January 6, 2022 at 11:05 a.m.
Road salt is not 'here today, gone tomorrow'
Road salt is not 'here today, gone tomorrow'
The Izaak Walton League of America's Salt Watch program encourages citizen scientists to not only monitor salt levels in streams at road crossings, but to also advocate for smarter salt use by municipalities and private winter maintenance companies.
Salt Watch, which just kicked off again for the 2021-22 season, has several goals. One of those goals is to raise awareness in the general public about the connection between salt and stream health. Another goal is to identify chloride hot spots in freshwater. Salt Watch personnel and volunteers also advocate for smarter application of road salt by sharing their findings with not only municipalities and state and local agencies, but also private land owners who may be in a problem area.
Many who live in an area with municipal water know there is chlorine in their water. Chloride, though, is different. This is salt that can come from road salt, water softeners or even commonly used fertilizers. The biggest problem with chloride is that it is difficult and expensive to remove once it gets into a waterbody or watershed. Chloride is not removed by wastewater treatment plants, meaning it will find its way back into streams, rivers and other waterbodies after leaving the plant. In severe cases, according to the League, salt can corrode pipes, leaching heavy metals such as lead into drinking water.
The Salt Watch program grew organically when a member of the Izaak Walton League found a pile of road salt near a stream crossing that was left by a municipal salt truck. Members of the League started to wonder what impact this was having on nearby surface water. Thus began Salt Watch, which now stretches across the Midwest as well as the Northeastern parts of the United States in areas where road salt is commonly used.
Volunteers are asked to monitor a stream crossing four times per year. The volunteer selects the crossing of their choice and emails the Salt Watch program for a testing kit. The kit comes with full instructions, four test strips and a conversion chart to show parts per million of chloride at the location the volunteer is testing. Each testing site is a road stream crossing where there is a high probability that rock salt will find its way into an adjacent waterway.
Volunteers soak the test strip in a container of water from the stream until a reading is achieved. The test strip is then held next to the conversion chart and a photograph taken of both, showing the full test strip as well as the chart. This photograph is uploaded to an app called Water Reporter to go into the Salt Watch database.
Water Reporter is a free app used by many different projects. Once a volunteer has created their account, they simply join the Izaak Walton Salt Watch. project. This is where they will upload their photographs and can see photographs taken by other volunteers as well.
Citizen scientists are asked to take four readings per year at their selected site. The first reading is a baseline reading. This is taken in the fall, before any salt has been applied to the roadways. The next reading is taken after salt has been applied to the roads for the first snow or ice event. A third reading is taken after the first warm day or rainstorm following a snow or freeze where runoff may cause the road salt to wash into the stream. The last reading is taken sometime in the spring after a rain event. The conversion chart measures chloride in parts per million (PPM). A reading of 0-30 ppm is below the detection level of the strips used in the kit. From 30-100 ppm, depending on the geology of the area tested, this may be chloride that exists naturally in the environment. Higher readings, from 100-229 ppm, are above any natural chloride levels and are cause for concern. The biggest cause for concern is a reading of 230 ppm or more. This reading is the threshold for chronic exposure to chlorides.
These readings will show the changes in chloride levels after different events at the road stream crossing. In the case where large rain events have recently happened, salt may have washed away from the road stream crossing area more quickly. In drought conditions, the salt may stay in place for longer periods of time. One of the overarching goals is to determine how weather events influence salt levels and to learn more about what factors may increase those levels.
The effects of chlorides in water are many. There can, of course, be effects to fish, but smaller organisms such as invertebrates, plankton and even microbes are often more sensitive to chloride levels. Exposure to chlorides at what is called chronic levels, or occurring at all times, exacerbates these negative effects even more.
Vernal pools may be more intensely affected, as could be the organisms that spawn in them. Even mammals drinking from streams and waterbodies with high chloride levels can be affected.
Sally Petrella of Friends of the Rouge, a river below Lake St. Clair in Detroit, spoke during this year's Salt Watch kick-off video. She is a monitoring manager with the 35-year-old nonprofit organization. This watershed, she said, is the most urbanized in the United States at 467 square miles and home to 1.3 million people. The Rogue River, she said, has a history of being one of the most polluted waterbodies in the country - so polluted, in fact, that it actually lit on fire many years ago due to the levels of those contaminants. The huge amount of runoff from the urban area make the watershed's problems even worse.
Today, however, the water has been cleaned up significantly. Of course, there are still places where chloride is an issue. And in these places, certain sensitive species no longer live. In areas where chloride levels remain low, however, Petrella said even two species of freshwater mussels, that are highly sensitive to contaminants, have been found.
Allison Madison, of Madison, also spoke during the kick off this year. She spoke about some success stories. Through Smart Salting Workshops, which have been virtual for the past two years, they have been able to speak with winter maintenance professionals about ways to cut salt use and still keep people safe. In Cudahy, near Milwaukee, she said, simply recalibrating salt trucks resulted in a 50% reduction in salt use. The use of brine has also improved the amount of rock salt that simply bounces off of the roadway, she said. Without brine laid down approximately 30% of rock salt will simply bounce off the roadway, with some of that finding its way to streams and rivers.
In Middleton, "smart trucks" are calibrated to use a specific amount of salt per lane mile. As the driver slows down, or comes to a stop, the truck automatically adjusts the amount of salt it releases, even stopping the release while the truck sits at a stop sign, for instance. These municipalities and other share their success stories with others as do private companies who have learned ways to reduce salt use and still have the same results.
More information about Salt Watch can be found on the Izaak Walton League of America can be found on their website iwla.org. The full presentation on Salt Watch Kickoff for this year, as well as many other League videos, can be found on their YouTube channel.
Beckie Gaskill may be reached via email at [email protected].
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