In light of the snow that is falling, may I take a moment to demonstrate some of the damaging effects of using salt as a de-icer for our sidewalks and roads during winter.
Salt in over-abundance is in fact toxic to our environment. When used on roads and sidewalks, it enters our surface water, groundwater, and soil through snowmelt, and enters the air as a windborne particles when cars, trucks, etc. splash the snow.Over 4.9 million tonnes of salt are deposited in Canada alone every year, accounting for over 3 million tonnes of chloride deposition.
In water, natural background concentrations of chloride are usually no more than a few milligrams per litre. With the obsessive use of salt, concentrations as high as 18,000 mg/L have been found in highway runoff. The Ministry of the Environment has determined the safe level of drinking water to be only 250 mg/L, yet we often found amounts close to or surpassing this in our municipal waters.
Biologically speaking, this is ridiculously damaging to the organisms that live in run-off ponds, etc. It only takes 1,400 mg/L of chloride concentration for some aquatic organisms to die within four days. Do you really want to kill all these creatures on the off chance you ‘may’ slip? It even kills fish. The embryos of many fish are extremely sensitive to this and are almost guaranteed not to live – 10% of fish species are affected at levels as low as 240 mg/L, compared that to 18,000 mg/L.
In terms of plants, changing salt concentrations in soil also allows certain species like cattails and reed-grass to invade these habitats, displacing many native species. More sensitive species have a reduction in their flowering and fruiting, retardation in their growth, shoot and root injury. etc. These reductions and shifts in communities can lead to a higher increase in road kill and predation of species that live in or near road-side habitats.
It also has major geographical effects that also damage living organisms while changing our environment. This includes (but is not limited to):
– The salinization of our groundwaters
– The salinization of our soil. In fact with increasing sodium content our soil destabilizes, swells, loses osmotic potential, erodes and gets deposited in our groundwaters as turbidity. Electrical conductivity increases greatly. Soil particles are attached to environmental contaminants such as heavy minerals, microbiota,nutrients etc., and when these are dispersed in higher numbers (due to salt usage), they end up in our water and around our environments in unsafe amounts.
– Elevated chloride concentrations
– Stratification of our ponds (meaning the layers of water become stabilized), this retards the seasonal mixing of the water layers, reducing oxygen and nutrient concentrations. If organisms cannot get the air and nutrients they need to live… they die!
Last but not least, road salt contains ferrocyanides. Under certain circumstances, the ferrocyanide can dissociate in solution, resulting in cyanide ions, which are known to be extremely toxic and lethal to many organisms.
Environment Canada (my employer of late) released a 5 year study on the use of road salts, demonstrating all these facts and many more. The report is publicly accessible at http://www.ec.gc.ca/substances/ese/eng/psap/final/roadsalts.cfm . The US government has also considered road salt a potential pollutant, under the National Pollutant Discharge Elimination System.
So what’s my point? The abuse of road salts kills microorganisms, aquatic organisms, fish, plants, and land animals. It drastically changes the wildlife communities. It destroys our soils, salinizes our groundwater (our drinking source!), upsets our surface water and ponds, and provides the opportunity for toxic chemicals to flourish. If we stopped using salt in Toronto immediately, it would take over 300 years for the system to return to natural chloride concentrations,
Is it really worth it?
Solution? Shovel – early and often. Kitty litter can be messy, so try sand instead. If you must use salt, please use it sparingly and mix it in with another natural product. Pick salt products that contain calcium chloride over sodium chloride, as it is more effective (works at a lower temperature and less is needed). At higher temperatures, salt is not even effective, and many communities turn to beet juice – yes, beet juice.
Our lives are not worth more than the planet we live on.
By the way, I am not against salt. I like it. We need it. I’m against the abuse of salt as a de-icer.