National Nutrient Strategy

Other Strategy Information

Current Status of States and Territories Numeric Nutrient Criteria

Updated May 2007

One of EPA's goals is to accelerate the progress of state adoption of numeric Water Quality Standards while building the scientific and technical infrastructure for developing new criteria to address nitrogen and phosphorus pollution.

What is the Environmental Problem?

  • Excessive nutrients (nitrogen and phosphorus) can cause negative ecological impacts to waterbodies on a national scale by stimulating harmful algal blooms.
    • Algal blooms block sunlight and result in the destruction of submerged aquatic vegetation (SAV). SAV serves as critically important habitat and food for many organisms.
    • Algal blooms eventually die off and consume dissolved oxygen (DO) from the water column. Low DO concentrations lead to die off of aquatic organisms.
    • One result of algal blooms is decreased biological diversity and populations, including smaller populations of game and commercial fish.
  • Excessive nutrients also pose public health risks.
    • Algal blooms can cause taste and odor problems in drinking water.
    • Hazardous algal blooms can cause respiratory distress and neurological problems in swimmers.
    • Excessive nitrates can cause blue baby syndrome.
  • Nutrient pollution is occurring at a national scale and has not been completely addressed.
    • Forty-nine states and four territories have 303(d) listings due to nutrients, and about 50% of the states have more than 100 water quality impairments due to nutrients.
    • Over 10,000 impairments are a result of nutrient pollution.

What is OW's Role in Reversing Nutrient Pollution?

EPA, through its Office of Water, Office of Science and Technology (OST), applies science and technology to build a comprehensive framework of state water quality standards, drinking water goals, public health programs, and technology-based solutions to implement the national clean and safe water program in collaboration with national, state, and public partners. As part of this mission, OST develops nutrient water quality criteria recommendations, ensures state adoption of protective nutrient water quality standards, develops tools to aid states in implementing their nutrient standards, and publishes regulations that reduce the discharge of nutrients by industries.

Over the last 10 years, OST has implemented a strong technical approach to address the negative impacts of nutrient pollution, which includes:

  • Creating a National Nutrient Team and Regional Technical Assistance Groups (RTAGs) with 10 Regional Nutrient Coordinators to support states in the management and evaluation of nutrient pollution.
  • Publishing 26 Ecoregional Nutrient Criteria documents for 131akes/reservoirs, 12 rivers/streams, and 1 wetland (Florida Everglades).
  • Publishing technical guidance documents for lakes/reservoirs (2000), rivers/streams (2000), coastal marine waters (2001), and wetlands (released for comment in 2006), and 14 wetland method modules to assist states in assessing wetland conditions.
  • Providing policy recommendations to states to develop nutrient plans which outline parameters they will set, the approach they will use, and the schedule they will follow.
  • Developing tools designed to aid states in developing numeric criteria (e.g., nutrient database for selecting reference conditions, N-Steps to provide scientific assistance on sampling and data analysis, a periphyton sampling methodology for rivers).

What is the OW National Nutrient Strategy?

Water quality standards (WQS) are the backbone of water quality improvements. Once established, numeric standards reduce states' time and effort to establish TMDLs and permits to control nutrient levels.

Thus, our goal is to accelerate the progress of state adoption of numeric WQS while building the scientific and technical infrastructure for developing new nutrient criteria. To accomplish this goal, we have four general themes:

  1. Provide direct assistance to states close to adopting numeric criteria.
  2. Build capacity of states that are further from adopting numeric criteria.
  3. Build a science-based foundation for developing new 304(a) criteria for estuaries, wetlands, and large rivers.
  4. Communicate the dangers of nutrient pollution and the merits of numeric nutrient criteria to states, nutrient sources, and the general public.

Work conducted under these themes should reflect a collaborative effort/partnership between EPA and states that builds on work to date and coordination/relationships between EPA and states.

We've developed specific projects under each of these themes based on input from states at the All States meeting in February 2006, subsequent discussions with regions, and the discussion with selected state managers at the WQSMA meeting in August 2006.

Theme 1: Direct assistance to states close to adopting numeric criteria

We've identified states that are further along in criteria development for some or all of their waters. These states identified implementation and policy support as their primary need. Under this theme, we are:

  • Developing implementation guidance that addresses technical and policy issues raised by these states.
  • Issuing a policy memorandum that clarifies EPA's recommendations, thus providing states with a clear statement supporting their work. EPA will foster adoption of standards reflective of states' priorities, and recognizing the importance of incremental progress.
  • Assessing the benefits and costs of reducing nutrients, thus providing states with information to support their rulemaking to adopt nutrient criteria.
  • Compiling information of treatment and BMP effectiveness, thus providing states with information demonstrating that their criteria can be attained.
  • Developing common principles for EPA review of state nutrient standards submittals, thus providing assurance to states that EPA review will be consistent among regions.
  • Making all tools more accessible to states via our website.

Theme 2: Build capacity of states that are further from adopting numeric criteria

We've identified states that are further along in criteria development for some or all of their waters. These states identified sampling/monitoring, data/statistical analysis, and assistance in developing criteria numbers as their primary needs. Under this theme, we are:

  • Providing states with on-demand statistical, sampling and data analysis support through N-STEPS.
  • Providing additional statistical, sampling and data analysis support through a variety of financial vehicles, with funds targeted towards progress with specific states.
  • Holding technical transfer workshops and training in regional offices to provide on-site hands-on training on OST technical tools.
  • Developing modeling tools that allow states to evaluate a causative approach for developing criteria and assessing the likelihood of criteria for being attained.
  • Making all tools more accessible to states via our website.

Theme 3: Build a science-based foundation for developing new 304(a) criteria for estuaries, wetlands, and large rivers

We've published technical guidance documents for developing criteria for lakes and reservoirs, rivers and streams, and estuaries and coastal waters. We still need to publish technical guidance and criteria or develop targets for other waters. Under this theme, we are:

  • Completing the technical guidance for developing wetland criteria.
  • Developing demonstration projects for estuarine and wetland criteria development.
  • Developing the scientific underpinnings for criteria for large rivers.
  • Supporting data collection to support developing criteria for estuaries and watersheds in the northern Gulf of Mexico.
  • Working to meet the goals of the Hypoxia Task Force.

Theme 4: Communicate the dangers of nutrient pollution and the merits of numeric nutrient criteria to states, nutrient sources, and the general public

To be successful, we must engage the general public in understanding the consequences of nutrient pollution and the benefits of nutrient controls. Under this theme, we are:

  • Building web-based and printed materials on the dangers of nutrient pollution.
  • Creating training materials for NGOs on the dangers of nutrient pollution.
  • Improving our Website to attract more students looking for information on nutrient pollution.
Note: EPA no longer updates this information, but it may be useful as a reference or resource.

1998 National Nutrient Strategy

The national nutrient strategy describes the approach we will follow in developing nutrient information and working with states and tribes to adopt nutrient criteria as part of their water quality standards. The strategy presents overenrichment assessment tools and recognizes current capabilities for conducting these assessments at the regional watershed and waterbody levels. The major focus of this strategy is the development of waterbody-type technical guidance and region-specific nutrient criteria by the year 2000.

Nutrient Pollution

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Last updated on November 30, 2023