Viral dispersal in the coastal zone: A method to quantify water quality risk. (May 2019)

• Record Type: Journal Article
• Authors: Robins, Peter E.; Farkas, Kata; Cooper, David; Malham, Shelagh K.; Jones, Davey L.
• Is Part Of: Environment international. Volume 126(2019)
• Page Start: 430
• Page End: 442
• Publication Date: 2019-05
• Subjects: Extreme events -- Combination Hazard -- Recreational waters -- Risk assessment -- Sewage discharge; Environmental protection -- Periodicals; Environmental health -- Periodicals; Environmental monitoring -- Periodicals; Environmental Monitoring -- Periodicals; Environnement -- Protection -- Périodiques; Hygiène du milieu -- Périodiques; Environnement -- Surveillance -- Périodiques; Environmental health; Environmental monitoring; Environmental protection; Periodicals; 333.705
• DOI: 10.1016/j.envint.2019.02.042
• Languages: English
• ISSNs: 0160-4120

Abstract

Abstract: Waterborne and shellfish-borne enteric viruses associated with wastewater-polluted coastal waters (e.g. Norovirus, Hepatitis A/E viruses, Adenovirus) represent a major threat to human health. Improved understanding of the locations and periods of heightened risks can help target mitigation measures and improve public health. We developed a river-estuary-coast model to simulate virus dispersal, driven by point source discharges and river flows in combination with tidal forcing. Viral inputs were based on measured wastewater adenovirus concentrations and the model was implemented with or without viral die-off. We applied the model to the Conwy river (North Wales, UK), through the estuary, to the Irish Sea coast where bathing waters and shellfisheries are known to be prone to viral contamination. Using a suite of scenarios, we showed that river flow was the primary control of viral export to the coast. Since the Conwy catchment is short and steep, and the estuary is small and river-dominated, short-duration high intensity 'flash floods' were shown to transport viruses through the estuary and out to sea, despite dilution or die-off effects. Duplicating flow events (i.e., storm clustering) did not double the virus export since the virus re-entered the estuary on the flood tide. The tidal magnitude and timing of high water relative to peak river flow were also important drivers regulating viral dispersal. A worst-case event simulation (i.e., combining high river flows with high viral loading and high spring tide) resulted in increased concentrations of virus at nearby coasts, although the spatial spread was similar to the previous scenarios. Our results suggest that impact models for predicting and mitigating episodes of poor microbiological water quality may require careful representation of the intensity and timings of river flow when evaluating pathogen exposure risk. Highlights: Enteric viruses can travel from catchment to estuary while active, within hours. Coastal recreational waters and shellfisheries have heightened exposure to viruses. The level of coast exposure is high during ebb tide and high river flow conditions. Our results represent small catchment-estuary systems, which are common in the UK. Models for mitigating coastal health risk require sub-daily river flow data.