Etude de la dynamique des Escherichia coli dans les rivières du bassin de la Seine

摘要: The purpose of our study was to describe the dynamics E. coli in rivers Seine watershed. This watershed is characterized by a poor microbiological water quality due an important population density, industrial activities and intensive agriculture. main objectives were obtain field data describing system understand underlying mechanisms order build model able predict fate fecal bacteria at scale whole built help management quality. To be modelize such large complex system, it first necessary identify quantify sources contamination processes affecting these once discharged rivers. quantification natural aquatic systems through traditional culture-based techniques has been strongly questioned during last years because they have long response delay (24 48 h) do not take into account viable but culturable (VBNC) which nevertheless could represent health thread. For this reason we developed two alternative methods: direct (without passing cultivation step) measurement â-D-glucuronidase activity fluorescent situ hybridization with specific probe coupled viability test. advangate give very rapid evaluation content while second one enumerate VBNC coli. revealed predominance, anthropogenicised watershed, point (effluents from wastewater tretament plants). Diffuse soil leaching surface runoff) may locally also quantified. influence land use on diffuse quantified demonstrating that runoff grazed areas mainly responsible rural areas.The attachment E .coli particles river waters studied as can kind systems. A linear regression found between percentage particle-associated SM water. Settling velocities determined. mortality rate analysed following various perspectives: order, particles, importance cultivability loss disappearance protozoan grazing. results confirmed grazing showed abondance free living decreased times more rapidly than In river, net 1.5 time higher Finally, no relationship order. These used models CF-SENEQUE CF-SiAM-3D respectively for estuary. Comparisons calcultaions coliforms abundances correctly simulated longitudinal distribution colifoms test impact scenarii .