State of California The Resources Agency Department of Water Resources Division of Local Assistance BIENNIAL REPORT OF THE MUNICIPAL WATER QUALITY INVESTIGATIONS PROGRAM Summary of Monitoring Results January 1992 - December 1993 April 1995 Table of Contents I. SUMMARY. . . . . . . . . . . . . . . . . . . . . . . . . . .1 II. PROGRAM DESCRIPTION . . . . . . . . . . . . . . . . . . . .3 A. Purpose . . . . . . . . . . . . . . . . . . . . . . . .3 B. Program Advisors . . . . . . . . . . . . . . . . . . .3 C. Monitoring Stations . . . . . . . . . . . . . . . . . .6 D. Field Sampling Methods. . . . . . . . . . . . . . . . 11 E. Analytical Methods. . . . . . . . . . . . . . . . . . 11 III. MONITORING RESULTS . . . . . . . . . . . . . . . . . . . 13 A. Delta Channels. . . . . . . . . . . . . . . . . . . . 13 1. Organic Constituents . . . . . . . . . . . . . . 13 2. Minerals . . . . . . . . . . . . . . . . . . . . 20 3. Metals . . . . . . . . . . . . . . . . . . . . . 25 B. Agricultural Drains . . . . . . . . . . . . . . . . . 26 1. Organic Constituents . . . . . . . . . . . . . . 26 2. Mineral. . . . . . . . . . . . . . . . . . . . . 33 APPENDIX A. DATA QUALITY REVIEW . . . . . . . . . . . . . . .A-1 A. Sample Holding Times. . . . . . . . . . . . . . . . .A-1 B. Method Blanks . . . . . . . . . . . . . . . . . . . .A-3 C. Matrix Spike Recoveries . . . . . . . . . . . . . . .A-5 D. Matrix Spike Duplicate Recoveries . . . . . . . . . .A-6 E. Laboratory Control Samples. . . . . . . . . . . . . .A-7 APPENDIX B. MWQI DATA . . . . . . . . . . . . . . . . . . . .B-1 A. TFPC Data Report. . . . . . . . . . . . . . . . . . .B-1 B. Minor Elements Data Report. . . . . . . . . . . . . .C-1 C. Mineral Data Report . . . . . . . . . . . . . . . . .D-1 List of Tables Table 1. 1992-93 Program Advisors and Participants. . . . . . .4 Table 2. Monitoring Stations. . . . . . . . . . . . . . . . . .7 List of Figures Figure 1. Channel Stations . . . . . . . . . . . . . . . . . .9 Figure 2. Agricultural Drain Sampling Stations . . . . . . . 10 Figure 3. North Delta DOC Ranges . . . . . . . . . . . . . . 14 Figure 4. South Delta DOC Ranges . . . . . . . . . . . . . . 15 Figure 5. North Delta THMFP Ranges . . . . . . . . . . . . . 16 Figure 6. South Delta THMFP Ranges . . . . . . . . . . . . . 17 Figure 7. North Delta TFPC Ranges. . . . . . . . . . . . . . 18 Figure 8. South Delta TFPC Ranges. . . . . . . . . . . . . . 19 Figure 9. North Delta EC Ranges. . . . . . . . . . . . . . . 21 Figure 10. South Delta EC Ranges. . . . . . . . . . . . . . . 22 Figure 11. North Delta Bromide Ranges . . . . . . . . . . . . 23 Figure 12. South Delta Bromide Ranges . . . . . . . . . . . . 24 Figure 13. Delta Soil Types . . . . . . . . . . . . . . . . . 27 Figure 14. Agricultural Drain 1992 DOC Ranges . . . . . . . . 28 Figure 15. Agricultural Drain 1993 DOC Ranges . . . . . . . . 28 Figure 16. Agricultural Drain 1992 THMFP Ranges . . . . . . . 30 Figure 17. Agricultural Drain 1993 THMFP Ranges . . . . . . . 30 Figure 18. Agricultural Drain 1992 TFPC Ranges. . . . . . . . 32 Figure 19. Agricultural Drain EC Ranges (1992). . . . . . . . 34 Figure 20. Agricultural Drain EC Ranges (1993). . . . . . . . 34 I. SUMMARY This report summarizes water quality data collected in the Sacramento-San Joaquin Delta under the Municipal Water Quality Investigations Program during the calendar years 1992 and 1993. Water year 1992 was classified as critically dry and water year 1993 was above normal based on the Sacramento River Index. Under the MWQI Program, major channel stations and agricultural drains were monitored on a monthly basis. Several times a year, synoptic surveys were also conducted where many stations were sampled in a three-day period with all channel stations being sampled on the same day. Water samples were measured for total concentrations of organic precursors to trihalomethanes, a disinfection by-product formed during water treatment. Disinfection by-products are becoming increasingly important to water treatment managers because of impending regulations. Water samples were also analyzed for standard minerals and selected sites were analyzed for trace metals. The data are summarized in this report. All data collected during this two-year period are presented in the Appendix. Selected data from the major channel stations and from all agricultural drains are summarized in plotted figures. An interpretive report which will cover five years of water quality data (1992-97) will provide detailed analysis the water quality trends. The following trends which have been observed and reported in previous MWQI reports, continue to be seen: The station at the North Bay Aqueduct pumping plant at Barker Slough is substantially influenced by local agricultural drainage. Concentrations of organics and minerals at this station are higher than at most other stations in either the North or South Delta. There are peaks in dissolved organic concentrations in the winter and spring months of each year. In general, the South Delta stations exhibit higher organic and mineral concentrations than stations in the North Delta. High bromide concentrations were seen in the South Delta during the fall months of 1992. These high bromide concentrations are a result of seawater intrusion into the Delta during a season of low river flow into the Delta. Copper and mercury were not detected at all channel stations. Arsenic was detected at concentrations (0.003 mg/l and less) below the Maximum Contaminant Level (0.05 mg/l) at a few channel stations. In general, the agricultural drainage from the more organic soils had a greater dissolved organic concentration than the agricultural drainage from intermediate organic soils. However, there were a few exceptions: low values for dissolved organics were observed in agricultural drainage from two islands that had peaty soils. High concentrations of organics and high specific conductance in the agricultural drains were observed in the fall and winter. This coincides with the time that farmers