Quality of Ground Water and Finished Water of Community Water Systems – Preliminary Findings U.S. Department of Interior U.S. Geological Survey Jessica A. Hopple May 11, 2006 San Jose, California

Focus of Today’s Talk Source Water Quality Assessment (SWQA) Design Source Water Quality Assessment (SWQA) Design Occurrence of Compounds in Source Water Wells Occurrence of Compounds in Source Water Wells Quality of Source and Finished Water and Comparison to Human-Health Benchmarks Quality of Source and Finished Water and Comparison to Human-Health Benchmarks

SWQA Design Phase 1Phase 1 –260 compounds analyzed –214 source water wells sampled Phase 2Phase 2 –Frequently occurring compounds in Phase 1 analyzed –86 source and finished water sites sampled

Twelve SWQAs Completed Study area 2 2 Largest producing Community Water Supply wells Largest producing Community Water Supply wells Important aquifers for drinking water supply Important aquifers for drinking water supply

Herbicides and Herbicide Degradates Fungicides Manufacturing Additives Insecticides and Insecticide Degradates Organic Synthesis Compounds Personal Care and Domestic Use Products Solvents Gasoline, Oxygenates, and Degradates Fumigant Related Compounds Pavement- and Combustion-derived Compounds Plant- or Animal-derived Biochemicals Disinfection By-products Refrigerants and Propellants Compounds Monitored Have Different Uses

Occurrence of Compounds in Source Water Wells (Phase 1) 260 compounds analyzed 260 compounds analyzed – 134 were not detected – 57 were detected 3 or more times

Compounds Detected in Source Water Wells Most Frequently Detected (11 – 37 % detection frequency) Emerging contaminants (ECs) (1 – 6 % detection frequency) AtrazineTetrachloroethene Trichloroethene Deethylatrazine Prometon Metolachlor Deisopropylatrazine MTBE Simazine Chloroform 4-tert-Octylphenol Caffeine Diethoxy octylphenol Menthol Methyl salicylate Monoethoxy octylphenol Tributyl phosphate Triphenyl phosphate AHTN

Quality of Source and Finished Water and Comparison to Human- Health Benchmarks (Phase 2) Maximum Contaminant Levels (MCLs)—Regulated Compounds Health-Based Screening Levels (HBSLs)—Unregulated Compounds

Frequency of Detection Similar in Source and Finished Water Atrazine Tetrachloroethene Trichloroethene Deethylatrazine Prometon Metolachlor Deisopropylatrazine MTBE Simazine - Most Frequently Detected

AtrazineTetrachloroethene Trichloroethene Deethylatrazine Prometon Metolachlor Deisopropylatrazine MTBE Simazine Concentrations Tend to be Less in Finished Than Source Water - Most Frequently Detected

Frequency of Detection Not Always Similar for Emerging Contaminants 4-tert-Octylphenol Caffeine Diethoxy octylphenol Menthol Methyl salicylate Monoethoxy octylphenol Tributyl phosphate Triphenyl phosphate AHTN

Concentration of ECs Typically Not Similar in Source and Finished Water 4-tert-OctylphenolCaffeine Diethoxy octylphenol Menthol Methyl salicylate Monoethoxy octylphenol Tributyl phosphate Triphenyl phosphate AHTN

Concentrations in Finished Water Below Human-Health Benchmarks MCLs HBSLs NoMCLsorHBSLs AtrazineTetrachloroethene Trichloroethene Deethylatrazine Prometon Metolachlor Deisopropylatrazine MTBE Simazine

Conclusions ~ ½ of the compounds analyzed were not detected in source water wells ~ ½ of the compounds analyzed were not detected in source water wells Frequently detected compounds – usually present in both source and finished water wells Frequently detected compounds – usually present in both source and finished water wells Emerging contaminants – not always present in both source and finished water wells Emerging contaminants – not always present in both source and finished water wells Concentrations usually were orders of magnitude below human-health benchmarks Concentrations usually were orders of magnitude below human-health benchmarks

Information on NAWQA: World Wide Web: Information on SWQAs: Name: Greg Delzer Phone: (605)

Information on NAWQA: World Wide Web: Information on SWQAs: Name: Greg Delzer Phone: (605)