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SELENIUM CONTAMINATION ASSOCIATED WITH IRRIGATED AGRICULTURE IN THE WESTERN UNITED STATES
Theresa S. Presser
National Research Program
Water Resources Division
Introduction
Adverse effects of selenium on fish and waterfowl in habitats receiving agricultural drainage was first noticed in the San Joaquin Valley of California in the early 1980s. Scientists in the USGS, including several from Menlo Park, California, have contributed considerable data and analysis on the scope of selenium contamination associated with salinized farmlands and on the hydrological and biogeochemical processes resulting in selenium bioaccumulation. These data have been important in helping to resolve selenium toxicity problems associated with irrigated agriculture in the arid West.
Further documentation for the history of selenium contamination at Kesterson National Wildlife Refuge and in the western United States is given in the Island Press book, Death in the Marsh by Tom Harris, a writer formerly with the Sacramento Bee. Several USGS scientists from the Western Region are prominently portrayed in the book.
Kesterson National Wildlife Refuge
A major factor in California's economic success is the federal and state investment in irrigation within the San Joaquin Valley. Salt build-up on farmland soils is a result of both the arid climate and poor drainage, thus requiring leaching by irrigation and disposal of subsurface irrigation wastewater. However, salts and selenium are mobilized and transported by irrigation drainage to wetlands and other water-bodies via tile drains and canals. Bioaccumulation of selenium to toxic levels occurs in these water bodies.
In 1968, water deliveries started in the San Luis Unit of the western San Joaquin Valley and the Bureau of Reclamation (BOR) began construction of the San Luis Drain (SLD) and Kesterson Reservoir. Completed in 1971, the Kesterson Reservoir was a series of 12 evaporation ponds within the Kesterson National Wildlife Refuge. The ponds were to function as a storage and control facility for the San Luis Drain. Eventually the San Luis Drain was to extend to the San Francisco Bay-Delta estuary. From 1971-78 Kesterson Reservoir received freshwater inflow (no agricultural drainage water). In 1975 funding limitations and environmental concerns stopped construction of the San Luis Drain north of Kesterson Reservoir. Beginning in 1979, saline agricultural drainage was used to enhance dwindling freshwater supplies at the refuge for the support of wildlife habitat.
By 1981 all water coming into Kesterson Reservoir consisted of agricultural drainage via the San Luis Drain. Prior to 1981 Kesterson Reservoir contained several species of warm-water fish, including striped and largemouth bass, catfish, carp, and mosquito fish. After 1981 only the salt-tolerant mosquitofish was found in Kesterson Reservoir. Habitat changes noticed at Kesterson Reservoir were dying cattails, algal blooms, and the declining use of Kesterson Reservoir by waterfowl.
In 1981 the BOR collected and analyzed water samples from the San Luis Drain and found the trace element selenium, along with other trace elements, in the water. In 1982, the United States Fish and Wildlife Service (USFWS) began an investigation to determine the suitability of agricultural drainage water from the San Luis Drain for use in managing waterfowl habitat. Water and fish samples were collected from the San Luis Drain, Kesterson Reservoir, and Volta State Wildlife Management Area, a wetland near Kesterson Reservoir that received only freshwater inflows. All concentrations of pesticides and trace elements, except for selenium, were similar among these sites. Selenium concentrations in mosquitofish from the San Luis Drain and Kesterson Reservoir were 100 times greater than those at Volta.
