Snow has returned to the Philadelphia area, and together with it the white residues on streets and sidewalks that consequence from the over-application of deicers corresponding to sodium chloride, or rock salt, in addition to extra fashionable salt possible choices.
As an environmental scientist who research water air pollution, I do know that a lot of the surplus salt flows into hurricane drains and in the long run into space streams and rivers.
As an example, a citizen science flow tracking marketing campaign led by means of the Stroud Water Analysis Heart in Chester County – about 40 miles west of Philadelphia – discovered that chloride concentrations in southeastern Pennsylvania streams remained upper than EPA-recommended ranges now not most effective after wintry weather snowfalls, but in addition in lots of circumstances right through some summer time months – appearing salt persists in watersheds year-round.
As soon as there, it might probably have a profound have an effect on on fish and different aquatic existence. This features a lower within the abundance of macroinvertebrates, which can be small organisms that shape the bottom of many freshwater meals webs, and discounts in enlargement and replica in fish.
Larger salt concentrations too can degrade and pollute the native water provide. Running with different researchers at Villanova College, I’ve measured spikes in sodium ranges in Philadelphia area faucet water right through and in an instant after snow melts. Those spikes can pose a well being chance to folks on low-sodium diets.
What native governments can do
Lately, many state and native governments national have followed best possible control practices – corresponding to roadway brining, extra environment friendly salt spreaders and advanced hurricane forecasting – to restrict harm from salt to infrastructure, together with roads and bridges.
Roadway brining works by means of making use of a salt resolution, or brine, that comprises about 23% sodium chloride by means of weight previous to a hurricane. Not like highway salt, brines adhere to all pavement and will save you ice from sticking to the roadway right through the hurricane. This probably reduces the will for next highway salt programs.
A view of I-676 right through the main wintry weather hurricane in Philadelphia on Jan. 25, 2026. Philly and different native governments pretreat main roads with brine to forestall ice.
Wolfgang Schwan/Anadolu by way of Getty Photographs
The environmental advantages of those best possible practices, when correctly administered, are promising. The Maryland State Freeway Management decreased its overall salt utilization on roadways by means of nearly 50% by means of the usage of a couple of best possible practices.
The level to which those methods will proceed to cut back the street salt burden on roads and, by means of extension, strengthen the water high quality of streams somewhere else will in large part rely on political will and corresponding financial investments.
But, roads aren’t the one supply of salt to our streams. Fresh research have prompt that the cumulative quantity of salt implemented to different impervious surfaces in a watershed, corresponding to parking loads, driveways and sidewalks, can exceed that implemented to roads.
As an example, one survey of personal contractors suggests their utility charge will also be as much as 10 instances upper than that of transportation departments.
I have no idea of any research which have been in a position to decide a family utility charge.
The way to salt at house
To raised know how people or families deice their houses, and what they know concerning the environmental affects of deicing, I collaborated with a workforce of environmental scientists and psychologists at Villanova College and the native conservation-focused nonprofit Decrease Merion Conservancy.
In wintry weather 2024-2025, the Decrease Merion Conservancy disseminated a survey in a social media marketing campaign that won over 300 responses from citizens in southeastern Pennsylvania. We’re finishing the research to decide a family utility charge, however a few of our preliminary findings supply a place to begin for attractive families on how you can prohibit the environmental have an effect on of deicers.
One key discovering is that most effective 7% of respondents reported being conscious about municipal ordinances relating to deicer use on residential sidewalks.
Of those that implemented deicers to their belongings, 55% indicated they had been not sure whether or not they used them in some way that would cut back environmental hurt.
About 80% of all respondents indicated hobby in finding out extra concerning the environmental affects of highway salt.
In response to those survey effects, listed below are a number of actionable steps that house owners can take to cut back their deicer use.
1. Take a look at your native municipal ordinance
Maximum municipalities within the higher Philadelphia space don’t require deicer use however as a substitute require clearing a walkable trail – normally, 3 ft broad – freed from snow and ice inside a undeniable period of time after a hurricane tournament ends.
As an example, the town of Philadelphia calls for this be executed inside six hours, the borough of Narberth inside 12 hours and Decrease Merion and Haverford townships inside 24 hours.
Narberth and Decrease Merion specify which abrasives – corresponding to sand, ashes and sawdust – or deicers, like rock salt, can be utilized if ice persists.
2. Use rock salt and different deicers judiciously
The commended quantity from conservation organizations is one 12-ounce espresso mug of deicer for each and every 10 sidewalk squares. Take into account that “pet-friendly” deicers aren’t essentially environmentally pleasant. Many of those deicers comprise magnesium chloride, which is destructive to vegetation and aquatic existence.
Deicers coupled with dyes could be a good selection to visually save you over-application. They are able to additionally quickly cut back concrete’s floor reflectivity, thereby expanding its warming impact and enabling melting.
After all, it’s necessary to understand that many deicers change into useless at or underneath positive temperatures. Rock salt/sodium chloride loses its effectiveness at 15 levels Fahrenheit (minus 9 Celsius), magnesium chloride at 5 F (minus 15 C) and calcium chloride at minus 20 levels F (minus 29 C). If temperatures are anticipated to fall underneath the ones numbers, it could make sense to skip the salt.
Coloured deicers could make it more uncomplicated not to unfold an excessive amount of.
Heather Diehl/Getty Photographs
3. Sweep up after
Now we have all noticed rock salt on sidewalks for days on finish, particularly when a hurricane by no means materializes. If the following hurricane brings rain, this leftover salt will shape a concentrated brine resolution that can wash down the closest hurricane drain and into an area waterway.
Leftover salt will also be swept up and reapplied after the following hurricane tournament, saving cash and provides.
