Health risk assessment based on indicator microorganisms in Wenyu River

Abstract

The urban river in North China are mostly replenished with unconventional water supplies. E.g. effluent from wastewater treatment plant and decentralized wastewater. Meanwhile, urban rivers are important ecological parts of the city and play a significant role in landscape/recreational function. Thus, the risk of effluent replenished urban river is needed to be evaluated. This study monitored sampling points set along Wenyu River-a typical unconventional river and systematically studied the indicator bacteria including fecal coliform(FC), Escherichia coli(EC), and enterococcus(ENT) in 2015. The influence of unconventional water on microbial pollution status and health risk is assessed by Quantitative Microbial Risk Assessment Method(QMRA). The results show that: (1)calculated with different dose-response equations, the value of the single exposure microbial risk of Wenyu River is in the range of 0.1 to 0.5, indicating most are unacceptable. The health risk of a single exposure by contacting downstream water that is heavily affected by unconventional replenished water may be as much as 50% higher than the upstream water. The results of risk assessment obtained from different dose-response relationships have some similarities. (2)Considering the one-time exposure health risk characterized by different microbes in Wenyu River, the exposure risk caused by swimming in both upstream and downstream was the highest in the four exposure pathways discussed in this study. By the one-year health risk characterization, river cleaning staff and cruise drivers who frequently contacted the water are faced with higher health risks.