In 1983, field observations by USFWS showed high incidence of mortality and deformities at Kesterson Reservoir among newborn coots, grebes, stilts, and ducks. The USFWS suggested that further study be done to determine the potential impact of selenium in waterfowl at Kesterson Reservoir. The BOR questioned USFWS's results and USFWS asked USGS for help. That year the USFWS asked USGS WRD scientists Ivan Barnes and Theresa Presser to test drainage water in the San Luis Drain to compare with BOR results. USGS and USFWS results showed higher concentrations of selenium than BOR data because the lab method used by BOR only determined the selenite form of selenium. Testing in USGS labs showed 95% of selenium in agricultural drainage was in the selenate form. BOR disputed these results and BOR asked USGS to review BOR field and laboratory methods. Marvin Fretwell, Regional Water Quality Specialist in Menlo Park, represented the USGS in the process of review and evaluation of USFWS and BOR data. A consistent set of analytical methodologies was developed and the results of Ivan Barnesâ and Theresa Presser's research was accepted as definitively showing that the source of selenium was the subsurface drains of the western San Joaquin Valley. USFWS concluded that selenium was the cause for the mortality and deformities of waterfowl at Kesterson Reservoir.
San Joaquin Valley Drainage Program
In 1984, the San Joaquin Valley Drainage Program (SJVDP) was created as a dedicated effort to develop solutions to the San Joaquin Valley salinity and agricultural drainage problems. USGS was named as the lead agency to conduct extensive studies on ground and surface water quality in the San Joaquin Valley and Tulare Basin to define the extent, magnitude, source, transport, fate and effects of selenium and other water-quality constituents in these areas. These studies were led by Bob Gilliom in Sacramento, California and coordinated by Marc Sylvester (now Assistant Regional Hydrologist, National Water Quality Assessment Program) in Menlo Park, California. The initial assessment included a compilation of historical data, execution of baseline field studies for the period 1985 through 1988, and development of planning objectives, criteria, and performance standards based on water-quantity, water-quality, land use, and public health. Results of these studies provided important information for a regional management plan addressing agricultural drainage problems in the San Joaquin Valley
As a result of these studies, the USGS developed several models of groundwater and geochemical pathways. Theresa Presser, research scientist in the National Research Program, developed a biogeochemical model which traced the pathway of selenium from a geological source to toxic levels in aquatic wildlife (see THE KESTERSON EFFECT--FROM ROCK to DUCK MODEL). The Coast Ranges, which border the San Joaquin Valley on the west, are composed of marine sedimentary rocks that are enriched in selenium. An internal reservoir of salt and selenium has accumulated through 1.0 to 1.2 million years within the San Joaquin Valley soils and aquifers as a result of runoff and erosion from the Coast Ranges. The most selenium-rich region of the San Joaquin Valley is the Panoche Creek alluvial fan, which continues to support intensively irrigated land.
National Irrigation Water Quality Program
There was widespread media attention and United States congressional interest in 1985 concerning the potential for similar toxic impacts from irrigation drainwater at other locations across the western United States. This prompted the Secretary of the Interior to open an investigation of the effects of irrigation drainwater in the western United States. A team of United States Department of the Interior (DOI) scientists including USGS scientists Bill Wilber, Reston, Virginia, and Marc Sylvester, Menlo Park, California, developed a workplan for this study. From this workplan, the National Irrigation Water Quality Program (NIWQP) was initiated in 1985 to identify and address irrigation-induced water quality and contamination problems related to DOI water projects in the western United States. The DOI was selected to manage the NIWQP with an advisory group of Bureau Coordinators representing the BOR, Bureau of Indian Affairs, USGS, and USFWS. Herman Feltz (USGS, Reston, Virginia) was the initial USGS coordinator, with Frank Rinella (USGS, Portland, Oregon) currently filling that position.
