Toledo Today, America Tomorrow: The Link between Population Growth and Microcystin

Residents of Toledo, OH breathed a sigh of relief in early August, as the Mayor lifted a tap water ban affecting up to 400,000 people.  After state and federal Environmental Protection Agency (EPA) officials found high levels of the toxin “microcystin” in the water supply of certain neighborhoods, officials decided to ban tap water use for the entire city – including using the water to cook, consume, or boil.

The city set up distribution centers for potable water throughout the area, asking residents to travel to them and collect supplies to use for the duration of the ban.  How long could that be?  It was anyone’s guess – however long it took for the toxins to subside.  But millions of Americans – particularly those in areas near the Great Lakes – were watching to see how the situation unfolded.  Everyone wanted to know:  what exactly was this microcystin, and how could it cause the water supply of a large urban area to become toxic?

In any body of water, there is a potential for algae to grow.  When a particular type of algae (a cyanobacteria often called “blue-green algae”) blooms, it produces large quantities of a toxin called microcystin.  Microcystin-LR, found throughout the Great Lakes, is the most toxic form.  While there are no known cases of human death attributed to microcystin-LR, it is often fatal to pets and can cause abdominal pain, breathing problems, skin reactions, and even liver damage in humans.  This is why, when officials found high levels of the toxin in some of Toledo’s water, they placed an immediate ban on tap water throughout the city.

So how does an algae problem relate to U.S. population growth?  When weather is warm and wet, blue-green algae blooms.  Phosphorous and nitrogen – both major components of agricultural and animal waste runoff, particularly after heavy rains – encourage this blooming.  Climate change is a major contributor to increased numbers of warm, wet days throughout the year.  With increased population numbers, we see increased consumption – regardless of conservation measures – and increased pollution.  This leads, inevitably, to climate change.  With a growing population, agricultural activity grows to meet the rising demand for food and to gain from current high world prices, implementing more nitrogen and phosphorous-rich fertilizers.  It’s a vicious cycle, and it’s one of our own making.

From 2010-2013, the population of Ohio – estimated at over 11.5 million in 2013 – grew by only 0.3%, a much smaller rate than the U.S. average of 2.4% over the same period.  In 2010, Greater Toledo’s population was estimated at just over 610,000 – and the area had actually decreased in size by 1.3% since 2000.  Yet this single water contamination affected the day-to-day lives of up to 400,000 area residents.  Just 60 miles north, the Detroit metropolitan area – home to nearly 4.3 million people in 2010 – also sits along the water’s edge.  Imagine the impact if a similar microcystin situation occurs there.  Or less than 250 miles away in the Greater Chicago area bordering Lake Michigan, which had a 2010 population estimate of nearly 9.5 million people.  The severity of this scenario should be cause for real concern – both for area residents and city officials alike.

The experts have determined that Toledo’s microcystin levels have returned to normal… for now.  Yet the root of this water problem – population growth – is very real, and it has been ignored throughout all of the debate surrounding Toledo.  The eight-state Great Lakes region is home to 25 million Americans.  The largest system of fresh surface water on earth, the Great Lakes contain over 20% of the world supply – and 84% of North America’s supply.  They provide drinking water to 40 million people.  With the American West suffering severe drought – and Colorado River levels reaching record-setting lows – many officials there are looking to the “promised land” of the Great Lakes as an obvious source to import their water.  However, if the Great Lakes become contaminated by further population growth and the resulting human activity, the results could be catastrophic for tens of millions of Americans.

As mankind continues to swell in numbers, more nitrogen and phosphorous are entering the water supply – and climate change creates an ideal breeding ground for algae growth and blooms.  It’s a perfect storm for a situation like the one in Toledo – and it’s a very real concern for residents all along the Great Lakes.  The planet is reacting to our growth, and our environment is paying the price.  Until we slow, halt, and eventually reverse our population growth, Toledo is another grim warning of what awaits our nation’s future.


Tracy Henke

Tracy Henke served as Deputy Director of NPG from 2012 to 2017, contributing to the structure and development of NPG’s publications programs. Acting as NPG’s principal editor and a contributing author – as well as a regular contact for the public and media, Tracy extensively researched U.S. population issues and worked to establish significant grassroots support for the NPG mission. She holds a degree in Leadership & Social Change from Virginia Tech, with a professional background in non-profit and program management.

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