Lake Erie Algae Blooms Point Out Need to Limit Phosphorus Pollution
Lake Erie, the smallest of the five Great Lakes, supports a billion-dollar angling and boating industry, not to mention beach-going tourists. However, the lake is in trouble: eutrophication, the process of nutrient overloading from fertilizers, and human and animal waste has caused an over-proliferation of plant life. Reduction of wetlands, which function to filter nutrients, has resulted in algal blooms – the result of growth of microcystis, a toxic blue-green algae. When microcystis dies and sinks in the lake’s waters, the decomposition process sucks up oxygen, creating low-oxygen dead zones zones where plants essential for feeding the fish cannot grow. Lack of oxygen also creates conditions favoring the growth of anaerobic bacteria such as botulism, the toxin of which can be quite fatal. Botulism is then transferred up the food chain when mussels and gobies are preyed on by larger fish.
The US-Canada International Joint Commission, responsible for policies regarding Lake Erie, has issued a report available on its website – ijc.org. It contains 16 different recommendations for combating harmful algal blooms, including improvements in municipal sewer systems and restoring wetlands and a ban on applying manure, bio-solids and fertilizer to frozen ground or ground covered by snow in Ontario and the states of Ohio, Michigan, New York, Pennsylvania and Indiana. The commission called for cutting the overall phosphorus levels 46 percent in order to diminish the low-oxygen dead-zone by half. It also recommended a 39 percent cut in phosphorus levels in western part of the lake, in order to decrease algae blooms that are particularly widespread there.
Although these measures might seem extravagantly ambitious, the truth is that Erie has been in trouble before, and has rebounded in the past. By the 1960s, Lake Erie was extremely polluted, due to factories that dumped pollutants into the lake and the waterways that flowed into it. Waste from city sewers, fertilizer and pesticides from agricultural runoff made their way into the lake too, contributing to the problem. As a result of these pollutants, levels of phosphorus and nitrogen increased in the lake, contributing to the development of massive algal blooms, depleting oxygen levels and leading to massive fish kills. In 1969, the Cuyahoga River caught fire, dramatically pointing up the need for action.
In 1972, Congress enacted the Clean Water Act, a measure that tightened regulations on industrial dumping. That year, the U.S. and Canada signed the Great Lakes Water Quality Agreement to lower the amount of pollutants entering the Great Lakes. The controls produced an effect, but only after some decades; in 1999 the presence of mayflies after an absence of forty years indicated some improvement. In late May 2001, the Cuyahoga River in Ohio was documented with healthier fish than it had seen in decades. In the mid-1990s, however, harmful algae and the associated dead zone made a reappearance. The problem accelerated steadily through the 2000s; in 2011, aquatic ecologists indicated that there were twice as many microcystis in the lake as in the previous year. The poisonous algae can kill animals and sicken people. Dead algae sink to the bottom of the lake, depleting oxygen in the water and killing the fish. Foul mats of dead algae also wash onto beaches discouraging swimmers. In August of 2011, Ohio officials posted signs on Lake Erie beaches warning swimmers against swallowing the water, and cautioning them to avoid the algae. Residents in an Ohio township were ordered to not drink tap water because of the algae. Some municipalities, including Toledo tested and treated their water supplies.
Where’s the phosphorus coming from?
The report attributes the algae’s resurgence on the usual suspects: chemical fertilizer and manure from farms, lawn fertilizers, leaky septic tanks, pet droppings, and storm water drains from urban sources. It recommends designating the lake an impaired waterway under the federal Clean Water Act to force phosphorus limits. Doing so will trigger a phosphorus Total Maximum Daily Load plan for Lake Erie’s western basin to be overseen by the U.S. EPA. The Ohio Environmental Council indicated on Thursday that it was supportive of this recommendation.
What are the options for limiting phosphorus release?
As an individual, one can greatly improve the quality of the water supply by reducing the use of phosphorus-based products like dishwasher detergent, which, before 2010, accounted for more than 10 percent of the phosphorus treated by city wastewater plants. Treatment plants can remove some, but not all of the phosphorus in wastewater. The phosphorus that treatment plants do not remove is released back into the environment. Other actions an individual might take include reducing fertilizer use on the lawn, mowing “high,” leaving grass clippings, maintaining septic systems and picking up pet waste. For the politically active newsreader, one might join with activist efforts to get states to enact laws restricting phosphorus in fertilizers detergents. Farmers are encouraged to practice management of the source, rate, time, and place of nutrient use. Farmers are urged to control the release of drainage water from tile drains and ditches.
If anything, the near-demise and resurgence of Lake Erie and the history of intervention in its fate bears witness to the fact that conscientious management and government action to limit pollutants can turn around what might seem a desperate situation. Lest one fall under the illusion that Lake Erie is the only body of water affected by pollution or algal bloom, however, keep in mind that the same rules apply to the water supply, no matter where one lives. But, as ever, a biological entity such as a lake can be stressed only so much, before the system breaks down irretrievably. Inaction can be fatal.
Opinion By Laura Prendergast