STATE WATER PROJECT TRlHALOMETHANE STUDY /- Central District April 1982 · ., FOREWORD Trihalamethanes, ar THMs, are patential cancer causing chemicals farmed in drinking water when certain substances in the water react with chlarine during water treatment.. The primary materials that react to. farm THMs come fram decaying plants and arganic sails. Chlarafarm is the mast·camman type af TBM faund in municipal water supplies~ Cancern aver the widespread accurrence af TBMs in drinking water supplies has recently led to. Federal regulatians limiting their allawable cancentratians. Stud.ies by the Califarnia Department af Health Services, the Metropalitan Water District af Sauthern California, and ather agencies have pravided evidence that water taken fram the sauthern Sacramenta-San Jaaquin Delta is higher in TBM-forming agents than is water fram upstream of the Delta. Treated drinking water fram the southern Delta generally fails to meet the new drinking water standard~ As a result, agencies supplying drinking water fram this saurce are faced with the possible requirement to pravide ' additional castly treatment far TBM removal. The purposes of the State Water Project Trihalomethane Study were to investigate the sources of TBM-forming agents in the State Water Project and to evaluate potential means of reducing their concentrations. In particular, the propased Peripheral Canal was evaluated in terms of its effects in reducing cancentratians of these agents. The study concluded that aperation of the Peripheral Canal would significantly reduce the levels of THMs in the water supplies of Alameda; Contra Costa, and Santa Clara Counties, and Southern California. ~~~C~~ Chief, Central District iii CONTENTS FOREWORD iii ORGANIZATION . vii ACKNOWLEDGEMl!:NTS' .0 0 _. .". e. ea. • • • , viii CONVERSION· FACTORS :' 0 ..0 0 • 0 0 .. 0 0 0 0 o· o· 0 o. 0 Inside. Back Covet: , . • , ;'. \ e" • • ,.' • ;,a • • • • Ii • • • e" o " 1 INTRODUCTION · . 3 FINDINGS AN:D CONCLUSJ:QNS 0 0 o. ,0 0 0 0 • 0 0 0 0 0 ',. .- . '. 7 Findings 0 00 0'0 • II • • • • • Ii • • • • • • • • 7 Conclusions · .:. ... 7 RECOMMENDATIONS o 0 0 ,~. .. o 0 0 9 METHODS 0 0 J 0 0 0 0', ..:~ ·0 :_.. • a: • • ,a • • e, • • •. • • • • • • 11 Sampling Mlathods; 0 · . • • • ti • .. 11 Analytical Methods . ,- .," .. .., ,. ~. 12 . DISCUSSION OF RESULTS • ,; •• ,',.,. e, •• .~ ~ i .,". ~ • 0 15 , .' ~ , ' , ' , " ' , • • ,e :'. '.. .. Comparison of Delta and SWP Ws"ters to ,NationWide Surv:ey 15 Additions of THM Precursors and Bromides Resulting from Water Transport Through the Delta • 0 0 00 0 • ~ 0 0 17 Expected Effects of the Peripheral Canal in Reducing THM Concentrations in State Water Project Water Supplies 0 '. 0 0 • 21 Expected Effects of Alternative Delta Facilities in Reducing THM Concentrations in Water Supplies of the State Water Project 0 0 0 0 0 0 • • 0 0 0 0 0 0 0 24 Sources of THM Precursors to the Proposed Second Phase of the North Bay Aqueduct 0 0 0 0 0 0 0 • • • 0 0 24 Agricultural Drains as Sources of THM Precursors 0 . 26 iv CONTENTS (Continued) DISCUSSION OF RESULTS (Continued) Waste Water Treatment Plant Discharges as Sources of THM Precursors • • • • • 27 Expected Contribution of THM Precursors from Soils Lining the Proposed Peripheral Canal • • • • • 213 Seasonal Fluctuations in Precursor Concentrations 10 Fluctuations Related to Seasonal Precipitation • • 30 Fluctuations Related to Seasonal Plant Growths • 31 REFERENCES 35 APPENDIX A. SUMMARY OF PREVIOUS STUDIES 39 APPENDIX B. DATA ••• 49 FIGURES 1. Molecular Structures of Methane and Triha10methanes • 5 2. Sampling Location Map • . 3. Relationship of Delta Outflow to Triha10methane Formation Potential • • • • • • • • • • • • • • 30 4. Location of O'Neill Forebay and Related Facilities . 33 v TABLES 1. Gas Chromatographic Conditions Employed • • • • ,. 13 2. Triha1omethaneConcentrations in Drinking Wate'!, of Sacramento-San Joaquin Delta Origin as Compared to N~ tionwide 'Survey • • '. • • • • • .. • • '. • .' .; ..' 15 3. fiiha1omethane"Concentrations iii Drinking Wafer of Sacramento-Sa~ Joaquin Delta Origin • • • • . 17 .~ (.',' '! ~ , .... ':.:', 4. Triha10methane Formation Potential at Five Delta Locations . 20 , t •. 5. Triha10methane Concentrations in Drinking Water from the Sacramento River at Sacramento •• ;".' • '~ •••••••• . 22 6. Ntitrien:t 'Comparison S'acramento River vs. Harvey O. Banks Delta Pumping Plant • • • • • • • • • • • • • • • • • • • • 23 7. Triha10methane Formation Potential at Three North Delta Locations • • • • • . 25 8. Triha10methane Formation Potential in Agricultural Drainage 26 9. Triha10methane Formation Potential of Waste Water Treatment Plant Effluents 27 10. Triha10methane Formation Potential of Soils in Proposed Peripheral Canal Alignment • . 