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Dr. Likens supplied us years ago
Updated: November 05, 2021

Handbooks, Research reports, and Educational videos can be downloaded from our OneDrive (also includes historical lake water quality & predictive phosphorus models of select watersheds):
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Primary index:
Overview    Limnology    References    Pollution    Sewage Management    Restoration/Protection

Lake/River Management    Climate change    Individual empowerment    Public Art    Culture    Knowledge_Videos

Lakes/Rivers-Nova Scotia    Credits and our history    Regulators-Nova Scotia    Articles in the media 

  • Narrative on water quality of freshwaters:

    • Browning & re-browning of lakes (potentially resulting in more favourable conditions for toxin-producing cyanobacterial blooms):

      • A 2019 leading paper in the prestigious Nature Scientific Reports co-authored by select renown paleolimnologists (Meyer-Jacob et al., 2019)
        • Excerpts:
          • Dissolved organic carbon (DOC) concentrations and water colour are increasing in many inland waters across northern Europe and northeastern North America. Potential drivers of this “browning” trend are complex and include reductions in atmospheric acid deposition, changes in land use/cover, increased nitrogen deposition and climate change. Examples of chemical and biological repercussions of the current browning trend include reduced fish growth, more favourable conditions for toxin-producing cyanobacteria blooms, reduced potential for the inactivation of pathogens by solar ultraviolet radiation, and increased contaminant transport.

      • Formal definition of trophic status:

        • Note of caution: During these times of gradual increases in the algal blooms of various species within our lakes, world renown Dr. Richard Vollenweider's advice from the 1990's is even more relevant. Click on the mp3 sound file (4-minute duration) to listen to the rationale behind the OECD Probability Distribution Diagrams relating to the scientifically credible methodology of ascertaining trophic states which can be achieved only in a `probabilistic sense'. Average conditions, expressed by "average nutrient concentrations", "average biomass values", "average transparency" do not necessarily express the degree of variability, particularly with regard to peak levels, frequency of their occurrence, and their qualitative nature (type of phytoplankton). From the management viewpoint, such situations and their frequency are as important as average conditions.

      • Chemical vs Biological monitoring

      • Predictive modelling

      • Primary restoration efforts: Emphasis should be on restoring lakes to their pre-cultural (i.e., modelled hindcast) phosphorus concentrations in order to minimize any negative impacts from undue cultural eutrophication. Otherwise, it may result in poor quality of lakes including increased algal blooms, some of which may be toxic.

      • "High concentrations of cyanobacterial (i.e., bluegreen) toxins may present risks to wildlife and humans from exposure to airborne cyanotoxins. Aerosols may be a more direct route of exposure to public health for those recreating or living by a contaminated body of water. There is also concern if these can be transferred to crops growing near blooms of cyanobacteria."  (Overview); (A selection of leading articles);  (Potential for high biomass of cyanobacteria, WHO)

  • Climate Change, and what we, as individuals, can do

  • Biological classification

Individual empowerment:

What we as individuals can do in our own backyards in order to minimize export of typical stressors tohalf hour video downstream lakes/rivers:- Watch a narrative of former Halifax County's Manager of Storm  Drainage in a half-hour video titled, "Environmental Impact on Water Courses" (link is opened in a new window). The recommendations in the video will not remove all the incremental stressors. In practice, we prefer centralized treatment systems along with such  stakeholder action.

Comprehensive municipal stormwater treatment is not a common practice. Laser particle sizing has indicated that a considerable proportion of the particulates in road runoff are less than 10 microns. This size fraction is difficult to capture in most stormwater pollution control devices and has been shown to contain significant quantities of heavy metals, phosphorus, and other stressors which are of concern in aquatic ecosystems. In addition, several stressors are in soluble form which may require centralized tertiary treatment and perpetual maintenance.

Leading references, and illuminating reports by other scientists & consultants worldwide

(Advanced textbooks & popular handbooks in limnology, and lake management; Also see Select References, and Freshwater Benthic Ecology references

    1. (textbook)  Mackie, G.L. 2004. Applied Aquatic Ecosystem Concepts. Second Ed. Kendall/Hunt Publishing Company. 784 pp. ISBN 0-7575-0883-9.  <-- (excellent undergrad/grad reference in limnology; also includes reference tables for the more advanced professional)
    2. (paleolimnology text)  Smol, J.P. 2008. Pollution of Lakes and Rivers: A Paleoenvironmental Perspective. 2nd ed. Blackwell Publishing, Oxford. x,383 pp. ISBN-13: 978-1-4051-5913-5.
    3. (textbook) Wetzel, R.G. 2001. Limnology. Lake and River Ecosystems. Third Ed. Academic Press, San Diego. xvi, 1006 pp. ISBN 0-12-744760-1.
    4. (textbook)  Wetzel, R.G., and Likens, G.E. 2000. Limnological Analyses. 3rd Ed. Springer, New York. xv, 429 pp.

