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published in the 2002 State of the Nation’s Ecosystems Report as well as the 2003 and 2005 Web-Only Updates have been superseded by the 2008 Report and thus should be used with caution.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.

This technical note also applies to:

• Coasts and Oceans: Contamination in Bottom Sediments
• Farmlands: Pesticides in Streams and Groundwater
• Urban/Suburban: Chemical Contamination

This technical note applies to the core national indicator for chemical contamination, the coastal indicator for sediment contaminants, the farmlands indicator for pesticide, and the urban/suburban indicator for chemical contamination. One technical note applies to these three indicators because they are designed in a very similar fashion. In addition, most of the data (i.e., all freshwater data) for these three indicators are from the same program.

The Indicator—General

In the core national indicator, as well as the indicators for farmlands and urban/suburban areas, a dual approach is used: how frequently compounds are detected, and how often such “occurrences” are at concentrations that are above established human health standards and guidelines and aquatic life guidelines— “exceedances.” The coastal sediment contamination indicator presents only data on exceedances of relevant guidelines.

Compounds reported here include many pesticides, polychlorinated biphenyls (PCBs), volatile organic compounds (VOCs), other compounds on the Environmental Protection Agency (EPA) priority pollutant list, potentially toxic trace elements, and a number of pesticide degradation products. The suite of compounds that were measured in different media varied depending on the use of the compounds in a particular area and the chemistry of the compounds. For example, many VOCs (e.g., solvents and fuel additives) are more heavily used in urban than agricultural settings. Further, because of their volatility, VOCs would be expected to be of greater concern in groundwater than in streams or sediments. In general, the suite of compounds was designed to include compounds that occur frequently in ecosystems and/or have a high potential for adverse effects on people or ecosystems.

In order to understand how frequently compounds from a particular suite of contaminants occur in the environment, the U.S. Geological Survey’s National Water Quality Assessment (NAWQA) program analyzes groundwater and water, sediments, and fish tissue from streams. EPA’s Environmental Monitoring and Assessment Program (EMAP) analyzes sediments and fish tissue from estuaries. It is important to note that all chemical analyses have “detection limits,” meaning that even if a compound is present at a concentration lower than the detection limit, the sample cannot be differentiated from one that completely lacks the compound. Analytical methods used for different environmental media are different (e.g., measurements of contaminant concentrations in stream water and groundwater use different techniques than are used in stream sediment analyses, and techniques used in fresh water differ from those used in salt water). However, within an environmental media (sediment, stream water, etc.), consistent analytical methods were used throughout the program. In addition, as data for this indicator are gathered over time, it will be important to consider the effect of improved detection methods (i.e., allowing contaminants to be detected at lower concentrations) on occurrence data.

The second component of the indicators provides a measure of the frequency (e.g., percentage of stream sites) of contaminants that exceeded established reference criteria for the protection of human health or aquatic life. These two types of reference criteria were established for different purposes and thus are based on different assumptions. Specifically, human health standards and guidelines assume that the water will be consumed daily over a person’s lifetime, and that the effects of the contaminant would be cumulative (often referred to as “chronic” exposure). Human health standards and guidelines are not currently applied to stream or estuary sediments.

In comparison, guidelines that are designed for the protection of aquatic life are based on shorter-term (about 4 days) exposure. (This refers to U.S. EPA guidelines; Canadian guidelines are different (see references)). This is because aquatic organisms are generally smaller and they are exposed to contaminants in water in a different way than humans are. Also, in general, different species have different sensitivities to specific contaminants.

Standards and guidelines for the protection of wildlife are used to evaluate whether contaminant levels in prey species (fish, in this case) are sufficiently high to cause adverse effects in predator species (often fish-eating birds such as eagles).

Specific standards and guidelines used in this indicator are listed under the appropriate media description below.

Data Sources—General

The data for freshwater streams and groundwater were collected and analyzed by NAWQA (http://water.usgs.gov/nawqa/) in 36 major river basins and aquifers across the United States during 1992–1998.

The data for sediments and fish contamination in coastal waters were collected and analyzed by EPA’s EMAP (http://www.epa.gov/emap/) from 1990 to 1997. The data were collected in a manner that allows conclusions to be drawn concerning the majority (approximately 76%) of the area of estuaries in the United States.

