Long-Term Monitoring of Waterborne Pathogens and Microbial Source Tracking Markers in Paired Agricultural Watersheds under Controlled and Conventional Tile Drainage Management

Abstract

f Surface waters from paired agricultural watersheds under controlled tile drainage (CTD) and uncontrolled tile drainage (UCTD) were monitored over 7 years in order to determine if there was an effect of CTD (imposed during the growing season) on occurrences and loadings of bacterial and viral pathogens, coliphages, and microbial source tracking markers. There were significantly lower occurrences of human, ruminant, and livestock (ruminant plus pig) Bacteroidales markers in the CTD watershed in relation to the UCTD watershed. As for pathogens, there were significantly lower occurrences of Salmonella spp. and Arcobacter spp. in the CTD watershed. There were no instances where there were significantly higher quantitative loadings of any microbial target in the CTD watershed, except for F-specific DNA (F-DNA) and F-RNA coliphages, perhaps as a result of fecal inputs from a hobby farm independent of the drainage practice treatments. There was lower loading of the ruminant marker in the CTD watershed in relation to the UCTD system, and results were significant at the level P ‫؍‬ 0.06. The odds of Salmonella spp. occurring increased when a ruminant marker was present relative to when the ruminant marker was absent, yet for Arcobacter spp., the odds of this pathogen occurring significantly decreased when a ruminant marker was present relative to when the ruminant marker was absent (but increased when a wildlife marker was present relative to when the wildlife marker was absent). Interestingly, the odds of norovirus GII (associated with human and swine) occurring in water increased significantly when a ruminant marker was present relative to when a ruminant marker was absent. Overall, this study suggests that fecal pollution from tiledrained fields to stream could be reduced by CTD utilization.

Human-Driven Microbiological Contamination of Benthic and Hyporheic Sediments of an Intermittent Peri-Urban River Assessed from MST and 16S rRNA Genetic Structure Analyses

“…Several Bacteroidales markers have been designed to detect fecal pollution from human (Seurinck et al, 2005), ruminant (Reischer et al, 2006), pig (Mieszkin et al, 2009), and wild animals (Fremaux et al, 2010; Marti et al, 2011a, 2013b). Correlations with the occurrence of human pathogens have been observed (Fremaux et al, 2009; Staley et al, 2012; Marti et al, 2013a; Wilkes et al, 2013, 2014). Ruminant-specific MST markers BacR and CF128, designed by Reischer et al (2006) and Bernhard and Field (2000b), respectively, and the human-specific marker HF183, were found positively correlated to an occurrence of Salmonella cells (Fremaux et al, 2009; Marti et al, 2013a; Wilkes et al, 2014).…”

Waterborne Viruses and F-Specific Coliphages in Mixed-Use Watersheds: Microbial Associations, Host Specificities, and Affinities with Environmental/Land Use Factors

“…Hence, its potential as a virus indicator is promising. To our knowledge, the studies by Wilkes et al (4,39) are some of the first to report NoV GIII in an agriculture-dominated watershed setting.…”

“…These viruses can contaminate surface waters via wastewater discharge, runoff and drainage from farming operations, and leakage from faulty septic systems (2)(3)(4)(5)(6)(7)(8). With ever-increasing anthropogenic stresses and pressures on surface water resources, identifying the driving factors that govern fecal pollution in open watershed systems and implementing management practices/strategies designed to ultimately reduce infection risks are becoming more crucial (9,10).…”

Quantitative Campylobacter spp., antibiotic resistance genes, and veterinary antibiotics in surface and ground water following manure application: Influence of tile drainage control

“…While most CD studies have focused on nutrient export and crop productivity (Evans et al, 1992;Drury et al, 1996;Skaggs et al, 2012;Sunohara et al, 2014), some recent research has documented the implication of CD for managing environmental fate of microorganisms. For example, Wilkes et al (2014) found that widespread implementation of CD in a watershed can reduce the occurrences of Arcobacter spp., Salmonella spp., and ruminant (livestock-based) Bacteroidales microbial source tracking markers in surface water. Also, Frey et al (2013) found that CD can significantly lower bacteria loads transmitted to surface water following the land application of liquid swine manure.…”