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writing:road_salt [2025/11/24 18:11] – JacobCoffinWriteswriting:road_salt [2026/07/02 20:52] (current) – JacobCoffinWrites
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 Once salt gets into the soil, or into a waterway, there really are no biological processes that will remove it. Salt can leave the system through transport and it can be diluted by fresher water coming in so that the levels become less concerning. However, without transport out of the system, like in an isolated lake or aquifer, [[https://news.climate.columbia.edu/2018/12/11/road-salt-harms-environment/|the salt will continue to persist over very long time scales.]] Costs of chloride clean ups [[https://saltresponsibly.com/the-problem-with-road-salt/|can run around $300,000,000, a cost that is estimated at 30-40% higher than efforts to protect drinking water in the first place]]. Once salt gets into the soil, or into a waterway, there really are no biological processes that will remove it. Salt can leave the system through transport and it can be diluted by fresher water coming in so that the levels become less concerning. However, without transport out of the system, like in an isolated lake or aquifer, [[https://news.climate.columbia.edu/2018/12/11/road-salt-harms-environment/|the salt will continue to persist over very long time scales.]] Costs of chloride clean ups [[https://saltresponsibly.com/the-problem-with-road-salt/|can run around $300,000,000, a cost that is estimated at 30-40% higher than efforts to protect drinking water in the first place]].
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 +It's also worth noting that chloride-polluted water is denser than freshwater, [which means it can become concentrated at lake bottoms](https://northernwoodlands.org/outside_story/article/road-salt-impacts). "In extreme cases, this can impede the vernal and autumnal vertical turnover of lake waters essential for distributing oxygen and nutrients to aquatic species." 
  
 Essentially, the only real way to remove salt from the environment is to stop adding it and to flush it out with fresh water over time. This won't work in every situation though, some contaminated surface water bodies are endorheric or slow draining and lose most of their water to evaporation, which increases their salinity over time. Similarly, many underground aquifers (which are often tapped for drinking water) are basically at the bottom of their local groundwater topology, making heavy contaminants very difficult to remove. Essentially, the only real way to remove salt from the environment is to stop adding it and to flush it out with fresh water over time. This won't work in every situation though, some contaminated surface water bodies are endorheric or slow draining and lose most of their water to evaporation, which increases their salinity over time. Similarly, many underground aquifers (which are often tapped for drinking water) are basically at the bottom of their local groundwater topology, making heavy contaminants very difficult to remove.
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 Even in solarpunk cities, where driving would hopefully be less of a common concern, people would need to accept that they can be safe in the winter without salt crunching underfoot and that's not easy. This is a fairly recent expectation, and it's driven by a mix of things including legal liability (a bag of salt is a lot cheaper than a personal injury lawsuit) and the present day need to hustle, even in bad weather, that demands that people go out during an ice storm and woe betide anyone who hasn't salted their sidewalk enough. Education is a big piece here, informing people on how salt works on ice, that a heap of dry salt isn't changing anything but the local wetlands, and the consequences of overusing road salt. Even in solarpunk cities, where driving would hopefully be less of a common concern, people would need to accept that they can be safe in the winter without salt crunching underfoot and that's not easy. This is a fairly recent expectation, and it's driven by a mix of things including legal liability (a bag of salt is a lot cheaper than a personal injury lawsuit) and the present day need to hustle, even in bad weather, that demands that people go out during an ice storm and woe betide anyone who hasn't salted their sidewalk enough. Education is a big piece here, informing people on how salt works on ice, that a heap of dry salt isn't changing anything but the local wetlands, and the consequences of overusing road salt.
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 +===Possible Phytoremediation Options===
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 +[[phytoremediation_bioremediation_mycoremediation|Phytoremediation]] is the practice of using living plants to clean soil, air and water by absorbing, containing, or breaking down hazardous substances. Normally this research is aimed more at heavy metals or Persistent Organic Pollutants, but I've found a few articles on remediating chloride-contaminated soils which may be relevant. The linked page from this wiki will provide more information on the processes used in phytoremediation.  
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 +[[https://www.sciencedirect.com/science/article/abs/pii/S0269749120310459|This paper]] identifies [[https://en.wikipedia.org/wiki/Atriplex_patula|Atriplex patula]] and [[https://en.wikipedia.org/wiki/Atriplex_canescens|Atriplex canescens]] as potential candidates for chloride remediation with decent results.
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 +[[https://link.springer.com/article/10.1007/s11104-025-07873-x|This paper]] identifies [[https://en.wikipedia.org/wiki/Panicum_virgatum|Panicum virgatum]] and [[https://en.wikipedia.org/wiki/Sporobolus_michauxianus|Sporobolus michauxianus]].
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 +This research is very new, and I'm not aware of any real life chloride phytoremediation projects currently underway. It looks like these plants would be used as chloride accumulators, and their contaminated above-ground biomass would be harvested and disposed of for years until chloride levels in the soil diminished. 
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 +It may be worth noting that some of these plants are [[https://www.sciencedirect.com/science/article/abs/pii/S0048969716317144|excretor halophytes]] (known as recretohalophytes) which have specialized salt glands that allow accumulated salt to be excreted onto their leaf surfaces and then dispersed via the wind in a process known as haloconduction. This make make them less effective for remediation purposes. 
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