Severe, toxic algae bloom predicted for Lake Erie

One of the biggest toxic blue green algae blooms ever recorded is predicted for Lake Erie this year.

Scientists say the harmful algae bloom season will be among the most severe in recent years and could become the second-most severe behind the record-setting 2011 bloom.

• Toxic algae blooms: What you should know about the mysterious phenomena

The U.S. National Oceanic Atmospheric Administration and partners say heavy June rains are causing heavy nutrient runoff into lake basin, feeding blue green algae.

Phosphorous, common in fertilizer, fuels algae growth and runs off into the waterways during heavy rains.

Windsor, Ont., alone shattered the rainfall record for June, soaked by more than 200 millimetresof rain last month.

The algae bloom severity index runs from a high of 10, which corresponds to the 2011 bloom, the worst ever observed, to zero. A severity above 5.0 indicates blooms of particular concern.

This year's bloom is expected to measure 8.7 on the severity index with a range from 8.1 to potentially as high as 9.5. That is more severe than the last year's 6.5, and may equal or exceed 2013, which had the second worse bloom in this century.

"While we are forecasting a severe bloom, much of the lake will be fine most of the time. The bloom will develop from west to east in the Lake Erie Western Basin, beginning this month. It is important to note that these effects will vary with winds, and will peak in September," Richard Stumpf, NOAA's ecological forecasting applied research lead said in a statement.

The effects of the blooms include a higher cost for cities and local governments to treat their drinking water, as well as risk to swimmers in high concentration areas, and a nuisance to boaters when blooms form.

Blooms of blue-green algae can produce toxins that may taint drinking water and recreational water.

People who drink or swim in water that contains high concentrations of these algae or the toxins may experience gastroenteritis, skin irritation and allergic responses, according to the U.S. Centres for Disease Control and Prevention.

In addition, algae blooms can stink up harbours, clog boat motors, reduce fish populations and sometimes lead to the formation of low-oxygen "dead zones" where most aquatic life cannot survive.