Impact de l'agroenvironnement sur la qualite microbiologique des eaux recreatives dans une perspective de sante publique

Microbial pollution of recreational waters may constitute a health risk for exposed populations. Fecal contamination of these waters represents an important component of this risk, especially due to the possible presence of pathogens and exposure to antimicrobial resistant microorganisms. Sources of fecal pollution are many and include agricultural activities and animal production. This project aims to better understand agroenvironmental factors influencing the microbiological quality of recreational waters of Southern Quebec and also suggests and assesses new sources of data which may contribute to the identification of these factors.;An evaluation of the presence of antimicrobial resistant Escherichia coli in the recreational waters studied was first performed. Given the positive results found, certain bodies of waters may represent a source of antimicrobial resistant microorganisms for people engaged in water activities. However the public health impact of such exposure is still unknown.;Agroenvironmental determinants associated with the presence of antimicrobial resistant microorganisms were investigated. Results of this chapter suggest that agricultural activities, especially liquid manure spreading, may be associated with the contamination of recreational waters with antimicrobial resistant microorganisms.;The next chapter assesses key time-independent agroenvironmental determinants associated with the fecal contamination of studied recreational waters. Various variables -- classified as either agricultural activities, human activities or geo-hydrological characteristics -- are explored through a multivariate logistic regression model. It appears that recreational waters with ruminant productions in their proximal environment, especially when they are within a radius of 2 km, may present a higher risk of fecal contamination. A positive association was also noticed between the level of fecal contamination of a beach and its presence in an urban area. From a public health perspective, recreational waters may be contaminated by animal and human sources and these sources may represent a risk for bathers' health.;Finally, association between fecal contamination of recreational waters and agroenvironment determinants was studied through a logistic regression model built from remote sensing data. This chapter assesses the utility of such data in the identification of these determinants and discusses the strengths and the limitations of their use in the context of the monitoring of the microbiological quality of recreational waters. In this study, positive associations were found between the level of fecal contamination and both the proximity of agricultural lands and the presence of impervious surfaces. Earth observation data may constitute an added value for the water quality monitoring program in allowing the surveillance of the determinants associated with this quality.;Keywords: Recreational waters, agroenvironment, public health, fecal contamination, antimicrobial resistance, remote sensing.