Chemical composition of playa dust?

[Rev. Harry Pants]

Does anyone know the basic chemical composition of playa dust? What is the predominant alkaline molecule(s) present? I ask this because I have an idea for a no-rinse, alcohol- and detergent-free disinfectant washing solution formulated to neutralize excess alkalinity and be a potential cure for/prophylaxis against playa foot.

[phil]

See if this helps:
http://www.foresight.org/Conferences/MN ... /Gillett1/

See Table 2; "BRP" is black rock playa.

[spoteditor]

any luck with your formula?

[Eric]

See if this helps:
http://www.foresight.org/Conferences/MN ... /Gillett1/

See Table 2; "BRP" is black rock playa.

wow.
That has got to be the most detailed analysis of the chemicals making up the playa I've ever seen.
I'm bookmarking it since this question seems to get asked regularly.

Thanks Phil!

[Rev. Harry Pants]

Ho-lee shiznit... That's a pretty detailed analysis. The table was somewhat helpful to give me an idea of what makes playa dust caustic. The following is my interpretation of the data...

Oxides of Group I and II alkali earth metals such as lime (calcium oxide), potash (potassium oxide), magnesium and sodium oxides seem to be present in abundance; their combined presence comprises 13.08% of playa dust. Also according to the analysis, phosphoric anhydride (P2O5) is present, but in considerably more miniscule amounts (0.19% versus 4.51% alone of CaO, the most prevalent alkali). When phosphoric anhydride is combined with water, it forms phosphoric acid. Clearly this is not enough to significantly neutralize the alkalinity of these hydroxides (which is, if my high-school chemistry serves me correctly, what forms when those oxides come into contact with water). Because the water isn't cold by the time it gets a chance to react with the alkali earth oxides (it, for argument's sake, is essentially sweat at or near body temperature), the resulting compounds are not as caustic as they could be, but yet playa foot *is* a reality.

As for the playa wash formulation, I still haven't taken delivery on any citric acid, but soon come. I will keep one and all posted.

[Grizelda]

Is there a reason why just using vinegar would somehow be wrong? Why does a playa foot wash need to be a disinfectant?

[theCryptofishist]

No reason that I know of. I guess there are some hardy bacteria that do live in the dust. The ESD footwash is, to the best of my knowledge, simply vineger and water. It's possibly more important to keep your feet in good condition so that the bacteria don't ahve a chance to get under your skin and infect you than it is to kill all microbes just because we can. (Or kill as many as we can.)

[Rev. Harry Pants]

I am less concerned with the extremophiles (microbes that withstand harsh conditions such as on the playa or -- for a more dramatic example -- alongside the volcanic vents at the bottom of the ocean) than with E. Coli, S. epidermidis, S. aureus and the plethora of more common wee beasties that can give one a case of the trots or worse due to unsanitary conditions. This is why I am formulating the playa wash. One of its functions is to counteract the caustics that cause playa foot, the other is to be used as a general hand and body wash in lieu of alcohol-based hand sanitizer.

Citric acid solution was used to disinfect boots, shoes and other items that came in contact with the ground during the Great Hoof & Mouth Epizootic of 2001 in the British Isles. It stands to logic that it can be used as a mild topical skin antimicrobial in addition to a neutralizer of alkalines. What pathogens the citric acid doesn't take care of, the tea tree & lavender oils will. Sure one could use vinegar, but let's face it: vinegar starts to smell obnoxious after a while.

My research is still underway. Thanks all for your continued input.

[Lysergic]

Frankly sounds like a great idea to me, best of luck with your project!

[bill_adams]

Hello fellow burners. I invented the vinegar foot wash several burns ago. It has become a playa standard. I have been using seltzer water (carbonic acid) for the last two years, instead of vinegar, and the results are great. Some burners still love the vinegar as it is soothing and fast. It takes twice as much seltzer water as vinegar to dilute the harsh alkali, so use twice as much. I did my research on the playa, and yes, I brought my chem lab to the playa to see real time results. I was interviewed by the official black rock newspaper last year and demonstrated my lab setup to the reporter. I also wrote the post you read in the burningman email list.
See you all at the playa!

[geekster]

I am less concerned with the extremophiles (microbes that withstand harsh conditions such as on the playa or -- for a more dramatic example -- alongside the volcanic vents at the bottom of the ocean) than with E. Coli, S. epidermidis, S. aureus and the plethora of more common wee beasties

What I am more worried about isn't the bacteria that is actively living but the spores that are mixed in with the dirt. Things such as anthrax (occurs naturally in a lot of California and Nevada, particularly where there are animals such as sheep) spores can be blown by the wind and remain dormant for years until coming into contact with the right environment and sprout. Legionella is the same way, is dormant spores in soil until the dirt contacts the right conditions.

The good news is the black rock desert gets a good bit of UV which tends to kill even most spores.

[shLong]

Apparently this thread is destined for a fresh bump every 5 years, so I'll try my hand at this..
Another member linked me here and I have an additional question after I've read the composition materials involved.
Perhaps there is a lingering geologist about.. Idk...

Did the prehistoric lake that was once here deposit the dust, or is it bedrock ground down, or what's the story with its origins...???
Thanks in advance.

[Eric]

Did the prehistoric lake that was once here deposit the dust, or is it bedrock ground down, or what's the story with its origins...???
Thanks in advance.

Honestly, the answer to this is "yes", for the most part. The playa "dust" (actually more of a clay) was deposited over centuries as weathered rock from the surrounding mountains was fed into the lake by streams & rainfall, and it's composition is that of the mountains it formed from. This link will take you to a .pdf that's a history of the geography of the area.

[shLong]

Excellent!

I find that really fascinating. We have nothing like that (a playa) in my area, and between the playa and the salt flats driving thru Utah, a lot of things came up in my head... And I guess it's taking me this long to finally quench that.

Thanks again, Eric

[BetaBox]

My quick article on the buffering capacity of playa:

[mdmf007]

No reason that I know of. I guess there are some hardy bacteria that do live in the dust. The ESD footwash is, to the best of my knowledge, simply vineger and water. It's possibly more important to keep your feet in good condition so that the bacteria don't ahve a chance to get under your skin and infect you than it is to kill all microbes just because we can. (Or kill as many as we can.)

we use a 10% solution of vinegar / water.

[digital]

we use a 10% solution of vinegar / water.

I do something similar but in a spray bottle. Works great.