Reconnaissance investigation of water quality, bottom sediment, and biota associated with irrigation drainage in the San Juan River area, San Juan County, northwestern New Mexico, 1990-91

Selenium is the trace element of major concern in the San Juan River area. Concentrations of selenium larger than established standards and criteria were present in water, bottom sediment, and biota in four areas on three irrigation projects: the middle and north ponds in Gallegos Canyon on the Navajo Indian Irrigation Project (NIIP) (two sites), the Ojo Amarillo Canyon drainage on the NIIP (two sites), a pond receiving irrigation drainage water on the West Hammond Irrigation Project (one site), and a drain on the eastern part of the Hogback Irrigation Project (one site). Ground-water return flow from irrigated areas contributes substantially to surface water at these sites. Selenium concentrations in nine surface-water samples collected from these sites exceeded the U.S. Environmental Protection Agency Primary Drinking Water Standard Maximum Contaminant Level of 50 j*g/L (micrograms per liter). One additional sample concentration also exceeded the State of New Mexico standard of 5 pg/L designated for the protection of fisheries. Selenium concentrations in five bottom-sediment samples from the middle pond in Gallegos Canyon, Ojo Amarillo Canyon, and the Hogback Project ranged from 4.5 to 37 j*g/g (micrograms per gram). The geometric mean concentration of selenium in soils of the Western United States is 0.23 /*g/g. Selenium concentrations in biota at six sites in Gallegos and Ojo Amarillo Canyons, the West Hammond Pond, and the Hogback east drain ranged from 3.0 to 32.3 ^g/g in eight invertebrate samples, 4.22 to 51.3 ^g/g in five amphibian samples, and 13.6 to 41.7 ^g/g in six fish samples. Selenium concentrations in 18 of these 19 samples were within or larger than the 4to 8-jig/g dry-weight waterfowl food-item criterion. Six fish samples from these sites also had concentrations larger than the 12-/ig/g whole-body concentration above which reproductive failure can occur. The largest median concentrations of selenium in bird liver and kidney tissue were in six bird samples from the Gallegos Canyon ponds (31.2 A*g/g) and four bird samples from Ojo Amarillo Canyon ponds (20.5 /zg/g). Embryo deformities usually occur when the median selenium concentration in a population is larger than 30 A»g/g; however, the potential for embryo deformities exists when the concentration of selenium is between 10 and 30 /jg/g. Due to lack of availability, however, only one embryo from the Gallegos and Ojo Amarillo Canyons was examined for teratogenesis. The results of embryo examinations conducted during this study, therefore, are inadequate to accurately determine conditions throughout the San Juan River area. Eleven of 15 plant samples, 6 of 15 invertebrate samples, and 4 of 14 fish samples collected from irrigation project sites had concentrations of lead larger than the criterion for predator protection of about 1 /Jg/g dry weight. Four of 13 common carp and flannelmouthed sucker samples had lead concentrations and 4 of 13 f lannelmouthed sucker samples had mercury concentrations larger than the respective 85th-percentile concentrations in these species collected for the National Contaminant Biomonitoring Program (NCBP). Concentrations of DDE were larger than laboratory reporting levels in 8 of 10 bottom-sediment samples, 6 of 6 flannelmouthed sucker samples, and 31 of 35 bird samples. In 8 of 16 killdeer samples, concentrations of DDE were equal to or larger than the 1.0-/zg/g wet-weight criterion for the protection of predators. No concentration in any of the 22 organochlorine compound analyses in the six fish samples was as large as the respective NCBP geometric mean concentration. INTRODUCTION During the last several years, there has been increasing concern about the quality of irrigation drainage and its potentially harmful effects on human health, fish, and wildlife. Concentrations of selenium greater than water-quality criteria for the protection of aquatic life (U.S. Environmental Protection Agency, 1987) have been detected in subsurface drainage from irrigated land in the western part of the San Joaquin Valley in California. In 1983, incidences of mortality, birth defects, and reproductive failures in waterfowl were discovered by the U.S. Fish and Wildlife Service at the Kesterson National Wildlife Refuge in the western San Joaquin Valley where irrigation drainage was impounded. In addition, potentially toxic trace elements and pesticide residues have been detected in other areas in western States that receive irrigation drainage. Because of concerns expressed by the U.S. Congress, the U.S. Department of the Interior (DOI) started a program in October 1985 to identify the nature and extent of irrigation-induced water-quality problems that might exist in the western States. The DOI developed a management strategy and formed an interbureau group known as the "Task Group on Irrigation Drainage," which prepared a comprehensive