siphon water onto the fields to remove salts. In 1993, an above normal water year, high concentrations of organics were also observed in the spring, possibly due to drainage from precipitation runoff. In conclusion, the water quality in the channels varies dramatically with the time of year, the location of a particular site within the Delta, and with the type of water year in general. However, water quality in the Southern part of the Delta tends to be well-mixed. As far as agricultural drainage from Delta islands, soil type appears to affect the concentration of dissolved organics in agricultural drainage, although it is not the only factor. Probably, hydrology of a particular island, degree of precipitation and dilution factors also affect the concentrations of organics in agricultural drainage. II. PROGRAM DESCRIPTION A. Purpose The MWQI Program staff collect water quality data for numerous purposes. The data are used to: (1) Alert water agencies about potential contaminant sources to Delta water supplies, (2) Document water quality under a variety of hydrologic conditions for studying water transfer alternatives, water quality standards, and predictive modeling capabilities, (3) Determine the influence of sea water intrusion, local and external sources of farm drainage, river input, in-channel processes, weather, and State Water Project and Central Valley Project operations on Delta drinking water quality. Selenium, bromide, and other inorganic constituents are used to trace the movement and mixing of water from different sources, and (4) Assist the Department and other participating water agencies in planning, protecting, and improving drinking water quality. B. Program Advisors The MWQI advisory committee provides policy level guidance and recommends program modifications as needed to respond to changing drinking water quality concerns. The technical subcommittee provides specific expertise in laboratory methodologies, regulatory updates, and review of the analyses, interpretation, and reporting of program data. The Delta Lands Advisory committee assists the Department with permission to sample drainages and provides information about farming activities in the Delta. The committees also review and comment on the program reports and give advice on program expenditures. Table 1. 1992-93 Program Advisors and Participants Municipal Water Quality Advisory Committee Chairperson: James U. McDaniel............................California Department of Water Resources Bruce Agee...............................................................California Department of Water Resources George Baumli.......................................................................................State Water Contractors Doug Chun...............................................................................Alameda County Water District Duane Georgeson................................The Metropolitan Water District of Southern California Lyle N. Hoag..........................................................................California Urban Water Agencies Roger James............................................................................Santa Clara Valley Water District Austin Nelson.................................................................................Contra Costa Water District Technical Subcommittee Chairperson: Richard P. Woodard..........................California Department of Water Resources Bruce Agee...............................................................California Department of Water Resources Mark Beuhler......................................The Metropolitan Water District of Southern California Francis Chung..........................................................California Department of Water Resources John Coburn..........................................................................................State Water Contractors Andrew Florendo..............................................................Alameda County Flood Control and Water Conservation District, Zone 7 Greg Gartrell..................................................................................Contra Costa Water District Judith Heath............................................................California Department of Water Resources Lyle N. Hoag............................................................................California Urban Water District Bob Hultquist.............................................................California Department of Health Services Tom Howard....................................................................State Water Resources Control Board Roger James............................................................................Santa Clara Valley Water District Marvin Jung........................................................................................Marvin Jung & Associates Stuart Krasner.....................................The Metropolitan Water District of Southern California Bruce Kuebler..........................................City of Los Angeles Department of Water and Power Michael Lanier..........................................................................Alameda County Water District Bruce Macler..................................................................U.S. Environmental Protection Agency John Marchand.........................................................................Alameda County Water District Edward Means.....................................The Metropolitan Water District of Southern California Alexis Milea................................................................California Department of Health Services Dale Newkirk.......................................................................East Bay Municipal Utility District Hoover Ng..............................................City of Los Angeles Department of Water and Power Kusum Perera.............................................................California Department of Health Services Table 1. 