# Screening of Plants and Indigenous Bacteria to Improve Arsenic Phytoextraction
## 1 Introduction  
Process industry, transport, urban sprawl, agriculture, and illegal dumping or landfill without adequate recovery of resources [1; 2; 3] represent just some of the many causes of direct or indirect release of organic and inorganic pollutants into the environment, with hazardous effects on the ecosystem and human health [4]. The remediation of contaminated sites is therefore of primary importance, as evidenced by the numerous physicochemical and biological solutions developed for the recovery of contaminated water [5; 6; 7; 8] and soils [9; 10; 11; 12] in recent years. However, an often-overlooked aspect is that remediation activities also have an environmental impact as they frequently rely on chemical products or processes, with consequent consumption of raw materials and energy. This can compromise the sustainability of the approach itself, or even invalidate its beneficial aspects [13], for example by generating harmful side effects [14]. An ecological and sustainable approach should allow not only to eliminate or reduce contamination, but also to minimize the environmental impact (emissions into the atmosphere, energy consumption, waste production, etc.) and to create synergies between different sectors and activities (protection of ecosystems, circular economy, climate change, and resilience). Remediation technologies based on the natural-based solution (NBS) approach can make a significant contribution in supporting this transition to sustainable remediation, achieving the natural resources' protection objectives established by current environmental policies [15]. Among the NBS remediation measures, a growing focus is on phytoremediation [16; 17; 18], which is the set of remediation technologies that see plants as main actors to clean up organic and inorganic contaminants in soil and other environmental matrices (sediments, water). The interest in these phyto-technologies has grown over time, thanks to their low cost, simplicity of operation, and environmental benefits [19; 20], and possible uses in combination with other solutions have also been proposed to further increase the overall sustainability [21; 22]. In this regard, experimentation of phytoremediation techniques in urban areas combined with other solutions aimed at mitigating climate change has intensified in recent years. For example, the use of green roofs [23], known to be able to improve the energy and environmental performance of urban environments [24; 25], combined with phytoremediation and bio-absorption techniques, have proven to be viable nature-based solutions, able to act as domestic wastewater treatment [26], improve the quality of roof runoff water [27], purify the air [28], and remove heavy metals [29], just to name a few. The promising results obtained should help to draw the attention of both public and private investors towards such green and sustainable approaches [30]. Among the different phytoremediation technologies, phytoextraction is considered a non-invasive technique to remove heavy metals from contaminated soil in an environmentally friendly and economical way by root absorption, transfer, and accumulation in the different tissues of the plant [31; 32]. Originally, the approach was based on the use of hyperaccumulating species, capable of absorbing large quantities of metal without suffering physiological damage, but which generally suffer from low biomass production and a slow growth rate, resulting in long lead times [33]. Several studies have explored the possibility of improving the efficiency of phytoremediation by using fast-growing and highly tolerant species, with the help of chelating agents to increase the uptake of metals from soil, such as ethylenediaminetetraacetic acid (EDTA) or ethylenediamine disuccinic acid (EDDS).