plan for reviewing irrigation-drainage concerns for which DOI may have responsibility. Initially, the task group identified 20 areas in 13 States that warranted reconnaissance-level investigations related to three specific activities: (1) irrigation or drainage facilities constructed or managed by the DOI, (2) National Wildlife Refuges managed by the DOI, and (3) other migratory-bird or endangered-species management areas that receive water from DOI-funded projects. Nine of the 20 areas were selected for reconnaissance investigations during 1986-87: Arizona-California: Lower Colorado-Gila River Valley area California: Salton Sea area Tulare Lake Bed area Montana: Sun River Reclamation Project area Milk River Reclamation Project area Nevada: Stillwater Wildlife Management area Texas: Lower Rio Grande-Laguna Atascosa National Wildlife Refuge atea Utah: Middle Green River Basin area Wyoming: Kendrick Reclamation Project area. Reports for these nine reconnaissance investigations have been published. On the basis of results of these investigations, four detailed studies were initiated in 1988 for the Salton Sea area, Stillwater Wildlife Management area, Middle Green River Basin area, and the Kendrick Reclamation Project area. Eleven more reconnaissance investigations were initiated in 1988: California: Sacramento Refuge Complex California-Oregon: Klamath Basin Refuge Complex Colorado: Gunnison and Uncompahgre River Basins and Sweitzer Lake Pine River Project Colorado-Kansas: Middle Arkansas River Basin Idaho: American Falls Reservoir New Mexico: Middle Rio Grande Project and Bosque del Apache National Wildlife Refuge Oregon: Malheur National Wildlife Refuge South Dakota: Angostura Reclamation Unit Belle Fourche Reclamation Unit Wyoming: Riverton Reclamation Project. Evaluation of results in published reports of these investigations, and a continuing evaluation of all data for the Irrigation Drainage Program led to initiating three more detailed studies in 1990-91: California-Oregon: Klamath Basin Refuge Complex Colorado: Gunnison River Basin/Grand Valley Project Montana: Sun River area. In October 1989, four reconnaissance investigations were begun and another was started in October 1990. The study areas are: Oregon-Idaho: Owyhee-Vale Projects Nevada: Humboldt Wildlife Management area Colorado: Dolores Project area New Mexico: San Juan River area Washington: Middle Columbia River Basin. All reconnaissance investigations are conducted by interbureau study teams composed of a scientist from the U.S. Geological Survey as team leader, with additional Geological Survey, U.S. Fish and Wildlife Service, U.S. Bureau of Reclamation, and U.S. Bureau of Indian Affairs scientists representing several different disciplines. The investigations are directed toward determining whether irrigation drainage: (1) has caused or has the potential to cause significant harmful effects to human health, fish, and wildlife; or (2) may adversely affect the suitability of water for other beneficial uses. Purpose and Scope The purpose of this report is to present information for determining if irrigation drainage from the DOI-sponsored irrigation projects in the San Juan River area: (1) has caused or has the potential to cause significant harmful effects to human health, fish, or wildlife; or (2) may reduce the suitability of water for beneficial uses. The San Juan River area was selected for study because data from previous studies in the area indicated that concentrations of some inorganic and organic substances may be large enough to cause or have the potential to cause these harmful effects or to reduce the suitability of water for beneficial uses. Additionally, the geologic units of the area, consisting of primarily sedimentary formations of Cretaceous and Tertiary age, have the potential to yield significant amounts of selenium and other trace elements to water, bottom sediment, and biota. The scope of this study included collection and analysis of water, bottom-sediment, and biota samples from the San Juan River upstream and downstream from and adjacent to the DOI-sponsored irrigation projects; from diversions from the San Juan River; and from wetlands, ponds, and streams within and at areas of discharge of the irrigation projects, including backwater habitats. Sample collection was conducted from April 1990 through December 1990. Samples were analyzed for concentrations of major ions, selected trace elements, and selected pesticides. Acute toxicity tests were conducted on water samples from selected sites to determine the toxicity of water to selected organisms. This report describes the areal distribution of concentrations of selected constituents in the various media and how these concentrations relate to irrigation drainage from the DOI-sponsored irrigation projects. Acknowledgment s Appreciation is extended to Ernest Teller and Phillip Tollenaar of the Agricultural Testing and Research Laboratory, Navajo Agricultural Products Industry, for use of laboratory facilities; to Jeffrey Cole, Navajo Nation Fish and Wildlife, f