1992-93 Program Advisors and Participants (cont.) Technical Subcommittee (cont.) Walt Wadlow..........................................................................Santa Clara Valley Water District Dennis Westcot......................................Central Valley Regional Water Quality Control Board Roy Wolfe...........................................The Metropolitan Water District of Southern California Delta Lands Advisory Committee Chairperson: Richard P. Woodard..........................California Department of Water Resources Bruce Agee...............................................................California Department of Water Resources Jack Baber...........................................................................................Reclamation District 1004 Mike Catino.............................................California Central Valley Flood Control Association Thomas M. Hardesty..........................................................................Reclamation District 2068 Judith Heath............................................................California Department of Water Resources Alex Hildebrand...............................Reclamation District 2075 and South Delta Water Agency Marvin Jung......................................................................................Marvin Jung and Associates Donald Kienlan...............................................................Murray, Burns, and Kienlan Engineers James Shanks..........................................................................................Reclamation District 38 John Winther...............................................................................................Delta Wetlands, Inc. C. Monitoring Stations The MWQI Program staff coordinate several monitoring tasks including the monthly monitoring of key Delta stations, synoptic surveys to study sea water intrusion, Delta island drainage sampling, and special studies. Water quality is a public health concern at major water supply intakes in the Delta. Five stations that are monitored routinely include the: (1) American River Water Treatment Plant intake that serves the City of Sacramento (Station 1) (2) North Bay Pumping Plant (Station 87) that serves Solano and Napa Counties. (3) Rock Slough at Old River (Station 9), 4 miles east of the Contra Costa Water District intake. (4) Harvey O. Banks Delta Pumping Plant Headworks (Station 12), which is the headworks of the California Aqueduct. (5) Delta Mendota Canal Intake at Lindemann Road (Station 11), which is upstream of the Tracy Pumping Plant for the Delta-Mendota Canal. In addition to these stations, other monitoring locations in the Delta provide information about the transport and mixing of Delta waters and enable a more comprehensive evaluation of water quality conditions. Synoptic surveys were performed to trace the movement of water entering the State Water Project, the Central Valley Project, and Contra Costa Water District pumping facilities. The synoptic surveys took place over three day periods at 30 channel stations and 42 drains. All channel stations, however, were sampled in one day. There were six synoptic surveys conducted each year. The synoptic survey data is not separated from the regular monthly sampling data for the purposes of this report. A separate interpretive report will be published in the future that will analyze the data of the synoptic surveys. Autosamplers were used in 1993 to study the daily variation of some water quality parameters. Samples were collected every 24 hours for electrical conductivity (EC), dissolved organic carbon (DOC), and ultraviolet absorbance at 254 nanometers (UVA254nm). Autosamplers were installed at two agricultural drains (King Island and Mandeville Island) and a channel station (Middle River at Borden Highway). Because the use of autosamplers was only introduced in 1993, these data will be discussed in the 1994 MWQI Annual Report. Table 2. Monitoring Stations STATION DWR ID STATION # STATION NAME STATION ABBREV. TYPE ---------- ----------------------------- --------------------------------------------------------- --------------------------------------------- ------------------------- 1 A0714010 American River at W.T.P AMERICAN HF 2 B9D82071327 Sacramento River at Greene's Ldg. GREENES HF 3 B9D81781448 Cache Slough @ Vallejo P.P. CACHE HF 7 B9D80371300 Little Connection Sl. @ Empire Tr. LCONNECT HF 8 B9V80361299 Ag Drain on Empire Tract, W.end 8-Mi.Rd. AGDEMPIRE AD 9 B9D75841348 Rock Slough @ Old River ROCKSL HF 10 KA000000 Clifton Court Intake CLIFTON HF 11 B9C74901336 DMC Intake @ Lindemann Rd. DMC HF 12 KA000331 Delta P.P. Headworks BANKS HF 13 B9D75351293 Middle R. @ Borden Hwy. MIDDLER HF 14 B0702000 San Joaquin R. near Vernalis VERNALIS HF 17 E0B80261551 Sacramento River @ Mallard Island MALLARDIS HF 20 A0V83681312 Natomas Main Drain NATOMAS AD 21 B9V80541310 Ag Drain on Bouldin Tract, PP. No. 1 BOULDIN1 AD 22 B9V80611335 Ag Drain on Bouldin Tract, PP. No. 2 BOULDIN2 AD 25 B9V80461224 Ag Drain on King Island, PP. No. 1 KINGISPP01 AD 26 B9V80271262 Ag Drain on King Island, PP. No. 2 KINGISPP02 AD 27 B9V80331273 Ag Drain on King Island, PP. No. 3 KINGISPP03 AD 44 B9V74811246 Ag Drain on Pescadero Tr., PP. No. 1 PESCADERO01 AD 45 B9V74811241 Ag Drain on Pescadero Tr., PP. No. 2 PESCADERO02 AD 46 B9V74821231 Ag Drain on Pescadero Tr., PP. No. 3 PESCADERO03 AD 51 B9V80271282 Ag Drain on Rindge Tract, PP. No. 2 RINDGEPP02 AD 60 B9V75641318 Ag Drain on Upper Jones Tr., PP. No. 2 UPJONESPP02 AD 61 B9V80671368 Ag Drain on Brannan Island, PP. No. 1 BRANNANPP01 AD 62 B9V80711377 Ag Drain on Brannan Island, PP. No. 2 BRANNANPP02 AD 63 B9V80721385 Ag Drain on Brannan Island, PP. No. 3 BRANNANPP03 AD 64 B9V80741398 Ag Drain on Brannan Island, PP. No. 4 BRANNANPP04 AD 65 B9V74961340 Ag Drain on Clifton Court AGDCLIFTON AD 68 B9V74781220 Ag Drain on Pescadero Tract, PP. No. 4 PESCADERO04 AD 69 B9V74661251 Ag Drain on Pescadero Tract, PP. No. 5 PESCADERO05 AD 75 B0704000 San Joaquin R. @ Maze Rd. Bridge MAZE HF 76 B9V75651318 Ag Drain on Lower Jones