Decay of Coliphages in Sewage-Contaminated Freshwater: Uncertainty and Seasonal Effects

Abstract

Understanding the fate of enteric viruses in water is vital for protection of water quality. However, the decay of enteric viruses is not well characterized, and its uncertainty has not been examined yet. In this study, the decay of coliphages, an indicator for enteric viruses, was investigated in situ under both sunlit and shaded conditions as well as in summer and winter. The decay rates of coliphages and their uncertainties were analyzed using a Bayesian approach. The results from the summer experiments revealed that the decay rates of somatic coliphages were significantly higher in sunlight (1.29 ± 0.06 day) than in shade (0.96 ± 0.04 day), but the decay rates of male-specific (F+) coliphages were not significantly different between sunlight (1.09 ± 0.09 day) and shaded treatments (1.11 ± 0.08 day). The decay rates of both F+ coliphages (0.25 ± 0.02 day) and somatic coliphages (0.12 ± 0.01 day) in winter were considerably lower than those in summer. Temperature and chlorophyll a (chla) concentration varied significantly (p < 0.001) between the two seasons, suggesting that these parameters might be important contributors to the seasonal variation of coliphage decay. Additionally, the Bayesian approach provided full distributions of decay rates and reduced the uncertainty, offering useful information for comparing decay rates under different conditions.

Decay of infectious adenovirus and coliphages in freshwater habitats is differentially affected by ambient sunlight and the presence of indigenous protozoa communities

“…Furthermore, the effect of ambient sunlight was more pronounced for somatic coliphages, compared to F+ coliphages and adenoviruses. This is consistent with previous studies [50, 66, 76, 82] reporting a greater susceptibility of somatic coliphages to sunlight compared to other viral groups. While exposure to both UV-A and UV-B spectrum is detrimental, earlier studies investigating the mechanism of sunlight action, suggest that indirect, photooxidative damage may be the primary mechanism for adenovirus and F+ coliphages [44, 51, 76], while direct damage caused by UV-B is the dominant mechanism for somatic coliphages [44, 76].…”

Viral and Bacterial Fecal Indicators in Untreated Wastewater across the Contiguous United States Exhibit Geospatial Trends

“…Finally, somatic coliphage, total coliphage (CB-390), Bacteroidetes (GenBac3), and E. coli (EC23S857) concentrations showed a significant correlation with average air temperature prior to sampling (Table 3). A recent review suggests that ambient water temperature is a key factor influencing the decay of many indicators (70), especially coliphage (71,72). In addition, meta-analyses of somatic and F ϩ coliphage decay rates confirmed the high sensitivity of these viral groups to water temperature across multiple studies (73), potentially explaining this geospatial trend in somatic coliphage assuming there is a predictable link between air and sewage temperatures in this study.…”

Modelling the seasonal impacts of a wastewater treatment plant on water quality in a Mediterranean stream using microbial indicators

“…In this study, the dry season, when the flow upstream of the WWTP was nearly 0 m 3 •s -1 , coincided with the highest temperatures. These results are in agreement with previous studies (Ballesté et al, 2018;Ballesté and Blanch, 2010;Bonjoch et al, 2009;Fauvel et al, 2017;Wu et al, 2016) where the seasonality of decay rates for different FIOs was strongly correlated to changes in temperature. Concurrently, SDDs were related with decay rates, indicating that in the wet season the stream capacity to self-depurate decreased, as longer transport distances were needed to return to the concentrations upstream of the WWTP.…”