Phytoextraction of Na+ and Cl− by Atriplex halimus L. and Atriplex hortensis L.: A promising solution for remediation of road runoff contaminated with deicing salts

Two halophytes, Atriplex halimus and Atriplex hortensis, were selected to be tested for phytodesalination of road runoff. A 60 d pot experiment was conducted and germination, survival, growth, and bioaccumulation of NaCl and trace metals by both species were monitored in conditions simulating those encountered in road runoff treatment systems. NaCl concentration was controlled in the hydration solution and ranged from 0 to 2 g/L. Germination and survival of young seedlings were not affected by salinity increase in the tested range. Growth was enhanced by NaCl in the hydration solution for A. halimus whereas water content (WC) was significantly and negatively correlated with NaCl concentration. No significant effect of NaCl concentration in the hydration solution was recorded on either growth or WC for A. hortensis. Both Atriplex species accumulated Na+ and other cations. Results for Na/K molar ratio indicated that A. halimus was not affected as much as A. hortensis in its homeostasis and nutritional capacities. These results show that both Atriplex species are able to germinate, grow and accumulate sodium when watered with hydration solutions polluted with NaCl. They are therefore good candidates for phytodesalination of road runoff polluted by deicing salts, and should be tested at the pilot scale.

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