Tr., PP. No. 1 LJONES01 AD 77 B9V75831305 Ag Drain on Lower Jones Tr., PP. No. 2 LJONES02 AD 87 B9D81661478 Barker Sl @ North Bay PP BARKERNOBAY HF 88 B9D80961411 Sacramento River @ Rio Vista Bridge SACRRIOVISTA HF 91 B9D80361275 Honker Cut at Atherton Road Bridge HONKER HF 100 B9D75891348 Old R. N/O Rock Sl (St 4b) STATION04B HF 103 B9D75351342 Old R. nr. Byron (St 9) STATION09 HF 105 B9D74971331 West Canal at Clifton Court FB Intake WSTCANCLIFT HF 107 B9D81481305 Delta Cross Channel Gate nr Walnut Grove DELTACRCHAN HF 108 B9D81441309 Georgiana Slough at Walnut Grove Bridge GEORGSLWALNUT HF 110 B9D75741317 Middle River at Bacon Island Bridge MRIVBACON HF 111 B9D75011229 Middle River at Mowry Bridge (Undine Rd) MIDMOWRY HF 112 B9D75881285 Turner Cut at McDonald Island Ferry TURNERCUT HF 113 B9D80191348 Old River at Sand Mound Slough SANDMOUND HF 114 B9D80011307 Middle River near Latham Sl (Ferry Site) LATHAM HF Table 2. Monitoring Stations (cont.) STATION DWR ID STATION # STATION NAME STATION ABBREV. TYPE ---------- --------------------------- --------------------------------------------------------- --------------------------------------------- ------------------------- 115 B9D80031294 Connection Sl. at Mandeville Isl Bridge CONNMAND HF 117 B9D75651333 Santa Fe-Bacon Island Cut nr Old River SANTAFEBACON HF 118 B9D75481334 Woodward/N. Victoria Canal nr Old River NVICWOOD HF 119 B9D75171329 North Canal nr Old River NORTHCAN HF 121 B9D74931328 Grant Line/Fabian/Bell Canals nr Old R. GRANTOLD HF 122 B9D74891331 Old River U/S from DMC Intake OLDRIVDMC HF 123 B9V80451387 Ag Drain on Webb Tract, PP. No. 1 WEBB01 AD 124 B9V80381361 Ag Drain on Webb Tract, PP. No. 2 WEBB02 AD 125 B9V75931350 Ag Drain on Holland Tract, PP. No. 1 HOLLAND01 AD 126 B9V80011348 Ag Drain on Holland Tract, PP. No. 2 HOLLAND02 AD 127 B9V80111361 Ag Drain on Holland Tract, PP. No. 3 HOLLAND03 AD 128 BV75881342 Ag Drain on Bacon Island, PP. No. 1 BACON01 AD 129 B9V80031328 Ag Drain on Bacon Island, PP. No. 2 BACON02 AD 130 B9D80311413 San Joaquin River at Jersey Point SJRJERSEY HF 131 B9D80301377 False River at Southerly Tip of Webb Tr. FALSETIP-WEBB HF 132 B9D74951331 Old River 6/10 mile below DMC intake. OLDR-DMC-CLIFT HF 133 B9591000 Contra Costa PP Number 01 CONCOSPP1 HF 140 B9V80881307 Ag Drain on Staten Island PP. No. 1 STATENPP01 AD 141 B9V80751335 Ag Drain on Staten Island PP. No. 2 STATENPP02 AD 142 B9V80481319 Ag Drain on Venice Island VENICE AD 143 B9V85491328 Ag Drain on Woodward Island WOODWARDPP AD 144 B9V80041319 Ag Drain on Mandeville Island PP. No. 01 MANDEVILLEPP01 AD 145 B9V80291321 Ag Drain on Mandeville Island PP. No. 02 MANDEVILLEPP02 AD 146 B9V85571345 Ag Drain on Orwood Tract ORWOODPP AD 147 B9V85651349 Ag Drain on Palm Tract PALMTRPP AD 411 B9D80771345 Mokelumne R. below Georgiana Sl MOKGEORGIANA HF 413 B9D80691298 L. Potato Slough @ Terminous LPOTTERM HF 602 B9D74711184 San Joaquin R. @ Mossdale Bridge SJRMOSSDALE HF 604 B9D74731285 Old River near Tracy OLDRTRACY HF 605 B9D75291273 Middle R @ Tracy Rd Bdg MRIVTRACY HF 606 B9D74921269 Grant Ln Can @ Tracy Rd Bdg GRANTLNCAN HF Type Code: AD refers to an agricultural drain. HF refers to a nondrainage station. The H code referred to the Interagency Health Aspects Monitoring Program station and the F code stands for freshwater sample type. Figure 1. Channel Stations Figure 2. Agricultural Drain Sampling Stations D. Field Sampling Methods Samples are collected in a specially designed stainless steel bucket developed by DWR. The sample bucket is equipped with two TeflonR valves to dispense the collected water. Before the bucket is used, it is washed in detergent, rinsed in tap water, and air dried. For some analyses, the samples are filtered in the field with a 0.45 micrometer filter using a peristaltic pump with TeflonR tubing. A Yellow Springs InstrumentR (YSI) electrical conductivity/temperature meter is used to record EC and temperature. The HelligeR colorimetric kit or a BeckmanR Model 10 portable pH meter was used to determine pH. Dissolved oxygen was measured with a Yellow Springs InstrumentsR Model 50 dissolved oxygen meter. All electrical conductivity meters, pH meters and dissolved oxygen meters are calibrated before use on each data collection run. Filtered samples for volatile organic analyses (VOA) were collected in 40 milliliter glass vials. Sample containers were completely filled to eliminate air space and air bubbles. The caps of the 40 milliliter vials were fitted with TeflonR coated septa, as specified by the U.S. Environmental Protection Agency. Samples were kept on ice, or refrigerated and delivered to the laboratory within 24 hours of collection. Separate sample containers were collected for laboratory measurements of bromide and ultraviolet absorbance at 254 nanometers (UVA254 nm). At least one blind field duplicate was collected on each sampling run (usually one duplicate in seven to ten samples). The duplicates were submitted to the laboratories with the regular samples as a quality assurance check. E. Analytical Methods THMFP/TFPC Analysis The total trihalomethane formation potential carbon (TFPC) results are computed by summing the amount of carbon in each of the four trihalomethane (THM) species in the DWR THMFP assay. The TFPC represents the amount of organic carbon that was converted to a trihalomethane under the DWR assay. This method allows comparison of raw water THM organic precursor levels to the anticipated THM levels after water treatment. At the laboratory, water samples for THMFP analysis were chlorinated (inoculated) with about 120 mg/l chlorine. This high dosage was used to assure a chlorine residual after the 7-day incubation period at 25 degrees Celsius. At the end of seven days, the chlorine residual was determined. The residual chlorine was then quenched using sodium thiosulfate, and the sample was analyzed for trihalomethanes by the gas chromatograph purge and trap method, EPA Method 502.2. For a more complete description of the modified THMFP analytical method, see