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Abstract We demonstrated that floods can induce severe microbiological contamination of drinking water from wells and suggest strategies to better address water safety plans for groundwater drinking supplies. Since 2002, the Italian Water Research Institute (IRSA) has detected hepatitis A virus, adenovirus, rotavirus, norovirus, and enterovirus in water samples from wells in the Salento peninsula, southern Italy. Perturbations in the ionic strength in water flow can initiate strong virus detachments from terra rossa sediments in karst fractures. This study therefore explored the potential health impacts of prolonged runoff injections in Salento groundwater caused by severe flooding during October 2018. A mathematical model for virus fate and transport in fractures was applied to determine the impact of floodwater injection on groundwater quality by incorporating mechanisms that affect virus attachment/detachment and survival in flowing water at microscale. This model predicted target concentrations of enteric viruses that can occur unexpectedly in wells at considerable distances (5–8 km) from the runoff injection site (sinkhole). Subsequently, the health impact of viruses in drinking water supplied from contaminated wells was estimated during the summer on the Salento coast. Specific unpublished dose-response model coefficients were proposed to determine the infection probabilities for Echo-11 and Polio 1 enteroviruses through ingestion. The median (50%) risk of infection was estimated at 6.3 · 10−3 with an uncertainty of 23%. The predicted burden of diseases was 4.89 disability adjusted life years per year, i.e., twice the maximum tolerable disease burden. The results highlight the requirement for additional water disinfection treatments in Salento prior to the distribution of drinking water. Moreover, monthly controls of enteric virus occurrence in water from wells should be imposed by a new water framework directive in semiarid regions because of the vulnerability of karst carbonate aquifers to prolonged floodwater injections and enteric virus contamination. Graphical abstract Unlabelled Image Highlights • Human health impact of prolonged floodwater injections in groundwater • Climate change impact makes virus presence in carbonate aquifers more likely. • Floodwater can enable virus detachments from terra rossa in limestone aquifers. • Virus occurrence in drinking water from wells far 8 km from flooding injections • Low count of fecal indicators does not prevent virus occurrence in drinking water. [ABSTRACT FROM AUTHOR]

Among the determinants of environmental health risk perception, health literacy and social media messages have been generally neglected. This study details the environmental health risk perception and its determinants in Italian university students, including a measure of functional health literacy and an analysis of newspapers and social media. A cross sectional survey was carried out among students from 15 Italian universities and different disciplines (grouped into Scientific-Health and Humanistic-Legal-Social sectors) using a self-administered anonymous questionnaire, divided into six sections: socio-demographic characteristics, information on health and environment, environmental health risk perception, trust, attitudes and behaviors and functional health literacy. Local newspapers and tweets in the same areas and period were analyzed in relation to quantity and topics. The study population included 4778 students (65.1% female) aged 21 ± 4.3 years, and functional health literacy was low (below the cutoff value) for 44.4% of students. A new outcome of the survey is that the detected association between high functional health literacy a higher global health risk perception and trust in institutions both as sources of information and as actors for protection against environmental risks. The internet and social networks were the most frequently consulted sources of information (77.7%), which was predictive of a higher risk perception. The possible relation between environmental health risk perception and tweet communication was highlighted by a comparison between the risk perception in the city with the highest number of tweets (Modena) and another one similar for socio-demographic characteristics (Pisa). In conclusion, the results of our study may be of help to strengthen information and education programs: functional health literacy should be taken into account in school programs, to produce a basic knowledge for a better understanding of health and environment. Moreover, mass and social media should be included in planning communication intervention and in verifying their results. Unlabelled Image • Nation-wide cross-sectional study enrolling 15 Italian universities • Topics: environmental health risk perception, trust, attitudes, information sources • Internet and social media are the most frequently sources of information • Risk perception associated with functional health literacy and internet use • Trust in Institutions associated with functional health literacy and residence [ABSTRACT FROM AUTHOR]

Legionella quantification in environmental samples is overestimated by qPCR. Combination with a viable dye, such as Propidium monoazide (PMA), could make qPCR (named then vPCR) very reliable. In this multicentre study 717 artificial water samples, spiked with fixed concentrations of Legionella and interfering bacterial flora, were analysed by qPCR, vPCR and culture and data were compared by statistical analysis. A heat-treatment at 55 °C for 10 minutes was also performed to obtain viable and not-viable bacteria. When data of vPCR were compared with those of culture and qPCR, statistical analysis showed significant differences ( P < 0.001). However, although the heat-treatment caused an abatement of CFU/mL ≤1 to 1 log 10 unit, the comparison between untreated and heat-treated samples analysed by vPCR highlighted non-significant differences ( P > 0.05). Overall this study provided a good experimental reproducibility of vPCR but also highlighted limits of PMA in the discriminating capability of dead and live bacteria, making vPCR not completely reliable. [ABSTRACT FROM AUTHOR]