Ahead of World Water Day (March 22, 2022), new studies at Flinders University provide valuable insights into removing toxins from polluted waterways and improving filtration in urban wetlands .
One study found a wetland plant capable of reducing PFAS in soil and water, and another researched better management of water flow from urban wetlands during the summer.
In a greenhouse experiment, the first study found a common Australian wetland native plant able to tolerate and reduce major perfluoroalkyl and polyfluoroalkyl (PFAS) contaminants.
“We found the marsh plant sarophore juncus has a high tolerance to PFAS and is capable of overall PFAS removal rates between 9% and 11% at a time, which could be increased with floating reed beds in the water column. It is also effective in accumulating and transferring PFOA and PFHxS from soil to aboveground plant biomass,” says Dr Ilka Wallis, hydrogeologist at Flinders University, National Groundwater Research and Training Centre, whose research focuses on pollutants and aquifer recharge.
“With its high growth rate, this plant appears to be a suitable candidate for phyto-extraction of short-chain PFAS compounds, but less effective in removing PFOS due to the long chains of this compound and its ability to be taken up by the grounds.”
PFAS has been detected globally in a wide range of environments, there is an urgent need for effective field-scale curative treatment solutions.
“Phyto-remediation presents a potential remediation strategy for PFAS that would allow efficient and cost-effective remediation at scale,” says co-author and environmental health researcher, Flinders University professor Howard Fallowfield.
In another article of Total Environmental ScienceFlinders University researchers returned to a popular suburban constructed wetland to conduct in-depth studies of the efficiency of water filtration by existing aquatic plants (macrophytes) and the accumulation of contaminants at various locations during the hottest and driest summer months.
“The Oaklands Park Wetland Spatial Assessment was one of the first studies of nutrients and contaminants in constructed wetland macrophytes as a performance indicator for wetland functionality and management. “, Professor Fallowfield said.
Reed beds and water were analyzed for accumulation of nutrients and contaminants in situ at the rainfed wetland and water remediation site in the southern suburbs of Adelaide, South South Australia. The macrophytes were sampled from 36 sites and the water from 46 sites selected by a systematic grid according to their input location for each site. A total of 144 stem and root samples were checked for carbon, nitrogen and trace elements and 183 water samples for the same elements, ammonia and total suspended solids.
Results showed higher concentrations of water chemistry but reduced macrophyte health and suspended solids from reed filtration with distance of inflow as water flow slowed during the summer.
“Our study highlights the need for wetland managers to adjust design, water flow, and vegetation control to better manage nutrients and contaminants away from inflow, especially during the driest months,” says PhD candidate Nick Wilkins.
“These flow regime issues obviously affect the water filtration performance of macrophytes, which can be further investigated to improve the health and performance of constructed wetlands elsewhere in the world,” he said. declared.
Effective filtration and removal of nitrogen, carbon, phosphorus and contaminants from stormwater, agricultural runoff and industrial wastewater will reduce the range of potentially harmful pollutants released to surrounding environments and improve treatment techniques. remediation of water quality in vital human-made wetlands in urban settings and other recreational settings.