Agriculture‐Related Trends in Groundwater Quality of the Glacial Deposits Aquifer, Central Wisconsin

Measuring and understanding trends in groundwater quality is necessary for determining whether changes in land‐management practices have an effect on groundwater quality. This paper describes an approach that was used to measure and understand trends using data from two groundwater studies conducted...

Full description

Saved in:
Bibliographic Details
Published inJournal of environmental quality Vol. 37; no. S5; pp. S-209 - S-225
Main Author Saad, David A.
Format Journal Article
LanguageEnglish
Published Madison American Society of Agronomy, Crop Science Society of America, Soil Science Society 01.09.2008
American Society of Agronomy
Subjects
Agriculture
Agriculture - trends
Atrazine
Atrazine - analogs & derivatives
Atrazine - analysis
Consumer protection
Dissolved oxygen
Fresh Water - analysis
Geography
Glacial aquifers
Glacial deposits
Groundwater
Groundwater data
Groundwater studies
Herbicides
Nitrates
Nitrates - analysis
Research Design
Time Factors
Water analysis
Water depth
Water levels
Water Pollutants - analysis
Water quality
Water sampling
Water Supply - standards
Wisconsin
Wisconsin
Online AccessGet full text

Cover

More Information
Summary:Measuring and understanding trends in groundwater quality is necessary for determining whether changes in land‐management practices have an effect on groundwater quality. This paper describes an approach that was used to measure and understand trends using data from two groundwater studies conducted in central Wisconsin as part of the USGS NAWQA program. One of the key components of this approach, determining the age of sampled groundwater, gave a temporal component to the snapshots of water quality that were obtained through synoptic‐sampling efforts. This approach can be used at other locations where groundwater quality data are collected, groundwater age can be determined, and associated temporal data are available. Results of these studies indicate measured concentrations of nitrate and atrazine plus deethylatrazine were correlated to historical patterns of fertilizer and atrazine use. Concentrations of nitrate in groundwater have increased over time; concentrations of atrazine plus deethylatrazine increased and then decreased. Concentrations of nitrate also were correlated to screen depth below the water level and concentrations of dissolved O2; concentrations of atrazine plus deethylatrazine were correlated to dissolved O2 and annual precipitation. To measure trends in concentrations of atrazine plus deethylatrazine, the data, collected over a near‐decadal period, were adjusted to account for changes in laboratory‐reporting levels and analytical recoveries. Only after accounting for these changes was it apparent that the median concentrations of atrazine plus deethylatrazine decreased over the near‐decadal interval between sampling efforts.
Bibliography:All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher.
ISSN:0047-2425
1537-2537
DOI:10.2134/jeq2007.0053