Attenuation and colloidal mobilization of bacteriophages in natural sediments under anoxic as compared to oxic conditions.
Redox conditions are known to affect the fate of viruses in porous media. Several studies report the relevance of colloid-facilitated virus transport in the subsurface, but detailed studies on the effect of anoxic conditions on virus retention in natural sediments are still missing. Therefore, we investigated the fate of viruses in natural flood plain sediments with different sesquioxide contents under anoxic conditions by considering sorption to the solid phase, sorption to mobilized colloids, and inactivation in the aqueous phase. Batch experiments were conducted under oxic and anoxic conditions at pH values between 5.1 and 7.6, using bacteriophages MS2 and PhiX174 as model viruses. In addition to free and colloid-associated bacteriophages, dissolved and colloidal concentrations of Fe, Al and organic C as well as dissolved Ca were determined. Results showed that regardless of redox conditions, bacteriophages did not adsorb to mobilized colloids, even under favourable charge conditions. Under anoxic conditions, attenuation of bacteriophages was dominated by sorption over inactivation, with MS2 showing a higher degree of sorption than PhiX174. Inactivation in water was low under anoxic conditions for both bacteriophages with about one log10 decrease in concentration during 16 h. Increased Fe/Al concentrations and a low organic carbon content of the sediment led to enhanced bacteriophage removal under anoxic conditions. However, even in the presence of sufficient Fe/A-(hydr)oxides on the solid phase, bacteriophage sorption was low. We presume that organic matter may limit the potential retention of sesquioxides in anoxic sediments and should thus be considered for the risk assessment of virus breakthrough in the subsurface.
Federal Environment Agency, Section Drinking Water Treatment and Resource Protection, Schichauweg 58, D-12307 Berlin, Germany. Electronic address: Sondra.klitzke@uba.de.
Sondra
S
Klitzke
Federal Environment Agency, Section Drinking Water Treatment and Resource Protection, Schichauweg 58, D-12307 Berlin, Germany. Electronic address: schroeder_jendrik@yahoo.com.
Jendrik
J
Schroeder
Federal Environment Agency, Section Microbiological Risks, Corrensplatz 1, D-14197 Berlin, Germany. Electronic address: Hans-christoph.selinka@uba.de.
Hans-Christoph
HC
Selinka
Federal Environment Agency, Section Microbiological Risks, Corrensplatz 1, D-14197 Berlin, Germany. Electronic address: regine.szewzyk@uba.de.
Regine
R
Szewzyk
Federal Environment Agency, Department of Drinking Water and Swimming Pool Hygiene, Schichauweg 58, D-12307 Berlin, Germany. Electronic address: Ingrid.chorus@uba.de.
Ingrid
I
Chorus
D000327:Adsorption; D001435:Bacteriophages / Q000737:chemistry*; D003102:Colloids / Q000737:chemistry*; D019015:Geologic Sediments / Q000821:virology*; D010084:Oxidation-Reduction; D016062:Porosity; D012988:Soil Microbiology
D003102:Colloids
Colloid mobilization; Phage; Riverbank filtration; Sesquioxide; Virus; Zeta potential