Note that the data published in the 2002 State of the Nation’s Ecosystems Report as well as the 2003 and 2005 Web-Only Updates have been superseded by the 2008 Report and thus should be used with caution. For the most recent data, purchase the 2008 Report from Island Press.

The Indicator

This indicator provides information on the concentration, in coastal bottom sediments, of four major classes of contaminants that can harm fish and other aquatic organisms and can adversely affect human health if ingested while consuming fish or shellfish. Sediment concentration levels will be reported separately for estuaries and the coastal ocean out to 25 miles; currently only data for estuaries are available.

The sediment quality guidelines used in this indicator were developed by the National Oceanographic and Atmospheric Administration, through its National Status and Trends Program (see http://response.restoration.noaa.gov/cpr/sediment/SPQ.pdf). Before these guidelines, there were no national criteria or other widely applicable numerical guidelines for sediment quality. These quality guidelines were developed as informal, interpretive tools to estimate the possible toxicological significance of chemical concentrations in sediments. The guidelines have not been promulgated as regulatory criteria or standards, cleanup or remediation targets, discharge attainment targets, pass–fail criteria for dredged material disposal decisions, or for any other regulatory purpose. See http://response.restoration.noaa.gov/cpr/sediment/SQGs.html.

These guidelines were derived from examination of a large number of individual contamination studies, all in salt water. Data from each study were arranged in order of ascending concentrations. Study endpoints in which adverse effects were reported were identified. From the ascending data tables, the 10th percentile and the 50th percentile (median) of the effects database were identified for each substance. The 10th-percentile values were named the “Effects Range—Low” (ERL), indicative of concentrations below which adverse effects rarely occur. The 50th percentiles were designated the “Effects Range—Median” (ERM) values, representative of concentrations above which effects frequently occur. In this report, ERL is referred to as the “possible effects” guideline and ERM as the “probable effects” guideline.

The Data

For this indicator, The Environmental Monitoring and Assessment Program for estuaries (EMAP-E) provided information assessing the contaminant levels in estuarine sediments and the condition of benthic organisms in those sediments. These information were collected from over 2000 sites from Cape Cod, Massachusetts, to Brownsville, Texas, and represent over 70% of the total estuarine acreage of the United States (excluding Alaska). These data and EMAP-E are described in more detail in the technical note for the national contaminants indicator.)

2003 Web Site Update: Data were provided by the EPA for this indicator update. It is important to note that the coverage of these data expanded greatly in the latest time point (1999-2000) as compared to the earlier time point (1990-1997); data for North Atlantic and Pacific Coast estuaries were added. As discussed in the text, this makes comparison between the time points very difficult. For that reason, it is probably most meaningful to focus on the more recent data in order to understand the extent and significance of chemical contamination in the nation’s estuaries. Note also that data are still not available for Alaskan or Hawaiian estuaries, although these data do include Puerto Rican estuaries.