Table 1.

Summary of PECs for three categories of estrogens in U.S. drinking water.

	PEC (ng/L)
	90th percentile		Average
Category, compound	Mean flow	Low flow	Mean flow	Low flow
Endogenous estrogens from diet and naturally produced
E1	0.1	1.1	0.03	0.26
E2	0.02	0.19	0.01	0.05
E3	0.02	0.02	0.01	0.02
Prescribed endogenous estrogens
E1	0.02	0.18	0.01	0.04
E2	0.002	0.02	0.0006	0.005
E3	0.000015	0.000013	0.000006	0.000016
Prescribed synthetic estrogens
EE2	0.003	0.05	0.001	0.01