Treatment of Salted Road Runoffs Using Typha latifolia, Spergularia canadensis, and Atriplex patula: A Comparison of Their Salt Removal Potential

Abstract

De-icing salts are used all around the world to improve driving security. Their impacts on the environment are a major concern, especially due to the production of salted road runoffs that induce rising of salinity of freshwater ecosystems. Some plants tolerate high salt concentrations and are able to accumulate large amounts of salt in their tissues. To protect freshwater ecosystems, constructed wetland incorporating this kind of plant could be used to treat salted road runoffs before they reached natural ecosystems. Lake Saint-Augustin, located near Quebec City (Quebec, Canada) is used as an experimental watershed area. Typha latifolia, Atriplex patula, and Spergularia canadensis have been selected and assessed for their ability to survive and grow in salted waters by accumulating salt in their tissues. Germination (20 days) experiments, recovery experiments (20 days), and chloride accumulation experiments (2 months) have been performed in a controlled environment. The three species showed no germination inhibition for salt concentrations found in the field (0, 150, 1500 mg NaCl/L). Accumulation of chloride has been found significant for all species. Typha latifolia showed the best accumulation of chloride (63 mgCl−/g of dry mass) which corresponds to a standing stock up to 230,000 mgCl⋅m2. This result is promising and supports the decision for upgrading the process to a constructed wetland.

Evaluation of Phytodesalination Potential of Vegetated Bioreactors Treating Greenhouse Effluent

“…Although this is much higher than our measured 1.2 mg·g −1 , it should be noted that the minimum starting concentration of Na + in the initial solution used in that experiment was more than 4 times greater than the concentrations found in the typical greenhouse effluent. This general correlation between the enhanced salt accumulation (particularly the accumulated Na + and Cl − ) in the plant tissue and the higher starting salt concentrations up to a certain level, has been reported in other studies as well (e.g., [25][26][27][28]). Nonetheless, Ca 2+ , Mg 2+ and K + contents in the halophytes biomass are much less sensitive to salinity variations (e.g., [28,29]).…”

Heavy metal concentrations inCipangopaludina chinensis(Reeve, 1863) and relationships with sediments in Saint-Augustin Lake, Québec City (Qc, Canada)

“…However, in an anoxic environment these bonds are weaker. Furthermore, a great impact on the ecosystem is due to the salt contributions (NaCl) from the highway network Fe´lix Leclerc, located at the north of the lake and characterized by high traffic activity (Morteau et al, 2009).…”

Impacts of Salinity on Saint-Augustin Lake, Canada: Remediation Measures at Watershed Scale

“…Moreover, halophyte plants were planted, such as Atriplex patula, Spergularia canadensis, and Salicornia europaea. Halophyte plants are an interesting alternative to plants traditionally used to treat the road effluents: (i) they are resistant to strong salinity; (ii) they can accumulate moderate to high quantities of salt in its biomass; and (iii) they can reduce the load of trace metals by bioaccumulation and biostabilisation [9,24].…”

“…The increase of salt concentration in groundwater is a concern for drinking water [8]. A high proportion of salts can also be accumulated in roadside soils and vegetation [9], which can affect soil physicochemical properties, biogeochemical cycles, and soil ecology. In addition, road runoff includes toxic trace metals such as Cd and Pb [10].…”