Data on sediment contamination in the Great Lakes are collected by a number of agencies. However, these monitoring programs generally focus on areas with highly polluted sediments. As such, these data are not comparable to the data presented here, in that they do not assess the occurrence of sediment contamination across the range of possible locations in the Great Lakes. The EPA Great Lakes National Program Office provided the Great Lakes fish contamination data that are noted in the text.

Freshwater Data: National Water Quality Assessment Program

Methods: The suite of compounds included in the Core National Indicator account for 75% of currently used agricultural pesticide applications (by amounts used), 90% of the nation’s historical use of organochlorine pesticide (most of these compounds are no longer permitted for use in agriculture in the United States), plus PCBs and other industrial compounds, VOCs that are currently or soon may become regulated, and other compounds on the EPA priority pollutant list. A number of pesticide degradation products were also included. Nitrate and ammonium were measured in streams and groundwater. Trace elements were measured in stream sediments and groundwater. Radionuclides were measured only in groundwater. All of these contaminants occur naturally in the environment. Thus, they are included in graphics showing exceedances of human health and/or aquatic life benchmarks, but not in graphics showing the occurrence of contaminants. Human health benchmarks apply to those contaminants listed above that were measured in streams and groundwater. Aquatic life benchmarks apply to the contaminants listed above that were measured in streams and stream sediments.

Additional information about the USGS data used in the Heinz Center report can be found at: http://water.usgs.gov/nawqa/heinz_ctr/.

The watersheds studied were selected to be generally representative of conditions in agricultural, urban, and mixed land uses. The national contaminants data are based on water samples collected from 109 stream sites and 3,549 wells, stream sediment from 558 stream sites, and composite whole-fish samples collected from 223 stream sites. The sites sampled are representative of a wide range of stream sizes, types, and agricultural, urban/suburban, and mixed land uses, but the sites were not selected to be a statistically representative sample of the nation’s streams.

Data for the urban/suburban indicator come from surface water sites on streams that drain 21 urban/suburban watersheds located across the nation. Note that the sites used in this analysis probably are included with “urban and suburban areas” as defined in this report; however, the selection of the sites for sampling was not based on the definition used in this report.

Data for the farmlands indicator are based on water samples from 50 streams and 1084 monitoring wells.

Benchmarks for protection of human health, wildlife, and aquatic life: A variety of U.S., Canadian, and bi-national (International Joint Commission) standards and guidelines were used to evaluate the significance of the detected contaminants in surface water, groundwater, stream sediment, and whole fish.

In conformance with the way the guidelines are written, a concentration exceeding the aquatic-life guidelines in any single surface water sample was counted as an exceedance of the guide-line. For human health standards or guidelines, exceedances were identified when a yearly time-weighted mean concentration exceeded the relevant standard or guideline at a surface water site.

For human health, three types of U.S. EPA standards and guidelines were used to evaluate NAWQA data: (1) Maximum Contaminant Level (MCL), (2) Risk-Specific Dose (RSD), and (3) Lifetime Health Advisory (HA-L). Values for these criteria were obtained by the U.S. Geological Survey (USGS) from U.S. EPA (2000, 2001). In all three cases, the standard and guideline levels are concentrations pertaining to lifetime exposure through drinking water.

The MCL is the maximum permissible annual average concentration of a contaminant in water that is delivered to any user of a public water system. The RSD is a guideline for potential carcinogens based on drinking-water exposure over a 70-year lifetime; an RSD value is always associated with a specified cancer risk. The RSDs presented are associated with a cancer risk of 1 in 100,000. The HA-L is an advisory guideline for drinking-water exposure over a 70-year lifetime, considering noncarcinogenic adverse health effects. More detail on these types of benchmarks, their derivation, and their underlying assumptions is provided in Nowell and Resek (1994). For some constituents, more than one of these three types of benchmarks are available. For these constituents, the MCL was used if available; otherwise, the lowest of the RSD (at 1 in 100,000 cancer risk) and HA-L values selected.

Note that the data on freshwater fish tissue do not include information relative to any human health standards because such standards apply to edible fish tissue (e.g., fillets), whereas entire fish were analyzed for the data reported here.

