Overview
Michigan roads would be unsafe and the economy would crash if there were no efficient ways to deice roads. Michigan roads are often kept clear by salting them with millions of tons every cold season. Ann Arbor, for instance, uses between 3500-7500 tonnes of salt per winter.
- All that salt eventually seeps into local streams and rivers, which eventually flow into the Great Lakes. Research The University of Wisconsins Center for Limnology and Michigan States Department of Earth and Environmental Science published a report in December 2021 showing that Lake Michigan’s salt level is increasing incrementally by a milligram every few years. They discovered that 1 million tons of salt were flowing into Lake Michigan each year.
- It is becoming clear that all that road salt is slowly building up in freshwater lakes, rivers and aquifers. The researchers discovered that the concentrations of chloride, an element in salt, have increased dramatically in Lake Michigan since 1800s. They ranged from 1-2 milligrams per Liter of water to 15.
- According to the CDC too much dietary saltHigh blood pressure and risk of stroke, heart disease, or high blood pressure can all increase. The levels have not been shown to cause harm to human health. Salt shock can shorten the life span of wildlife and plants. Even low salt concentrations can alter ecosystems and corrode pipes. Vehicles can also be damaged by them. The Huron River Watershed Council monitors the levels of chloride in the local watershed. However, rising salinity was detected at low levels.
- Alternatives to road salt include sugar beet products, which are abundantly available in Michigan. However, they have been less effective than salt and can cause harm to ecosystems. Sugar that replaces salt causes bacteria to grow in waterways. Synthetic deicers can be expensive. (Calcium magnesium Acetate is used on Zilwaukee Bridge for oxidation prevention and costs 50x more than calcium chloride mined under Detroit. (Source: *directly quoted* https://www.greatlakesnow.org/2022/01/road-salt-michigan-lakes/)
- Ann Arbor and Washtenaw County are now experimenting with salt brine, a mixture of chloride salts that is applied to roads in icy conditions. Because less salt is required, it is economical. Critics of salt brine claim it can cause more damage to vehicles. However the Washtenaw County mix is thought to be comparable to traditional road salt. A 2019 studyIn the journal Environmental Science & Technology, it was shown that salt brine had a 45 percent reduction in chloride runoff to streams. The state reported a decrease in salt consumption to less than 5% in 2020. 325,000 TonsSince the early 2000s, the least amount has been used in salt. (Sources: https://www.wpr.org/study-finds-more-1m-tons-salt-flowing-lake-michigan-each-year; https://www.mlive.com/news/ann-arbor/2020/02/ann-arbor-now-using-salt-brine-to-combat-ice-snow-on-city-streets.html)
- If heated or solar roads cannot be made safe and economical, road salts or chemical deicers will be used for the foreseeable future. Anthony Kendall, Research Assistant Professor, Michigan State University, states that ongoing research will help monitor environmental distress, and that researchers will continue to search for viable alternatives.
Transcription
David Fair:We are grateful for the crews who brave the elements to clear the roads and plow snow. However, there is a cost. I’m David Fair. Welcome to Issues of the Environment, 89 one WEMU. Halite is the traditional road salt. It’s the mineral salt of sodium chloride that is naturally mined. It works well along our roads, sidewalks, and driveways. It then gets plowed into our lawns, onto the sides of roads and eventually runs into our waterways. Did you know that over a million tons worth of road salt end up in the Great Lakes each year? If you’re anything like me, you think, “That can’t be good.” Let’s learn more together. Anthony Kendall is our guest today. He is a research assistant professor of earth and environmental services at Michigan State University. Thank you for taking the time to speak today.
Anthony Kendall: Oh, absolutely. David, thank you.
David Fair: Am I right? This is not healthy.
Anthony Kendall: It’s something we should be aware of. It’s amazing how much road salt gets into the Great Lakes. The one thing I would say is that our Great Lakes are fantastic freshwater resources. Even with all of the salt additions, they still remain freshwater lakes. And that’s something we can be proud to call a resource. We must be aware of how salt is entering those lakes and how it is moving around the landscape, including into our rivers, groundwater, and streams.
David Fair: And I wanted to bring it down to that for a minute. Ann Arbor uses between 3500 to 7500 tons of salt per winter. That salt is carried into all the creeks, tributaries, and rivers of the Huron River that flows into Lake Erie. It is also affecting the inland lakes throughout the country and county. What does that mean for the water’s salinity and quality?
Anthony Kendall: Salt concentrations can rise to dangerous levels in some areas, especially when they are near salty areas like major roads or urban subdivisions. This is because freshwater lakes, and wetlands, have evolved over the millennia to handle low levels of salt water. So, unlike the ocean which is constantly contaminated with salt, and even our own bodies, these ecosystems are able to handle very low levels of salt water. The tiny organisms at the bottom of this food chain, the plankton or the phytoplankton as they are known, are tiny algae that float in water column and get energy from the sun. They have trouble reproducing and thriving in these saltier environments since they are freshwater species. If you take the ecosystem’s bottom rung and make it less healthy, everything else in the food chain will suffer. The basic problem is that salt concentrations rise and create problems for other ecosystem creatures.
