Pesticides in streams in the Tar-Pamlico drainage basin, North Carolina, 1992-94

Water-Resources Investigations Report 2001-4067
Prepared in cooperation with the National Water-Quality Assessment Program
By:  and 



From 1992 to 1994, 147 water samples were collected at 5 sites in the Tar-Pamlico drainage basin in North Carolina and analyzed for 46 herbicides, insecticides, and pesticide metabolites as part of the U.S. Geological Survey's National Water-Quality Assessment Program. Based on a common adjusted detection limit of 0.01 microgram per liter, the most frequently detected herbicides were metolachlor (84 percent), atrazine (78 percent), alachlor (72 percent), and prometon (57 percent). The insecticides detected most frequently were carbaryl (12 percent), carbofuran (7 percent), and diazinon (4 percent). Although the pesticides with the highest estimated uses generally were the compounds detected most frequently, there was not a strong correlation between estimated use and detection frequency. The development of statistical correlations between pesticide use and detection frequency was limited by the lack of information on pesticides commonly applied in urban and agricultural areas, such as prometon, chlorpyrifos, and diazinon, and the small number of basins included in this study. For example, prometon had the fourth highest detection frequency, but use information was not available. Nevertheless, the high detection frequency of prometon indicates that nonagricultural uses also contribute to pesticide levels in streams in the Tar-Pamlico drainage basin.

Concentrations of the herbicides atrazine, alachlor, and trifluralin varied seasonally, with elevated concentrations generally occurring in the spring, during and immediately following application periods, and in the summer. Seasonal concentration patterns were less evident for prometon, diazinon, and chlorpyrifos. Alachlor is the only pesticide detected in concentrations that exceeded current (2000) drinking-water standards.

Suggested Citation

Woodside, M.D., and Ruhl, K.E., 2001, Pesticides in streams in the Tar-Pamlico drainage basin, North Carolina, 1992-94: U.S. Geological Survey Water-Resources Investigations Report 2001–4067, 20 p.,

Study Area

Table of Contents

  • Abstract
  • Introduction
  • Pesticides in streams in the Tar-Pamlico drainage basin
  • Summary
  • References
Publication type Report
Publication Subtype USGS Numbered Series
Title Pesticides in streams in the Tar-Pamlico drainage basin, North Carolina, 1992-94
Series title Water-Resources Investigations Report
Series number 2001-4067
DOI 10.3133/wri014067
Year Published 2001
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) South Atlantic Water Science Center
Description vi, 20 p.
Country United States
State North Carolina
Other Geospatial Tar-Pamlico drainage basin
Google Analytic Metrics Metrics page
Additional publication details