A Comparison of Water Quality Measures by Standard and Novel Methods at Chicago Beaches

Water quality at three Chicago beaches was measured by traditional and rapid methods. An evaluation of the method performance was conducted by measuring the method detection limit, rate of false positives, precision, and precision of dilutions for each of six methods. The association between results of traditional and rapid methods was measured. The effect of shift and location on the observed associations was characterized by testing for statistical interaction. Quantitative polymerase chain reaction (qPCR) and EasyPhage, two of the rapids methods, performed well and demonstrated strong associations with Colilert and Enterolert, the traditional methods. Performance of the Immunomagnetic Separation / Adenosine Triphosphate (IMS/ATP) method for E. coli and enterococci was inconsistent and demonstrated weak associations with Colilert and Enterolert.