USGS - science for a changing world

Open-File Report 2008-1271

U.S. GEOLOGICAL SURVEY
Open-File Report 2008-1271

Year 3 Summary Report: Baseline Selenium Monitoring of Agricultural Drains Operated by the Imperial Irrigation District in the Salton Sea Basin

Prepared in cooperation with the Imperial Irrigation District

By Michael K. Saiki, Barbara A. Martin, and Thomas W. May

Abstract

This report summarizes findings from the third year of a 4-year-long field investigation to document selected baseline environmental conditions in 29 agricultural drains and ponds operated by the Imperial Irrigation District along the southern border of the Salton Sea. Routine water quality and fish species were measured at roughly quarterly intervals from April 2007 to January 2008. The water quality measurements included total suspended solids and total (particulate plus dissolved) selenium. In addition, during April and October 2007, water samples were collected from seven intensively monitored drains for measurement of particulate and dissolved selenium, including inorganic and organic fractions. In addition, sediment, aquatic food chain matrices (particulate organic detritus, filamentous algae, net plankton, and midge [chironomid] larvae), and two fish species (western mosquitofish, Gambusia affinis; and sailfin molly, Poecilia latipinna) were sampled from the seven drains for measurement of total selenium concentrations. The mosquitofish and mollies were intended to serve as surrogates for desert pupfish (Cyprinodon macularius), an endangered species that we were not permitted to take for selenium determinations. Water quality values were typical of surface waters in a hot desert climate. A few drains exhibited brackish, near anoxic conditions especially during the summer and fall when water temperatures occasionally exceeded 30C. In general, total selenium concentrations in water varied directly with conductivity and inversely with pH. Although desert pupfish were found in several drains, sometimes in relatively high numbers, the fish faunas of most drains and ponds were dominated by nonnative species, especially red shiner (Cyprinella lutrensis), mosquitofish, and mollies. Dissolved selenium in water samples from the seven intensively monitored drains ranged from 0.700 to 24.1 g/L, with selenate as the major constituent in all samples. Selenium concentrations in other matrices varied widely among drains and ponds, with at least one drain (for example, Trifolium 18) exhibiting especially high concentrations in food chain organisms (in detritus, 13.328.9 g Se/g; in net plankton, 11.919.3 g Se/g; in midge larvae, 12.715.4 g Se/g) and fish (in mollies, 12.8-25.1 g Se/g; in mosquitofish, 13.2-20.2 g Se/g; all concentrations are dry weights). These elevated concentrations approached or exceeded average concentrations reported from flowing waters in seleniferous wetlands in the San Joaquin Valley.

Contents

Abstract
Introduction
Study Area and Methods
Results and Other Progress
References Cited
Appendix: Raw Data from Field and Laboratory Measurements of Water, Sediment, and Various Aquatic Biota, Including Fish

This report is available online in Portable Document Format (PDF). If you do not have the Adobe Reader, it is available for free download from Adobe Systems Incorporated.

Download the report (PDF, 1.09 MB)

Document Accessibility: Adobe Systems Incorporated has information about PDFs and the visually impaired. This information provides tools to help make PDF files accessible. These tools convert Adobe PDF documents into HTML or ASCII text, which then can be read by a number of common screen-reading programs that synthesize text as audible speech. In addition, an accessible version of Adobe Reader 8.0 for Windows (English only), which contains support for screen readers, is available. These tools and the accessible reader may be obtained free from Adobe at Adobe Access.

For more information about USGS activities at the WFRC, visit the USGS Western Fisheries Research Center home page.

Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: https://pubs.usgs.gov/ofr/2008/1271
Page Contact Information: Publications Team
Page Last Modified: Wednesday, 07-Dec-2016 21:28:52 EST