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Nutrients, suspended sediment, and pesticides in waters of the Red River of the North Basin, Minnesota, North Dakota, and South Dakota, 1970-90

Water-Resources Investigations Report 93-4231

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Abstract

Available data on nutrients (phosphorus and nitrogen), suspended sediment, and pesticides in the Red River of the North Basin, a study unit under the U.S. Geological Survey National Water-Quality Assessment (NAWQA) Program are reviewed. These data were collected by several agencies during 1970-90. Nutrient concentrations in surface water are higher downgradient from agricultural and urban areas than in other areas, but generally do not exceed U.S. Environmental Protection Agency's (USEPA) Maximum Contaminant Levels (MCLs). The 10 milligram per liter (mg/L) drinking water MCL for nitrate (as nitrogen) was rarely exceeded. Some of the largest nutrient inputs to the surface-water system appear to come from the Fargo-Moorhead area. The highest concentrations of nitrogen and phosphorous usually were found in the Red River of the North. Median nitrate concentrations in ground water were less than 1.0 mg/L as nitrogen in all counties in the basin except in Otter Tail and Traverse Counties in Minnesota. Half of the wells in Otter Tail County had nitrate nitrogen concentrations exceeding 2.8 mg/L. Shallow, surficial aquifers tended to have the highest nitrate concentrations. Median suspended- sediment concentrations were less than 100 mg/L except on the Red River of the North near the Canadian border at Emerson, Manitoba and the Pembina River. The Pembina River occasionally had high suspended sediment concentrations; about 10 percent of the samples exceeded 2,000 mg/L. For both surface and ground water, available pesticide data were limited in spatial and temporal coverage. The majority of pesticide analyses for the Red River of the North Basin show no concentrations above laboratory reporting limits. Reported concentrations usually were below the U.S. Environmental Protection Agency's (USEPA) MCLs. Only a few analyses of pesticides in ground water had concentrations above laboratory reporting limits. A relatively large fraction of stream samples had detectable quantities of 2,4-D, a- and y-HCH, and atrazine. These samples covered time spans of as much as 15 years and were from sites downstream from large drainage basins; however, concentrations were well below USEPA MCLs. Following the 1972 ban on DDT, concentrations of DDT in fish samples from the Red River of the North quickly decreased. Fish concentrations of DDE and DDD decreased more slowly. Low levels of DDE and DDD were detected in fish 14 years after the DDT ban.

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Nutrients, suspended sediment, and pesticides in waters of the Red River of the North Basin, Minnesota, North Dakota, and South Dakota, 1970-90
Series title:
Water-Resources Investigations Report
Series number:
93-4231
Edition:
-
Year Published:
1994
Language:
ENGLISH
Publisher:
U.S. Geological Survey ; Books and Open-File Reports [distributor],
Description:
viii, 62 p. :ill., maps ;28 cm.