The three types of aquatic-life guidelines used are U.S. EPA chronic water-quality criteria for protection of aquatic organisms (U.S. Environmental Protection Agency 1999), Canadian waterquality guidelines (Canadian Council of Ministers of the Environment 2001a), and Great Lakes water-quality objectives (International Joint Commission [IJC] 1978). All guideline values used in this report are for freshwater aquatic life. The U.S. EPA chronic water-quality criterion for protection of aquatic organisms is the estimated highest concentration of a constituent that aquatic organisms can be exposed to for a 4-day period, once every 3 years, without deleterious effects. If no U.S. EPA chronic water-quality criterion for protection of aquatic organisms exists for a given constituent, then Canadian water-quality guidelines are used, if available. The older Great Lakes water-quality objectives are used only if neither U.S. EPA chronic water-quality criteria for protection of aquatic organisms nor Canadian water-quality guidelines are available for that constituent. The IJC water-quality objectives and Canadian water-quality guidelines are intended to specify maximum concentrations that should not be exceeded at any time.

For contaminants in sediment, the aquatic-life guideline used was the “probable effect level” from the Canadian Council of Ministers of the Environment (2001b). These guidelines are empirically based; they were derived by compiling data from multiple types of studies in the literature that measured both toxicity and contaminant concentrations in sediment. The Canadian probable effect level defines a concentration above which toxicity to aquatic organisms is likely.

For contaminants in whole fish, the New York fish-flesh criteria for protection of piscivorous (fish-eating) wildlife (Newell et al. 1987) were used. These guidelines are intended to protect target wildlife species from adverse effects other than cancer, such as mortality, reproductive impairment, and organ damage. Wildlife guidelines from the state of New York were used because no comparable national guidelines are available for a large number of contaminants.

Additional information on the standards and guidelines used in this report for pesticides is provided at http://ca.water.usgs.gov/pnsp/source/. Information on the numerical values for the standards and guidelines applied to herbicide, insecticide, and volatile organic compounds can be found at http://oregon.usgs.gov/sumrpt/Benchmrk.1.html, http://oregon.usgs.gov/sumrpt/Benchmrk.2.html, and http://oregon.usgs.gov/sumrpt/Benchmrk.3.html.

Estuarine Data: USEPA Environmental Monitoring and Assessment Program (EMAP)

EMAP conducts annual surveys to measure indicators of the health of plants and animals, the quality of their surroundings, and the presence of pollutants (see http://www.epa.gov/emap/). The program, at present, is developing appropriate designs and sets of indicator requirements to characterize the condition of the nation’s aquatic resources. Once these developmental issues are addressed, the goal of the program is long-term monitoring that will provide information on the overall health of the environment and the effectiveness of pollution prevention and control strategies.

EMAP-Estuaries (EMAP-E), implemented through partnerships between EPA, the National Oceanographic and Atmospheric Administration (NOAA), USGS, coastal states, and academia, will provide information on the ecological condition of the nation’s estuaries as part of the larger program. The data from the EMAPE program provided in this report spans the period from 1990 through 1997. Beginning in 2000, the EMAP-E effort expanded into a series of annual national surveys (National Coastal Assessment, or NCA) including all coastal states and Puerto Rico. Ecological health is being assessed by investigating the state, regional, and national distributions of fish and bottom-dwelling organisms (benthos). NCA is determining what portions of estuaries can support these plants and animals and finding out why certain areas do not support them. Data from NCA will be available for the next iteration of this report (1999–2005).

For this report, EMAP-E provided information assessing the contaminant levels in estuarine sediments and the condition of benthic organisms in those sediments. These data 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).

Data Collection Methodology: Evaluation of the potential effects of contaminated sediments on estuarine organisms is difficult because few applicable state or federal regulatory criteria exist for determining acceptable sediment concentrations of all substances. However, contaminated sediments and their potential toxicity to aquatic life are viewed by the public as a major threat to estuarine ecosystems. All site selections were based on probabilistic designs which permit the extrapolation of the data to the entire area. Using a Young-modified Van Veen grab, 5–10 grabs were collected from each site and homogenized. Separate 100- milliliter samples for organics and metals were retrieved from the homogenate and forwarded for quantification of about 125 different compounds (as outlined below). For this report, information assessing the portion of estuarine area with contaminants above ERL or ERM guidelines (see definitions below; Long et al. 1995; Long et al. 1998a,b) is reported.

