SALT on the roads

man.about.town

i started thinking about this the other day and wonder can anyone tell me if there is any environmental effects from the use of salt on the roads.

if you think about it, during the last couple of weeks, local county councils have been pouring thousands of tons of salt on the roads and paths to melt the ice. i was wondering what effect this has on the environment, surely when it melts most/some of the salted water is going to flow back to rivers, streams, lakes and canal systems. i would imagine this isn't to good for the wildlife, particularly sensitive creatures like frogs, snails etc.. must be effected from this. does anyone know the effects it has and is there any alternatives as in, is salt the only option to combat the ice effectively.

El Siglo

man.about.town wrote: »

i started thinking about this the other day and wonder can anyone tell me if there is any environmental effects from the use of salt on the roads.

if you think about it, during the last couple of weeks, local county councils have been pouring thousands of tons of salt on the roads and paths to melt the ice. i was wondering what effect this has on the environment, surely when it melts most/some of the salted water is going to flow back to rivers, streams, lakes and canal systems. i would imagine this isn't to good for the wildlife, particularly sensitive creatures like frogs, snails etc.. must be effected from this. does anyone know the effects it has and is there any alternatives as in, is salt the only option to combat the ice effectively.

I came across this document in me travels, but that's America so totally different setup for using road salt. Here's one on the frogs as you mention, but to be honest the concentrations are so high in the lab experiments they carried out on the tadpoles and for the period of time they did it for, I can hardly expect to see the same in Ireland. What happens with a lot of salt is that it's simply diluted in surface and groundwater while some of it will adhere to something else. I wouldn't think that there's a huge impact, I mean how many really bad winters has there been in even the last five years that have required tons of road salt to such a quantity as to impact fauna?

Technically, it's a 50% mixture of salt and sand, 100% salt would corrode cars so that's the mixture used. Anything else would be way worse, either expensive or have a negative environmental impact (e.g. ethylene glycol (anti freeze, C2H6O2) used on airport runways and in cars, it's moderately toxic to humans, so probably a lot worse for animals).

hoser expat

Parts of Canada and the northern USA use lots of salt on their roads for several months of the year. I know there have been quite a few studies of the impact on wetlands, hydrology, water quality, impact on fauna etc. I know there have been quite a few studies in the Adirondack Mountains of New york mainly because it is a state park but with lots of roads.

See these links
http://www.springerlink.com/content/m8089v71l43x1516/
http://www.adirondackalmanack.com/2010/02/road-salt-study-raises-concerns-offers.html
http://www.adirondackcouncil.org/A_call_for_task_force_on_road_salt.pdf
http://pressrepublican.com/0100_news/x155050628/Report-Investigate-alternatives-to-road-salt

Bear in mind they use far more salt on the roads than in Ireland. So much so that many cars rust out after about 8 years.

Thomasofmel

Scandinavian countries have reduced the use of salt due to the proven impact to groundwater quality - see the following article.

"Current standards in Finland require that all roads with average daily traffic above 6,000 be treated with salt through the winter. Sodium chloride is used in solid, prewetted, and liquid form, typically 120,000 t/winter. Calcium chloride is used as prewetter or in liquid form; annual quantities are less than 200 t. The application rates of salt vary from 5 to 40 g/sq m. The main argument against road salt has been the proven or suspected effects on groundwater resources, partly because of the glacial origin of Finland's soil. Thus, the pressure to minimize or even stop the use of salt has increased. One example shows that after an area of groundwater was contaminated, it took about 30 years for the soil to return to normal. The new strategy for reducing salt use is to use only prewetted salt and liquid salt whenever sensible. Low-volume roads are no longer treated. Accurate and fast snow clearing is one of the basic issues: dual-blade plows and hydraulically extendable plows have been developed for better snow and slush removal."