Causal factors for pesticide trends in streams of the United States: Atrazine and deethylatrazine

Journal of Environmental Quality
By: , and 



Pesticides are important for agriculture in the United States, and atrazine is one of the most widely used and widely detected pesticides in surface water. A better understanding of the mechanisms by which atrazine and its degradation product, deethylatrazine, increase and decrease in surface waters can help inform future decisions for water-quality improvement. This study considers causal factors for trends in pesticide concentration in streams in the United States and models the causal factors, other than use, in structural equation models. The structural equation models use a concomitant trend in corn and a latent variable model indicating moisture supply and management. The moisture supply and management latent variable incorporates long-term moisture conditions in the individual watersheds by using the Palmer Hydrologic Drought Index; human influence on the hydrologic cycle through the percent of the watershed drained by tile drains in 2012; and the base-flow contribution to streamflow, using the base-flow index. The structural equation models explain 77% and 38% of the variability in atrazine and deethylatrazine trends, respectively, across the conterminous United States. The models highlight future water-quality challenges, particularly in tile-drained settings where fall precipitation and heavy precipitation are increasing.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Causal factors for pesticide trends in streams of the United States: Atrazine and deethylatrazine
Series title Journal of Environmental Quality
DOI 10.1002/jeq2.20045
Volume 49
Issue 1
Year Published 2020
Language English
Publisher ACSESS
Contributing office(s) WMA - Earth System Processes Division
Description 11 p.
First page 152
Last page 162
Country United States
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