Open-File Report 03-386
A 6-month study was begun in April 2001 to determine the concentrations of pesticides or oil and grease in selected stream reaches and lakes with in the Ouachita, Tensas, and Black River Basins in northeastern Louisiana. During April through September 2001, six monthly water samples for analysis of pesticides were collected from 22 sites: 17 sites were on 11 streams, and 5 sites were on 5 lakes. During April through July 2001, four monthly samples for analysis of oil and grease were collected from 5 sites: 4 sites were on three streams, and 1 site was on a lake. A total of 131 water samples were analyzed for 17 pesticides (15 insecticides and 2 herbicides). The following classes of pesticides, as classified from the Pesticide Anlysis (U.S. Environmental Protection Agency Region 6 Laboratory), are reported:organochlorine, nitrogen-phosphorus, and carbamate. The 8 pesticides detected in samples, in decreasing frequency, were as follows: atrazine, molinate, methyl parathion, 4,4'-DDT, carbofuran, diazinon, toxaphene, and 4,4'-DDE. Organochlorine pesticides (insecticides) represented the majority (12 out of 17) of the pesticides analyzed. Of those 12 organochlorine pesticides, only 3 (4,4'-DDT, 4,4'-DDE, and toxapehene) were detected in the 131 samples. Of the organochlorine pesticides, 4,4'-DDT was detected most rfrequently (in 11 percent of the samples), and concentrations ranged from 1.22 to 4.70 ng/L (nanograms per liter). Nitrogen-phosphorus pesticides were the most frequently detected and abundant pesticides. Of all the pesticides analyzed, atrazine and molinate (nitrogen-phosphorus herbicides) were the pesticides most frequently detected (in 93 and 21 percent of the samples), had the highest and most wide-ranging concentrations (10.8 to 15,100 ng/L and 10.0 to 11,600 ng/L), and were most widely distributed throughout the study area. Carbofuran, a carbamate insecticide, was detected at 8 of the 22 pesticide data-collection sites and in 9.2 percent of the 131 samples analyzed for pesticides. Concentrations of carbofuran ranged from 30.7 to 946 ng/L. Of the 22 pesticide data-collection sites, the frequency of pesticide detection was highest at 6 sites: Boeuf River near Arkansas-Louisiana State line, Boeuf River near Fort Necessity, Big Creek at Louisiana Highway 135 near Winnsoboro, Crew Lake at Crew Lake, Joe's Bayou near Waverly; and Bayou Macon at Louisiana Highway 562 near Wisner. All water samples analyzed for oil and grease had concentrations less than the reporting limit of 5 milligrams per liter. |
First posted May 4, 2010 For additional information contact: Part or all of this report is presented in Portable Document Format (PDF); the latest version of Adobe Reader or similar software is required to view it. Download the latest version of Adobe Reader, free of charge. |
McGee, Benton D., 2002, Pesticides and oil and grease in selected streams and lakes in northeastern Louisiana, 2001: U.S. Geological Survey Open-File Report 03-386, 20 p.
Abstract
Introduction
Data Collection and Methods
Pesticide and Oil and Grease Data
Quality Assurance and Quality Control
References Cited