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Water: Industry Effluent Guidelines

Environmental Effects

Environmental assessment is the process of describing and quantifying the impact of environmental stressors on ecological and human welfare. As part of the effluent guideline development process, EPA performs environmental assessments of the water quality related benefits that would be expected when effluent guidelines are promulgated for an industry. These assessments evaluate environmental impacts occurring as a result of loadings to the environment by facilities or sites within an industry, and then project the environmental impacts of the reduced loadings expected under the effluent guideline. Environmental assessments typically consider pollutant concentrations in waters into which they are discharged as compared to water quality criteria for those pollutants, impacts on aquatic ecosystems, and the impacts on human populations using surface water for recreation, food, or drinking water.

There are a number of tools (models, databases, and reports) that EPA may utilize to evaluate environmental impacts. Several of these are discussed in the sections that follow. This list is not exhaustive.

Modeling Tools

BASINS (Better Assessment Science Integrating point and Nonpoint Sources is a multipurpose environmental analysis system designed for performing watershed and water quality-based studies. BASINS allows the user to assess water quality at selected stream sites or throughout an entire watershed.

AQUATOX is a freshwater ecosystem simulation model that predicts the fate of various pollutants, such as nutrients and organic chemicals, and their effects on the ecosystem, including fish, invertebrates, and aquatic plants. AQUATOX is a valuable tool for performing ecological risk assessments for aquatic ecosystems.


Provide EPA with feedback on the beta version of a new tool the Agency has developed to help you determine who is discharging wastewater into surface waters, which pollutants they are discharging and how much, and where they are discharging.

The Permit Compliance System (PCS) is the national database used to track compliance with National Pollutant Discharge Elimination System (NPDES) Permit requirements. This page provides links to database information, including laws and regulations, customized queries of the database, and contacts. PCS will eventually be superceded by The Integrated Compliance Information System (ICIS).

The Toxics Release Inventory (TRI) is a publicly available EPA database that contains information on toxic chemical releases and other waste management activities reported annually by certain covered industry groups as well as federal facilities. This page contains links to database information, ways to query to database, and contacts.

STORET (short for STOrage and RETrieval) is EPA's largest computerized environmental data system. It is a repository for water quality, biological, and physical data and is used by state environmental agencies, EPA and other federal agencies, universities, private citizens, and many others. This page provides links to database information, ways to download data from the database, and training information.

WATERS (Watershed Assessment, Tracking, and Environmental Results) unites water quality information that was previously available only from several independent and unconnected databases. EPA gathers water quality information to address public concerns the quality of their local surface waters. EPA contains useful information in several different databases, such as PCS and STORET. WATERS has the power to connect these databases and display the information by generating maps and reports.

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Reports generated under CWA sections 303(d) and 305(b) provide information on water quality impairments, and the pollutants and sources of pollutants associated with these impairments. Most of the information is based on data collected and evaluated by the States, tribes, and other jurisdictions. There are limitations associated with using this information as a screening tool. First, not all of the nation's waters are assessed, and those that are assessed are based on a variety of data sources (e.g., ambient monitoring, water quality modeling, and land use data). Each State uses its own approach for evaluating and reporting on waters, and only limited data are currently available on sources of the impairments.

Another source of information is data generated by the U.S. Geological Survey (USGS) under its National Water Quality Assessment (NAWQA) program. Under NAWQA, USGS scientists collect and interpret data about water chemistry, hydrology, land use, stream habitat, and aquatic life in more than 50 major river basins and aquifers covering nearly all 50 states. National summary reports, published under the signature title "The Quality of Our Nation's Waters," describe water quality from a national perspective. 

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