Soil inactivation of DNA viruses in septic seepage

Abstract

Aims: To generate field‐relevant inactivation data for incorporation into models to predict the likelihood of viral contamination of surface waters by septic seepage. Methods and Results: Inactivation rates were determined for PRD1 bacteriophage and Adenovirus 2 in two catchment soils under a range of temperature, moisture and biotic status regimes. Inactivation rates presented for both viruses were significantly different at different temperatures and in different soil types (α = 0·05). Soil moisture generally did not significantly affect virus inactivation rate. Biotic status significantly affected inactivation rates of PRD1 in the loam soil but not the clay‐loam soil. Adenovirus 2 was inactivated more rapidly in the loam soil than PRD1 bacteriophage. Conclusions: Virus inactivation rates incorporated into models should be appropriate for the climate/catchment in question with particular regard to soil type and temperature. Given that PRD1 is similar in size to adenoviruses, yet more conservative with regard to inactivation in soil, it may be a useful surrogate in studies of Adenovirus fate and transport. Significance and Impact of the Study: A better understanding of the factors that govern virus fate and transport in catchments would facilitate the design of barrier measures to prevent viral contamination of surface waters by septic seepage.

Transport of Human Adenoviruses in Water Saturated Laboratory Columns

“…The extremely small size (25-100 nm) of viruses allows them to infiltrate soils, and eventually to invade aquifers. Depending on factors such as rainfall, temperature, soil structure, organic carbon content, soil water pH, cation concentrations, ionic strength, virus taxon-specific factors (e.g., capsid diameter and isoelectric point), and the presence of other biota, viruses can migrate over considerable distances in the subsurface (Dowd et al 1998;Borchardt et al 2007;Davies et al 2006;Cao et al 2010;Horswell et al 2010;Syngouna and Chrysikopoulos 2013). Viruses persist for several months in soils and groundwater when temperatures are low and soils are moist (Borchardt et al 2003), and they are less efficiently eliminated during soil passage than other microorganisms (Frohnert et al 2014).…”

“…Most viral transport studies focus on bacteriophages, with MS2 being the most common (Powelson et al 1991;Dowd et al 1998;Schijven et al 2002;Weaver et al 2013;Chu et al 2003;Zhuang and Jin 2003a, b;Han et al 2006;Zhuang and Jin 2008;Syngouna and Chrysikopoulos 2011;Wong et al 2014). Other frequently used bacteriophages are: phiX174 (Schijven et al 2002;Kenst et al 2008;Zhuang and Jin 2008;Han et al 2006;Chu et al 2003;Zhuang and Jin 2003a, b;Syngouna and Chrysikopoulos 2011), PRD1 (Schijven et al 2002;Abudalo et al 2005;Foppen et al 2006;Sadeghi et al 2013;Davies et al 2006), and T7 (Flynn et al 2004). Bacteriophages were widely employed as surrogates for human viruses, because they share many properties and features such as size, structure, morphology, and composition.…”

“…Moreover, they are nonpathogenic to human, specific to host bacteria, simple to assay, and have good survival characteristics (Cao et al 2010). However, relatively less attention has been given to pathogenic viruses (Pancorbo et al 1988;Quanrud et al 2003;Attinti et al 2010), and specifically to adenoviruses as indicator viruses (Davies et al 2006;Horswell et al 2010;Wong et al 2012Wong et al , 2014. Fluorescent polystyrene nanospheres (FPNS) have also been used as virus surrogates in studies of virus transport in porous media, where 70-nm sized silica nanoparticles were covalently coupled with specific proteins and a DNA marker for sensitive detection (Pang et al 2014).…”

“…They are widespread in the environment and are found in marine, river, ground, drinking, recreational, and waste waters (Wong et al 2014). Due to their high prevalence and environmental stability, hAdVs have been included in the U.S. Environmental Protection Agency's contaminant candidate lists (Davies et al 2006;Wong et al 2014). Adenoviruses are more UV light and heat resistant, compared to other enteric viruses (Horswell et al 2010), and remain infectious for at least one year, in groundwater, with their DNA being detectable for as long as 22 months (Pang et al 2014).…”

On-Site Wastewater Systems: Investigating Dynamics and Diurnal Patterns Impacting on the Performance of Mound Systems

“…Furthermore, Davies et al [8] cites research that has identified key factors influencing virus inactivation rates in septic seepage. These factors include temperature, moisture content, pH, soil type, virus type [9], organic matter content, electrolyte concentration [10], and the presence of other biota [11][12][13].…”