International Joint Commission (IJC)
More than a century of cooperation protecting shared waters

Annex 4 - Nutrients

A. Purpose

The purpose of this Annex is to contribute to the achievement of the General and Specific Objectives of this Agreement by coordinating binational actions to manage phosphorus concentrations and loadings, and other nutrients if warranted, in the Waters of the Great Lakes.

B. Lake Ecosystem Objectives

To achieve the purpose of this Annex and pursuant to Article 3(1)(b)(i), the Parties hereby adopt Lake Ecosystem Objectives related to nutrients, including:

  1. minimize the extent of hypoxic zones in the Waters of the Great Lakes associated with excessive phosphorus loading, with particular emphasis on Lake Erie;
     
  2. maintain the levels of algal biomass below the level constituting a nuisance condition;
     
  3. maintain algal species consistent with healthy aquatic ecosystems in the nearshore Waters of the Great Lakes;
     
  4. maintain cyanobacteria biomass at levels that do not produce concentrations of toxins that pose a threat to human or ecosystem health in the Waters of the Great Lakes;
     
  5. maintain an oligotrophic state, relative algal biomass, and algal species consistent with healthy aquatic ecosystems, in the open waters of Lakes Superior, Michigan, Huron and Ontario; and
     
  6. maintain mesotrophic conditions in the open waters of the western and central basins of Lake Erie, and oligotrophic conditions in the eastern basin of Lake Erie.

C. Substance Objectives

To achieve Lake Ecosystem Objectives, the Parties deem it essential to establish Substance Objectives, in accordance with Article 3(1)(b)(ii),for phosphorus concentrations for the open waters and nearshore areas of each Great Lake. To achieve these Substance Objectives for phosphorus concentrations, the Parties shall develop phosphorus loading targets and allocations for each Party for each Great Lake, as required.

The Parties shall retain the following Substance Objectives on an interim basis for phosphorus concentration in the open Waters of the Great Lakes until updated:

 

Interim Substance Objectives for Total Phosphorus Concentration
in Open Waters
 (ug/l) (as represented by Spring means)

Lake Superior

5

Lake Huron

5

Lake Michigan

7

Lake Erie (western basin)

15

Lake Erie (central basin)

10

Lake Erie (eastern basin)

10

Lake Ontario

10

To help achieve these Substance Objectives, the Parties shall use the following phosphorus loading targets for the Waters of the Great Lakes on an interim basis until the loading targets are updated:

Interim Phosphorus Load Targets
 (Metric Tonnes Total P Per Year)

Lake Superior

3400

Lake Michigan

5600

Main Lake Huron

2800

Georgian Bay

600

North Channel

520

Saginaw Bay

440

Lake Erie

11000

Lake Ontario

7000

The Parties, in cooperation and consultation with State and Provincial Governments, Tribal Governments, First Nations, Métis, Municipal Governments, watershed management agencies, other local public agencies, and the Public, shall:

  1. for the open Waters of the Great Lakes:

(a)  review the interim Substance Objectives for phosphorus concentrations for each Great Lake to assess adequacy for the purpose of meeting Lake Ecosystem Objectives, and revise as necessary;

(b)  review and update the phosphorus loading targets for each Great Lake; and

(c)  determine appropriate phosphorus loading allocations, apportioned by country, necessary to achieve Substance Objectives for phosphorus concentrations for each Great Lake;

2. for the nearshore Waters of the Great Lakes:

(a)  develop Substance Objectives for phosphorous concentrations for nearshore waters, including embayments and tributary discharge for each Great Lake; and

(b)  establish load reduction targets for priority watersheds that have a significant localized impact on the Waters of the Great Lakes.

In establishing Substance Objectives for phosphorus concentrations and phosphorus loading targets, the Parties shall take into account the bioavailability of various forms of phosphorus, related productivity, seasonality, fisheries productivity requirements, climate change, invasive species, and other factors, such as downstream impacts, as necessary.

The Parties shall complete this work for Lake Erie within three years of entry into force of this Agreement and complete this work for the other Great Lakes on a schedule to be determined by the Parties.

The Parties shall periodically review the Substance Objectives for phosphorus concentrations, phosphorus loading targets, and phosphorus loading allocations, apportioned by country to ensure that Lake Ecosystem Objectives are met.

The Parties shall establish Substance Objectives, loading targets and loading allocations for other nutrients apportioned by country, as required, to control the growth of nuisance and toxic algae to achieve Lake Ecosystem Objectives.

