This project will focus on global changes impact on the microbiological quality of urban and peri-urban lakes in Ile-de-France (France). The goal is to better understand the impact of anthropogenic pressures and changes of land use on bacterial populations in urban lakes, to identify indicators of quality and ecological status and to better evaluate the ecology of emerging waterborne pathogens such as nontuberculous mycobacteria. The study will include an annual survey of forty eight lakes and a monthly monitoring of the Créteil Lake to assess the temporal and spatial variations of bacterial communities, faecal contamination indicators and nontuberculous mycobacteria. A supplementary study will be undertaken to identify the favorable habitats of mycobacteria in urban lakes.