WSP06488

• File Number: 8240.300.31.J
• Description: San Juan River - Environmental Studies
• Basin: San Juan/Dolores
• Water Division: 7
• Date: 11/1/2000
• Title: The Chronic Toxicity of Dietary and Waterborne Selenium to Adult Colorado Pikeminnow in a Water Quality Simulating that in the San Juan River
• Water Supply Pro - Doc Type: Report/Study

.,
I
0
1 C)
, : .'::~ t',
,;::.
-). -J

..\

..,

.;';

7,2 (1, I) mg/L. Mean daily water temperatures (averaged across all tanks) during the 3-week

acclimation period ranged from 13, I to 15.90C.

Prior to starting the test, fish were fed Silver Cup Brood 6.35-mm ('I. inch) dry pellets

(Nelson and Sons Inc., Murray, UT) 3-4 times daily at a rate of about 1.0% body weight per day.

This diet contained 1.37 ~g/g selenium dry weight (average of duplicate analysis) and 7.9%

moisture. Each tank was siphoned daily after the last feeding to remove lilleaten food, fecal

material, and detritus.

Test Water

All fish were tested in a nonstandardized reconstituted water designed to simulate the

major water quality characteristics (without the inorganic contaminants) of the San Juan River at

Shiprock, NM, Station ID 09368000 on November 5, 1985 (Table I; BeaI and Gold 1987). This

date was selected because it was a year with average river flows, The test water was prepared by

adding appropriate amounts of calcium cliloride, calcium sulfate dihydrate, magnesium

carbonate, sodium bicarbonate, and potassium bicarbonate to deionized water in large (5,678-L

or 11,355-L) polyethylene blending tanks, Each blending tank was fitted with a recirculating

pump to mix and aerate the water. To facilitate the dissolution of magnesium carbonate, carbon

dioxide (C02) gas was bubbled in the tank for about 5 minutes after the salt was added, The

water was then vigorously aerated with compressed air for least 2 hours to drive off the excess

C02, Each tank of test water prepared was analyzed for general water quality characteristics

prior to use in the study to insure that the water quality parameters were within 10% (II % for

magnesium) of their desired concentrations, except for chloride, Chloride concentrations in the

blending tanks were about 2.2 times higher than that measured in the San Juan River because of

the type of mineral salts used to prepare the water. The flow of reconstituted test water to the

5