**2.3 Biological remediation**

### *2.3.1 Phytoremediation*

Phytoremediation is a recently developed technology that offers a cost-effective solution by using plants, and associated soil microbes, to reduce the content, or toxic effects, of contaminants in the environment [43]. Botano-remediation, vegetative remediation, green remediation, and agro-remediation are all synonyms for phytoremediation [44]. Recently, there has been a lot of interest in and usage of phytoremediation, a natural, solar-powered, and environmentally benign method, especially in combination with other methods like biological, physical, and chemical methods for the treatment of hazardous pollutants [45]. A phytoremediation system

can effectively clean-up sites with low-to-moderate levels of heavy metals while being environmentally friendly, appealing, esthetically pleasing, non-invasive, energy efficient, and cost-effective. Through mental accumulation, precipitation, or root surface absorption, heavy metals in the soil are strengthened during the solidification process [46]. Phytoremediation is usually divided into phytoextraction, phytostabilization, phytotransformation, and phytovolatilization. In practice, the selection of phytoremediation technology should be based on the types of soil and plants, the structure of rhizosphere microorganisms, and the complex coupling between the geochemical forms of pollutants.
