Friday, 19 September 2014

By on September 19th, 2014 in Barbara, emergency kits

09:38 – With Barbara leaving at 0400 Sunday morning, I’m trying to keep her from exhausting herself before she leaves. These tours are often physically demanding, with lots of walking. Barbara said she’d stop at the supermarket on the way home from work, then make dinner, then go out and cut the grass. Tomorrow, she’s planning to clean house in addition to all the preparations for the trip. I’m trying to convince her to take it easy.

The second bottle of Polar Pure showed up in yesterday’s mail. The confusion could have been avoided if the vendor had simply stated that the two items would ship separately. Instead, it said they’d ship together in one package and they provided only one tracking number.

Incidentally, I was wrong about using strong Lugol’s solution for water disinfection. As it turns out, the triiodide ion is much less effective than free iodine. I should have remembered that, because I read Iodine Disinfection in the Use of Individual Water Purification Devices several years ago. That PDF is well worth reading if you have any interest in the topic.

The Polar Pure bottles are each supposed to contain 8 grams of crystal iodine. Polar Pure considers this amount adequate to disinfect 2,000 quarts/liters, which means an iodine concentration of 4 mg/L. I’m more comfortable at 8 mg/L or even 16 mg/L, so I think I’ll modify these Polar Pure bottles by adding more crystal iodine to each bottle and updating the instructions to achieve a final concentration in the 16 mg/L range. Alternatively, you can use an unmodified Polar Pure bottle simply by doubling or quadrupling the recommended amounts, which of course cuts the capacity down to 1,000 or 500 liters. Even at 500 liters, that’s still a 250 person-day supply at 2 L/day, which isn’t bad for that small bottle.

Even at the higher concentrations, Cryptosporidium remains a problem. Three interrelated factors affect disinfection effectiveness: iodine concentration, temperature, and contact time. Achieving even a 2-log reduction in Cryptosporidium requires by one source a CT of 1,015 mg-min/L, presumably at 20C. In other words, to kill 99% of the Cryptosporidium oocysts at 16 mg/L, the contact time required would be 1015/16 = ~ 64 minutes. At Polar Pure’s recommended 4 mg/L, a 2-log reduction takes more than four hours. Much better just to boil the water if at all possible.

27 Comments and discussion on "Friday, 19 September 2014"

  1. Adding more iodine to the bottle will make it last longer, but won’t change the amount of iodine that can dissolve in a milliliter of water.

    I measured 6.6 grams of iodine in the bottle I just received. I suppose this is old stock, and the rest evaporated during storage. The instructions say to “keep bottle filled and capped to avoid iodine loss”, so I filled it for storage (despite the desirability of keeping it unfilled so as not to risk breaking from the water freezing).

  2. Robert Bruce Thompson says:

    Yes, of course. Iodine is not very soluble in water, but its solubility differs significantly over the range of 0C to body temperature. That’s why they have the little thermometer on the side of the bottle, to allow users to judge how much iodine is in solution at a given temperature.

    I haven’t weighed the crystals in either of the bottles I received, and I don’t think I’ll bother. I’ll just add more. Iodine’s density if about 5 g/mL, so adding another eight grams or whatever won’t reduce the water capacity of the bottle by much.

    As far as breakage, I’d suggest keeping the bottle filled to a level that’ll let the water freeze without breaking the bottle.

    The main reason I bought these PP bottles wasn’t for me. In that case, I’d just have put some crystal iodine in one of the 30 mL brown glass bottles we use in kits and cap it with a phenolic-cone cap, which does in fact keep iodine from escaping. That’d be fine for me, but these kits may be needed when I’m not there, so it was worth the money to buy the two commercial PP bottles to add to the kits.

  3. Come to think of it, I’m a bit skeptical as to whether filling the bottle with water could really help with iodine loss. For that, the water would have to be more of a barrier to iodine diffusion than the cap is, and that doesn’t seem too likely. Well, I suppose even a modest barrier helps a little.

    Quickly looking up phenolic cone caps, to see if one might be readily acquired to fit the Polar Pure bottle, I don’t see any where the actual cone is made out of phenolic material; instead it’s the bulk of the cap which is phenolic, and the cone is a clear material, probably polyethylene or polypropylene. With those, the iodine could diffuse through the clear stuff and out around the threads. Maybe I didn’t look hard enough?

  4. Robert Bruce Thompson says:

    I’m not sure what the construction is of the phenolic-cone caps we use for solutions that contain iodine, but they work pretty well. We haven’t had any problems with iodine vapor escaping a glass bottle sealed with one of them.

