Office of the Regional Executive for Biology - Central Region
BUREAU OF RECLAMATION
BIN REPORT
Title:Interpretation and Appropriate Management Response to Selenium
Concentrations in
Flow-through Systems Receiving Irrigation Return Flows
SUBMITTING BUREAU: Bureau
of Reclamation
ORIGINATING OFFICE: Technical
Service Center (TSC)
BIN NUMBER:
BOR07CR99
BRD REGION:
Central
and Western
DESCRIPTION OF
NEED: Many areas throughout the Western United
States are underlain with deposits of marine shales. Soils formed from, or in association with these shale deposits
often contain constituents such as selenium.
Selenium can enter surface waters—like streams and other
wetlands—through natural runoff and/or through constructed pathways such as irrigation
return flows. Humans and animals
require selenium in small quantities for good health, but at higher
concentrations, selenium can cause birth defects; reproductive failure; and
death in fish, wildlife, and livestock.
Irrigation
activities can cause concentration of selenium in water and sediments, and may
ultimately lead to bioaccumulation in the aquatic food chain. The adverse effects to fish and wildlife
associated with selenium bioaccumulation in closed-basin systems—such as
Kesterson National Wildlife Refuge—are well documented. However, in some areas of the West, background concentrations of
selenium in open or flow-through systems are often within the “level of
concern” (2-8 g/g dry weight) identified
for sediments and biota in closed-basin systems. Within such systems, streams receiving irrigation return flows
commonly exhibit selenium concentrations from invertebrates and fish within or
above the level of concern.
Flow-through system studies are limited, and resource mangers responsible
for both efficient irrigation operations and the health and well being of
aquatic resources in streams receiving irrigation return flows need guidance in
interpreting selenium concentrations in such systems.
The basic question
is: can selenium concentrations and their effects in closed-basin systems, and
techniques that aid in their interpretation (e.g., Lemly’s Protocol), be used
to interpret risk to aquatic resources in flow-through systems?
Objectives/Questions:
1.
Are
the results from closed-basin studies of selenium concentrations and aquatic
organisms also applicable to flow-through systems?
2.
Can
techniques designed to aid in the interpretation of risk from selenium
concentrations in closed-basin systems be reliably used—without modification—in
flow-through systems?
3.
What
are effective management actions for lowering selenium concentrations in
flow-through systems?
MANAGEMENT PROBLEM WITH NEED: The Bureau of Reclamation, Fish and Wildlife
Service, Environmental Protection Agency, and various state agencies are
concerned about the potential effects of various soil constituents and
agro-chemicals in irrigation return flows on aquatic resources in streams
receiving return flows. While a fairly
extensive body of research results exist for closed-basin systems, little
information is available concerning the potential risk to aquatic resources from
elevated selenium concentrations in flow-through systems. Thus uncertainty exists in interpretation of
selenium concentrations from flow-through systems, especially in systems
supporting elevated background levels of selenium. While this uncertainty exists, effective management and
appropriate protective measures for aquatic resources are difficult to
implement. The Biological Resources
Division of the Geological Survey is uniquely positioned to assist with long-term
studies to provide information that will help ensure responsible management of
all resources in flow-through systems with elevated selenium concentrations.
BUREAU CONTACT:
Michael J.
Armbruster; Bureau of Reclamation; Denver Federal Center, Bldg. 56 (D-8210)
P.O. Box 25007;
Denver CO 80225; Tel: 303-445-2232, Fax: 303-445-6328; E-Mail: marmbruster@do.usbr.gov
BRD PRIMARY
CENTER: Columbia
Environmental Research Center (CERC)
BRD CENTER
CONTACT: Susan Finger
RESULTS OF BRD
INITIATED COMMUNICATION (FY00): CERC is working on an ecological risk
assessment on selenium in aquatic communities of the Colorado River Basin. This project was formulated in discussions
with the BOR Salt Lake City office and funding was provided by BOR to cover a
portion of this effort. The risk assessment will focus mainly on information
included in the National Irrigation Water Quality Data Base, but will
incorporate values from the scientific literature as well as information from
other regional sources. The assessment will
address response to selenium across ecological boundaries including comparisons
among wetland, reservoir, stream, and river habitats. No new data will be generated for this project. Products from this work will developed
during FY2001.
DATE SUBMITTED TO
REGIONAL OFFICE: March 13, 2000
PREPARED BY:
Susan Finger and John Besser, CERC
RESULTS OF BRD
INITIATED COMMUNICATION (FY99): CERC has historically
contributed to the toxicological information available on selenium. Scientists at CERC have evaluated toxicity
of selenium in laboratory and field situations. In addition, studies have been conducted in both flowing and
closed systems in the western United States.
CERC is evaluating the current literature on selenium toxicity in
flowing systems and is preparing a response to the first two questions posed in
this BIN. Discussions are continuing
with BOR as these responses are being prepared. BRD will compare the results of selenium fate and transport
models developed for closed and flowing system. BOR is correct in assuming that the understanding of selenium
dynamics in closed systems is better defined than in flowing waters. However, it is possible that depositional
areas in stream and rivers may function similarly in some respects to closed systems.
Interactions of selenium and mercury, particularly in western systems is also
relevant to this BIN.
DATE SUBMITTED TO
REGIONAL OFFICE: December 18, 1998
PREPARED BY:
Susan Finger and Steve Hamilton, CERC
|
|
U.S. Department of the Interior | U.S. Geological Survey
