Are You part of the Problem? III

Republished from Penn State Extension- Jennifer Latzgo, Master Watershed Steward, Lehigh Valley

Impacts of Chloride Pollution on Stream Ecosystems
Chloride is problematic for stream organisms because it reduces oxygen levels and creates osmotic stress. "EPT" organisms: Ephemeroptera (mayflies), Plecoptera (stoneflies), and Trichoptera (caddisflies) are a vital part of the food web and are used as bioindicators of stream health. Research has shown that their numbers decrease significantly as chloride levels increase. Current research indicates that the threshold for long-term toxicity for these creatures for chloride is 50 mg/l.
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Chloride also has an impact on other aquatic life. Studies have shown that chloride affects frogs and salamanders during their larval stages in vernal pools, causing deformities and increased mortality. Fish have been found to have reduced hatching rates and reduced growth overall, and aquatic plants are also affected because chloride affects their ability to absorb water through their roots. In ponds and lakes, salty water is denser and forms a layer of oxygen-deficient water at the bottom, which is harmful to wildlife.

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Soil
Road salt ends up in soil as a result of runoff, plowing, bouncing, and splashing. This effect can be as far as 10 meters from the road edge. Accumulation of chloride can reduce soil permeability and fertility and increase alkalinity and density, causing chemical changes and a reduction in the soil's ability to retain water. Soil microbes are also impacted, and studies show a reduction in their activity, biomass, and community structure.
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Drinking Water 
Pollution of rivers and groundwater also has the potential to affect our drinking water supply. Water with more than 20 mg/l of sodium is unhealthy for people with high blood pressure. Sodium levels are not typically measured, but if we measure the quantity of chloride in water, 31 mg/l  of chloride indicates that it will have 20 mg/l of sodium.
Here in the Lehigh Valley, our local water supplier draws water from the Little Lehigh Creek in Allentown and has been measuring the chloride levels since 2001. (See graph below) This data reflects the levels year-round. During that time, the amount of chloride has more than doubled.  Since 2007, it has consistently exceeded the 31 mg/l level for hypertension. Also, note that it has been above the 50 mg/l levels of toxicity for EPT organisms since 2012.

Effects on Infrastructure
Chloride corrodes vehicles, bridges, and roads at a cost of approximately $5 billion a year. It causes chemical changes and freeze-thaw effects in concrete structures, causing cracks, crumbles, and discoloration.  It also accelerates the corrosion of water pipes, which can lead to them leaching harmful metals like lead into the water supply.

Green Infrastructure
Green infrastructure like riparian buffers and rain gardens slow chloride infiltration, but unfortunately, they do not fully mitigate it. This is because chloride anions are negatively charged, which are repelled by soil particles and move very easily down into the ground.  As it passes through, chloride can damage plants and soil and reduce the ability of microorganisms to degrade or alter other pollutants.
 
Pennsylvania Road Salt Action
Many people around the state have worked on the issue of road salt pollution locally, but so far, there has been no coordinated state-wide effort to allow sharing of expertise and resources. So, in January 2025, the Pennsylvania Road Salt Action working group was formed to bring this about.  The group includes representatives from numerous organizations and groups and has the following initial goals:
 

• Develop protocols and strategies for talking to municipalities and large landowners about adopting best management practices
• Create a website with materials and resources that can be used for advocacy
• Encourage PennDOT to promote their training program for municipalities and emphasize road salt reduction
• Lobby state lawmakers to pass legislation for a limited liability program for private contractors
• Work with providers to create a state-wide training program for private contractors
• Find sources of grant money for equipment upgrades and assistance to municipalities

As the project moves forward, other goals may be added to this list.
 
Along with the working group, we are developing a network of advocacy partners. These are organizations like watershed groups, conservation organizations, or individuals who are concerned about road salt pollution in their area and want to take action locally. They will be able to use the resources on our website and then share their successes and challenges so that others might benefit from their experiences. They will also be able to participate in coordinated calls of action to their lawmakers about proposed legislation which will amplify our message around the state.
 
The Bradford County Conservation District is committed to helping people manage resources wisely.  You can visit the Bradford County Conservation District at 200 Lake Rd in Wysox across from the Wysox Fire Hall. Contact us at (570) 485-3144 or visit our web page at www.bccdpa.com.