Microbial exposure risk assessment of urban wastewater by irrigation of agricultural products

This study was designed to investigate microbial exposure risk assessment and consequences of adverse health effects due to the use of irrigation of fields with wastewater in Qom province Environmental monitoring program for ۳ pathogens including Escherichia coli, Vibrio cholerae and Ecoli O۱۵۷ in raw sewage and treated wastewater and irrigated products with wastewater, was performed. Results was shown that in the raw wastewater, concentrations of E.coli, Vibrio Cholerae and E.coli O۱۵۷:H۷, ۳.۴×۱۰۳ ± ۵۰۰, ۲.۱×۱۰۳ ± ۱۰۰ and ۳۱۲ respectively were determined. Concentrations of E.coli, Vibrio Cholerae and E.coli O۱۵۷:H۷ in wastewater effluent ۲.۱×۱۰۳ ± ۱۰۰, ۰.۸×۱۰۳ ± ۱۰۰ and ۱۷۶ respectively were determined. Based on these findings, it is determined that the conventional wastewater treatment system has been effective in removing E.coli, Vibrio Cholerae and E.coli O۱۵۷: H۷ by ۵۰%, ۵۹% and ۴۳%, respectively. Irrigated crops with wastewater effluent containing ۴۰۰ ± ۲۵۰, ۰.۱×۱۰۳ ± ۰.۰۱۹ and ۵۲ for E.coli, Vibrio Cholerae and E.coli O۱۵۷:H۷ respectively were measured. In this study according to the exposure scenarios including accidental drinking, food crop consumption, dermal contact by wastewater effluent and dermal contact by raw wastewater, total annual Probability of infection in studied population for E.coli, Vibrio Cholerae and E.coli O۱۵۷:H۷, ۸×۱۰-۲, ۸×۱۰-۴ and ۰.۱۷ respectively was determined. Implementing of wastewater safety plans (WWSP) to safeguard wastewater quality, raising awareness in the population in contact with urban wastewater and upgrading wastewater treatment plants is inevitable.

Keywords:

Microbial , Wastewater , Risk , Qom , Irrigation , Products.