and also published by Elsevier Science Ltd.
view Water Research, Vol. 34, No. 10, pp. 2770-2778, 2000
Comparison of Methods for Determing Escherichia coli Concentrations in Recreational Waters
By Donna S. Francy and Robert A. Darner
Seventy water samples were collected from three Lake Erie beaches to compare recoveries of Escherichia coli (E. coli) using the USEPA-recommended method for recreational waters (mTEC) to recoveries using three alternative methods (MI, modified mTEC, and Colilert). The MI method compared most closely to the mTEC method in recoveries of E. coli and assessments of recreational water quality. The modified mTEC and Colilert methods generally recovered fewer E. colithan the mTEC method, and the range of differences between Colilert and mTEC was widest among the three alternative methods. More than 5 percent of the time the bacterial water quality was assessed as acceptable with the modified mTEC and Colilert methods when the standard was actually exceeded with the mTEC method. However, because samples were collected in a small geographic area, more work is necessary to test within-method variability of the modified mTEC, MI, and Colilert methods and to evaluate these methods as substitutes for the mTEC method in a variety of recreational waters.