Table 2.  Concentrations of pesticides detected in Barton Springs (Main and Eliza Springs) and Barton and Williamson Creeks, May-July, 2000

Site

Date

Time

Pesticide concentrations
(micrograms per liter; e, estimated value1; <, non-detection)

Atrazine

Deethyl-
atrazine

Carbaryl

Diazanon

Simazine

Prometon

Barton Springs:

 

 

 

 

 

 

 

 

Main Springs

5/1/00

1055

0.0075

e0.0079

<0.003

<0.002

<0.005

  <0.018

 

5/1/00

1820

  .0078

  e.0093

  <.003

  <.002

  <.005

  <.018

 

5/1/00

2305

  .11

  e.013

  e.0065

    .0089

  <.005

  <.018

 

5/2/00

1145

  .27

  e.025

  e.011

    .021

  <.005

   <.018

 

5/2/00

1420

  .40

  e.023

  e.0090

    .024

  <.005

   <.018

 

5/2/00

1812

  .45

  e.033

  e.012

    .028

    .0069

  <.018

 

5/3/00

1240

  .54

  e.025

  e.013

    .019

  <.01

  <.018

 

5/4/00

1015

  .56

  e.024

  e.0066

    .0075

    .011

   <.018

 

5/8/00

1300

  .25

  e.018

  <.003

  <.002

    .013

  <.018

 

 

 

 

 

 

 

 

 

Barton Springs

6/9/00

1940

  .023

  e.016

  <.003

  <.002

  <.005

  <.018

 

6/10/00

1030

  .0891

  e.035

  e.037

  <.0090

    .0086

  <.018

 

 

 

 

 

 

 

 

 

 

7/5/00

0930

  .015

  e.012

  <.003

  <.002

  <.005

  e.0034

Eliza Springs

5/2/00

1855

  .086

  e.013

  <.003

    .0051

  <.005

  <.018

Barton Creek

5/2/00

20135

  .44

  e.0097

  e.30

    .18

  <.005

  <.018

Williamson Creek

5/1/00

20400

  .80

  e.031

  e.47

    .26

  <.005

  <.018

1 An estimated value is a confirmed detection that is less than the long-term method detection limit.

2 Sample is a flow event composite; time is first sample collection time.