Can someone please explain why just walking down the street or across a parking lot makes your feet 10 times dirtier in the winter than in the summer. Do the road salts have something to do with it?
I've had the opposite experience. I find barefooting on a hot, humid summer day gets my feet much dirtier than in the cold weather. I guess it depends on your definition of 'dirty'. I've never thought of muddy or natural dirt as found in a garden or grass as being 'dirty'. I suppose the amount of skin moisture, condition of your soles, etc. all influences how much dirt and stain the skin retains. Everyone is different. I've had two ex-girlfriends who were city barefooters. One had very tough soles, like leather and the other had hard callouses. Neither were affected by hot pavement, gravel, glass, etc. And I've seen women with soft soles just as immune to those conditions. Every person is different, and that's what makes us interesting and human!
There are many different salts used to melt ice and a source of big debate in several snowy states around me. Some will leave a slimy residue that I can only imagine attracts dirt when it is on your feet. Others will have chemical reactions with metal or organic material and change the surface of the metal or organic material - think about rusting metal or black carbon from a flame. Many are bad for the water supply and toxic to vegetation. They are not allowed near local reservoirs. Why would they be good for your feet? I have personally been exposed to some salt that caused pretty severe burning of my feet and I had to rinse them off quickly.
Wow, that is not good to hear. Myranya mentioned the same reaction on another post about winter barefooting. I guess nobody considers if it will hurt people or not, because they don't even consider the notion of people not wearing shoes in the winter.
Probably. Also, snow cleans the pollution out of the air and traps it on the ground. The snow melts too slow to wash the dirt away. Rain cleans the air too, but it carries that dirt right on into the creeks and rivers.
I was thinking about this today and was going to post this, but you read my mind. Rain washes the streets, where as snow just sits there and deposits all of it's dirt right onto the street.
The road salts combining with the snow turn it into water, which probably helps loosen a bit of the oil and dirt on the asphalt.
What kinds of vile salts are being applied to your streets ? What you're after is a freezing point depression to keep the ice/snow liquid so it will drain off the road. The old standard was to apply sodium chloride or table salt. The mechanism at play is one of ionic strength causing freezing point depression. Sodium chloride (NaCl) goes into aqueous solution with 2 equivalents of ions (one each of Na & Cl) per equivalent of molecular NaCl. This was replaced in recent years by calcium chloride (CaCl2) which produces 3 equivalents of ions (1 Ca and 2 Cl) per equivalent of molecular CaCl2 when it goes into aqueous solution. The 3 equivalents produce a higher ionic strength versus NaCl which results in enhanced freezing point depression. You can also get the same effect using strong acids or bases, but I doubt the DOT is going to that extreme. The street cracking/potholes that occur in the winter is the result of water seeping into existing cracks and freezing. Water, unlike most other liquids, initially expands as it freezes. This expansion pries open the crack, more liquid water seeps in, freezes, more expansion, crack enlarges, etc. As the ice is further subcooled it will contract, but by then the damage is done. To enhance the effect of the salts, many DOTs are making the salt solutions incorporating a glycol solution (i.e., automobile antifreeze). This is why the salts can be sprayed as liquids opposed to being "flung" as solids. The glycol also accounts for the slimy consistency of the solutions that make them more difficult to remove from your car. As far as burns from road treatments, I guess this could happen from prolonged exposure. Salts have a dessicating effect and suck moisture out of materials. This is why the pioneers used salt for "curing" meat. It would suck liquids out of the meat, make an uninviting environment for microbial growth, and the meat would be preserved for later consumption. If you expose your skin to salts for too long the same mechanism will start to occur. As far as one's feet getting dirtier in the winter, that must be the result of "black ice" LOL!! (Probably desn't mean anything to warm weather folks, but...)
Well as I mentioned in the other post, there are quite a few websites mentioning dogs having trouble, that much is well known. Many Dutch folks own dogs, and people care lots about their pets. Also it's quite well known that salt (even the regular kind) does damage to the environment -the trees lining the road and also wildlife. But people need to be able to keep driving, they have to get to work, the stores have to be supplied, we're also bicycle country and it's no fun riding a bicycle on an icy road, then there's the elderly to think of... Okay, I'm sure they didn't think specifically of barefooters in the snow but even if they did think of it they wouldn't change what they put down on the streets for the handful of folks who keep walking barefoot in icy weather. More so, *I* wouldn't want them to do anything different; I had a hard enough time getting to work as it was, biking only on those streets where they had put down the salt and walking part of the way because many residential streets are not cleared. We live on one of those residential streets and my own mom left the house for the first time in three weeks yesterday. As long as there are thousands of elderly for every one of us, it would be selfish to the extreme to expect folks to use less salt on my account. I'll just use the bag balm and stay on the fresh snow as much as I can.
According to the sites I've read, what is needed after using 'regular' salts is quite a bit of traffic to 'mix' the salt sprayed on top with the snow & ice underneath. If there is too little traffic, like on a quiet road on Sunday morning, the salt will mostly run off to the sides and melt only part of it (especially if it's packed-down snow or ice, rather than fresh snow which of course it sinks in easier with less help). I can't speak for the places where MrEd encountered the 'burning' salt, but the two places I encountered it were places with little traffic -a parking lot and a bicycle shed- where they still wanted to clear the ice for their customers, but probably had to use something more aggressive to melt the ice immediately with little 'mixing'.
My encounter was in a high traffic parking lot right off one of our major highways and it was treated with the same agent as the highway. The pain was immediate and I did not have any cracks in my feet that would have lead to the kind of feeling you get with salt in a wound. Since you had this experience as well (I presume in the Netherlands) I will look into it further and repost - probably later in the week. There are references regarding this type of experience and pets (wonder why not people - LOL). When barefootjaime first posted this, I came across a huge list of what is commonly used in the US and started to look at the MSDS (Material Safety Data Sheets - required in the US) for theses substances. Some of the salts can be highly alkaline and bases can burn just like acids.
I wouldn't think winter feet would be as dirty as summer feet with all of the moisture on the ground either in the form of snow or melted snow. I'd think that would be enough to keep them clean
Magnesium chloride (aka Mag chloride, MgCl2) is another salt commonly used. I don't suspect that would produce burns. As far as MSDS's, those need to be interpretted carefully. They list all kinds of "nasties" for common componds. Look at an MSDS for water or sodiun chloride (table salt). You'd swear they're poisons.
I have a question. I live in the burbs and what u are describing sounds like what would be used on major city streets. Where I am it is very unusual to throw melting agents on sidewalks......no?
It used to be common to put table salt on icy sidewalks and steps - at least when I was a kid. The problem is it can cause the concrete to crack - same mechanism as potholes. A lot of hardware stores sell some type of "Ice Melt" which is usually calcium chloride. I just try to shovel the ice/snow as soon as possible before it gets hard-packed. I'm traveling this week and it's friggin' cold! At home it's 60 deg (15-16 deg C). It's just not fair!!!. My feet need freedom!!!