the description of the modified THMFP assay on page 90 of The Five-Year Report of the Municipal Water Quality Investigations Program 1987-1991 published by DWR. THM analyses were performed at Pace Environmental Laboratory from January through June 1992 and at Clayton Environmental Laboratory from July 1992 through December 1993 (see Appendix A- Data Quality Review). DWR's Bryte Chemical Laboratory performed mineral, trace element, and some organic analyses. Further detail about laboratory methods used by Bryte Laboratory may be found in Appendix A and in The Five-Year Report of the Municipal Water Quality Investigations Program 1987-1991, published by DWR. III. MONITORING RESULTS A. Delta Channels 1. Organic Constituents Dissolved Organic Carbon The results of DOC analyses at major channel stations in the North Delta are shown in Figure 3. At the Barker North Bay pumping plant, DOC concentrations ranged from about 5 to 24 mg/l, whereas at the major Sacramento and American River stations, the DOC concentrations were less than 5 mg/l. There were peaks in DOC concentrations for all stations in the months of January and February of both years, probably due to winter storm runoff. Another peak is seen in June 1992, probably due to local agricultural drainage. DOC concentrations at major channel stations in the South Delta are shown in Figure 4. These concentrations varied similarly over time and ranged from about 2 to 11 mg/l. As in the North Delta, there were peaks in DOC concentrations in January and February of both years that was probably the result of seasonal storms. Somewhat lower level peaks in May probably represent typical summer agricultural drainage from the San Joaquin Valley and local agricultural drainage. Trihalomethane Formation Potential The results of THMFP analyses at major channel stations in the North Delta are shown in Figure 5. These concentrations vary similarly to the DOC concentrations in Figure 3. The concentrations range from 200 to 1600 mg/l with the concentrations at Barker North Bay pumping plant being greater than the other channel stations. There appears to be more agricultural runoff at Barker North Bay pumping plant than in the Sacramento River. South Delta THMFP analyses results at major channel stations are shown in Figure 6. These THMFP concentrations are generally somewhat higher than those in the North Delta with less difference in values between the different stations. This close pattern of values implies that there are similar levels of precursor material at these stations and that the water in the South Delta stations is relatively well mixed. Total THM Formation Potential Carbon Figures 7 and 8 show total trihalomethane formation potential as carbon for the North and South Delta, respectively. These figures show the same data as Figures 5 and 6, but in the units of TFPC. The range of TFPC for both regions is from 16 to 160 mg/l. Figure 3. North Delta DOC Ranges Figure 4. South Delta DOC Ranges Figure 5. North Delta THMFP Ranges Figure 6. South Delta THMFP Ranges Figure 7. North Delta TFPC Ranges Figure 8. South Delta TFPC Ranges 2. Minerals Specific Conductance The EC measurements at major channel stations are shown in Figures 9 and 10. EC fluctuated greatly depending on the station with the specific conductance for Sacramento River at Rio Vista and at Barker North Bay pumping plant having the highest EC value (150-700 microsiemens per centimeter). EC readings at the American River at the Water Treatment Plant intake were lowest at about 50 microsiemens per centimeter. The fluctuating readings at Sacramento River at Rio Vista are a result of tidal influence at this station. The high readings at the North Bay Aqueduct pumping plant at Barker Slough in the summer months are probably a result of local agricultural drainage. The low specific conductance at the American River station shows little tidal influence. In the South Delta, EC ranges were higher than those in the North Delta varying from about 200 to 1200 microsiemens per centimeter. However, these readings show less variability than those in the North Delta. The EC readings at Harvey O. Banks pumping plant are less variable than the Delta-Mendota canal because of the Clifton Court forebay operations. The highest reading was at the San Joaquin River near Vernalis (almost 1200 microsiemens per centimeter) that was probably a result of upstream drainage discharges. The periodic high readings at the Delta-Mendota canal are a result of tidal influence, and probably also reflect the influence of the San Joaquin River. Bromide Figure 11 shows bromide ranges at North Delta channel stations. Bromide concentrations were highest at the Sacramento River at Rio Vista (0.03 to 0.48 mg/l) showing significant variation due to tidal influence. Bromide concentrations at the Sacramento River at Greenes Landing, Little Connection Slough at Empire Tract, and the North Bay Aqueduct pumping plant at Barker Slough were similar and ranged from below the reporting limit to 0.05 mg/l showing little if any tidal influence at these three stations. South Delta bromide ranges are shown in Figure 12. There was a peak in bromide concentrations for all stations in July-October 1992. The highest peak in bromide concentration was at Rock Slough (approximately 0.8 mg/l) reflecting significant seawater intrusion during the dry months of 1992. Figure 9. North Delta EC Ranges Figure 10. South Delta EC Ranges Figure 11. North Delta Bromide Ranges Figure 12. South Delta Bromide Ranges 3. Metals Arsenic, copper and mercury were analyzed at major channel stations. All copper and mercury analyses were below the levels of reporting (at reporting limits of 0.005 mg/l and 0.001 mg/l, respectively). Arsenic was detected at some stations at low concentrations. For example, arsenic was detected at Banks pumping plant at a concentration of 0.002 mg/l, at Barker North Bay pumping plant at a concentration of 0.003 mg/l, and at the San Joaquin River near Vernalis and Greenes Landing at concentrations