Selection of NIWQP study sites was based on USGS research defining six essential factors: (1) a basin of saline marine sedimentary origin; (2) oxidized, alkaline soils that promote the formation of selenate, the mobile form of selenium; (3) an arid to semiarid climate with evaporation greater than precipitation; (4) irrigated agriculture served by DOI-supported irrigation-drainage facilities; (5) saline groundwater aquifers resulting from impeded movement of irrigation water; and (6) drainage by natural gradient or through buried tile drain networks to DOI managed migratory-bird refuges, wetland areas, or other areas in receipt of DOI waters. The results of the NIWQP studies are given at http://www.usbr.gov/niwqp/ and http://water.usgs.gov/pubs/pp/pp1655/. Those sites elevated for further study and/or for remediation planning because of irrigation drainage are:
http://www.usbr.gov/niwqp/
1. Tulare Basin, San Joaquin Valley, California
2. Salton Sea, California
3. Middle Green River Basin, Utah
4. Stillwater Management Area, Nevada
5. Kendrick Reclamation Project, Wyoming
6. Gunnison River Basin-Grand Valley Project, Colorado
7. San Juan River area, New Mexico
8. Sun River area, Montana
9. Riverton Reclamation Project, Wyoming
10. Belle Fourche Reclamation, South Dakota
11. Dolores-Ute Mountain Area, Colorado
12. Lower Colorado River valley, Texas
13. Middle Arkansas River Basin, Colorado-Kansas
14. Pine River area, Colorado
San Francisco Bay-Delta Estuary and Extension of the San Luis Drain
Extension of the San Luis Drain to the San Francisco Bay-Delta Estuary again is being considered as part of the eventual solution to the drainage problems of the western San Joaquin Valley. In order to predict the effects of selenium, USGS National Research Program researchers Sam Luoma and Theresa Presser, at the request of the U.S. Environmental Protection Agency, Contra Costa County, and Contra Costa Water District developed the Bay-Delta Selenium Model (http://water.usgs.gov/pubs/ofr/ofr00-416/ and http://wwwrcamnl.wr.usgs.gov/tracel/data/se_model/index.htm). The Bay-Delta Selenium Model is viewed as a new tool to predict ecological effects based on the major processes leading from loading through consumer organisms to predators.
Additional References--Books
Harris, Tom, 1991, Death in the Marsh: Island Press, Washington, D.C., 245 p.
Frankenberger, W.T., Jr., and Benson, S., eds., 1994, Selenium in the Environment: New York, Marcel Dekker Inc., 456 p.
Frankenberger, W.T., Jr., and Engberg, R.A., eds., 1998, Environmental Chemistry of Selenium: New York, Marcel Dekker Inc.713 p.
Dinar, A., and Zilberman, D., eds., 1991, The economics and management of water and drainage in agriculture: Boston, Kluwer Academic Publishers, 894 p.
San Joaquin Valley Drainage Program, 1990, A management plan for agricultural subsurface drainage and related problems on the westside San Joaquin Valley: San Joaquin Valley Drainage Program, Sacramento, California, 183 p.
Articles
Gilliom, R.J., Belitz, K., Heimes, F.J., Dubrovsky, N.M., Deverel, S.J., Fio, J.L., Fujii R., Clifton, D.G., 1989, Preliminary Assessment of sources, distribution, and mobility of selenium in the San Joaquin Valley, California: U.S. Geological Survey Water-Resources Investigations Report 88-4186, 129 p.
Luoma, S.N. and Presser, T.S., 2000 Forecasting selenium discharges to the San Francisco Bat-Delta Estuary: Ecological effects of a proposed San Luis Drain Extension, U.S. Geological Survey Open-File Report 00-416, 358 p. (http://water.usgs.gov/pubs/ofr/ofr00-416/)
Presser, T.S., 1994a, The Kesterson effect: Environmental Management, v. 18, p. 437-454.
Presser, T.S., 1994b, Geologic origin and pathways of selenium from the California Coast Ranges to the west-central San Joaquin Valley, in Frankenberger, W.T., Jr., and Benson, S., eds., Selenium in the Environment: New York, Marcel Dekker Inc., p. 139-155.
Presser, T.S., and Ohlendorf, H.M., 1987, Biogeochemical cycling of selenium in the San Joaquin Valley, California, USA: Environmental Management, v. 11, p. 805-821.
Presser, T.S., and Piper, D.Z., 1998, Mass balance approach to selenium cycling through the San Joaquin Valley, sources to river to bay, in Frankenberger, W.T., Jr., and Engberg, R.A., eds., Environmental Chemistry of Selenium: New York, Marcel Dekker Inc., p. 153-182.
