CLEVELAND, Ohio – More than 50 years ago, Lake Erie was declared “dead,” and while its environmental health has improved, the shallowest of the five Great Lakes still lags its peers.
The recently released State of the Great Lakes 2025 Report ranks Lake Erie’s overall status as poor while the other four lakes are assessed as being in the fair or good range.
The report, produced by the U.S. Environmental Protection Agency and its counterpart in Canada, looked at nine ecosystem indicators. One of them was toxic chemicals and another was nutrients and algae.
The Great Lakes overall rated fair for toxic chemicals, although the trend was categorized as “unchanging to improving.” Legacy chemicals that include mercury and PCBs “show long-term declines in most monitored media,” the report states.
Compared with the other lakes, however, Lake Erie and Lake Ontario had higher concentrations of four specific contaminants in sediment, water and whole fish, including three known as forever chemicals.
Lake Erie also ranked poor when it came to nutrients and algae, largely because of the harmful algal blooms at the western end of the lake that are brought on each summer by the excessive amount of phosphorus in the water.
Fertilizer runoff from farms in the Maumee River watershed is considered the main culprit.
And yet, there is hope that Lake Erie can eventually rid itself of the mess it’s in, if only the people living around it can stop sending pollutants spilling into its tributaries, said Chris Winslow, director of the Ohio Sea Grant Program and Ohio State University’s Stone Laboratory.
In fact, all things being equal, Lake Erie could clean itself much more quickly than other Great Lakes because it holds less water, he said.
That smaller volume, which causes pollutants to be more concentrated in Lake Erie than in the larger lakes, works in Lake Erie’s favor when it comes to flushing them out.
Here’s why. All five lakes are connected, with water flowing down from Lake Superior and eventually reaching the Atlantic Ocean by way of the St. Lawrence River. But each lake has a different hydraulic residence time, which is how long it would take for it to drain if inflow stopped, or to refill if outflow ceased.
Or, as some would say, how long it takes for the average drop of water to go from one end of the lake to the other. Lake Erie’s residence time is 2.6 years, compared with 6 years for Lake Ontario, 22 years for Lake Huron, 99 years for Lake Michigan and 191 years for Lake Superior. according to the U.S. EPA.
But even if pollution stopped entering Lake Erie today, it would take closer to 8-10 years for most existing waterborne contaminants to pass over Niagara Falls.
Experts use a simple experiment to explain why. If you fill a five-gallon bucket with dyed water, you will need to pour three more buckets of clean water into it before most of the dye splashes out.
The same dynamics are at play in Lake Erie. Surface water driven by wind can reach the eastern end in days or months, while water near the bottom might take decades, according to Eric Anderson, associate professor at Colorado School of Mines. Temperature changes also affect flow, with water sinking as it cools in fall and allowing oxygen-depleted water to rise.
But because Lake Erie has a relatively short residence time, it could recover in our lifetime if allowed to, Winslow believes. Not every pollutant would leave at the same rate. Chemicals such as mercury and PCBs, as well as some microplastics, tend to get buried in sediment. But what’s floating in the water column would get whisked away over time.
The phosphorus that fuels the algal blooms is a good example, he said. It infiltrates the lake and then moves eastward over time, only to be invaded by another round the following year.
“It’s just nice to know if we can stop the source of some of these things, the lake isn’t dead forever,” Winslow said.