WSP02344

• File Number: 8210.310
• Description: Colorado River Basin Organizations and Entities - Colorado River Water Conservation District
• State: CO
• Basin: Western Slope
• Date: 1/1/1994
• Author: US DoI - USGS
• Title: Salinity Fact Sheets
• Water Supply Pro - Doc Type: Publication

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backwaters and streams where fish and waterfowl
live and reproduce. Selenium then moves through
the aquatic environment and bioaccumulates in
fish and birds. Human consumers of locally
caught fish and waterfowl who have a varied and
well balanced diet shouid have seienium intakes
which are both safe and adequate.

DATA COLLECTION &
INTERPRET A TION

Data have been collected since 1987 in the
Uncompahgre Valley and since 1991 in the Grand
Valley. Samples of water, sediment, food chain
items (plants, invertebrates), fish, birds and bird
eggs have been collected from ponds, drains,
back-waters and streams. Although examined for
an extensive list of contaminants (e.g. lead,
mercury, zinc) and pesticides, selenium was found
to be the major concern. Biologists suspect the
primary effect of these elevated levels of selenium
is reproductive failure in both fish and birds,
including reduced hatching of eggs and birth
defects. Some native fish species may be more
susceptible to reproductive problems than some of
the more recently introduced non-native species.

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WHAT IS BEING DONE?

A detailed study of the Uncompahgre and Grand
Valleys was conducted during 1991-92. Based on
the results of that investigation. the Uncompahgre
and Grand Valleys have been identified as two of
the most significant selenium problem areas in the
western United States. A team of USGS, FWS
and Reclamation representatives continues to
study the scope of these problems. Current efforts
are focused on further investigation of selenium
effects on local fish and waterfowl and identifying
where remediation may be needed. Also high on
the team's priorities is providing information to
interested water users, other local, state and
Federal agencies, and the general public.
Ultimately, individuals interested in selenium
issues may wish to help identify and implement
solutions to the problems.

FOR MORE INFORMATION:

Please call Mike Baker at [phone] or write
to: Bureau of Reclamation
Western Colorado Area Office
P.O. Box 60340
Grand Junction, CO 81506

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Figure 1. Some selenium (Se) carried in irrigation drainage is deposited in sediment and is available to plants,
invertebrates and small fish. It is bioaccumulated as the larger fish and birds eat these food chain items.