U.S. Geological Survey
WRIR 02-4163
Online version 1.0

Priority-Pollutant Trace Elements in Streambed Sediments of the Cook Inlet Basin, Alaska, 1998-2000

By Steven A. Frenzel

Abstract

Trace element concentrations in 48 streambed sediment samples collected at 47 sites in the Cook Inlet Basin, Alaska, were compared to concentrations from studies in the conterminous United States using identical methods and to Probable Effect Concentrations. Concentrations of arsenic, chromium, mercury, and nickel in the 0.063-mm size fraction of streambed sediments from the Cook Inlet Basin were elevated relative to reference sites in the conterminous United States. Concentrations of cadmium, lead, and zinc were highest at the most urbanized site in Anchorage and at two sites downstream from an ore body in Lake Clark National Park and Preserve. At least 35 percent of the 48 samples collected in the Cook Inlet Basin exceeded the Probable Effect Concentration for arsenic, chromium, or nickel. More than 50 percent of the samples were considered to have low potential toxicity for cadmium, lead, mercury, nickel, selenium, and zinc. A Probable Effect Concentration quotient that reflects the combined toxicity of arsenic, cadmium, chromium, copper, lead, mercury, nickel, and zinc was exceeded in 44 percent of the samples from the Cook Inlet Basin. The potential toxicity was high in the Denali and Lake Clark National Parks and Preserves where organic carbon concentrations in streambed sediments were low. However, potential toxicity results should be considered in context with the very small amounts of fine-grained sediment present in the streambed sediments of the Cook Inlet Basin.

Contents

Abstract
Introduction
    Sample Collection and Analysis
    Data Analysis
Methods
Results Water
Discussion
    Priority-Pollutant Trace Element Concentrations
    Potential Toxicity
Summary
References Cited

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, 2.9 MB)

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, a version of Acrobat Reader 5.0 for Windows that contains support for screen readers is available (English only). These tools and the accessible reader may be obtained free from Adobe at Adobe Access.

For questions about the content of this report, contact Steven Frenzel

For information about USGS programs in Alaska, please visit our Web site