10.5772/intechopen.103907*

anemia have all been documented as symptoms of zinc toxicosis [49]. Zinc is widely used in various industries such as galvanization, paint, batteries, smelting, fertilizers and pesticides, fossil fuel combustion, pigment, polymer stabilizers, and so on, and zinc is present in large amounts in effluent from these industries [50].

The process is affected by a variety of factors. Adsorption (chemisorption), complexation on the surface and pores, ion exchange, microprecipitation, heavy metal hydroxide condensation onto the biosurface, and surface adsorption are some of the processes involved in the biosorption process [51].
