Road Salt Article
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The Story of Salt: Continuing Questions, and Emerging Technology The clouds darken, the cold air swirls, droves of snowakes gather , and then trucks with plow and sa lt make the roads clear again. We have witnessed this progression of a snowstorm so often that seeing a road covered in chunks of clear or colored salt has become something of a traditi on after a winter stor m. This is especiall y true during the 2013-201 winter! wher e "arlisle! along with most of the northern #nited $tates! was repeatedl y blanketed with several ma%or stow storms. This was why the bureau of "arl isle eventually used up all of the salt reserves! and also why one &nvironmental $cience class measured a conductivity of over 13!000 u$'cm in the local (olly )rub stream in *ebruary 201. The industrial use of deicer s began in +merica in 1, 1! the #nited $tates epartment of T ransportation began using sodium chloride the primary ingredient in road salt/ as a de-icing agent! spreading only !000 tons nationwide Kelly et. Findlay 2010/. $ince then! salt has been a reliable way to keep drivers safe when out in icy conditions! and! according to a study by (aruette #niversity! has reduced vehicle crashes by Kuemmel et. an!ali 1""2/. This would e4plain why the #nited $tates currently spreads between 10 and 20 million tons of salt annually Cary Institute 2010/. 5oad $alt is such a lifesaver because like most salts! sodium chloride easily dissolv es in water . When it comes into contact with ice under the right conditions! the salt breaks apart into sodium and chlorine ions. The ions char ged atoms/ of the dissolved salt want to push apart the many closely-bound water molecules! making the water molecules more able to move around and thus more able to become liuid water . This lowers the standard fr ee6ing point of water 32 0 */! allowing ice and snow on the road to melt at lower temperatur es around 1 0 */. This phenomeno n! known as a fre e6ing point depression! is why we put antifree6e in cars and use salt for making ice cream. The increased appli cation does however have ne gative conseuences7 salt is known to damage bridges! sidewalks! roads! nearby plant and animal communities! ground and well water reserv es! and auatic ecosystems Corsi # $rac%&y, 'S$S/. The problems arise af ter the salt dissolves wi th the melted snow and ice. The salt dissociate s into sodium and chlor ine ions in the solution and around of the salt travels through soils and into groundwater auifers and roadside vegetation! and appro4imately of road-salt are transported in surface runo8 "hurch and *ries6! 1,,3/.
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Transcript of Road Salt Article
8/9/2019 Road Salt Article
http://slidepdf.com/reader/full/road-salt-article 1/3
The Story of Salt:Continuing Questions, and Emerging Technology
The clouds darken, the cold air swirls, droves of snowakesgather, and then trucks with plow and salt make the roads clear again.
We have witnessed this progression of a snowstorm so often thatseeing a road covered in chunks of clear or colored salt has becomesomething of a tradition after a winter storm. This is especially trueduring the 2013-201 winter! where "arlisle! along with most of thenorthern #nited $tates! was repeatedly blanketed with several ma%orstow storms. This was why the bureau of "arlisle eventually used upall of the salt reserves! and also why one &nvironmental $cience classmeasured a conductivity of over 13!000 u$'cm in the local (olly )rubstream in *ebruary 201.
The industrial use of deicers began in +merica in 1,1! the
#nited $tates epartment of Transportation began using sodiumchloride the primary ingredient in road salt/ as a de-icing agent!spreading only !000 tons nationwide Kelly et. Findlay 2010/. $incethen! salt has been a reliable way to keep drivers safe when out in icyconditions! and! according to a study by (aruette #niversity! hasreduced vehicle crashes by Kuemmel et. an!ali 1""2/. Thiswould e4plain why the #nited $tates currently spreads between 10 and20 million tons of salt annually Cary Institute 2010/.
5oad $alt is such a lifesaver because like most salts! sodiumchloride easily dissolves in water. When it comes into contact with iceunder the right conditions! the salt breaks apart into sodium and
chlorine ions. The ions charged atoms/ of the dissolved salt want topush apart the many closely-bound water molecules! making the watermolecules more able to move around and thus more able to becomeliuid water. This lowers the standard free6ing point of water 320*/!allowing ice and snow on the road to melt at lower temperaturesaround 10*/. This phenomenon! known as a free6ing pointdepression! is why we put antifree6e in cars and use salt for making icecream.
