Bioremediation as an agroecology tool for the elimination of different persistent soil pollutants

The increasing development of urbanization and industrialization has released a plethora of different pollutants that end up being deposited in soils. Therefore, it is crucial to investigate cost-effective, feasible and environmentally friendly solutions to minimize the damage they cause. Bioremediation is a safe technique that has demonstrated satisfactory results and is easy to apply and maintain. This technique explores the degradation pathways of various biological agents (microorganisms, plants, algae, etc.) to neutralize contaminants. It is based on biodegradation and achieves the complete mineralization of organic pollutants into inorganic innocuous compounds such as carbon dioxide and water. Bioremediation, as a cleanup technology, is a widespread technique used for soils contaminated with pesticides, agrochemicals, chlorinated compounds, heavy metals, organic halogens, greenhouse gases, petroleum hydrocarbons and many others, either in situ (at the contaminated site) or ex situ (in excavated samples). Ex situ bioremediation techniques are usually more costly due to their required digging and transport from the polluted site. However, they can be used to treat a wider range of contaminants. Alternatively, in situ techniques do not have an extra cost for excavation; nonetheless, the cost of the in situ set-up of equipment, effective adhesion, and subsurface control of the contaminated site may render some in situ bioremediation methods ineffective. Some general limitations of the technique are, for example, its limitation to biodegradable compounds, its specificity and its limited scale-up. This study also addresses the economic and technical barriers to bioremediation, along with the outlook for the role of microorganisms in this process.