The dreaded salt

[animartco]

What was it 10,000tons of salt strewed on our roads? More I think. I complained to the local council last year, and found a sympathetic chap in charge who said he would look into not gritting roads that run through SSIs. But he emphasised that he couldn't risk any danger to the public. If this is the attitude we take, all wildlife on the planet will soon be extinct. This enormous amount of salt running off into our streams and contaminating all road verges will be the final death knell of our hard pressed amphibians.
The sad thing is that in the very cold temperatures we are currently having, the salt is no earthly use anyway! I would love it if we all pushed whoever we have access to, to reinstitute the use of chains on tyres which is a much safer method of coping in weather like this. At present half the roads in England would need chains, but the major gritted roads don't. Abroad they let all the roads go to white ice so that people can use chains throughout all journeys while the cold lasts.
I would love to hear some thoughts on this.
Cheers Animartco

[Hedgehoggy]

Hi animartco,

I too wonder about the domino effect all this salt/grit will have on our environment and had a very similar conversation with a friend who recently moved to Edmonton, Canada, where temperatures are currently -20+ and the snow is measured in feet, not inches!! When I suggested we should all invest in snow-chains for our tyres, like they do in Canada, he said that our roads in the UK couldn’t withstand the damage the snow-chains can cause because our road surface material is lacking a certain substance which other countries (e.g. Canada) specifically use in their road surfaces to enable such usage (or something similar along those lines!) Do you know if this is true?

On the few occasions I’ve ventured out in my little car recently, the salt/grit sprinkled on some of the frozen snowy roads have been as effective as a chocolate teapot!

They don’t use salt/grit In Canada, the local authorities send out the snow ploughs regularly to clear the roads, and residents are responsible to clear snow from the pavements outside their homes and pile it up ready for the snow trucks to collect it all to take to a ‘snow dump’. After the roads and pavements have been cleared of snow, a layer of clean gravel/stones is sprinkled onto the roads (and, I think he said, pavements too), then in April after the last snow has fallen, all the gravel/stones are water-jetted into the kerbsides, hosed clean, and scooped up to be re-used the following winter. Why can’t we employ such an environmentally-friendly scheme here I wonder? After the initial expenditure of stockpiling re-usable gravel/stones (instead of disposable salt/grit), surely it would also be far more cost-effective in the long-run too.

Just my thoughts!...

[Beekeeper]

An additional problem of salting the roads here in the New Forest is that it attracts ponies which like to lick the salt, of course to do this they often stand in the middle of the road and become casualties of vehicle movements.

Ian

[BloomingMarvellous]

Don't forget the damage it does to Lino and Tiles and those nice wooden floors.

Don't forget to take your shoes off, that's a very good tip, especially in this weather.

[Ukwildlifeo]

One consquence of the salting of roads is 'coastal' plants spreading inland. Many of these salt tolerant plants are right at home in the more salty soil in road verges.

[mbaldw]

I too wonder about the domino effect all this salt/grit will have on our environment

This is a very interesting subject and there have been quite a few studies (largely in the USA) looking at the environmental impact of gritting salt. In 1991 the Transportation Research Board published a special report (entitled Highway Deicing - Comparing Salt and Calcium Magnesium Acetate) that assessed the use, efficiency and impact of NaCl and CMA (which is a mixture of Calcium carbonate, magnesium carbonate, and acetic acid) in the USA. You can download a PDF of the fourth chapter (Road Salt Impacts on the Environment) here (note the link is directly to the PDF). The full report, downloadable as individual PDFs of the various chapters, can be found here. More recently, there was a pretty good review of the subject published in the journal Stormwater during 2001, which is now available online. I expect that there's quite a bit of work currently being done in the UK to look at road salt, but the only study I'm immediately familiar with is that by York University, who are looking into whether/how road salt might act to destabilise the nitrogen cycle - more details here.

I must confess that I don't know a lot about amphibian biology (I'm sure there's someone on here who can enlighten me), but there does appear to be quite a bit of data to suggest that they (with their highly permeable skin) can be badly hit. I know that Nancy Karraker at the State University of New York College of Environmental Science and Forestry has done quite a bit of research on this subject, although she has come up with some mixed data. Dr Karraker has demonstrated that the eggs and embryos of some frog species died during experiments where they were subjected to salt concentrations at the 'high end' of those she found in the wild. However, she has also found that some amphibians are more tolerant of salt than others and the problems are far more evident at the high end. In a 2007 paper to the journal Herpetological Conservation and Biology, Dr Karraker wrote of the Green frog Rana clamitans:

"Larval growth was unaffected by road salt, but 15% of larvae were malformed at the highest conductivity level. Rana clamitans appears to be relatively tolerant to road salt at low and moderate concentrations and less sensitive than other North American amphibians. At conductivity levels observed in the field, it is unlikely that road salt currently impacts populations of R. clamitans.

Although this is quite a big topic in the USA, I'm not aware of anyone conducting similar amphibian studies here in the UK - presumably this is at least in part because very harsh winters are still comparatively rare for much of the country.

Cheers,
Marc.

[Hedgehoggy]

Thanks for those interesting links, Marc. It appears that a lot more conclusive research, and subsequent alternative de-icing agents, is needed p.d.q. - especially if this current winter and de-icing methods used are going to be regular trends of the future.

One aspect I overlooked was the detrimental impact on our own health!

Excerpt taken from the University of York. ‘ Road Salting: The implications for the roadside environment.’ via the link you provided:

Britain’s uplands supply the majority of our potable waters, yet these areas are subject to heavy de-icing during winter. Since many upland trunk roads track river courses, salting these roads poses a real threat to the chemical and ecological quality of our water supply.

So, unless an alternative de-icing agent is used, I think I can safely conclude that fatal hypernatremia will be the cause of mankind’s demise sometime in the future!

[tom00_uk]

Originally Posted by Beekeeper

An additional problem of salting the roads here in the New Forest is that it attracts ponies which like to lick the salt, of course to do this they often stand in the middle of the road and become casualties of vehicle movements.

Ian

molasses is added to the rock salt to make it sticky and so makes it even more attractive to animals

[Monkey Orchid]

Originally Posted by BloomingMarvellous

Don't forget to take your shoes off, that's a very good tip, especially in this weather.

Wouldn't your feet get a bit cold?