Pesticides in Surface Drinking-Water Supplies of the Northern Great Plains

• Published in: Environmental health perspectives Vol. 115; no. 8; pp. 1183 - 1191
• Main Authors: Donald, David B., Allan J. Cessna, Ed Sverko, Glozier, Nancy E.
• Format: Journal Article
• Language: English
• Published: United States National Institute of Environmental Health Sciences. National Institutes of Health. Department of Health, Education and Welfare 01.08.2007; National Institute of Environmental Health Sciences
• Subjects: Canada; Causes of; Complications and side effects; Drinking water; Environmental Monitoring; Freshwater; Groundwater; Health aspects; Herbicides; Herbicides - analysis; Insecticides; Insecticides - analysis; Pesticides; Potable water; Rain; Stormwater; Surface water; Water Pollutants, Chemical - analysis; Water pollution; Water samples; Water Supply - analysis; Water treatment; Canada; North America
• ISSN: 0091-6765; 1552-9924
• DOI: 10.1289/ehp.9435

Background: Human health anomalies have been associated with pesticide exposure for people living in rural landscapes in the northern Great Plains of North America. Objective: The objective of this study was to investigate the occurrence of 45 pesticides in drinking water from reservoirs in this area that received water primarily from snowmelt and rainfall runoff from agricultural crop lands. Methods: Water from 15 reservoirs was sampled frequently during the spring pesticide application period (early May to mid-August) and less frequently for the remainder of the year. Drinking water was sampled in early July. Sample extracts were analyzed for pesticide content using mass spectrometric detection. Results: We detected two insecticides and 27 herbicides in reservoir water. Consistent detection of a subset of 7 herbicides suggested that atmospheric deposition, either directly or in rain, was the principal pathway from fields to the reservoirs. However, the highest concentrations and number of herbicides in drinking water were associated with runoff from a localized 133-mm rainfall over 15 days toward the end of spring herbicide application. Water treatment removed from 14 to 86% of individual herbicides. Drinking water contained 3-15 herbicides (average, 6.4). Conclusions: We estimated the mean annual calculated concentration of herbicides in drinking water to be 75 ng/L (2,4-dichlorophenoxy)acetic acid, 31 ng/L (2-chloro-4-methylphenoxy)acetic acid, 24 ng/L clopyralid, 11 ng/L dichlorprop, 4 ng/L dicamba, 3 ng/L mecoprop, and 1 ng/L bromoxynil. The maximum total concentration of herbicides in drinking water was 2,423 ng/L. For the seven herbicides with established drinking water guidelines, all concentrations of the individual chemicals were well below their respective guideline. However, guidelines have not been established for the majority of the herbicides found in drinking water or for mixtures of pesticides.