Pesticide persistence and its dependence on soil characteristics and hydrologic conditions suggest the importance of considering soil, geology, and hydrology in developing and implementing land-management plans. Nitrate and pesticide concentrations were well below drinking-water standards in ground water deeper than these aquifers, particularly buried aquifers naturally protected by overlying sediments. Detectable concentrations of nutrients and pesticides that have reached ground water indicate the potential for further contamination over time. Shallow ground water beneath sandy soils is particularly vulnerable to contamination, and this study provided a perspective on how decades of agricultural activity affects the current variability of ground-water quality. More work would be useful to better assess the effects of land use, nutrients, and pesticides on the aquatic ecosystem .
Agriculture is the dominant land use in the Red River of the North Basin Study Unit.
Wastewater from urban areas along the Red River of the North has a minimal effect on the river's quality. The median concentration of ammonia , commonly associated with wastewater, was not higher in the river than in the tributaries, but ammonia concentration was slightly higher in the river downstream from the Fargo-Moorhead area. Compared to historical data for the river, concentrations of ammonia have decreased and nitrate have increased slightly downstream from the Fargo-Moorhead area. These trends likely reflect improved aeration of wastewater effluent over time. Fargo, North Dakota and Moorhead, Minnesota, the largest urban area in the basin, moderately affected Red River of the North water quality during flow conditions observed from 1993 to 1995.