TABLE 5.

Summary of phase 3 Dunnett's test results for time 0 comparisons (alpha = 0.05)

Laboratory	Site	Method	Spiked	Coolant	Mean no. of E. coli/100 ml at time 0	No. of E. coli/100 ml (significant change in density) at indicated time (h) after sample collectiona
						8	24	30	48
Fairfax County Water	Potomac River	Colilert	Yes	Wet ice	73	NS	51 (D)	NS	NS
Fort Worth Water	Rolling Hills WTPb	Colilert	Yes	Utek	63	NS	NS	NS	NS
Indianapolis Water	Fall Creek	Colilert	No	Utek	337	NS	NS	NS	NS
	White River	Colilert	No	Utek	534	NS	NS	NS	NS
City of Phoenix	Squaw Peak WTP	Colilert	No	Wet ice	11	NS	NS	NS	NS
	Union Hills WTP	Colilert	Yes	Wet ice	69	NS	NS	NS	NS
Jefferson Parish	Mississippi River	mTEC	No	Wet ice	310	NS	NS	NS	NS
Southern Nevada	SNWS Pumping Plant 1	mTEC	Yes	Utek	17	30 (I)	32 (I)	34 (I)	44 (I)
Passaic Valley	Passaic & Ramapo Rivers	mFC/NA-MUG	No	Blue ice	193	NS	90 (D)	108 (D)	85 (D)
Portland Water Bureau	Station 2	mEndo/NA-MUG	Yes	Blue ice	44	NS	55 (I)	NS	NS
Mohawk Valley	Hinckley Reservoir	mEndo/NA-MUG	Yes	Utek	42	97 (I)	NS	NS	NS
Wisconsin State Laboratory of Hygiene	Willow Creek	mEndo/NA-MUG	No	Wet	56,000	NS	NS	NS	NS
	Wingra Springs	mEndo/NA-MUG	No	Wet	367	NS	NS	NS	NS

^aD, significant decrease in E. coli density compared to the time 0 results; I, significant increase in E. coli density compared to the time 0 results; NS, no significant difference in E. coli density compared to the time 0 results.

^bWTP, water treatment plant.