VOCs, pesticides, nitrate, and their mixtures in groundwater used for drinking water in the United States

Environmental Science & Technology
By: , and 



Samples of untreated groundwater from 1255 domestic drinking-water wells and 242 public supply wells were analyzed as part of the National Water-Quality Assessment Program of the U.S. Geological Survey between 1992 and 1999. Wells were sampled to define the regional quality of the groundwater resource and, thus, were distributed geographically across large aquifers, primarily in rural areas. For each sample, as many as 60 volatile organic compounds (VOCs), 83 pesticides, and nitrate were analyzed. On the basis of previous studies, nitrate concentrations as nitrogen ≥3 mg/L were considered to have an anthropogenic origin. VOCs were detected more frequently (44%) than pesticides (38%) or anthropogenic nitrate (28%). Seventy percent of the samples contained at least one VOC, pesticide, or anthropogenic nitrate; 47% contained at least two compounds; and 33% contained at least three compounds. The combined concentrations of VOCs and pesticides ranged from about 0.001 to 100 μg/L, with a median of 0.02 μg/L. Water from about 12% of the wells contained one or more compounds that exceeded U.S. Environmental Protection Agency drinking-water standards or human health criteria, primarily because of nitrate concentrations exceeding the maximum contaminant level in domestic wells. A mixture is defined as a unique combination of two or more particular compounds, regardless of the presence of other compounds that may occur in the same sample. There were 100 mixtures (significantly associated with agricultural land use) that had a detection frequency between 2% and 19%. There were 302 mixtures (significantly associated with urban land use) that had a detection frequency between 1% and <2%. Only 14 compounds (seven VOCs, six pesticides, and nitrate) contributed over 95% of the detections in these 402 mixtures; however, most samples with these mixtures also contain a variety of other compounds.

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Publication type Article
Publication Subtype Journal Article
Title VOCs, pesticides, nitrate, and their mixtures in groundwater used for drinking water in the United States
Series title Environmental Science & Technology
DOI 10.1021/es015591n
Volume 36
Issue 9
Year Published 2002
Language English
Publisher American Chemical Society
Publisher location Easton, PA
Contributing office(s) Iowa Water Science Center
Description 8 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Environmental Science and Technology
First page 1923
Last page 1930
Country United States
Online Only (Y/N) N
Additional Online Files (Y/N) N
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