    We formerly used a similar cap, but with a polypropylene body and a flat PE liner. Those work great for anything that doesn’t contain iodine, but iodine vapors escaped through them pretty badly.

    I suspect the success of the phenolic cone caps comes down both to the plastics used and the physical tightening of the cap on the bottle. I suspect that the phenolic resin is impervious to iodine vapor, as is the glass. When the threads are tightened down, there’s not a whole lot of gap for the iodine vapor to escape through. Unlike most caps, you can actually feel resistance as you tighten the phenolic cone ones.

    Incidentally, the permeability of different plastics to iodine vapor varies hugely. Most common plastics like PP, HDPE, and LDPE present little barrier to iodine vapor. If I fill a bottle made of one of those with iodine solution, it’s obvious within a day or less that the iodine is escaping. Surprisingly, PET (soda bottles) is just about impermeable to iodine vapor. I generally make up the iodine solution we use in kits 2, 4, or 6 liters at a time, in 2-liter Coke bottles. One time, a year or more ago, I happened to have maybe 100 mL left and wondered how long it would take to penetrate the Coke bottle. After a year, it hadn’t penetrated at all that I could tell. The white label was still pristine white. The inner surface of the bottle was stained reddish from iodine that had sublimated from the solution and redeposited on the inner surface, but none appeared to have escaped. I actually wondered why Polar Pure doesn’t use PET bottles.

  5. Lynn McGuire says:

    Time to bug out? I saw no mention of zombies in the news.

    Am reading a scifi book, “Under a Graveyard Sky” about an eco terrorist modifying a flu virus and adding a extremely modified rabies virus as secondary payload. The rabies virus causes neurological failure and reversion to the hind brain in most people.

  6. Chad says:

    Sometimes social networking is worth a good laugh…

    #NationalSitOnMyFaceDay is currently a Trending Topic on Twitter. I lol’d.


  7. MrAtoz says:

    Suck it Europe. Oh, yeah, you too Obuttwad.

    Russian strategic nuclear bombers carried out air defense zone incursions across Northern Europe this week in the latest nuclear saber rattling by Moscow.

    Maybe Putin could drop some nukes on those ebola ridden cities in Freaka.

  8. Lynn McGuire says:

    Hey Bob, looks like California took your advice and is using Solar for peaking power:

    I am impressed. Up to 20% of the power used in California during the day is solar. And that power comes on quick. They must be using using sun tracking on their panels.

  9. Threads almost always have clearance, which results in a helical leakage path. When they want to seal threads (as in pipe threads), the way it’s done is to use a tapered thread plus sealant. Using tapered threads means you can have diameter tolerances, rather than having to make everything of precise diameter so as to fit together without gaps. The sealant fills in the inevitable gaps due to surface imperfections. So I suspect the greater resistance you find from phenolic caps is due to the phenolic not being as slippery as other plastics, or perhaps from it being stiffer, not from the threads forming any real seal against the glass. The helical leakage path is narrow, no doubt; but being filled just with air, it’s much less of a barrier to diffusion than is any plastic. Sealing is mainly done by the plastic liner at the top.

    Of course it still does help a lot if the cap itself is impervious; that way leakage through the liner has to go through the liner the long way (through a plastic passage maybe 3mm long and 1mm high) and then out through the clearance in the threads, not merely through the liner the short way (the 1mm direction) and then through the cap itself.

    With the science kits, you’re dealing with a shorter storage timescale than for survival kits, where one might assemble a survival kit, stash it away, and then use it a decade or two later. So whereas in the science kits you might need to avoid polypropylene caps, in a survival kit even a polypropylene cap liner might be too much.

    The Polar Pure bottles come with what looks like an aluminized cap liner, which presumably also is pretty impervious (until, perhaps, the iodine oxidizes holes in it).

  10. MrAtoz says:

    Ruh Roh! Here come the PRC riots in New York.

    Shop now if you depend on food stamps or cash assistance from New York.
    Neither will work starting early Sunday morning. The system will go down at midnight and isn’t expected to come back online until noon Sunday.

    1/3 of people in NYC are on foodstamps.

  11. Lynn McGuire says:

    1/3 of people in NYC are on foodstamps.

    Wow! 15% total of the nation but twice as high in NYC. Something is really wrong there.

    I know, replace food stamps with one 2,000 calorie MRE per day. At least I will be able to buy the MREs on ebay.

  12. OFD says:

    “Barbara said she’d stop at the supermarket on the way home from work, then make dinner, then go out and cut the grass. Tomorrow, she’s planning to clean house in addition to all the preparations for the trip. I’m trying to convince her to take it easy.”

