QMRAcatch: Microbial Quality Simulation of Water Resources including Infection Risk Assessment

Abstract

Given the complex hydrologic dynamics of water catchments and conflicts between nature protection and public water supply, models may help to understand catchment dynamics and evaluate contamination scenarios and may support best environmental practices and water safety management. A catchment model can be an educative tool for investigating water quality and for communication between parties with different interests in the catchment. This article introduces an interactive computational tool, QMRAcatch, that was developed to simulate concentrations in water resources of Escherichia coli, a humanassociated Bacteroidetes microbial source tracking (MST) marker, enterovirus, norovirus, Campylobacter, and Cryptosporidium as target microorganisms and viruses (TMVs). The model domain encompasses a main river with wastewater discharges and a floodplain with a floodplain river. Diffuse agricultural sources of TMVs that discharge into the main river are not included in this stage of development. The floodplain river is fed by the main river and may flood the plain. Discharged TMVs in the river are subject to dilution and temperature-dependent degradation. River travel times are calculated using the Manning-GaucklerStrickler formula. Fecal deposits from wildlife, birds, and visitors in the floodplain are resuspended in flood water, runoff to the floodplain river, or infiltrate groundwater. Fecal indicator and MST marker data facilitate calibration. Infection risks from exposure to the pathogenic TMVs by swimming or drinking water consumption are calculated, and the required pathogen removal by treatment to meet a health-based quality target can be determined. Applicability of QMRAcatch is demonstrated by calibrating the tool for a study site at the River Danube near Vienna, Austria, using field TMV data, including a sensitivity analysis and evaluation of the model outcomes.

The QMRAcatch approach for guiding sustainable water safety management options at a large river

“…Concentrations of virus particles were determined by virus concentration and subsequent quantification in tissue culture. The QMRA integrated with hydrological process modelling was realized with the computational tool QMRAcatch (Schijven et al, 2015) free download link: www.waterandhealth.at). In QMRAcatch concentrations of health-related microbes/viruses in rivers and river/floodplain systems are simulated.…”

“…In order to determine the required virus removal by RBF and further disinfection for safe drinking water production, dose-response models were used. The dose response model for norovirus and enterovirus is the hypergeometric dose response model (Schijven et al, 2015;Teunis et al, 2008). It accounts for beta-distributed infectivity levels of the viruses and for Poisson-distributed virus particle numbers for the dose estimation.…”

“…This case study highlights a quantitative microbial risk assessment (QMRA) integrated with hydrological process modelling using QMRAcatch for drinking water resources located in a large river/floodplain area (Derx et al, 2016;Schijven et al, 2015). The presented approach addresses the sustainable development goal (SDG) 6.3 to prioritize on where and how to reduce the pollution.…”

Critical Role of Preferential Flow in Field‐Scale Pathogen Transport and Retention

“…The World Health Organization has recommended a healthbased target for tap water consumption of not more than one infection per 10,000 people per year, which is consistent with a maximum pathogen concentration on the order of 10 −6 N L −1 (World Health Organization, 2011). In contrast, typical concentrations of pathogenic Cryptosporidium and of enteroviruses in the effluent of large wastewater treatment plants are on the order of 100 N L −1 (e.g., Schijven et al, 2015). Hence, effluent from wastewater treatment plants needs an additional 8 log 10 (10 0 million-fold) reduction in pathogen concentration before it can serve as drinking water.…”

Molecular Analyses of Fecal Bacteria and Hydrodynamic Modeling for Microbial Risk Assessment of a Drinking Water Source

“…However, the suppliers have difficulties estimating putative pathogen concentrations at the water intake, due to sparse monitoring of pathogens and lack of quantitative data. Thus, to support risk assessment and evaluate risk reduction measures, fate and transport modeling of FIB and pathogens has been applied [18][19][20][21][22]. In Sweden, coupling fate and transport modeling with QMRA is still relatively rare, but some examples exist [23] and simplified methods have been developed for practical application to meet the increasing interest and need, see e.g., Åström and Johansson [24], Åström, Lindhe, Bergvall, Rosén, and Lång [17].…”