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Review
. 2023 Jul 3;11(7):580.
doi: 10.3390/toxics11070580.

Toxicity of Heavy Metals and Recent Advances in Their Removal: A Review

Manar K Abd Elnabi  1   2 , Nehal E Elkaliny  1 , Maha M Elyazied  1 , Shimaa H Azab  1 , Shawky A Elkhalifa  1 , Sohaila Elmasry  3 , Moustafa S Mouhamed  1 , Ebrahim M Shalamesh  1 , Naira A Alhorieny  1 , Abeer E Abd Elaty  1 , Ibrahim M Elgendy  1 , Alaa E Etman  1 , Kholod E Saad  1 , Konstantina Tsigkou  4 , Sameh S Ali  1   5 , Michael Kornaros  4 , Yehia A-G Mahmoud  1
Affiliations
Review

Toxicity of Heavy Metals and Recent Advances in Their Removal: A Review

Manar K Abd Elnabi et al. Toxics. .

Abstract

Natural and anthropogenic sources of metals in the ecosystem are perpetually increasing; consequently, heavy metal (HM) accumulation has become a major environmental concern. Human exposure to HMs has increased dramatically due to the industrial activities of the 20th century. Mercury, arsenic lead, chrome, and cadmium have been the most prevalent HMs that have caused human toxicity. Poisonings can be acute or chronic following exposure via water, air, or food. The bioaccumulation of these HMs results in a variety of toxic effects on various tissues and organs. Comparing the mechanisms of action reveals that these metals induce toxicity via similar pathways, including the production of reactive oxygen species, the inactivation of enzymes, and oxidative stress. The conventional techniques employed for the elimination of HMs are deemed inadequate when the HM concentration is less than 100 mg/L. In addition, these methods exhibit certain limitations, including the production of secondary pollutants, a high demand for energy and chemicals, and reduced cost-effectiveness. As a result, the employment of microbial bioremediation for the purpose of HM detoxification has emerged as a viable solution, given that microorganisms, including fungi and bacteria, exhibit superior biosorption and bio-accumulation capabilities. This review deals with HM uptake and toxicity mechanisms associated with HMs, and will increase our knowledge on their toxic effects on the body organs, leading to better management of metal poisoning. This review aims to enhance comprehension and offer sources for the judicious selection of microbial remediation technology for the detoxification of HMs. Microbial-based solutions that are sustainable could potentially offer crucial and cost-effective methods for reducing the toxicity of HMs.

Keywords: biomineralization; bioremediation; biosorption; biotransformation; heavy metals; heavy metals toxicity.

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Conflict of interest statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Figures

Figure 1
Figure 1
Origins and impacts of HMs on humans through the food chain.
Figure 2
Figure 2
Oxidative stress and human organ toxicity following exposure to HMs.
Figure 3
Figure 3
Intoxication mechanisms in humans following exposure to HMs.
Figure 4
Figure 4
Distribution of HMs in aquatic environments.
Figure 5
Figure 5
Microbial remediation mechanisms of soils contaminated with HMs.
Figure 6
Figure 6
Transfer route and phytoremediation mechanism of HMs into plant cells and tissues.
Figure 7
Figure 7
Toxicity of HMs on microorganisms.
Figure 8
Figure 8
Mechanisms of microbial bioremediation of heavy metals. GSH, glutathione; GSSG, glutathione disulfide; MT, Metallothionein.
Figure 9
Figure 9
Mechanisms of HM removal by fungi.
Figure 10
Figure 10
Mechanisms of bacterial exopolysaccharide (A) and encapsulation (B) for HM removal.
Figure 11
Figure 11
Bacterial bioleaching mechanism for HM removal.
Figure 12
Figure 12
Mechanisms of HM removal via microbial fuel cells (A) and adsorption of metal ions across mesoporous magnetite nanoparticles (B).
See this image and copyright information in PMC

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