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

Table 11. Statistical summary of concentrations of detected pesticides atfixed-station sites in the Upper Colorado River Basin,
October 1996-January 1998
[µg2, micrograms per liter; --, not computed; E, estimated; HPLC, high-performance liquid chromatography]

Pesticide Number
of
samples
Number of
detections
Percentage
detected Method
reporting limit
(µg~-) Statistics for detections
Minimum Median Maximum
(µg~) ~µg~) (µg~)
Gore Creek at mouth near Minturn (urban/forest site)
Atrazine 10 1 10 0.001 -- -- 0.014
Benfluralin 10 1 10 0.002 -- -- E 0.002
Cyanazine 10 1 10 0.004 -- -- 0.006
Metolachlor 10 1 10 0.002 -- -- 0.007
Dry Creek near Begonia Road, near Delta (agriculture site)
Atrazine 15 15 100 0.001 E 0.003 0.021 0.105
Deethylatrazine 15 14 93 0.002 E 0.003 E 0.009 E 0.028
Alachlor 15 9 60 0.002 E 0.003 0.011 0.031
DCPA 15 6 40 0.002 E 0.002 E 0.004 0.016
Cyanazine 15 5 33 0.004 0.004 0.008 0.013
Benfluralin 15 4 27 0.002 E 0.003 E 0.004 0.004
EPIC 15 3 20 0.002 E 0.002 E 0.002 E 0.003
Metolachlor 15 3 20 0.002 E 0.002 E 0.003 E 0.003
Diazinon 15 2 13 0.002 0.004 0.006 0.008
Ethalfluralin 15 2 13 0.004 0.004 0.006 0.009
Trifluralin 15 2 13 0.002 E 0.003 E 0.004 0.006
Oryzalin 114 1 7.1 0.019 -- -- E 0.030
Acetochlor 15 1 6.7 0.002 -- -- 0.008
Azinphos-methyl 15 1 6.7 0.001 -- -- E 0.003
2,4-D 15 1 6.7 0.035 -- -- E 0.620
Propargite 15 1 6.7 0.013 -- -- 0.046
Reed Wash near Mack (agriculture site)
Atrazine 24 18 75 0.001 E 0.001 0.009 0.127
Metolachlor 24 17 71 0.002 E 0.003 0.043 0.281
Alachlor 24 16 67 0.002 E 0.002 0.008 0.513
Trifluralin 24 14 58 0.002 E 0.002 0.006 0.021
2,4-D 24 13 54 0.035 0.120 0.270 E 0.980
Carbofuran (HPLC) 24 10 42 0.028 0.040 0.200 E 1.60
Chlorpyrifos 24 10 42 0.004 0.005 0.006 0.013
DCPA 24 9 38 0.002 E 0.002 E 0.003 0.026
EPIC 24 9 38 0.002 E 0.003 0.025 0.853
Cyanazine 24 8 33 0.004 0.006 0.020 0.159
Deethylatrazine 24 7 29 0.002 E 0.002 E 0.004 E 0.006
Propargite 24 4 17 0.013 0.043 0.168 0.230
2,4-DB 24 2 8.3 0.035 0.050 0.440 0.830
Dicamba 24 2 8.3 0.035 E 0.090 E 0.120 E 0.150
Terbufos 24 2 8.3 0.013 0.017 0.017 0.017
Azinphos-methyl 24 1 4.2 0.001 -- -- E 0.062
Benfluralin 24 1 4.2 0.002 -- -- E 0.003
Bentazon 24 1 4.2 0.014 -- -- E 2.60
Malathion 24 1 4.2 0.005 -- -- 0.026
OCCURRENCE AND DISTRIBUTION OF PESTICIDES 27