TABLE 10.

Comparison in viral nucleic acid reductions in surface waters and groundwaters incubated at 4°C

Virus	Mean nucleic acid reduction rate ± 95% CI (log10/day)a for:		P for comparison between rates
	Surface water	Groundwater
MS2	0.04 ± 0.01	0.02 ± 0.04	0.158
MNV	ND	ND
FCV	0.15 ± 0.11	0.02 ± 0.11	0.001
PV	0.10 ± 0.02	0.02 ± 0.05	<0.001
NV	0.04 ± 0.02	0.01 ± 0.05	<0.001

^aEstimated mean reduction rates and 95% confidence intervals as determined by multiple linear regression models. ND, not done.