    5. (CCME)  Canadian Council of Ministers of the Environment- Water (link is opened in a new window)
    6. (CCME)  Fact sheet for the phosphorus guidance framework, CCME, 2004 (link is opened in a new window)
    7. (CCME) Krzyzanowski, J. 2010., Krzyzanowski Consulting. Review and Identification of Research Needs to Address Key Issues Related to Reactive Nitrogen (RN) Deposition and Eutrophication in a Canadian Context. Final Report. Prepared for: Acid Rain Task Group Canadian Council of Ministers of the Environment. PN 1450. 96p.
    8. (CCME)  Developing Biocriteria as a Water Quality Assessment Tool, CCME, 2006 (Canadian Council of Ministers of the Environment) (link is opened in a new window)

    9. (USEPA handbook on streams)  A Function-Based Framework for Stream Assessment and Restoration Projects. 2012. Harman, W., Starr, R.,  Carter, M.,  Tweedy, K., Clemmons, M., Suggs, K., and Miller, C. 2012. US Environmental Protection Agency, Office of Wetlands, Oceans, and Watersheds, Washington, DC. EPA 843-K-12-006. 344pp. (link is opened in a new window)
    10. (NALMS & USEPA handbook on lakes)  Holdren, C., Jones, W., and Taggart, J. 2001. Managing Lakes and Reservoirs. EPA 841-B-01-006. N. Am. Lake Manage. Soc. and Terrene Inst., in coop. with Off. Water Assess. Watershed Prot. Div. U.S. Environ. Prot. Agency, Madison, WI. xiv, 382 pp. (link is opened in a new window)
    11. (USEPA handbook on lakes)  Gerritsen, J., Carlson, R.E., Dycus, D.L., Faulkner, C., Gibson, G.R., Harcum, J., and Markowitz, S.A. 1998. Lake and Reservoir Bioassessment and Biocriteria. Technical Guidance Document. US Environmental Protection Agency. EPA 841-B-98-007. 10 Chapters, Appendices A-G.  (link  is opened  in a new  window)
    12. (NALMS & USEPA handbook on lakes)  Wedepohl, R.E., D.R. Knauer, G.B. Wolbert, H. Olem, P.J. Garrison, and K. Kepford. 1990. Monitoring Lake and Reservoir Restoration. EPA 440/4-90-007. Prep. by N. Am. Lake Manage. Soc. for U.S.E.P.A. 142 pp. (link is opened in a new window)
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Eutrophication is the response in water due to overenrichment by nutrients, primarily phosphorus and nitrogen, and can occur under natural or manmade (anthropogenic) conditions. Manmade (or cultural) eutrophication, in the absence of control measures, proceeds at an accelerated rate compared to the natural phenomenon and is one of the main forms of water pollution. The resultant increase in fertility of affected lakes, reservoirs, slow-flowing rivers and certain coastal waters causes symptoms such as algal blooms (with potential toxicity in cases), heavy growth of rooted aquatic plants (macrophytes), algal mats, deoxygenation and, in some cases, unpleasant odour, which often affects most of the vital uses of the water such as water supply, recreation, fisheries (both commercial and recreational), or aesthetics. In addition, lakes become unattractive for bathing, boating and other water oriented recreations. Most often economically and socially important species, such as salmonids decline or disappear and are replaced by coarser fish of reduced economic/social value.

Potential sources of phosphorus:- Phosphorus has been reduced or eliminated in most laundry detergents but there are several other sources as follows:- fertilizers (farm, golf course, residential); animal, pet and bird feces; gasoline (as a result of the addition of penta phosphates; c.f., Hart, 2020); wastewater treatment plant discharges (WWTP’s do not remove all phosphorus, and the discharge is highly biologically available more so than other sources); overflows/bypasses from WWTPs and pumping stations; high concentration of septic systems within 300 metres of lakes and/or failures; cross connections between sanitary and storm sewer laterals; certain industrial discharges; and high sedimentation. In some lakes, there could be internal loading, i.e., re-suspension, from bottom sediments as well.

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Sewage Management

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Lake/River Management

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  • Homepage
  • Stormwater treatment
  • Lake Water Residence Times

  • Any potential restoration: Emphasis should be on restoring lakes to their pre-cultural (i.e., modelled hindcast) phosphorus concentrations in order to minimize any negative impacts from undue cultural eutrophication.

    Extensive original international peer-reviewed literature has clearly recommended restoring lakes to their natural background values, primarily the limiting nutrient, TP (c.f. OECD, 1982. Monitoring, Assessment and Control; 15-year multi peer-consensus studies of 18 countries of the western economies, at 50 institutes). The concept is also embodied in the much later CCME policy (2004) on phosphorus:--

    "Natural limnological conditions vary considerably among countries and also among different regions, particularly the larger countries. Consequently, the water quality objectives would differ in each country, taking local conditions and expectations into account. In the absence of human activities, the nutrient load and the trophic response in waterbodies are determined by the natural fertility of soils on the drainage basin which in turn depends on the geology and the climate of the area in question. Ideally, the objective of lake management should be to maintain or restore waterbodies to their natural state determined by the basic natural nutrient load of the area in question (e.g. free from human activities). In practice, this is not always possible."
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Lakes/Rivers-Nova Scotia

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Credits and our history

'In memory of our deceased associates'(link is opened in a new window)

  • Shalom M. Mandaville Post-Grad Dips. (, Soil & Water Conservation Society of Metro Halifax (SWCSMH) with varied assistance from our leading scientist-partners (present/past) and other professionals, mostly published/peer reviewed.

  • Overview on our founding and update: We were founded on the express encouragement of the senior staff of the Nova Scotia Environment Department in 1989 although some of our science-based members were active long before that. The inaugural invitation was sent to a host of provincial and municipal bodies. Our scientific research, to various degrees, was conducted as volunteers.

  • Select compliments and requests received

  • The Challenge of Change, Our Province, Our Future, Our Choice, March 1991

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

Shalom M. Mandaville