# Potential of Halophytes-Associated Microbes for the Phytoremediation of Metal-Polluted Saline Soils
## 1 Introduction  
Metal pollution related to urbanization and industrialization and associated with a rapid economic growth has increased in the coastal areas during the last decades [1; 2; 3]. Anthropogenic activities such as mining, textile industries, and agriculture--and, more generally, soil degradation--lead to the transfer of metals-rich particles to the coastal environments. About 80% of the pollutants from human activities are introduced into coastal environments, contaminating waters, sediments, and biological systems [1; 4]. Indeed, salt marshes and other saline ecosystems are often the target for the dumping of toxic pollutants and the establishment of landfills. The reason for this is that for, a long time, they were considered to be areas of little interest, especially due to the absence of glycopytes, on which agriculture is mainly based [5]. According to [PERSON] et al. [6], 75-96% of European seas are contaminated with metals. Many coastal regions are highly polluted. There are almost 620,000 km of coastlines worldwide, and over one-third of the total human population lives within 100 km of the coast. The intertidal ecosystems are very important for terrestrial and marine organisms, whose life cycles are often partially or entirely dependent them. Although coastal environments act as buffering zones at the land-sea interface, limiting the spread of contaminants to the ocean, contamination levels are such that the retention effects of these ecosystems are often insufficient, and metals still accumulate in the food chain of surrounding ecosystems [7]. Affecting marine organisms [3; 8; 9], invertebrates [3; 10], plants [11], microorganisms [12], and representing a threat for human health [3; 13; 14], metal pollution in coastal areas has become a matter of crucial major concern. Over the last decades, the removal of metals in coastal wetlands with biological remediation means has thus received much attention from scientists, especially for mangroves,estuaries, salt marshes, and forests [15; 16]. Indeed, biological solutions have received interest since the costs and eco-friendly solutions needed to remediate metal contaminations have increased, especially in highly industrialized areas of poor and in-development countries. According to [PERSON] et al. [17], interest for phytoremediation strategies has only thrived during the past 20 years because of growing commercial issues, especially in the Northern American countries. Phytoextraction of metals is a phytoremediation technique that consists of absorbing metals from the soil, using plants that preferentially accumulate these elements in their aerial parts [18; 19; 20]. The metals can potentially be recovered from plant biomass in forms that can be subsequently further exploited for several industrial purposes [21]. On the other hand, metal phytostabilization uses plants that reduce \"the mobility and bioavailability of metals within the surroundings, thereby preventing their migration to groundwater or their entry into the food chain\" [20]. [PERSON] et al. [17] put forth the engagement for sustainable development when developing such biotechnologies. [PERSON] and [PERSON] [22] highlighted the psychological and social implications of phytoremediation in the brownfield redevelopment. Phytoremediation and, more especially, green spaces development have shown positive effects on people in terms of medical needs, work productivity, and social relationships. Moreover, biological remediation techniques are cost-effective solutions and are increasingly recommended in scientific publications. Indeed, the costs of phytoremediation applications are particularly low compared to conventional techniques [23]. For [PERSON] and [PERSON] [24], the costs/effectiveness ratio of phytoremediation was higher than in the case of excavation and disposal or soil washing only for low contamination levels for a duration of 5 years of treatment. These authors recommend combining phytoextraction and physicochemical techniques to accelerate and improve the process.