ranging from below the reporting limit of 0.001 mg/l to 0.003 mg/l. (The current maximum contaminant level for arsenic is 0.050 mg/l). The highest arsenic levels were seen in June-July and in September-October. B. Agricultural Drains 1. Organic Constituents A comprehensive analysis of temporal and spatial patterns in DOC, TFPC, THM and UVA254 nm was presented in the MWQI Five-Year Report 1987-1991. Patterns seen in 1992 and 1993 followed those seen in earlier years. The results from the agricultural drains are related to the soil types of the respective areas. Figure 13 shows different soil types in the Delta (1994, MWQI Five-Year Report 1987-1991). According to this figure, soils are classified as either mineral, intermediate organic, or peaty. Mineral soils are defined as soils that have less than ten percent organic matter and peaty soils are defined as soils that have fifty to eighty percent organic matter. Dissolved Organic Carbon DOC concentrations for all agricultural drains sampled (see Figure 2) are shown in Figure 14. All samples taken in 1992 are shown here with the x-axis being the calendar month (1=January, 2=February, etc.). DOC concentrations ranged from about 3 mg/l at the agricultural drain on Bacon Island, pumping plant No. 1, to about 63 mg/l at an agricultural drain on Bouldin Tract, pumping plant No. 2. Both the soil types on Bacon Island and Bouldin Tract are peaty. The high DOC values occurred in January and September of 1992. In 1993 (Figure 15), DOC ranges varied similarly over the year as in 1992. The DOC concentrations ranged from about 3 mg/l at the agricultural drain on Bouldin Tract, pumping plant No. 1 to a high of about 75 mg/l at the agricultural drain on Bouldin Tract, pumping plant No. 2. Bouldin Tract has soil that is generally classified as peaty. In both Figures 14 and 15, DOC concentrations were lowest in June through August and greatest in October and January. The January peak is likely due to drainage from precipitation and winter leaching. The April peak is probably due to runoff from initial spring irrigation, and the October peak is probably due to runoff from fall leaching. Figure 13. Delta Soil Types Figure 14. Agricultural Drain 1992 DOC Ranges Figure 15. Agricultural Drain 1993 DOC Ranges Trihalomethane Formation Potential During 1992, the THMFP ranged from about 110 mg/l at the agricultural drain on Brannan Island to a high value of about 6400 mg/l at the agricultural drain on Bouldin Tract, pumping plant No. 2 (see Figure 16). Brannan Island has soil classified as intermediate organic while the soil at Bouldin Tract is peaty. In 1993, the THMFP range was similar (180-6200 mg/l), with the low THMFP value measured at the agricultural drain on Bacon Island, pumpling plant No. 1 and the high THMFP value measured at the agricultural drain on Empire Tract (see Figure 17). The peak observed in June is not readily explainable but may be due to concentrated agricultural drainage. Figure 16. Agricultural Drain 1992 THMFP Ranges Figure 17. Agricultural Drain 1993 THMFP Ranges Trihalomethane Formation Potential as Carbon The 1992 TFPC values range from about 9 mg/l at the agricultural drain on Brannan Island, pumping plant to about 630 mg/l at the agricultural drain on Bouldin Tract, pumping plant No. 1 (see Figures 18). Brannan Island has soil classified as intermediate organic and Bouldin Tract has soil classified as peaty. In 1993, the TFPC values ranged from about 16 mg/l at Bacon Island, pumping plant No. 1 to a high value of 560 mg/l at the agricultural drain on Empire Tract (see Figure 19). Both Bacon Island and Empire Tract soils are classified as peaty. Figure 18. Agricultural Drain 1992 TFPC Ranges Figure 19. Agricultural Drain 1993 TFPC Ranges 2. Mineral Specific Conductance Figures 19 and 20 show EC ranges measured in the agricultural drains in 1992 and 1993, respectively. EC values ranged from about 250 microsiemens per centimeter at Staten Island pumping plant No. 1 to about 6400 microsiemens per centimeter at the agricultural drain at Clifton Court Forebay. Both the soils at Staten Island and the soils around Clifton Court Forebay are classified as intermediate organic soils. The highest EC value occurred in August. In 1993, EC values ranged from about 140 microsiemens per centimeter at Bouldin Tract, pumping plant No. 1 to about 8000 microsiemens per centimeter at the agricultural drain at Clifton Court Forebay. Bouldin Tract has peaty soil whereas the soils around Clifton Court Forebay are classified as intermediate organic. The annual trends were different for EC in 1992 and 1993. In 1992, the high EC value occurred in August, whereas in 1993, the high values occurred in January and April. The different trends may be related to the fact that 1992 was a critically dry water year, whereas 1993 was above normal in precipitation. Figure 20. Agricultural Drain EC Ranges (1992) Figure 21. Agricultural Drain EC Ranges (1993) Summary of Agricultural Drain Results High values for DOC, THMFP and TFPC of the agricultural drains sampled for both 1992 and 1993 occurred at Bouldin Tract, pumping plants No. 1 and 2 and at the agricultural drain on Empire Tract, areas characterized as having peaty soils. The lowest values for DOC, THMFP, and TFPC were seen at Bacon Island, Brannan Island, Staten Island and Bouldin Tract. Staten and Brannan Islands have intermediate organic soils, whereas Bacon and Bouldin Island have peaty soils. High values for specific conductance (EC) were observed at the agricultural drain at Clifton Court Forebay (intermediate organic soil), whereas low EC values were observed at the agricultural drains at Bouldin Tract and Bouldin Tract (both with peaty soils). The EC readings are probably not primarily a result of soil type, but rather a result of tidal influence and dilution. APPENDIX A. DATA QUALITY REVIEW As a function of Quality Assurance/Quality Control (QA/QC), a data quality assessment was conducted on the 1992/93 MWQI data. Environmental samples (and their respective QC