Herbicides and degradates in shallow aquifers of Illinois: Spatial and temporal trends

Journal of the American Water Resources Association
By: , and 



During the fall of 2000, the occurrence was examined of 16 herbicides and 13 herbicide degradates in samples from 55 wells in shallow aquifers underlying grain producing regions of Illinois. Herbicide compounds with concentrations above 0.05 μg/L were detected in 56 percent of the samples. No concentrations exceeded regulatory drinking water standards. The six most frequently detected compounds were degradates. Water age was an important factor in determining vulnerability of ground water to transport of herbicide compounds. Unconsolidated aquifers, which were indicated to generally contain younger ground water than bedrock aquifers, had a higher occurrence of herbicides (73 percent of samples) than bedrock aquifers (22 percent). Temporal analysis to determine if changes in concentrations of selected herbicides and degradates could be observed over a near decadal period indicated a decrease in detection frequency (25 to 18 percent) between samplings in 1991 and 2000. Over this period, significant differences in concentrations were observed for atrazine (decrease) and total acetochlor (increase). The increase in acetochlor compound concentrations corresponds to an increase in acetochlor use during the study period, while the decrease in atrazine concentrations corresponds to relatively consistent use of atrazine. Changes in frequency of herbicide detection and concentration do not appear related to changes in land use near sampled wells.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Herbicides and degradates in shallow aquifers of Illinois: Spatial and temporal trends
Series title Journal of the American Water Resources Association
DOI 10.1111/j.1752-1688.2005.tb03753.x
Volume 41
Issue 3
Year Published 2005
Language English
Publisher Wiley
Contributing office(s) Iowa Water Science Center, Toxic Substances Hydrology Program
Description 11 p.
First page 537
Last page 547
Country United States
State Illinois
Online Only (Y/N) N
Additional Online Files (Y/N) N
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