Table 1.

RRs and aRs of bathing above NOAELs versus nonbathing, and aRs of swallowing water versus not swallowing water below and above NOAELs by exposure definition, fecal indicator, and definition of gastroenteritis 1 week after exposure.

Exposure definitiona	Fecal indicator	Definition of GE	NOAEL (MO/100 mL)	RR, bathing > NOAEL	95% CI	aR (%), bathing > NOAEL	aR (%), SW ≤ NOAEL	aR (%), SW > NOAEL
1	E. coli	UK	180	3.55	1.79–7.02	3.6	1.3	3.9
		UK-wf	78	2.51	1.55–4.05	4.3	1.6	2.9
		NL-2	167	1.96	1.32–2.89	5.0	1.0	3.3
	Intestinal enterococci	UK	24	3.2	1.64–6.27	3.1	1.3	3.7
		UK-wf	21	2.67	1.65–4.32	4.7	0.7	3.4
		NL-2	24	1.9	1.30–2.77	4.7	2.8	2.3
	C. perfringens	UK	13	3.34	1.72–6.51	3.3	0.4	4.1
		UK-wf	13	2.61	1.60–4.25	4.5	0.9	3.3
		NL-2	13	1.86	1.27–2.73	4.5	0.8	3.5
	Somatic coliphages	UK	150b	4.61	2.1–10.11	5.1	1.3	6.7
		UK-wf	10	2.47	1.51–4.04	4.2	1.6	2.8
		NL-2	10	1.77	1.21–2.60	4.0	2.1	2.1
2	E. coli	UK	1,453	4.41	2.17–8.96	5.2	1.6	5.3
		UK-wf	—c	—	—	—	—	—
		NL-2	2,163	2.33	1.48–3.67	8.6	0.5	8.6
	Intestinal enterococci	UK	123	3.41	1.74–6.68	3.7	1.1	4.0
		UK-wf	123	2.78	1.71–4.51	5.7	1.9	2.8
		NL-2	145	1.93	1.31–2.84	6.0	3.8	1.6
	C. perfringens	UK	38	3.12	1.62–6.03	3.2	−0.4	4.1
		UK-wf	38	2.43	1.50–3.93	4.6	0.8	3.3
		NL-2	36	1.71	1.18–2.47	4.6	0.0	3.2
	Somatic coliphages	UK	330	3.77	1.87–7.61	4.2	1.4	3.2
		UK-wf	50	2.44	1.49–3.98	4.6	1.7	2.7
		NL-2	119	1.76	1.18–2.62	4.9	0.7	3.1

Abbreviations: CI, confidence interval; GE, gastroenteritis; MO, microorganisms; SW, swallowing water.

^aExposure definitions 1 and 2 as explained in “Materials and Methods.”

^bValue is probably too high because of a second local minimum of the Pearson’s chi-squared p-values.

^cPotential NOAEL estimate does not fulfill all criteria of validity (incidence rate of bathers below NOAEL is significantly lower than incidence rate of nonbathers).