New ways to improve urban wetlands
Aquatic plant to remove PFAS, better filtration systems

Date:
March 21, 2022
Source:
Flinders University
Summary:
New studies provide valuable insights into removing toxins from
polluted waterways and improving filtration at urban wetlands. One
study found a wetland plant capable of reducing PFAS in soil and
water, and another looked for better urban wetland water flow
management during summer.



FULL STORY ========================================================================== Ahead of World Water Day (22 March 2022), new studies at Flinders
University provide valuable insights into removing toxins from polluted waterways and improving filtration at urban wetlands.


==========================================================================
One study found a wetland plant capable of reducing PFAS in soil and
water, and another looked for better urban wetland water flow management
during summer.

In a glasshouse experiment, the first study found a common Australian
native wetland plant capable of tolerating and reducing major contaminant Perfluoroalkyl and polyfluoroalkyl substances (PFAS).

"We found the wetland plant Juncus sarophorus has a high tolerance to
PFAS and 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 also is effective at accumulating and transferring PFOA and
PFHxS from the soil to an above- ground vegetation biomass," says Flinders University hydrogeologist Dr Ilka Wallis, from the National Centre for Groundwater Research and Training whose research covers pollutants and
recharge of aquifers.

"Together with its high growth rate, this plant appears to be a suitable candidate for phyto-extraction of short-chained PFAS compounds, but less effective at removing PFOS owing to this compound's long chain-lengths
and ability to be absorbed by soils." PFAS has been detected globally
in a wide range of environments, there is an urgent need for effective
remedial treatment solutions at the field scale.



========================================================================== "Phyto-remediation presents a potential remediation strategy for PFAS that would allow efficient and cost-effective remediation at large scales,"
says co- author and environmental health researcher Flinders University Professor Howard Fallowfield.

In another article inScience of the Total Environment, Flinders University researchers returned to a popular suburban constructed wetland to conduct indepth studies of water filtration efficiency by existing aquatic plants (macrophytes) and contaminant accumulation at various locations during
hotter, drier summer months.

"The spatial assessment of the Oaklands Park wetland was one of the first studies of nutrients and contaminants in constructed wetlands macrophytes
as a performance indicator for wetland functionality and management,"
Professor Fallowfield says.

The reed beds and water were analysed for nutrient and contaminant
accumulation in-situ at the stormwater-fed wetland and water remediation
site in the southern suburb of Adelaide, South Australia. Macrophytes
were sampled at 36 sites and water at 46 sites selected by a systematic
grid according to their location from inflow 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 reduction
in macrophyte health and suspended solids from reed filtration with
distance from the inflow as water flow slowed down during summer.

"Our study highlights the need for wetland managers to adjust design,
water flow and vegetation control to better manage nutrients and
contaminants with distance from inflow, particularly during the drier
months," says PhD candidate Nick Wilkins.

"These issues with flow regimes obviously affect macrophyte water
filtration performance, which can be further investigated to improve constructed wetland health and performance elsewhere in the world,"
he says.

Efficient filtration and removal of nitrogen, carbon, phosphorus
and contaminants from stormwater, agricultural runoff and industrial
wastewater will reduce the range of potentially damaging pollutants
discharged into the surrounding environments and improve water quality remediation techniques at vital constructed wetlands in urban and other recreational settings.


========================================================================== Story Source: Materials provided by Flinders_University. Note: Content
may be edited for style and length.


========================================================================== Journal References:
1. Jiawen Zhu, Ilka Wallis, Huade Guan, Kirstin Ross, Harriet Whiley,
Howard
Fallowfield. Juncus sarophorus, a native Australian species,
tolerates and accumulates PFOS, PFOA and PFHxS in a glasshouse
experiment. Science of The Total Environment, 2022; 826: 154184 DOI:
10.1016/ j.scitotenv.2022.154184
2. Nicholas R. Wilkins, Howard Fallowfield, Ryan Baring. Spatial
performance
assessment of reed bed filtration in a constructed wetland. Science
of The Total Environment, 2022; 820: 153060 DOI: 10.1016/
j.scitotenv.2022.153060 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/03/220321091924.htm

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