HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Schneider, A. D. Articles by Jones, O. R. Search for Related Content PubMed Articles by Schneider, A. D. Articles by Jones, O. R. Agricola Articles by Schneider, A. D. Articles by Jones, O. R.

Movement of Three Herbicides in a Fine Sand Aquifer¹

In order to determine movement of farm chemicals that night accidentally contaminate underground water supplies, low concentrations of three herbicides and NaNO₃ as a tracer were injected into a sand aquifer through a dual-purpose well. Herbicides used were picloram (4-amino-3,5,6-trichloropicolinic acid), atrazine (2chloro-4-(chylamino)-6-(isopropyl-amino)-s-triazine), and trifluralin (, , -trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine). Recharge by injection continued for 10 days at an average rate of 81.8 m³/hour. After a 10-day pause, the well was pumped for 12 days to determine if the herbicides and tracer could be recovered. Water samples were pumped from observation wells located 9, 20, and 45 m from the dual-purpose well. Herbicides were detected in the 9- and 20-m distant wells, but none of the herbicides or the tracer was detected in the 45-m distant well. Picloram and atrazine moved freely through the aquifer, but some trifluralin adbsorbed to aquifer particles around the well. Although two herbicides moved freely from the point of injection, all of the chemicals were removed from the aquifer by pumping the contaminated water. Ninety-three percent of the NO₃ tracer and more than 91% of each herbicide were recovered with the pumped water. This study indicates that herbicides accidentally injected into a well in a relatively static aquifer can be recovered by pumping. Water could be utilized for irrigation of tolerant crops.

Key Words: Miscible displacement • Hydrodynamic dispersion

² Agricultural engineer, ARS-USDA, professor of weed science, Texas Agric. Exp. Stn., and soil scientist, ARS-USDA Southwestern Great Plains Research Center, Bushland, TX 79012.

Received for publication July 10, 1976.