Lake Erie

Studies have shown Lake Erie to have the highest concentration of microplastics among the five Great Lakes due to its location downstream of three other, larger lakes and the density of population along its shore. Microplastics are plastic pieces less than 5mm and include microbeads, microfibers, and macroplastics that have broken down into smaller pieces.

More research is needed to better understand microplastics, including their effects on human health, how to best identify and measure them, and how they're affected by drinking water treatment processes. Because of this lack of understanding, there are no state or federal regulations on microplastics.

The location of our four raw water intakes is the first line of defense in limiting the prevalence of microplastics in drinking water. All four intakes are located far offshore and pull water from deep in the water column and are therefore less impacted by plastic pollution, which tends to concentrate at the surface or sink to the bottom of the lake

In addition, our water treatment plants are very effective at removing extremely small contaminants, such as microscopic organisms, that are measured in microns. While there is no research on the efficacy of water treatment processes removing microplastics, since equivalent-size substances are removed, it would be anticipated that microplastics are removed as well. Reducing pollutants in our source water reduces the water treatment costs associated with removing those pollutants.

A serious threat to the Lake Erie ecosystem is invasive species. Many of these species have entered the Great Lakes through the ballast water of ships. At least 25 non-native species of fish have entered the Great Lakes since the 1800s, including:

Zebra & Quagga Mussels

Zebra mussels arrived in North America in 1988. Quagga mussels invaded the Great Lakes in 1989 and are now found throughout Lake Erie. Quagga mussels are slightly larger than zebra mussels and have a higher tolerance for cold water. They disrupt the Lake’s ecosystem by competing with many native algae since they eat many of the same organics. Such conditions allow cyanobacteria (also known as blue-green algae) to thrive. Cyanobacteria can release toxins into the Lake water that pose a hazard to swimmers and other recreational users.

Asian Carp

Based on the problems caused by non-native species, scientists are closely watching other species that have invaded nearby ecosystems. Asian carp are of particular concern because they have been found in nearby waterways that eventually connect to the Great Lakes. Asian carp entered the Mississippi River watershed after floods in the mid-1990s allowed them to escape from fish-rearing and wastewater treatment ponds in the southern United States, where they had been brought in to remove algae and organic matter. These carp are filter feeders that consume huge volumes of plankton from the food chain, starve out the young of native species, and quickly spread and overwhelm resident populations of game fish. If the Asian carp enter the Great Lakes watershed it will produce another huge change in the ecosystem. The U.S. Environmental Protection Agency(EPA) and state and local agencies have constructed a permanent electric barrier to prevent the fish from entering the Great Lakes through Lake Michigan.

During the late summer, water near the bottom of Lake Erie can become hypoxic, meaning it has very low levels of dissolved oxygen. Large areas of hypoxic water are sometimes called “dead zones” because aquatic life needs a certain level of oxygen to survive. Hypoxic water doesn’t usually present a health or safety concern for drinking water, but it can cause taste and odor issues.

How does hypoxic water form?

Changes in farming practices along Lake Erie's western shore have caused increasing amounts of phosphorus to enter Lake Erie. The timing and amount of phosphorous that ultimately reach the Lake each year are dependent on weather conditions. Hypoxic events have become more frequent in Lake Erie due to an increase in the occurrence and severity of storms. The phosphorus is food for algae living in the top layer of water and can lead to large-scale harmful algal blooms (HABs). As algae die, they sink to the bottom of the lake and consume oxygen as they decompose. The larger the algal bloom, the greater the probability of hypoxic water. 

How does hypoxia affect drinking water?

When the oxygen level drops very low the pH also drops, changing the chemistry of the water. The hypoxic water pulls naturally occurring metals, particularly iron and manganese, from the lakebed and dissolves them. If hypoxic water reaches any of our water intakes, the high levels of manganese in the lake water can be very difficult to treat. To counteract the high levels of manganese in the hypoxic water entering the plant, we add potassium permanganate (KMnO4) during the treatment process. However, it is extremely challenging to match the dose of potassium permanganate required for the concentration of manganese as levels of manganese wildly vary and rapidly fluctuate as pockets of hypoxic water in the lake form, move, and re-form. If water with higher levels of manganese does manage to reach the distribution system and customers, there are no health or safety concerns but the water can be discolored.

The presence of PFAS (per- and polyfluoroalkyl substances) in drinking water has drawn increasing attention nationwide. PFAS are a group of synthetic chemicals used since the 1940s in a variety of industrial and consumer products due to their ability to repel water, oil, and stains. They are also used in firefighting foams and industrial processes. 

PFAS are often referred to as “forever chemicals” because they do not decompose or breakdown easily and remain in the environment for a long time. Studies have shown that continued exposure to high levels of certain PFAS can lead to a range of adverse health effects.

According to the EPA, most people are exposed to these chemicals through consumer products. PFAS can enter the drinking water supply through the discharge of industrial waste, firefighting foam, and other sources that then enter surface water via run-off or seep into soil and groundwater.

Recent testing completed by the Ohio Environmental Protection Agency (Ohio EPA) confirmed that PFAS are not detectable in the drinking water Cleveland Water produces. This testing confirmed the results of our own voluntary testing conducted in previous years. 

With nearly 300 individual tests taken between 2014 and now, we have not had a reportable detection level for the six routinely analyzed PFAS chemicals. While it’s unlikely that significant quantities of PFAS will appear, we'll continue to monitor water quality and support initiatives that protect Lake Erie from potential pollution sources.