David Fair: Continued conversation with Anthony Kendall, MSU research assistant, about WEMU’s Issues of the Environment. Anthony, if we don’t change our course, what are the long-term effects of increased salinization on these other species, to our water supplies, and perhaps to our drinking water supply, in the long term?
Anthony Kendall: Sure. Let’s get back to the Great Lakes. Our Great Lakes will remain as such for many centuries. They are a huge source of freshwater in the long-term. The problem is that the water quality could drop to the point where ecosystems are threatened. This is true even if it is only in a few places along the Great Lakes shoreline. It could lead to the disappearance of species that are most sensitive, which would alter their essential nature. It turns it into something we would recognize in other parts of the country. Geology has created a few saltwater marshes in the Great Lakes. They wouldn’t be in the same areas as we know now. There aren’t all the wetlands, streams or lakes, but some would be affected. That’s why we are actively researching how to identify the most vulnerable inland waters and what we can do to reduce the amount of chloride in ground water and surface water to protect these areas.
David Fair: According to scientific estimates, between 10,000-100,000. species per year are disappearing from the earth. Will salt consumption, if it remains unchanged, have an impact on animals and plants?
Anthony Kendall: It’s possible. I don’t know much about it in terms extinction. But one of the main concerns ecologists have is the elimination of species locally or regionally and the possible impact that this can have on ecosystems that are all interconnected. Although I don’t believe we would be extincting any more species, we would exert pressure on them. This would be one of many problems that these species would have to face.
David Fair: Let’s now talk about alternatives. First, I thought of something I had used before. It works great! However, I feel that it may be worse for the environment. I’m referring to calcium chloride. What can you tell us about this in terms of research?
Anthony Kendall: Calcium chloride is more effective at lower temperatures and can be a great substitute. The problem is not the sodium in sodium chloride. It’s the chloride. Even in calcium chloride formulations, we still put chloride on our pavement and eventually it gets into the waterways. It’s possible to use different amounts, so I am not certain if it’s better. Road salt application and septic tanks are the main uses. People who rely on private water wells to soften their water will use chloride salts to improve the water’s quality and taste. We could say that areas with high levels of salt roads, septic tanks, and private drinking water well usage are areas where we can reduce the amount of what we do. However, we should also consider alternatives that use less chloride to get the same benefits.
David Fair: Anthony Kendall, a MSU research assistant, is our guest on WEMU’s Issues of the Environment 89. Ann Arbor has been testing salt brine mixes since 2020. But it’s used differently. The salt brine is applied before any ice or snow arrives to prevent buildup. Although it is cheaper, it is not as effective in heavy winter events. Is this a long-term viable solution for you?
Anthony Kendall: That is the way MDOT and its county transportation departments see it. They view it as one part of their toolkit. This includes road salting, which they use to reduce costs and make roads safer and more environmentally friendly. Salt brine is often applied to sidewalks before salt is applied. You will also see the residue of that drying on sidewalks in large urban areas. It can help clear the sidewalks faster and with less salt later, when snow and ice are present.
David Fair: What about organics such as sugar beet byproducts. This is a plentiful supply in Michigan.
Anthony Kendall: I have read a lot about this. Although this is not my main area of research, they are often less effective and more limited in scope. However, there may be regional solutions which are more suitable for certain areas. In the Upper Peninsula for instance, road salt can be used in some areas, while sand is used elsewhere. This is also true in rural areas of the southern counties. It is possible to identify local sources of affordable materials that meet the need. This might not necessarily mean clear roads all the time. However, it might be salting or sanding hills or roads. This will help both reduce costs and make the process more pleasant. These county transportation departments are looking at other sources.
David Fair: I know people who have heated their driveways. It seems like this technology could be used on a large scale. I was shocked when the same people told me how much it would cost. I believe that if we can’t afford potholes to fill them, developing and implementing this technology for the entire state is already out of the question.
Anthony Kendall: Yeah. It is not affordable for anyone except the most heavily populated areas. That’s why it might be more effective in a small area, or in large cities with power plants that produce essentially heat that is then distributed. This can be a solution. Michigan State University’s campus has heated sidewalks at certain locations. This helps the power plant run more efficiently and distributes heat.
David Fair: As our time together ends, I think we have made it clear that road salts and chemical deicers will be a part our future. As a researcher, what are you going to be monitoring and looking for in the future?
Anthony Kendall: We will be looking for areas in the landscape that have high salt use and septic tank usage over the next few years. This will allow homes to not send their wastewater to a wastewater treatment facility. These are the areas where we will say that we need to monitor our surface water bodies to ensure that they stay fresh. We also encourage local communities to engage us in finding solutions, because this problem can be found everywhere. However, it is the local communities that will need specific solutions that work for them.
David Fair: There are many conversations to be had. Anthony, I want to thank you for the conversation.
Anthony Kendall: OK, yes. David, thank you.
David Fair: Anthony Kendall, MSU research associate, is our guest on Issues of the Environment. David Fair is my name. This is 89 one WEMU FM. HD One Ypsilanti.
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