Table 2.

Arsenic distribution by water supply and residential history strata for lifetime exposure reconstruction of cases and controls, South-eastern Michigan, Enrolled 2002–2006

	Cases		Controls
	Person-years (%)	Arsenic distribution (µg/L) (5%, 50%, 95%)	Person-years (%)	Arsenic distribution (µg/L) (5%, 50%, 95%)
Measurements at current residence
Private well	11.6	0.1, 5.3, 37.4	11.8	0.02, 1.8, 27.7
Public supply	15.7	0.1, 0.3, 3.6	15.0	0.02, 0.3, 3.5
Bottled water	0.6	0.02, 0.2, 1.0	0.6	0.02, 0.20, 0.20
Past residencesa in study area
Private wellb	16.4	0.02, 4.0, 24.9	16.0	0.02, 4.3, 21.7
Public supplyc	23.0	0.3, 0.3, 11.1	21.8	0.3, 0.9, 8.4
Past residencesa outside of study area
Detroit public supply	12.8	0.3, 0.3, 0.3	13.8	0.3, 0.3, 0.3
Other public supplyd	12.0	0.3, 0.3, 4.6	14.7	0.3, 0.3, 4.1
Private wellse	5.7	0.3, 0.3, 5.0	4.8	0.3, 0.3, 8.0
International	1.2	0.3, 0.3, 0.3	1.0	0.3, 0.3, 0.3
Residence not provided	1.0		0.5
Residences
Total	3,741		5,082
Average per person	9.1		9.0

^aBottled water not reported at past residences

^bArsenic estimates from geostatistical model

^cArsenic estimates from Michigan Department of Environmental Quality database, and water supplier history

^dArsenic estimates from Natural Resources Defense Council database of arsenic in public water supplies

^eArsenic estimates from United States Geological Survey database of arsenic in groundwater