Water Quality Monitoring Coming to a Close

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The days are getting shorter... That can only mean one thing - fall is here! As summer fades into distant memory, the District's recreational water quality monitoring program is wrapping up for the year.   

During the monitoring season, the District conducts weekly E. coli tests of the freshwater beaches and major tributaries of Devils Lake, as well as conducts a bi-weekly Harmful Algal Bloom Surveillance (HABs) program. Typically, the monitoring season runs from Memorial Day to Labor Day, when recreation on the lake is highest.

The Harmful Algal Bloom Surveillance program is a monitoring system for "blue-green algae" and algal toxins. Blue-green algae, scientifically known as cyanobacteria, are small, mostly microscopic, photosynthetic organisms. Some blue-green algae naturally produce toxins, which is why they can be a concern. 

As of July 31st, a water contact advisory has been in effect due to a Harmful Algal Bloom in Devils Lake.  The water contact advisory is due to potential health risks, including nausea, vomiting, skin rashes, and irritation. Significant ingestion or inhalation of blue-green algae can lead to diarrhea, nausea, cramps, fainting, numbness, dizziness, tingling, and in rare cases, paralysis and death. Children and pets are most at risk.

The District will continue to monitor for HABs until toxin levels are low enough to lift the advisory.  To learn more about algal toxins and the amount of water necessary to consume to reach the toxic thresholds scroll down to Limnology 101! 

HABs stands for "Harmful Algal Blooms", and is an umbrella term to represent species of small plants (phytoplankton), algae, and blue-green algae (scientifically known as cyanobacteria).   

Cyanobacteria are bacteria that function like algae with regard to photosynthesis and respiration, and that are capable of producing toxins that can be harmful to humans and wildlife. The total worldwide number of species is unknown, but they are common in both marine and freshwater systems.  

Potential problems associated with HABs are water taste, odor, and drops in dissolved oxygen in lakes and oceans. Depending on the species, toxins produced can affect the liver, nervous system, or skin.

In Devils Lake, the most common genera of cyanobacteria to be found are Microcystis, Anabaena, and Gloeotrichia.  Each can produce a variety of toxins, including microcystin and anatoxin. 

What are drinking water and recreational water standards for HABs?  

The World Health Organization (WHO) drinking water standard for microcystin-LR (produced by Microcystis) is 1 ppb (part per billion).

The state of Oregon's drinking water standard for microcystin-LR is 1 ppb and the recreational standard is 10 ppb.   

Besides the microcystin-LR toxin, no other WHO standards are established for other toxins, and no U.S. national standards are established for any toxin. In the U.S.A., toxin standards are set by the states. 

Table 1. Health advisory guidelines for Oregon's recreational waters (as recreated from Oregon Health Authority HABs Sampling Guidance - Oct. 2012)

For a full list of toxigenic cyanobacteria possible in the USA & Oregon's recreational waters, click here for the Oregon Harmful Algae Bloom Surveillance (HABS) Program Public Health Advisory Guidelines Harmful Algae Blooms in Freshwater Bodies 

and scroll to pg. 11 (Appendix B, Table B-1) 

It is important to note that:

1. Not all species are blue-green in color       

How do HABs contribute to low-oxygen conditions in fresh and marine environments if they produce oxygen? 

HABs rely on photosynthesis to survive by converting energy from the sun into chemical energy food stores. They produce oxygen as a bi-product.

As mentioned above, the quantity of oxygen they produce (30% of all oxygen production on earth) is only one of several positive attributes of cyanobacteria.  

Eventually, not unlike all other living organisms, the life cycle of a cyanobacterium or other form of HABs comes to an end and this end has consequences felt by all members of the aquatic ecosystem.

Bacteria and other types of microscopic organisms that live in aquatic ecosystems need oxygen just like fishes and humans do for respiration. When HABs die, bacteria and other decomposers use large amounts of oxygen to respire ("breathe") when breaking down HABs structures (cell walls, organelles, ...). This leads to anoxic (low oxygen) conditions that are not suitable for most species of fish and aquatic wildlife that are not adapted to live in these conditions.

 "Cyanobacterium" by Kelvinsong - Own work. Licensed under Creative Commons Attribution-Share Alike 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Cyanobacterium.svg#mediaviewer/File:Cyanobacterium.svg   

Cyanobacteria are prokaryotes. This means that each cell does not have a well-defined membrane to enclose the nucleus and organelles. Basically, they are molecules surrounded by a membrane and cell wall. They are able to grow and reproduce more rapidly with excessive nutrients, and sunlight. Sources of nutrients include excessive fertilization runoff, inadequate sewage treatment, runoff from roads, etc...

A lot of times, the problems are just aesthetic; it looks "bad" but there aren't toxins present in levels that could be harmful. Other times, there are situations where we recommend that people limit their recreational activities on the lake that may result in accidental water immersion, ingestion, and inhalation.  

These activities may include swimming, water skiing, and other high contact activities. There are no consistent combination of conditions, such as temperature and amount of sunlight, where we can predict what the water quality will be, which is why the testing we do is so important.

What kind of monitoring for HABs does the Devils Lake Water Improvement District do?

The District has the capacity to do semi-quantitative lab analysis on our water samples to tell us whether the concentration of microcystin is greater or less than 10 ppb, and the capacity to do quantitative analysis which can give us actual values (e.g. 13.34 ppb).  

To check-out how we do semi-quantitative toxin analysis, click here  

To check-out a video demonstration of how we perform quantitative toxin analysis, click below  

Devils Lake Quantitative Microcystin Analysis

How much water containing HABs do I have to ingest or inhale to make me sick?

Due to lack of sufficient data, the World Health Organization is unable to provide a guideline for the amount of consumption of any cyanotoxin besides microcystin-LR.

For microcystin, the WHO was able to provide a provisional guideline for drinking water of 1 ppb (part per billion) or 1 microgram per liter. This was calculated from the below equation:

In this equation,

TDI: Tolerable Daily Intake of the contaminant; the "safe" amount of daily intake; the amount of a contaminant your body can process and not be adversely affected by over a lifetime
bw: body weight
P: Proportion of your microcystin intake in your diet that is coming from your drinking water (e.g. not from food)
L: Liters of water

You can read more about how a TDI is determined, safe levels, and safe practices by clicking here.

 

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