Table 5. Counts of samples and detections for pesticides analyzed from 1999 to 2009, sites where pesticides were detected, and concentration, date, and site of the maximum detected concentration for the entire period of record and for 2009.
[Sample size includes all (unscreened) samples. µg/L, micrograms per liter; –, not detected in 2009]
Pesticide type |
Class |
Pesticide |
Number of samples |
Number of detections |
Sites where detected |
Maximum concentration
1999–2009 |
|
Maximum concentration
2009 |
Measurement (µg/L) |
Date |
Site |
Measurement (µg/L) |
Date |
Site |
Herbicide |
Triazine |
Atrazine |
920 |
2 |
Lenz |
0.032 |
05-31-02 |
Lenz |
|
– |
– |
– |
|
Simazine |
933 |
157 |
Baldwin; Evans; Hood, East Fork;
Hood, mouth; Hood, Indian;
Lenz; Neal, middle; Neal, mouth;
Neal, upper, below diversion; Rogers |
1.9 |
06-13-03 |
Lenz |
0.299 |
09-16-09 |
Lenz |
Insecticide |
Organophosphate |
Azinphosmethyl |
939 |
76 |
Evans; Hood, Middle Fork;
Hood, mouth; Lenz; Neal, middle;
Neal, mouth; Neal, upper, above diversion |
0.375 |
09-12-03 |
Lenz |
|
0.028 |
09-16-09 |
Lenz |
|
Chlorpyrifos |
944 |
66 |
Evans; Hood, East Fork;
Hood, Middle Fork; Hood, mouth;
Indian; Lenz; Neal, middle;
Neal, mouth; Neal, upper, above diversion; Rogers |
0.482 |
03-22-99 |
Neal,mouth |
– |
– |
– |
|
Diazinon |
945 |
4 |
Baldwin; Neal, mouth |
0.19 |
06-20-00 |
Neal,mouth |
– |
– |
– |
|
Malathion |
946 |
7 |
Lenz; Neal, mouth |
0.098 |
06-16-04 |
Lenz |
– |
– |
– |
|
Phosmet |
895 |
14 |
Evans; Lenz; Neal, middle;
Neal, mouth; Neal, upper, above diversion |
0.278 |
06-13-02 |
Lenz |
– |
– |
– |
|
First posted June 17, 2011
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