Figure.

16.1

Application

Nnanoremediation techniques

for

reducing

heavy

metal

contamination in the environment

Table 16.1. Effects of metal(loid)s on human health.

Metal(loid)s

Effect on Human

References

Arsenic (As)

Inflammation, chronic respiratory illness, liver fibrosis, cardiovascular disorders, skin

cancer, lung cancer may be caused by As, which is classified as a class I carcinogen.

Mawia et al.

2021

Mercury (Hg)

The human neurological system is extremely susceptible to mercury, which causes

acrodynia, or pink sickness. Mercury is a highly carcinogenic element that can disrupt

brain functioning and cause timidity, difficulties in memory, tremors, irritability and

visual or hearing abnormalities.

Khanam

et al. 2020

Cadmium (Cd)

Cadmium is Group 1 carcinogen for humans. Most common occurring toxicity

symptoms are kidney diseases, bone disorders, anemia and cancer.

Khanam

et al. 2020

Lead (Pb)

Long-term exposure can induce birth abnormalities, mental retardation, brain damage,

psychosis, autism, weight loss, hyperactivity, paralysis, muscle weakness, kidney

damage and death.

Khanam

et al. 2020

Chromium (Cr)

Chronic exposure can lead to the respiratory tract and stomach cancer and liver damage Khanam

et al. 2020

280

Bioremediation for Sustainable Environmental Cleanup

particles, nanodots, carbon nanotubes and nanocomposites, etc., for breaking down contaminants

(Shafi et al. 2021). These nanomaterials in the form of sensors, catalysts and adsorbents ensure

rapid detection and immediate detoxification of pollutants such as heavy metals and metalloids from

contaminated land sites (Figure 16.1). This chapter summarizes the application of nanotechnology

(1) to detect and quantify trace pollutants in the environment. (2) to decontaminate the environment

using nano adsorbents, nanocatalysts, nano clay composites, etc.

16.2 Human Health and Heavy Metal Toxicity

Large quantities of metals (Cu, Cd, Pb, Zn, etc.) and metalloids (particularly As) have been released

into the environment as a result of industrial operations, causing significant ecological harm.

Refineries, mining activities, sludge disposal and manufacturing sectors such as paints, electronic

and electrical gadgets, batteries, fertilizers, pesticides and other industries all contribute to the

contamination of water bodies. Furthermore, metals and metalloids cause a risk to human health

because many of them are hazardous even at low concentrations, and some are even carcinogenic

(e.g., As). Unlike organic contaminants, which break down into nontoxic smaller molecules,

metal(loid)s are resistant to many biological processes and hazardous to humans and other living

things. Lead, Cd, Cr, Hg and As metals are well-known hazardous metals. These metals have no

beneficial biological role, but they can mimic other beneficial elements and hinder biological

activities. As a result, metal toxicity has emerged as a serious concern, with several health risks,

such as lung cancer, skin cancer, bladder cancer, etc. (Table 16.1).

Nanoseners

Figure 16.1. Application nanoremediation techniques for reducing heavy metal contamination in the environment.