Canada's freshwater quality in a global context: indicator

Data Sources and Methods

March 2011

This report is released under the Canadian Environmental Sustainability Indicators (CESI) initiative. Each indicator reported under CESI has an associated "data sources and methods" report to provide technical detail and other background to facilitate interpretation of each indicator or allow others to conduct further analysis using the CESI data and methods as a starting point.

This report addresses the underlying methods and data for the Canada's Freshwater Quality in a Global Context indicator as published on the CESI website. The Data Sources and Methods report is also available in PDF (326 KB).

How the measure was calculated

The water quality indicator developed for Yale and Columbia universities' Environmental Performance Index (EPI) is a proximity-to-target composite of freshwater quality for lakes and rivers adjusted for monitoring stations' density in each country. It has a possible maximum score of 100.

Calculated using the Canadian Council of Ministers of the Environment's Water Quality Index, five water quality parameters were chosen for inclusion in the 2010 EPI: dissolved oxygen, pH, conductivity, total nitrogen and total phosphorus. The parameters included in the Water Quality Index (WQI) were chosen because they are good indicators of common water quality problems (eutrophication, salinization, acidification, and organic pollution) and because they are commonly reported to international agencies, such as the United Nations Environment Programme Global Environment Monitoring System (UNEP GEMS) Water Programme and the European Environment Agency. Table 1 shows the guidelines used to calculate the EPI.

Table 1. Summary of targets for water quality parameters included in Environmental Performance Water Quality Index. Table adapted from Carr and Rickwood 2008
Parameter Target Details References
Dissolved oxygen 6 mg L-1 DO must not be less than target when average water temperatures are >20ºC CCME 1999
Dissolved oxygen 9.5 mg L-1 DO must not be less than target when average water temperatures are ≤20 ºC CCME 1999
pH 6.5 - 9 pH must fall within target range CCME 1999
US EPA 2006
EEA 2006
WHO 2004
Conductivity 500 µS cm-1 Conductivity must not exceed target Weber-Scannell and Duffy 2007
Chapman 1996
Peterka 1972
LeBlond and Duffy 2001
Sorensen et al. 1977
Derry et al. 2003
Total Nitrogen 1 mg L-1 Total nitrogen must not exceed target Nurnberg1996
Wetzel 2001
Dodds et al. 1998
Total Phosphorus 0.05 mg L-1 Total phosphorus must not exceed target OECD 1982
Wetzel 2001
Nurnberg 1996
Waikato Regional Council NZ (1999-2007)
UNEP GEMS/Water 2006
Dodds et al. 1998

The countries selected for comparison with Canada were the G8 group of leading industrial countries in the world (France, Germany, Italy, the United Kingdom, the United States, Japan, Canada and Russia), Australia and Sweden. Australia was included as it has a similar population, population density, and territorial extent to Canada. Sweden was included because its climate is similar to Canada's.

Caveats and limitations

Data from 53 freshwater quality monitoring stations were used to calculate the Canadian score.

Calculation of the EPI was based on the most recent data available at the time of the analysis for each country. Data up to 2006 was used to calculate the EPI for Canada.

Caution is needed when considering the EPI water quality results because it is extremely challenging to develop assessments of environmental quality at the international level based on comparable and sufficient data collection.

For more information

Environmental Performance Index


Australian and New Zealand Environment and Conservation Council [ANZECC] (1992) Australian water quality guidelines for fresh and marine waters. Canberra, 202pp

Carr GM and Rickwood CJ (2008) Water Quality Index for Biodiversity Technical Development Document. Report prepared for Biodiversity Indicators Partnership, World Conservation Monitoring Center, 219 Huntingdon Road, Cambridge CB3 0DL, United Kingdom. 64 p.

Canadian Council of Ministers of the Environment [CCME] (1999) Canadian Environmental Quality Guidelines. Canadian Council of Ministers of the Environment. Winnipeg, Manitoba.

Chapman D (ed.) (1996) Water Quality Assessments. A Guide to the Use of Biota, Sediments and Water in Environmental Monitoring. Second Edition. Published on behalf of UNESCO, WHO, and UNEP.  Chapman and Hall, London.

Derry AM, Prepas EE, Hebert PDN (2003) A comparison of zooplankton communities in saline lakewater with variable anion composition. Hydrobiologia, 505, 199-215

Dodds WK, Jones JR, and Welch EB (1998) "Suggested classification of stream trophic state: distributions of temperate stream types by chlorophyll, total nitrogen, and phosphorus." Water Research 32:1455-1462.

European Environment Agency [EEA] (2006) Directive 2006/44/EC of 6 September 2006 on the quality of fresh waters needing protection or improvement in order to support fish life. Official journal of the European Union, L 264/31

LeBlond JB and Duffy LK (2001) Toxicity assessment of total dissolved solids in effluent of Alaskan mines using 22-h chronic Microtox® and Selenastrum capricornutum assays. Sci. Tot. Environ., 1-3: 49-59.

Nürnberg GK (1996) Trophic state of clear and colored, soft- and hardwater lakes with special consideration of nutrients, anoxia, phytoplankton and fish. J. Lake Reservoir Management 12:432-447.

Organization for Economic Cooperation and Development [OECD] (1982) Eutrophication of Waters. Monitoring Assessment and Control, Final Report. OECD Cooperative Programme on Monitoring of Inland Waters (Eutrophication Control). OECD, Paris.

Peterka JJ (1972) Effects of saline waters upon survival of fish eggs and larvae and upon the ecology of the fathead minnow in North Dakota. PB-223 017, National Technical Information Service, Springfield, Va. 22161.

Sorensen DL, McCarthy M, Middlebrooks EJ and Porcella DB (1977) Suspended and dissolved solids effects on freshwater biota: A review. US Environmental Protection Agency, EPA-600/3-77-042.

UNEP GEMS/Water (2006) Water Quality for Ecosystem and Human Health. Burlington, Canada. A publication of the UNEP GEMS/Water Programme. ISBN 92-95039-10-6.

United States Environmental Protection Agency [U.S. EPA] (2006) National Recommended Water Quality Criteria. Office of Water, Office of Science and Technology (4304 T).

Waikato Regional Council, New Zealand (1999-2007) Water Quality Glossary, Table 1: Typical levels of total phosphorus, total nitrogen and chlorophyll a and Secchi depth in New Zealand lakes for different trophic states. (Accessed October 25 2007).

Weber-Scannell PK, Duffy LK (2007) Effects of total dissolved solids on aquatic organisms: A review of literature and recommendation for salmonid species. Amer. J. Environ. Sci., 3, 1-

Wetzel RG (2001) Limnology, Third Edition. Academic Press, 850 pages.

World Health Organization [WHO] (2004) Guidelines for Drinking-water Quality. Third Edition Volume 1: Recommendations. World Health Organisation, Geneva.

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