batches) were randomly selected from the study period to provide a least a 20% sample size. (This was the sample size stated in the QA/QC budget). The data quality review involved comparing data from these samples against acceptable control limits provided by the laboratories that performed the analyses. Data that fell outside these control limits were flagged. Three environmental laboratories provided analyses of MWQI water samples during the 1992/93 period. DWR's Bryte Chemical Laboratory analyzed water samples for minerals and minor elements. Pace Environmental Laboratories, Novato, California, analyzed water samples for TFPC from January to June 1992. Pace used EPA Method 601 which had a broad acceptable recovery range of 65-135%. Clayton Environmental Laboratory, Pleasanton, California, performed TFPC analyses from July 1992 to the end of 1993. Clayton used EPA Methods 502.2 and 524.2 which had acceptable ranges of 80-120% and 75-125% respectively. QC data from each respective laboratory were compiled for the randomly selected samples. The QC data from Pace and Clayton were on file in summary form at DWR which enabled 100% review. The QC data from Bryte laboratory were manually compiled from the original work sheets. The TFPC data quality review indicates that although the overall data from Pace Laboratory (January-June 1992) were acceptable, there was a large (53%) chloroform method blank contamination compared to Clayton Laboratory's 14%. Pace also analyzed with EPA Method 601 which had wider acceptance limits than the EPA Methods 502.2 and 524.2 used by Clayton. It should also be noted that all Pace Laboratory analyses were based on the original DWR TFPC assay. Clayton Laboratory analyses were based on the DWR's modified buffered" TFPC assay. (For a complete description of these two methods, see the modified THMFP assay description, page 90 of the MWQI Five-Year Report, November 1994). Mineral and metals data quality review indicated that the data were generally of acceptable quality. The quality review results are summarized below. A. Sample Holding Times The date from when the TFPC samples were spiked to the date they were quenched was the incubation period and should not have exceeded seven days. The samples had to be analyzed within fourteen days of quenching. This 14-day period is the holding time. 1. Pace Laboratory Seventy-five samples out of three hundred and three samples (25%) were reviewed (Table A-1). There were no holding time exceedances. Table A-1: Frequency of Holding Time Exceedances for Pace Analyte Holding Time (days) No. of samples reviewed Samples outside holding times Frequency of Exceedances (%) Bromodichloromethane 14 75 0 0 Bromoform 14 75 0 0 Chloroform 14 75 0 0 Dibromochloromethane 14 75 0 0 2. Clayton Laboratory One hundred and ninety-nine samples out of eight hundred samples (24%) were reviewed (Table A-2). Two samples exceeded the holding times by one and three days respectively. These exceedances were considered insignificant because MWQI's Delta Drainage Investigation Report of the Interagency Delta Health Aspects (June 1990) established that a holding time of up to eighty days may not cause a significant TFPC loss. Clayton Laboratory only reported the date the samples were prepared and the date they were analyzed which made it impossible to distinguish between incubation and holding times. The above exceedances were still within the twenty-one days allowed for incubation plus holding time. Table A-2: Frequency of Holding Time Exceedances for Clayton Analyte Holding Time (days) No. of samples reviewed Samples outside holding times Frequency of Exceedances (%) Bromodichloromethane 14 191 2 1 Bromoform 14 191 2 1 Chloroform 14 191 2 1 Dibromochloromethane 14 191 2 1 3. Bryte Laboratory Minerals One hundred and thirty-six samples out of approximately five hundred and fifty-four (24%) were examined for holding times exceedances (Table A-3). All QC batches examined were analyzed within the allowable time limits. Minor Elements Nineteen samples out of approximately sixty-one samples (31%) were reviewed (Table A-3). One copper sample exceeded the holding time by seventeen days. This was not considered to be significant. Table A-3: Frequency of Holding Time Exceedances for Bryte Laboratory Analyte Holding Time (days) No. of samples reviewed Samples outside holding times Frequency of Exceedances (%) Standard Mineral 180 136 2 1.5 Minor Elements 180 19 3 16 B. Method Blanks The purpose of the method blanks was to detect and quantify contamination introduced through sample preparation or analysis procedure (some 'background noise' is allowed). If no contamination was detected or if the detected value was low (up to 10% of the sample concentration for Pace Laboratory and up to 20 g/l for Clayton Laboratory), the sample batches associated with that blank were considered to be free of contamination. Each laboratory determined the level of acceptance based on the analysis method performed. 1. Pace Laboratory All the method blanks (100%) performed by Pace Laboratory during the study period were reviewed. A larger number (53%) of method blanks were found to have chloroform contamination. This makes Pace Laboratory's chloroform results suspect. The other parameters were within acceptable control limits (Table A-4). Table A-4: Contamination Frequency of Pace Laboratory Method Blanks Analyte Method Detection Limit Blank Analyses Performed Positive* Blanks Frequency of contamination (%) Bromodichloromethane 5 g/l 59 0 0 Bromoform 5 g/l 59 0 0 Chloroform 5 g/l 59 31 53 Dibromochloromethane 5 g/l 59 0 0 *Positive blanks: Detected blank concentration over 10% of sample concentration (Pace Laboratory's interpretation). 