1. slide 1

2. Water-supply system Treatment slide 2 Ambientgroundwater Watercaptured by supply wells Drinkingwater

3. slide 3 Hawaii Oahu Alaska No VOC Detection VOC Detection

4. VOC concentrations in aquifers Not detected Detected, below 1 ppb slide 4 Detected, above 1 ppb

5. Chloroform was the most frequently detected VOC in aquifer samples slide 5 DETECTION FREQUENCY, IN PERCENT Toluene TCE PCE Chloroform 02468MTBE

6. PCE and TCE were also frequently detected in aquifer samples slide 6 DETECTION FREQUENCY, IN PERCENT Toluene TCE PCE Chloroform 02468MTBE

7. MTBE was the third most frequently detected VOC in aquifer samples slide 7 DETECTION FREQUENCY, IN PERCENT Toluene TCE PCE Chloroform 02468 MTBE

8. Domestic wells slide 8 Public wells and

9. slide 9 Hawaii Oahu Alaska No VOC Detection Concentration less than MCL or HBSL Concentration greater than MCL

10. 0510152025 30 Public wells Domestic wells DETECTION FREQUENCY, IN PERCENT concentrations below MCLs and HBSLs concentrations greater than MCLs slide 10

11. VOCs with concentrations greater than MCLs slide 11 DBCPX 1,2-DichloropropaneX EDBX 1,1-DichloroetheneXX Vinyl chlorideX TCEXX PCEXX Methylene chlorideX Domestic Compound Public Well type Fumigants Chemical production Solvents Group

12. THMs in domestic and public wells Chloroform Bromodichloromethane Dibromochloromethane Bromoform 024681012 DETECTION FREQUENCY, IN PERCENT slide 12 Domestic Public

13. Summary Widespread occurrence of VOCs Concentrations seldom of potential concern Large number of vulnerable aquifers slide 13