Data Access: The data presented here were obtained directly from EPA.

List of Contaminants Targeted in Sediments by EMAP

• Pesticides. Pesticides were chosen because of their current and historic prevalent use in society. Sediments were tested for concentrations of 14 pesticides plus six different forms of DDT, which has been banned in the United States since 1972. These pesticides included Aldrin, Alpha-Chlordane, Dieldrin, Endosulfan I, Endosulfan II, Endosulfan sulfate, Endrin, Heptachlor, Heptachlor epoxide, hexachlorobenzene, Lindane (gamma-BHC), Mirex, Toxaphene, Trans- Nonachlor, 2,4’-DDD, 4,4’-DDD 2,4’-DDE, 4,4’-DDE, 2,4’-DDT, and 4,4’-DDT.
• Polychlorinated biphenyls (PCBs). EPA began to phase out the use and manufacturing of PCBs in the United States in 1976, but they are still found in the environment. Human health effects that have been associated with exposure to PCBs include acne-like skin conditions in adults and neurobehavioral and immunological changes in children. PCBs are known to cause cancer in animals. EMAP targeted 21 different PCB congeners.
• Polycyclic aromatic hydrocarbons (PAHs). A group of over 100 different chemicals that are formed during the incomplete burning of coal, oil and gas, garbage, and other organic substances like tobacco or charbroiled meat, PAHs are usually found as a mixture containing two or more of these compounds, such as soot. Some PAHs are manufactured––they are found in coal tar, crude oil, creosote, and roofing tar, and a few are used in medicines or to make dyes, plastics, and pesticides. PAHs are included because of their role as a suspected carcinogen. The following compounds were targeted (plus several isomers of the listed PAHs): Acenaphthene, Anthracene, Benz(a)anthracene, Benzo(a)pyrene, Biphenyl, Chrysene, Dibenz(a,h)anthracene, Dibenzothiophene, 2,6-dimethylnaphthalene, Fluoranthene, Fluorene, 2-methylnaphthalene, 1-methylnaphthalene, 1- methylphenanthrene, 2,6-dimethylnaphtalene, Naphthalene, Pyrene, Benzo(b)fluoranthene, Acenaphthylene, Benzo(k)fluoranthene, Benzo(g,h,i)perylene, Ideno(1,2,3-c,d)pyrene, and 2,3,5-trimethylnaphthalene.
• Heavy metals. Heavy metals occur naturally in the marine environment; however, their concentrations can be increased by human activities such as discharges from industrial processes, burning of fossil fuels, and runoff from roadways that have had an accumulation of particulates from brake drums, for example. Sediments were tested for a total of 15 trace elements: aluminum, antimony, arsenic, cadmium, chromium, copper, iron, lead, manganese, mercury, nickel, selenium, silver, tin, and zinc. Metal concentrations were normalized using metal:aluminum ratios (see Windom et al. 1989).

Benchmarks for sediment quality: The sediment quality guidelines used in this indicator were developed by NOAA 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, or 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, the ERL is referred to as the “possible effects” guideline and the ERM as the “probable effects” guideline.

The Data Gap

There are large amounts of data on contaminated sediments in the Great Lakes, but these data have for the most part been collected at sites known or suspected of being contaminated, rather than as part of efforts to determine the extent and severity of contamination. Sediments in the defined Areas of Concern (http://www.epa.gov/glnpo/aoc/) are generally the most contaminated. Sediments in the open waters tend to have much lower concentrations, and they tend to migrate to sediment depositional areas. See the following for information on surveys that can identify “toxic substances in toxic amounts,” which are found in the tributary mouths and embayments of the Areas of Concern: http://www.epa.gov/glnpo/glindicators/sediments/sedqualitya.html.

Data are not presently available to compare fish tissue contamination to human health standards and guidelines in a consistent way across the country. See the technical note for Selected Contaminants in Fish and Shellfish for additional discussion.

