Evaluation of chemical, molecular, and traditional markers of fecal contamination in an effluent dominated urban stream.

In this paper we present a quantitative sanitary survey of the Middle Santa Ana River, in southern California, utilizing a variety of source tracking tools, including traditional culture-dependent fecal markers (Enterococcus and Escherichia coli by IDEXX), speciation of enterococci isolates, culture-independent fecal markers (human-specific HF183 Bacteroides and Enterococcus by quantitative polymerase chain reaction, qPCR), and chemical markers of sewage and wastewater (nutrients, enantiomeric fraction (EF) of propranolol and ethylenediaminetetraacetic acid). To facilitate comparison of these different methods, data are interpreted in a loading (i.e., mass per time) framework that enables a quantitative apportionment of fecal markers and nutrients to specific source waters in the Middle Santa Ana River. Multiple lines of evidence support the hypothesis that Enterococcus in the Middle Santa Ana River originates primarily from in situ growth in streambed sediments, not from significant and persistent source...