    Sounds like Mrs. OFD before the plane rides all over the country. Always tries to do a million things at the last minute and has all million going on at once. Then is utterly exhausted to the point she can’t even sleep at night.

    “…The system will go down at midnight and isn’t expected to come back online until noon Sunday.”

    Yeah, noon the FOLLOWING Sunday, maybe. And the panic will not only be in Babylon On The Hudson but also “Upstate” and the “North Country” of the state, as well as out in the ‘burnt-over district’ that is fah more like the Midwest than the city.

    Hey, Mr. SteveF: Lock and Load, dude! Batten down the hatches.

  13. SteveF says:

    Lock and load? Why would I do that? I feel nothing but sympathy for the poor, vastly-put-upon victims of systematic racism and other abuse.

  14. Chuck W says:

    Hmm. We in broadcasting move whole stations without ever having any downtime. Zero downtime. Why is it the US government cannot learn how to do that? I remember when my brother worked for the VA. He was at the center they called ‘the drug store’. One of his co-workers was always wanting to take the system down for software upgrades that often did not work out, then they could not get this national system back up. My brother would get a call at 03:00 and have to go in and get the previous software iteration going again before 06:00 when they HAD to be back online, as surgeries started then and the drug store had to be back up for them. That happened repeatedly, but his boss would not force their unit to construct a testbed system, instead of going online untested. So he left the VA for the Fed. They did not test new software online there.

  15. SteveF says:

    Many NYS state agencies have problems with database backups. It’s frequently “necessary” to take the Oracle database offline for four hours or more to back it up. Restores often don’t work, and the attempt takes at least a full working day.

    I’ve never seen this kind of difficulty with private firms which use Oracle databases. Or any other non-Microsoft database, for that matter.

  16. Jim B says:

    What, no pirate talk?

  17. SteveF says:

    I was doing Talk Like a Pirate Day before it became cool. Now it’s all commercial ’n’ shit.

    My sister’s birthday is today. How cool is that? Alas, she’s not cool enough to do the whole talking like a pirate thing. How uncool is that?

  18. Lynn McGuire says:

    Today was take your dog and cat to work day so that the house can be flea bombed. The wife is now home venting the house.

    I now have one less business casual short sleeve oxford shirt. A 15 lb Siamese male cat can really twist around while walking down the hallway. And those claws really shred light 100% cotton fabric.

  19. OFD says:

    I would have had to take the dawg and three catz to work; the dawg woulda sniffed around for a while and then curled up and gone to sleep. Ditto the two adult catz. The runty female cat would have been all over the place and probably shut down the servers and the network while bouncing off the walls.

    Incidentally, Mr. Lynn, pretty much any cat can shred shirts and pants and socks very easily. Also birds, one of which I found on the dining room rug this morning. Barely identifiable as such. The clue was the scattered feathers.

    40 degrees here now and dropping. Leaves really starting to turn. This being the last coupla days of summuh….

  20. SteveF says:

    My neighbor had an injured feral cat in his garage some years ago. He was an older guy with a bad heart and a young daughter, so I went in to get the cat out and preferably get it into a cage. No dice. My reflexes are much better than human normal*, but that injured cat was moving so fast I could barely track it, let alone get a good grip on it. I could barely protect my face once it decided I wasn’t going to leave it alone. It bit through my heavy leather work gloves several times and shredded the flannel shirt I was wearing, along with part of my arm. Yes, that pussy licked me.

    * More than thrice normal when was in college, but I’d certainly slowed down by my late 30s. It was funny when the grad student tech was measuring them. He kept having me do the tests over because I couldn’t be as fast as was being measured. Finally called the professor over to supervise and, yup, they were that fast.

  21. Chuck W says:

    Remember that kid at Purdue U who killed another one early in the year? He admitted the crime. Apparently, killed the other guy in the presence of witnesses and tortured the other kid before finally killing him.

    Two doctors testified he’s severely mentally deranged, but guess what? He’ll be 65 years in prison, not in a mental institution.

    Motive seemed to be that the deceased flunked the killer, but tried to help the killer with lab experiments when the killer was having trouble. Apparently, the killer could not stand to be bested or helped.

  22. Jim B says:

    No fleas here. Not sure why.

  23. Jim B says:

    Didn’t get the memo about Talk Like a Pirate day. Sad.

  24. Lynn McGuire says:

    No fleas here. Not sure why.

    Come over to the Land of Sugar. We have spares.

  25. OFD says:

    That was pretty funny, Mr. Chuck, thanks, I need a laugh after today.

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