Link to USGS home page.
USGS South Dakota Water Science Center Publication

Reconnaissance-Level Assessment of Water and Bottom-Sediment Quality, including Pesticides and Mercury, in Yankton Sioux Tribe Wetlands, Charles Mix County, South Dakota, June–July 2005

By Bryan D. Schaap and Roy C. Bartholomay

U.S. GEOLOGICAL SURVEY
Scientific Investigations Report 2006–5132

ONLINE ONLY

Prepared in cooperation with the Yankton Sioux Tribe


Abstract

During June and July 2005, water and bottom-sediment samples were collected from selected Yankton Sioux Tribe wetlands within the historic Reservation area of eastern Charles Mix County as part of a reconnaissance-level assessment by the U.S. Geological Survey and Yankton Sioux Tribe. The water samples were analyzed for pesticides and mercury species. In addition, the water samples were analyzed for physical properties and chemical constituents that might help further characterize the water quality of the wetlands. The bottom-sediment samples were analyzed for mercury species.

During June 2005, water samples were collected from 19 wetlands and were analyzed for 61 widely used pesticide compounds. Many pesticides were not detected in any of the water samples and many others were detected only at low concentrations in a few of the samples. Thirteen pesticides were detected in water samples from at least one of the wetlands. Atrazine and de-ethyl atrazine were detected at each of the 19 wetlands. The minimum, maximum, and median dissolved atrazine concentrations were 0.056, 0.567, and 0.151 microgram per liter (µg/L), respectively. Four pesticides (alachlor, carbaryl, chlorpyrifos, and dicamba) were detected in only one wetland each. The number of pesticides detected in any of the 19 wetlands ranged from 3 to 8, with a median of 6. In addition to the results for this study, recent previous studies have frequently found atrazine in Lake Andes and the Missouri River, but none of the atrazine concentrations have been greater than 3 µg/L, the U.S. Environmental Protection Agency's Maximum Contaminant Level for atrazine in drinking water.

During June and July 2005, water and bottom-sediment samples were collected from 10 wetlands. Water samples from each of the wetlands were analyzed for major ions, organic carbon, and mercury species, and bottom-sediment samples were analyzed for mercury species. For the whole-water samples, the total mercury concentrations ranged from 1.11 to 29.65 nanograms per liter (ng/L), with a median of 10.56 ng/L. The methylmercury concentrations ranged from 0.45 to 14.03 ng/L, with a median of 2.28 ng/L. For the bottom-sediment samples, the total mercury concentration ranged from 21.3 to 74.6 nanograms per gram (ng/g), with a median of 54.2 ng/g. The methylmercury concentrations ranged from <0.11 to 2.04 ng/g, with a median of 0.78 ng/g. The total mercury concentrations in the water samples were all much less than 2 µg/L (2,000 ng/L), the U.S. Environmental Protection Agency's Maximum Contaminant Level for mercury in drinking water. However, water samples from four of the wetlands had concentrations larger than 0.012 µg/L (12 ng/L), the State of South Dakota's chronic standard for surface waters, including wetlands. Maximum methylmercury concentrations for this study are larger than reported concentrations for wetlands in North Dakota and concentrations reported for the Cheyenne River Indian Reservation in South Dakota.

Contents

Abstract

Introduction

Purpose and Scope

Description of the Study Area

Previous Investigations

Methods of Investigation

Sampled Wetlands

Sample Collection

Analytical Methods

Reporting Levels

Quality Assurance and Quality Control

Field Equipment Blank Samples

Replicate Samples

Quality of Water in Wetlands

Physical Properties

Major Ions

Organic Carbon

Pesticides

Mercury

Quality of Bottom Sediment in Wetlands

Synopsis of Atrazine and Mercury Results

Atrazine

Mercury

Summary

Selected References

Supplemental Information

Section A. Chlorophyll a and Pheophytin a in Water Samples from Yankton Sioux Tribe Wetlands A and B

Section B. Nitrogen and Phosphorus in Water Samples from Yankton Sioux Tribe Wetlands A and B

Section C. U.S. Fish and Wildlife Service wetlands inventory codes and definitions

Suggested Citation:

Schaap, B.D., and Bartholomay, R.C., 2006, Reconnaissance-Level Assessment of Water and Bottom-Sediment Quality, including Pesticides and Mercury, in Yankton Sioux Tribe Wetlands, Charles Mix County, South Dakota, June–July 2005: U.S. Geological Survey Scientific Investigations Report 2006–5132, 40 p.


This report is available online in Portable Document Format (PDF). If you do not have the Adobe Acrobat PDF Reader, it is available for free download from Adobe Systems Incorporated.

Download the Report (PDF, 1.5MB).

Document Accessibility: Adobe Systems Incorporated has information about PDFs and the visually impaired. This information provides tools to help make PDF files accessible. These tools convert Adobe PDF documents into HTML or ASCII text, which then can be read by a number of common screen-reading programs that synthesize text as audible speech. In addition, an accessible version of Acrobat Reader 5.0 for Windows (English only), which contains support for screen readers, is available. These tools and the accessible reader may be obtained free from Adobe at Adobe Access.

Send questions or comments about this report to GS-W-SD_webmaster.

For more information about USGS activities in South Dakota, visit the USGS South Dakota Water Science Center home page.

FirstGov button   Take Pride in America button