Multitiered Approach Using Quantitative PCR To Track Sources of Fecal Pollution Affecting Santa Monica Bay, California

摘要: The ubiquity of fecal indicator bacteria such as Escherichia coli and Enterococcus spp. in urban environments makes tracking contamination extremely challenging. A multitiered approach was used to assess sources pollution Ballona Creek, an watershed that drains the Santa Monica Bay (SMB) near Los Angeles, Calif. mass-based design at six main-stem sites four major tributaries over a 6-h period (i) flux E. by using culture-based methods (tier 1); (ii) levels quantitative PCR detect and/or quantify additional markers human contamination, including human-specific Bacteroides sp. marker enterovirus, reverse transcriptase 2); (iii) specific types enterovirus genomes found via sequence analysis 3). Sources were ubiquitous, concentrations high, throughout with no single tributary dominating inputs. averaged 10 9 cells h 1 high head mouth prior discharge into SMB. In addition, signal for consistently detected: 86% samples taken extent during study tested positive. Enteroviruses quantifiable 14 36 (39%), highest site furthest upstream (Cochran). These results indicated power multiple approaches freshwater conduits high-use, high-priority recreational swimming areas. (SMB), California, is home some most popular beaches world. It located adjacent metropolitan more than 50 million beachgoers visit SMB shorelines every year—more those visiting all other California combined (38). However, there are serious concerns about beach water quality because continued exceedances thresholds based on total coliforms, or spp., particularly areas impacted runoff. Thirteen percent shoreline mile-days exceeded between 1995 2000, 50% these storm (37). public health risk associated runoff has been directly demonstrated through epidemiology studies. Haile et al. (19) swimmers drain discharges had higher likelihood respiratory gastrointestinal symptoms 400 m from drain. Despite impairment risks health, identification elimination responsible warnings remain elusive. difficulty identifying eliminating three important factors. First, traditional indicators basis which developed not humans.