Pollution Source Identification, Tracking, and Sanitary Survey on Italian Beaches

In Italy, sea-bathing tourism is a very important socioeconomic resource, but it is being impacted by the rapid urbanization of the coastal environment, which represents pollution pressure on water quality with point and diffuse sources of fecal contamination. This study was carried out at Versilia, a popular bathing destination northwest of Tuscany, where short-term pollution posed the problem of possible classification as “scarce” (according to the current European Bathing Water Directive) because of fecal contamination from drainage ditches. Our goal was to understand the impact of polluted streams on seawater contamination and the effect of meteorological conditions on freshwater and seawater bacterial indicator levels. The monitoring results from the 2012 to 2015 bathing seasons were analyzed and, only for 2015, we used cultural and biomolecular techniques to detect fecal-oral pathogens and viral indicators at ditch mouths. Our results demonstrate a relationship between bacterial indicator levels and rainfall amount; however, microbiological pollution also was highly variable in dry weather, suggesting the presence of undetected sources of fecal contamination. Collected data from seawater and river mouths show a timedependent dilution effect of the sea that varied between the two halves of each bathing season. During 2015—the last year of monitoring—besides bacteria indicators, we found only the human adenovirus genome. This analytical survey of the pollution sources in Versilia recreational water could be used to create larger monitoring data sets for developing predictive models of microbial contamination in relation to climatic conditions and disinfection intervention