D. Programs and Other Measures

The Parties, in cooperation and consultation with State and Provincial Governments, Tribal Governments, First Nations, Métis, Municipal Governments, watershed management agencies, other local public agencies, and the Public, shall develop and implement the following programs and other measures to achieve the Lake Ecosystem and Substance Objectives for phosphorus concentrations, loading targets, and loading allocations apportioned by country, established pursuant to this Annex:

  1. the Parties shall assess and, where necessary, develop and implement regulatory and non-regulatory programs to reduce phosphorus loading from urban sources including:

(a)  programs to prevent further degradation of the Waters of the Great Lakes from wastewater treatment plants located in the Great Lakes basin;

(b)  programs to optimize existing wastewater treatment facilities;

(c)  programs to ensure that construction and operation of municipal wastewater treatment facilities that discharge one million liquid gallons or more per day achieve a maximum effluent concentration of 1.0 milligram per litre total phosphorus for plants in the basins of Lakes Superior, Michigan, and Huron, and of 0.5 milligram per litre total phosphorus for plants in the basins of Lakes Ontario and Erie;

(d)  more stringent restrictions on phosphorus discharges from wastewater treatments plants may be considered as action plans are developed and implemented; and

(e)  new approaches and technologies for the reduction of phosphorus from wastewater, storm water discharge, and other urban sources;

2. the Parties shall develop and implement regulatory and non-regulatory programs to reduce phosphorus loading from industrial discharges, and continue to develop and implement new technologies, as necessary;

3. the Parties shall assess and, where necessary, develop and implement regulatory and non-regulatory programs to reduce phosphorus loading from agricultural and rural non-farm point and non-point sources including:

(a)  programs to assess the effectiveness of current phosphorus management options including best management practices; and

(b)  programs to support the ongoing development and implementation of new approaches and technologies for the reduction of phosphorus from agricultural and rural non-farm sources;

4. the Parties shall take appropriate measures to reduce phosphorus in household laundry and dishwashing detergents and household cleaners to 0.5 percent by weight, where necessary to meet the Substance Objectives for phosphorus concentrations, loading targets, and loading allocations apportioned by country to be developed pursuant to this Annex;

5. the Parties shall evaluate programs and practices to manage phosphorus inputs;

6. the Parties shall develop for Lake Erie, within five years of entry into force of this Agreement and for other Great Lakes as required, phosphorus reduction strategies and domestic action plans to meet Substance Objectives for phosphorus concentrations, loading targets, and loading allocations apportioned by country, developed pursuant to this Annex. These strategies and action plans shall include:

(a)  assessment of environmental conditions;

(b)  identification of priorities for binational research and monitoring; and

(c)  identification of priorities for implementation of measures to manage phosphorous loading to the Waters of the Great Lakes;

7. the Parties shall identify watersheds that are a priority for nutrient control, and shall develop and implement management plans, including phosphorus load reduction targets and controls, for these watersheds, as appropriate.

E. Science

The Parties, in cooperation and consultation with State and Provincial Governments, Tribal Governments, First Nations, Métis, Municipal Governments, watershed management agencies, other local public agencies, and the Public, shall undertake the necessary research, monitoring and modeling to establish, report and assess Substance Objectives for phosphorus concentrations, loading targets, and loading allocations apportioned by country for the management of phosphorus and other nutrients, as required, and to further the understanding of issues such as:

  1. nutrient distribution and movement within the Great Lakes;
     
  2. the causes of toxic algal blooms and nuisance algal blooms;
     
  3. phosphorus sources and forms;
     
  4. nutrient conditions and biological responses in the Great Lakes;
     
  5. adverse effects from excessive inputs of phosphorus;
     
  6. the influence of climate change on nutrient inputs to the Waters of the Great Lakes and the formation of algae and other emerging issues related to nutrients;
     
  7. non-point source phosphorus control methods;
     
  8. the use of objectives and targets based on soluble reactive phosphorus (or bioavailable phosphorus), or use of surrogate measures; and
     
  9. improved technologies and management practices.

The Parties shall do the following to maximize the effectiveness of the scientific activities referred to in this Annex:

  1. establish and regularly review and revise binational priorities for nutrient science; and
     
  2. collect and share binational monitoring data and other scientific information related to nutrients in the Waters of the Great Lakes.

F. Reporting

The Parties shall report on progress toward implementation of this Annex every three years through the Progress Report of the Parties. This report shall document:

  1. Lake Ecosystem Objectives and Substance Objectives;
     
  2. implementation of the binational strategies and domestic action plans;
     
  3. changes in phosphorus loading and concentrations; and
     
  4. progress toward achievement of the Substance Objectives for phosphorus concentrations, loading targets and loading allocations apportioned by country, established under to this Annex.