Abstract
The incidence of enteric viruses in treated wastewater and their potential release into the environment or use for agriculture are very critical matters in public health. In our study, PCR (polymerase chain reaction) analysis of enteric viruses was performed on 59 samples of influents and effluents collected from Tubli wastewater treatment plant (Water Pollution Control Center (WPCC)) and Tubli Bay, where the effluents were discharged, in Kingdom of Bahrain during two sampling periods. Four clinically essential waterborne enteric viruses were examined: enterovirus (EV), hepatitis A virus (HAV), astroviruses (AV), and rotaviruses (RV) and compared to standard bacterial and bacteriophages indicators of fecal pollution. Detection rates of EV, AV, HAV, and RV in the influent samples were 100%, 75%, 12.5%, and 12.5%, respectively, while 50% of the effluent samples from Tubli WPCC contained only EV RNA. None of the tested enteric viruses could be detected in any of the samples collected directly from Tubli Bay. Effluent samples from Tubli plant did not show significant seasonal differences. Since detection of enteric viruses genome does not necessarily indicate infectivity, the infectivity of these viruses was evaluated through isolation and growth of indictor bacteria and bacteriophages. High concentration of fecal bacteriological indicators was detected in all effluents samples (100%): 3.20 × 103 cfu/mL for E. coli, 1.32 × 103 cfu/mL for Salmonella spp., and 1.92 × 103 cfu/mL for Shigella spp. E. coli and Salmonella specific bacteriophages were also detected in the effluent samples in high titers. The combined results of PCR and bacterial enumeration point to a probable public health risk via the use of these wastewaters in agriculture or their discharge into the sea. Continuous surveillance of viral and bacterial prevalence and their resistance to sewage disinfection procedures could contribute to a better control of risks associated with the recycling of effluent wastewater and its release into the environment.
Highlights
Despite the decline of waterborne diseases’ incidence over the past decades, due to enhanced water treatment procedures, waterborne epidemics yet persist to happen [1]
Enterovirus was detected in tertiary treated sewage water from Tubli Water Pollution Control Center (WPCC), which is used for irrigation purposes, suggesting it could be resistant to the currently applied treatment processes in Tubli WPCC
Bacterial pathogens were detected at high concentrations in effluent samples, such as E. coli, Salmonella spp., and Shigella spp
Summary
Despite the decline of waterborne diseases’ incidence over the past decades, due to enhanced water treatment procedures, waterborne epidemics yet persist to happen [1]. Coastal reclamation intensified along the coastline of Tubli Bay during the last decades, resulting in densely populated residential areas nearby the outfall of Tubli WPPC This could pose a possible health risk for the public from viruses and microbial pathogens associated with sewage discharge. The presence of various pathogens in the tertiary treated effluent of wastewater treatment plants has been well documented [24,25,26]; monitoring pathogens, including viruses, is of high importance for the public health. The main objective of this study was to detect several human enteric viruses (EV, AV, RV, and HAV) in tertiary treated wastewater from Tubli WPCC as well as analyzing water samples from Tubli Bay during two sampling periods, to examine the infectious potential of treated effluents and to estimate the efficiency of decontamination procedures. Public Health 2020, 17, x FOR PEER REVIEW wastewater treatment processes that can be valuable for environmental risk assessment of sewage plants
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