2. Clayton Laboratory All the method blanks (100%) in the study period were reviewed (Table A-5). Twelve had chloroform and one had bromodichloromethane contamination. This level of contamination was lower than that of Pace laboratory and the data less biased. Table A-5: Contamination Frequency of Clayton Laboratory Method Blanks Analyte Method Detection Limit Blank Analyses Performed Positive* Blanks Frequency of contamination (%) Bromodichloromethane 5 g/l 84 1 1 Bromoform 5 g/l 84 0 0 Chloroform 5 g/l 84 12 14 Dibromochloromethane 5 g/l 84 0 0 *Positive blanks: Detected blank concentration over 20 /l. 3. Bryte Laboratory According the laboratory personnel, method blanks analyses were performed and corrections made when contamination problems were detected. However, since it was not the practice of the laboratory to maintain and archive the data from the method blank analyses, no records were available. C. Matrix Spike Recoveries Matrix spike recoveries indicate the matrix spike bias on the analytical method. An environmental sample is spiked with a known concentration of the analyte of interest and analyzed in the usual manner. The percent recovery must fall within acceptable range for the data to be acceptable. 1. Pace Laboratory All the matrix spikes reported by Pace Laboratory (100%) were reviewed (Table A-6). No matrix recovery control limits were given, so the conservative laboratory control sample (LCS) recovery limits were used instead. All the parameters analyzed exceeded the LCS control limits to some degree. Chloroform had the largest number of exceedances (31%) which meant there may have been a high matrix bias in the chloroform results. Table A-6: Matrix Spike Recovery for Pace Laboratory Analyte LCS Recovery Limits* (%) Total Analyses Performed Samples outside recovery limits Frequency of Exceedances(%) Bromodichloromethane 65-135 59 3 5 Bromoform 65-135 59 7 12 Chloroform 65-135 59 18 31 Dibromochloromethane 65-135 59 2 3 *EPA Method 601. No matrix spike recovery ranges were given, so the conservative LCS recovery limits are used instead. 2. Clayton Laboratory All the matrix spikes recoveries (100%) reported by Clayton Laboratory were reviewed (Table A-7). All the recoveries were within the acceptable control limits except two chloroform batches (2%). Clayton Laboratory data therefore had low matrix bias. Table A-7: Matrix Spike Recovery for Clayton Laboratory Analyte MS* Recovery Limits Total Analyses Performed Samples outside recovery limits Frequency of Exceedances(%) Bromodichloromethane 80-120 84 0 0 Bromoform 80-120 84 0 0 Chloroform 80-120 84 2 2 Dibromochloromethane 80-120 84 0 0 *MS: Matrix Spikes using EPA Methods 502.2 and 524.2. Clayton Laboratory utilized the same control limits for LCS and matrix spikes. 3. Bryte Laboratory Minerals Twenty-six out of approximately one hundred and ten matrix spike samples (24%) were reviewed. All the reviewed recoveries were within the control limits. Minor Elements Nineteen minor element spike recoveries were reviewed. Two nickel batches had recoveries higher than the control limits . D. Matrix Spike Duplicate Recoveries Matrix spike duplicate results indicate the precision of the analytical method. The difference between the duplicate samples is reported as a relative percent difference (RPD). This difference is compared against the individual laboratory control limit. 1. Pace Laboratory All the matrix spike duplicates (100%) were reviewed (Table A-8). Only two chloroform batches were above the acceptable limits. This indicates good precision of Pace Laboratory results. Table A-8: Matrix Spike Duplicate Recovery (Pace Laboratory) Analyte Acceptable RPD*(%) Total Analyses Performed Analyses outside limits Frequency of samples out of limits (%) Bromodichloromethane 35 59 0 0 Bromoform 35 59 0 0 Chloroform 35 59 2 3 Dibromochloromethane 35 59 0 0 *RPD: Relative Percent Difference 2. Clayton Laboratory All ninety-six matrix spike duplicates reported by Clayton Laboratory during the study period were reviewed (Table A-9). Only two chloroform batches had recoveries greater than the acceptable control limits indicating a high precision of Clayton Laboratory analyses. Table A-9: Matrix Spike Duplicate Recovery (Clayton Laboratory) Analyte Acceptable RPD*(%) Total Analyses Performed Analyses outside limits Frequency of samples out of limits (%) Bromodichloromethane 20 96 0 0 Bromoform 20 96 0 0 Chloroform 20 96 3 3 Dibromochloromethane 20 96 0 0 *RPD: Relative Percent Difference E. Laboratory Control Samples Laboratory control samples (LCS) recoveries are used to assess the accuracy of the analytical method. A known concentration of analyte is spiked into a clean medium and then analyzed. The results are compared to the laboratories' control limits. 1. Pace Laboratory All fifty-nine (100%) LCS results reported by Pace Laboratory during the study period were reviewed (Table A-10). Chloroform results had the most number of upper limit exceedances (36%) indicating a high end bias. Table A-10: Laboratory Control Sample Recovery (Pace Laboratory) Analyte Method Control Limits (%) Total Analyses Performed Analyses outside limits Frequency of samples out of limits (%) Bromodichloromethane 65-135 59 3 5 Bromoform 65-135 59 4 7 Chloroform 65-135 59 21 36 Dibromochloromethane 65-135 59 4 7 2. Clayton Laboratory All thirty-six (100%) LCS analyses reported by Clayton Laboratory were reviewed (Table A-11). Only three (8%) had recovery limits above control limits. Clayton Laboratory did not report LCS's after July 1993. Table A-11: Laboratory Control Sample Recovery for Clayton Laboratory Analyte Method Control Limits (%) Total Analyses Performed Analyses outside limits Frequency of samples out of limits (%) Bromodichloromethane 80-120 36 0 0 Bromoform 80-120 36 0 0 Chloroform 80-120 36 3 8 Dibromochloromethane 80-120 36 0 0 3. Bryte Laboratory Minerals Thirty mineral QC batches out of approximately one hundred and thirty batches (about 23%) were reviewed. All the LCS recoveries were within the acceptable control limits indicating good recovery for minerals. Minor Elements Nineteen minor element QC batches out of approximately one hundred and thirty (about 24%) were reviewed. All the recoveries were within acceptable limits. APPENDIX B. MWQI DATA A. TFPC Data Report B. Minor Elements Data Report C. Mineral Data Report