28 f ".,., 11. rriha10methane Formation Potential Associated with Aquatic' Veget'atidn' • -. '.' '. '~ •• ' ••• ' •• ' •••••••••' ... '-32 ',' vi State of California EDMUND G. BROWN JR., GOVERNOR The Resources Agency HUEY D. JOHNSON, Secretary for Resources Department of Water Resources RONALD B. ROBIE, Director CHARLES R. SHOEMAKER M. CATHARINE BERGREN ROBERT W. JAMES , ., I Deputy Director Assistant Director Deputy Director MARYANNE MARK GERALD H. MERAL Deputy Director Deputy Director CENTRAL DISTRICT Wayne MacRos tie • District Chief Kenneth L. Woodward Chief, Planning Office Robert L. McDonell • Chief, Special Studies Branch This report was prepared by Richard Woodard • • Environmental Specialist IV William J. McCune Water Resources Engineering Associate Under the direction of B. J. Archer. Chief, Water Quality and Reuse Section With assistance from r i Thomas E. Morgester Water Resources Technician II Vera L. Doherty • Editorial Technician Sharon K. Holderman Office Assistant II Marilyn P. Williams Office Assistant II Merilea Partch Graduate Student Assistant Cathy Wilson Word Processing Technician vii ACKNOWLEDGEMENTS' ' The authors of this report wish to thank the many persons who contributed information and ideas, to ,this study. Special thanks go to, Elizabeth Haden of Santa Clara yalleYWater District, to ' Elizabeth Kawczynski of Contra Costa Water District, to Stephen Nelson of the California Department of Health Services, and, to Johnie Seals and Eugene O'Reilly of the Department of'Water Resources Bryt~'Laboratory for their generous assistance and' cooperation in the conduct of the study. viii SUMMARY Trihalomethanes (TID1s) are potential DWR then took soil samples from the cancer-causing chemicals that are formed proposed alignment of the Peripheral in drinking water when naturally occur­ Canal to determine Whether these soils ring substances in the water react with are likely to affect the precursor load chorine during water treatment. From in the State Water Project if the September 1981 through January 1982, the Peripheral Canal were operational. Department of Water Resources (DWR) conducted a monitoring program to To examine possible seasonal fluctua­ determine: tions in TBM precursor concentrations, DWR collected water samples under very 1. The sources of THM-forming agents dry, fall weather conditions and during (precursors) in the waters of the very wet, winter conditions. To Sacramento-San Joaquin Delta, evaluate possible inputs of precursors Sacramento River, and State Water from aquatic vegetation, two locations Project. in the California Aqueduct were monitored. 2. Whether operational alternatives exist for reducing present As a result of the study, the Department concentrations. concluded that: DWR monitored five locations in the o Construction and operation of the Delta to measure whether TBM precursors Peripheral Canal should reduce TBM result from transporting water through precursor and bromide concentrations the Delta. This monitoring also helped in State Water Project waters south of determine whether the Peripheral Canal the Delta to levels that would meet or a through-Delta conveyance facility drinking water standards in treated would reduce precursor concentrations in water. State Water Project waters. The Delta monitoring also indicated that ocean­ o The source of water in the second derived bromide is a significant factor phase of the North Bay Aqueduct is in TBM formation. relatively low in TBM precursors. Treated water from this source should To examine the probable inputs of TBM meet the drinking water standard for precursors into the proposed North Bay TBMs. Aqueduct, DWR monitored three locations in the area of that proposed project. o Agricultural drainage and waste water treatment plant effluents contribute DWR also evaluated impacts of agricul­ measurable amounts of TBM precursors tural discharges into State Water to State Water Project waters; Project source waters by sampling two however, the most significant source agricultural drains in the Sacramento of precursors appears to be runoff River watershed. The effects of urban from soils. waste discharges upon TBM precursor concentrations in State Water Project o The soils that would line the proposed waters were evaluated by monitoring Peripheral Canal contain TBM pre­ effluents of three waste water treatment cursors. However, the leaching rate plants discharging into waters used by of these precursors into canal water the Project. should be min imal • 1 INTRODUCTION Trihalomethanes are a family of In compliance with the monitoring chemicals named after methane, which requirement of the EPA regulations, consists of a single carbon atom bonded treated water of State Water Project to four hydrogen atoms. THMs consist of origin has