Data are not presently collected in a consistent manner to allow reporting on soil contamination in urban and suburban areas. Individual studies (see Pouyat et al. 1991) have been conducted to determine the extent and nature of such contamination.

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. In addition, the pesticide Dieldrin is no longer included in the suite of contaminants used to predict “possible effects” or “probable effects,” which further complicates comparisons between the 1990-1997 data and the 1998-2000 data (see Long et al. 1995; also, EPA is in the process of recalculating the data for 1990-1997 considering the change in the Dieldrin standard). 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.

References

Canadian Council of Ministers of the Environment. 2001a. Canadian water quality guidelines for the protection of aquatic life: Summary table. In Canadian environmental quality guidelines, 1999. Winnipeg: Canadian Council of Ministers of the Environment. http://www.ec.gc.ca/ceqg-rcqe/English/Pdf/water_summary_table-aquatic_life.htm. Accessed July 24, 2001.

Canadian Council of Ministers of the Environment. 2001b. Canadian sediment quality guidelines for the protection of aquatic life: Summary tables. Updated. In Canadian environmental quality guidelines, 1999. Winnipeg: Canadian Council of Ministers of the Environment. http://www.ec.gc.ca/ceqg-rcqe/English/Pdf/sediment_summary_table.htm. Accessed July 24, 2001.

International Joint Commission. 1978. Great Lakes Water Quality Agreement of 1978, as amended by Protocol signed November 18, 1987, Annex I—Specific objectives.

International Joint Commission. http://www.ijc.org/agree/quality.html#ann1. Accessed July 24, 2001.

Long, E.R., L.J. Field, and D.D. McDonald. 1998a. Predicting toxicity in marine sediments with numerical sediment quality guidelines. Environmental Toxicology and Chemistry 17(4):714–727.

Long, E.R., D.D. McDonald, S.L. Smith, and F.D. Calder. 1995. Incidence of adverse biological effects within ranges of chemical concentrations in marine and estuarine sediments. Environmental Management 19(1):81–97.

Long, E.R., G.I. Scott, J. Kucklick, M. Fulton, B. Thompson, R.S. Carr, K.J. Scott, G.T. Chandler, J.W. Anderson, and G.M. Sloane. 1998b. Magnitude and extent of sediment toxicity in selected estuaries of South Carolina and Georgia. NOAA Tech. Memo. NOS ORCA 128. Silver Spring, MD.

Newell, A.J., D.W. Johnson, and L.K. Allen. 1987. Niagara River Biota Contamination Project: Fish flesh criteria for piscivorous wildlife. New York State Department of Environmental Conservation, Division of Fish and Wildlife, Bureau of Environmental Protection, Technical Report 87-3.

Nowell, L.H., and E.A. Resek. 1994, National standards and guidelines for pesticides in water, sediment, and aquatic organisms: Application to water-quality assessments: Rev. Environ. Contam. Toxicol. v. 140, pp. 1–164.

Pouyat, R.V., and M.J. McDonnell. 1991. Heavy metal accumulation in forest soils along an urban-rural gradient in southeastern New York, USA. Water, Air, and Soil Pollution 57–58:797–807.

U.S. Environmental Protection Agency. April 1999. National recommended water quality criteria—Correction. U.S. Environmental Protection Agency, Office of Water, EPA-822- Z-99-001. http://www.epa.gov/ost/pc/revcom.pdf. Accessed July 24, 2001.

U.S. Environmental Protection Agency. Summer 2000. Drinking water standards and health advisories: U.S. Environmental Protection Agency, Office of Water, EPA-822-B-00-001. http://www.epa.gov/ost/drinking/standards/. Accessed July 24, 2001.

U.S. Environmental Protection Agency. 2001. Integrated Risk Information System (IRIS) database: U.S. Environmental Protection Agency, Office of Research and Development, National Center for Environmental Assessment. http://www.epa.gov/iris/. Accessed July 24, 2001.

Windom, H.L., S.J. Scropp, F.D. Calder, J.D. Ryan, R.G. Smith, I.C. Burney, F.G. Lewis, and C.H. Rawlinson. 1989. Neutral trace metal concentrations in estuarine and marine sediments of the southeastern United States. Environmental Science and Technology 3: 314–327.