Relationship between precipitation, flow, water temperature and soil use with adenovirus contamination in surface water resources 106 frequency and loads of Enterovirus (EV), HAdV-C and F, Rotavirus (RV) and Hepatitis A (HAV) species in sand and water samples from the sites used during the 2016 Summer Olympics Games in the city of Rio de Janeiro the results show that 95.9% of the water samples were contaminated with at least one type of virus. Viral loads ranged from 103gc.L-1 to 109 gc.L-1 (water) and 103gc.g-1 to 106 gc.g-1 (sand). Dalla Vecchia et al. (2015) and Rodrigues et al. (2015) in studies conducted with water samples collected in the Sinos River Watershed (SRW), located next to the CRW, also detected the presence of HAdV with viral load between 104 and 108 gc.L-1. AnalyzingtheHAdVconcentration,wasobservedthat thehighest concentrations occurred on the dates of 09/24/2016, 12/03/2016, 06/27/2016 and 03/18/2017; these dates that had previous precipitations of 0.5; 41.3; 1.85 and 95.7 mm, respectively, see Table 1. This fact leads us to verify that the HAdV concentration was inversely proportional to rainfall events, as shown in Table 2, in which a strong and moderate negative correlation is observed, respectively. That is, the greater the rainfall event, the lower the concentration of HAdV, as these pathogens will be diluted due to the increase in the volume of water in the river (Senhorst and Zwolsman 2005; Hofstra 2011). From this it, can be concluded that the HAdV inputs are constant in time, due to the discharge of in natura effluents in the watercourses of the watershed. It is observed that there is a low relationship between the presence of BAdV and hydrological events (Table 1). This fact can be explained by the high presence of cattle around the watercourse, in which the herd accesses the banks for their desiccation, defecating near the banks of the rivers and their feces are carried diffusely to the water course. In the study region there are around 38,400 head of cattle (Ferguson et al., 2003; Lenaker et al., 2017; Sebrae, 2017). The hydrological peculiarities of each watershed influence the dispersion dynamics and are able to affect the DNA stability of viral particles, as well as their viability in the environment. Studies relating precipitation to the presence of AdV were presented by Parker et al. (2010); Hata et al. (2014); Rodrigues et al. (2015); Steele et al. (2018), among others. In addition to precipitation, Enriquez et al. (1995) and Yates et al. (2016) report that temperature seems to play a fundamental role in the survival of enteric viruses in water
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