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U.S. GEOLOGICAL SURVEY
Scientific Investigations Report 2007–5106

Development and Application of Health-Based Screening Levels for Use in Water-Quality Assessments

National Water-Quality Assessment Program

By Patricia L. Toccalino

Download the report (PDF, 245 KB)

Table of Contents

Foreword

Abstract

Introduction

Revisions to the HBSL Methodology

Guidance on the Use of Benchmarks in Screening-Level Assessments

Acknowledgments

References

Tables

Table 1. Relationships between the alpha-numeric 1986 USEPA Weight-of-Evidence cancer classifications and the three equations used to calculate HBSLs.

Table 2. Relationships between the descriptive 1996, 1999, and 2005 USEPA Weight-of-Evidence cancer classifications and the three equations used to calculate HBSLs.

Table 3. The most recent USEPA sources of cancer classifications and toxicity data are used in the development of HBSLs.

Table 4. Interpretation of Benchmark Quotients in relation to potential human-health significance and implications for water-quality monitoring.

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, 245 KB)

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 7.0 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 the author, Patricia L. Toccalino, (916) 278-3090.

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