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Management of Phosphorus

(Discussions on the Canadian Council of Ministers of the Environment (CCME), and Environment Canada documents)

Soil & Water Conservation Society of Metro Halifax (SWCSMH)

Updated: August 12, 2015

Preamble

Significant parts of the federal policy have been familiar for considerable years to those of us who are practicing `applied limnologists'; in addition, it does not cover the entire spectrum of related published literature but it does give some updates. We are indeed quite excited that this overdue policy has finally been adopted by the CCME thus giving some of the extensively published literature a national stamp of approval!

CCME's `no degradation policy'

"It is stressed at this point that the CCME endorses a no degradation policy, and that these values therefore do not provide, and must not be used as pollute up to levels!" (cf. pg. 56, Environment Canada, 2004)

Overview

"The approach accommodates the non-toxic endpoints associated with phosphorus and can be incorporated into existing management strategies. The framework offers a tiered approach in which (i) phosphorus concentrations should not exceed predefined `trigger ranges'; and (ii) phosphorus concentrations should not increase more than 50% over the baseline (reference) levels. The trigger ranges are based on the range of phosphorus concentrations in water that define the reference trophic status for a site."

Trigger ranges:

Trigger ranges of TP based on trophic classification of lakes and rivers derived from the OECD research; *cf.* Table 4.3, pg. 55, Environment Canada, 2004
--- (may not apply to dystrophic lakes)
Trophic level	Trigger Ranges for Total Phosphorus (痢/l)
Trophic level	Lakes	Rivers and streams
Ultra-oligotrophic	< 4	-
Oligotrophic	4-10	< 25
Mesotrophic	10-20	25-75
Meso-eutrophic	20-35	-
Eutrophic	35-100	> 75
Hypereutrophic	> 100	-

Modelling- (Environment Canada, 2004):

cf. pg. 62

"TP, TN, chlorophyll a, and Secchi depth must all be considered when modelling lakes and reservoirs. It is advised that additional variables to these also be considered."

.... derived from the OECD research

[Img-ccme_trophic_lakes.jpg]

[Img-ccme_trophic_rivers.jpg]

When modelling shallow lakes (i.e., lakes which are completely mixed, and in which light penetrates to the bottom sediments), sediment phosphorus plays an important role in phosphorus cycling and should also be considered. Benthic and sestonic chlorophyll a also needs to be considered for these systems."

Severe shortcomings of the Fixed Boundary approach; prefrred methodlology are the OECD (Organization for Economic Co-Operation and Development)'s Probability Distribution Diagrams!

General Effects of Eutrophication (Environment Canada, 2004):

[Img-ccme_eutro1.jpg]
[Img-ccme_eutro2.jpg]

Prologue

Vollenweider's dictum- the OECD Probability Distribution Diagrams:

Notwithstanding the above fixed boundary of the CCME which was adapted from the fixed boundary of the OECD (1982), listen to his 4-minute mp3 sound file emphasizing the value of the OECD Probability Distribution Diagrams in order to establish trophic states with a high confidence level!

Vollenweider was the first of four in Canada to have ever received the Naumann-Thienemann Medal, the highest honour that can be bestowed internationally for outstanding scientific contributions to limnology!

The CCME's trophic standards were derived from the 14-year, 18-country, OECD research headed by Richard Vollenweider!

Narrative on predictive modelling:

Firstly, an assessment has to be made of the recent data in comparison with a lake's modelled natural background (+ direct aerial deposition) TP (total phosphorus) value.

The assessment should also take into account the predictive TP modelling based on future land use patterns as the Future Probable and as the Future Ultimate values depending upon the urban export coefficients utilised; assumption to be based on typical urban stormwater discharge practices.

Stormwater treatment:

But the high values resulting from the Predictive TP Modelling based on future scenarios can perhaps be minimized by mandating almost ZERO phosphorus export through a combination of total stormwater treatment as well as through sound stewardship practices!

Total stormwater treatment should also include removal of other inevitable urban stressors as well, not just phosphorus!

Indicator thresholds for anthropogenic stressors:

Comparisons could also be made with the indicator thresholds for anthropogenic stressors of lakes, freshwater and dystrophic (colour ≥ 30-35) as the case may be (after Mandell, 1994)! The anthropogenic stressors cover several parameters over and above TP!

[Img-mandell_reference.jpg]

Acknowledgements

Salutations to Sushil S. Dixit PhD and associates at the National Guidelines and Standards Office Water Priorities Branch, Water Policy and Coordination Directorate, Environment Canada for all their utmost cooperation.

The source of the phosphorus cycle is the Central Michigan University.

We salute the Chebucto Community Net (CCN) of Halifax, Nova Scotia, Canada for hosting our web site, and we applaud its volunteers for their devotion in making `CCN' the best community net in the world!