Herbicides and nitrate in near-surface aquifers in the midcontinental United States, 1991 /
Kolpin, Dana W.
Burkart, M. R.
Thurman, E. M.(Earl Michael),1946-
Washington : U.S. G.P.O. ; Denver, CO : for sale by USGS Map Distribution,
1994.
Includes bibliographical references (p. 33-34).
Herbicides
Nitrates
Groundwater