Fig. 3. Change in mean concentration of E. coli (cfu/100 mL) in surface water runoff samples held for 6, 24, 48, and 72 h from collection (time = 0 h) before processing. Data points represent the mean concentration of five replicates with an initial concentration of 10³, 10⁴, 10⁶, and 10⁷ cfu/100 mL, respectively. Error bars report one standard error of the mean.