8277

• UCREFRP Catalog Number: 8277
• Author: Bauch, N. J. and N. E. Spahr.
• Title: Pesticides in Surface Waters of the Upper Colorado River Basin, Colorado, 1996-98.
• USFW Year: 2000.
• USFW - Doc Type: Water-Resources Investigations Report 00-4005,
• Copyright Material: NO

TABLES
1. Harvested acreage for crops and percentage of harvested acreage irrigated in 10 counties in the
Upper Colorado River Basin study unit, Colorado, 1997 ....................................................................................... 5
2. Description of surface-water-sampling sites for pesticides in the Upper Colorado River Basin
fixed-station network ............................................................................................................................................... 6
3. Agricultural synoptic surface-water-sampling sites, Grand Valley, Upper Colorado River Basin ......................... 7
4. Agricultural synoptic surface-water-sampling sites, Uncompahgre River Valley, Upper Colorado River Basin... 8
5. Pesticide target analytes, method reporting limits, drinking-water standards, and aquatic-life criteria ................. 9
6. Concentrations and relative percent differences for pesticides detected in replicate samples ................................ 15
7. Mean and standard deviation of pesticide recovery in 30 field-spiked samples determined by gas
chromatography/mass spectrometry ........................................................................................................................ 20
8. Mean and standard deviation of pesticide recovery in 30 field-spiked samples determined by
high-performance liquid chromatography ............................................................................................................... 20
9. Mean and standard deviation of pesticide surrogate recovery ................................................................................ 21
10. Summary of pesticide occurrence and concentrations for a1144 surface-water sites sampled in the
Upper Colorado River Basin study unit, October 1996 through January 1998 and May 1998 .............................. 24
11. Statistical summary of concentrations of detected pesticides at fixed-station sites in the Upper Colorado
River Basin, October 1996-January 1998 ............................................................................................................... 27
12. Pesticide detections per land use and site type at fixed-station sites in the Upper Colorado River Basin,
October 1996-January 1998 ................................................................................................................................... 34
13. Statistical summary of concentrations of detected pesticides at 43 agricultural synoptic sites in the
Upper Colorado River Basin, May 1998 ................................................................................................................. 35
14. Pesticide concentrations exceeding freshwater criteria guidelines for the protection of aquatic life,
Grand Valley and Uncompahgre River Valley, Upper Colorado River Basin agricultural synoptic study,
May 1998 ................................................................................................................................................................ 38
15. Summary of selected pesticide occurrences and concentrations for all 1,058 surface-water sites sampled as
part of 20 National Water-Quality Assessment Program study units, 1992-96 ...................................................... 42
CONVERSION FACTORS AND ABBREVIATIONS
Multiply By To obtain
acre 4,047 square meter (m~)
acre-foot (acre-ft) 1,233 cubic meter (m3)
cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s)
inch 25.4 millimeter (mm)
inch per year (in/yr) 25.4 millimeter per year (mm/yr)
kilogram (kg) 2.2046 pound (lb)
liter (L) 0.2642 gallon (gal)
square mile (mid) 2.590 square kilometer (km~)
Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as follows:

VI CONTENTS