Specific Viruses Present in Polluted Groundwater Are Indicative of the Source of Nitrates and Faecal Contamination in Agricultural Areas

Abstract

Microbial source tracking (MST) tools are used to identify sources of faecal pollution to accurately assess public health risks and implement best management practices. Many different viruses are excreted by humans and animals and are frequently detected in water contaminated with faeces or/and urine. Because of the large degree of host specificity of each virus and the substantial stability of many excreted viruses in the environment, some viral groups are considered to be accurate MST indicators. The Laboratory of Virus Contaminants of Water and Food at the University of Barcelona has proposed the use of viral indicators as well as cost-effective methods for the concentration of viruses from water. The developed procedures have been used to determine the levels of faecal pollution in environmental samples as well as for tracing the origin of faecal contamination. Such tools were recently used by the Catalan Water Agency to identify nitrate contamination sources in groundwater. Human adenoviruses, human polyomavirus JC, porcine adenoviruses, bovine polyomaviruses, chicken/turkey parvoviruses, and ovine polyomaviruses can be quantified in samples using molecular methods (qPCR). The selected DNA viruses specifically infect their hosts and are persistently excreted in faeces and/or urine throughout the year in all geographical areas studied. The procedures that have been developed to quantify these viruses have been applied to bathing, coastal, surface and groundwater. In this study, the source of nitrate contamination in groundwater was identified by analysing viral markers, thereby demonstrating the usefulness of