The increased application does however have negativeconseuences7 salt is known to damage bridges! sidewalks! roads!
nearby plant and animal communities! ground and well water reserves!and auatic ecosystems Corsi # $rac%&y, 'S$S/. The problems arise after the salt dissolves with the melted snow andice. The salt dissociates into sodium and chlorine ions in the solutionand around of the salt travels through soils and into groundwaterauifers and roadside vegetation! and appro4imately of road-saltare transported in surface runo8 "hurch and *ries6! 1,,3/.
8/9/2019 Road Salt Article
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The salty solution poses signi9cant health concerns for peopledue to the increased groundwater and well water contaminationassociated with increased road salt use. + #$)$ study on well in(adison! W:! found that foreign sodium and chlorine levels have beensteadily increasing since 1,;7 this has led to a number of wells being
replaced! costing around 3. million dollars annually "orsi < )rac6ky/. This especially threatens the nearly 2 percent of +mericans whosu8er from hypertension! which respires them to have a low sodiumdiet Transportation 5esearch =oard! 1,,1/. &ven more troubling thenis the concern that salt levels in reservoirs across the country aree4ceeding the level that can be removed at 9ltration plants W=+>201/.
+dditionally! the increased salinity of a body of water puts thegeneral health of surrounding organisms. :t is well documented thatchlorine can be to4ic to 9sh! macroinvertibrates! and auatic plants
and that many freshwater organisms can only survive within a narrowthreshold for salinity levels! so the increase in sodium chloride ions inthe water has many worried &$ 2011/.
"urrent studies on the long-term e8ects of road salt on auaticecosystems have been mi4ed. ?ne study found that while there areacute increases of sodium and chlorine ions in waterways! theseincreases has no lasting impact on the auatic communities &$2011/. +nother study says that ant colonies actually bene9t fromgreater amounts of salt $mithsonian 2010/. ?ther studies howeverfound that increases salt use has had a detrimental e8ect on
organisms &$ 2011/.
There is a variety of possible solutions to mitigate theseproblems. There are alternatives to using $odium "hloride! such as+cetate "(+/! which is far less motile than sodium chloride! but alsomuch more e4pensive @uemmel et. Aanbali 1,,2/. $ome cities aretrying to use beet %uice or molasses derivatives as alternatives tosodium chloride and while these new methods appear to be promisingfor small-scale applications! both are not yet ready to be used forlarge-scale applications. The most feasible solution right now would befor salt-laying trucks to strictly adhere to the best management
principles outlines by the epartment of Transportation. ?therimprovements to the current system include using )B$ sensors tobetter coordinate responses! constructing salt drainage pools in criticalcites.
The overall e8ects of road salt usage are still not wellunderstood. )oing forward! it is important to be mindful of what andhow much deicer we should use while also still being able to ensure thesafety of the roads during an after winter weather.
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Sources 'sed:
$"A&&>! . 1,. 5oad salt contaminates well7 causes health ha6ard. Cournal of &nvironmental Aealth. ;D202-203.
Church, Peter E. and Paul J. Friesz. 1993. Effectiveness of Highway Drainage Systems inPreventing Road-Salt Contamination of Groundwater: Preliminary Findings. Washington, D.C.:Transportation esearch ecord.
Corsi, !te"en . and Da"id J. #racz$%. &''( Road Salt: !ides"read #$uatic %o&icity and!ater-'uality (m"acts on Environmental !aters: ).!. #eological !ur"e$.
Depart*ent o+ En"iron*ental !er"ices. oad !alt and Water -ualit$., accessed &&/,&'1/,http:des.nh.go"organizationco**issionerpip+actsheets0*docu*ents0*2/.pd+ .
Friederici, Peter. &''/. !alt on the Earth: o0 !no0 Control has Created igh2!odiu*
4andscapesthat Fa"or a Fe0 5n"asi"e !pecies. Chicago !ilderness )aga*ine.
5rele$, 6rian. &'1'. !tud$ e"eals oad !alt *a$ Pro*ote ealth and Well2eing o+ oadside7nt Colonies. Smithsonian Science.
8ell$, . ictoria and !tuart E. #. Findla$. &'1' Road Salt: )oving %oward the Solution: TheCar$ 5nstitute o+ Ecos$ste* !tudies.
8ue**el, Da"id 7. and ashad . anali. 199& #ccident #nalysis of (ce Control +"erations.il0au%ee, W5: ar;uette )ni"ersit$.