Presser, T.S., Sylvester, M.A., and Low, W.H., 1994, Bioaccumulation of selenium from natural geologic sources in the western United States and its potential consequences: Environmental Management, v. 18, p. 423-436.
Presser, T.S., Swain, W.C., Tidball, R.R., and Severson, R.C., 1990, Geologic sources, mobilization, and transport of selenium from the California Coast Ranges to the western San Joaquin Valley: a reconnaissance study: U.S. Geological Survey Water-Resources Investigations Report 90-4070, 66p.
Seiler, R.L., Skorupa, J.P., Naftz, D.L. and Nolan, B.T., 2003, Irrigation-induced contamination of water, sediment, and biota in the western United States÷Synthesis of the data form the National Irrigation Water Quality Program, U.S. Geological Survey Professional Paper 1955, 123 p. (http://water.usgs.gov/pubs/pp/pp1655/)
United States Department of the Interior, 1998, Constituents of concern: selenium, in Guidelines for interpretation of the biological effects of selected constituents in biota, water, and sediment, National Irrigation Water Quality Program Information Report No. 3: U.S. Department of the Interior, Washington, DC, p. 139-184 (http://www.usbr.gov/niwqp).
The Kesterson Effect÷from Rock to Duck
The most well known case of Se poisoning in an aquatic ecosystem was at Kesterson National Wildlife Refuge in the San Joaquin Valley, California. Widespread fish mortality and deformities in ducks, grebes, and coots occurred in wetlands fed by agricultural irrigation drainage. The deformities most frequently observed in birds were defects of eyes, feet or legs, beak, brain, and abdomen. Further south in the San Joaquin Valley, a higher level of tetratogenicity (56.7%) occurred in shorebirds inhabiting ponds where accelerated evaporation was taking place as part of a management program.
The geohydrologic balance of Se ultimately determines the degree of contamination build-up in the San Joaquin Valley. The primary geologic inventory of Se in the Coast Ranges is the ultimate source of influx. Drainage from the valley is the source of efflux, whether natural or artificially accelerated by engineering means. The internal reservoir of labile Se in valley is growing because the rate of removal of Se-enriched salts from the valley is naturally slow.
Selenium concentrations in agricultural drains exceeded the criterion for a water-extracted hazardous Se waste (1000 μg Se/L). Levels of Se in the San Joaquin Valley wetlands, streams, and rivers that support beneficial uses for fish and birds exceeded levels for protection of aquatic life (> 5 μg Se/L). Food web biota, although food chains are specific to each water body, exceeded ecological thresholds for dietary Se toxicity (>7 μg Se/g). Levels of Se in tissues of fish, mostly non-native, exceeded ecological thresholds for substantive risk (> 6 μg Se/g), as did Se concentrations in bird eggs (> 10 μg Se/g).
Map of San Joaquin Valley and San Luis Drain.
Caption: Marine sedimentary rocks of the Moreno and Kreyenhagen Shales contribute selenium to soil, surface water and ground water of the San Joaquin Valley. Kesterson Reservoir was closed and buried-in-place in 1988. Current drainwater management efforts include drainage recycling, storage in groundwater aquifers, mitigated evaporation ponds, and discharge to the San Joaquin River. Since 2001, BOR is re-evaluating drainage options for the western San Joaquin Valley in an effort to provide drainage service. Alternatives reviewed are discharge to the San Francisco Bay-Delta Estuary or Pacific Ocean through an extension of the San Luis Drain and storage in valley evaporation ponds.
Photo of San Luis Drain (Theresa Presser, USGS, 1996).
In 1996, a 45-kilometer section of the San Luis Drain was re-opened to transport agricultural drainage to the San Joaquin River and ultimately to the San Francisco Bay-Delta estuary. Because of Se contamination, agricultural drainage canals are posted with human health advisories against consumption of fish.
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