Shelf life of Selenium Toner working solution

Discussion in 'B&W: Film, Paper, Chemistry' started by Holly Gettings, Jun 7, 2005.

  1. Holly Gettings

    Holly Gettings Member

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    I discovered some selenium toner working solution while cleaning out my school darkroom for the summer, and since it is dated May 2003, I wonder if it is worth keeping or should I discard it. I have plenty of concentrate. The solution hasn't been used much: perhaps 4 large prints were toned at the time I made the batch.

    Any ideas out there?

    Thanks,
    Holly Gettings
    Belmont Hill School
     
  2. Tom Stanworth

    Tom Stanworth Member

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    I keep the working solution for ages, but not 2 years! It seems to go on working forever. When it becomes too slow, I chuck it. Try it on a scrap print....or smell for the ammonia smell. If the smell aint there its dead. It'll cost peanuts to mix fresh, so why not chuck it anyway?
     
  3. ann

    ann Subscriber

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    just test it and see what happens.

    when getting rid of selenium toners, we place a couple of old prints in a tray and let them sit there for about a week.

    Putting active selenium back into the environment is not a good thing, IMHO
     
  4. Tom Stanworth

    Tom Stanworth Member

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    Does anyone know what the consequences are to discarding selnium toner? Pouring things into the soil is generally much more sensible than down the plug hole I would imagine.....

    I realise selenium is an element and in trace quantities rather important to stave off death, but in the form of toner, what harm does it cause if discarded? Ansel seemed happy to dunk his hands in it...can't say I have ever felt the same way.

    Some say the smell is of ammonia and that the selenium itself does not get airborne/gaseous. True or false?
     
  5. Dave Miller

    Dave Miller Member

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    Mine goes on the roses.
     
  6. BWGirl

    BWGirl Member

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    Ermmm... might be a good time to point out that Ansel is dead. :wink: Oh sure, maybe all those chemicals leaching into his skin had nothing to do with it, but hey! Why tempt fate?? haha :smile:

    I'd be interested to know how your experiment turns out with the old selenium toner, Holly!
     
  7. Tom Stanworth

    Tom Stanworth Member

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    So that's how prize winning roses with 800 petals are made!
     
  8. Bob F.

    Bob F. Member

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    Can't speak of the safe disposal, but the ammonia smell is courtesy of the ammonium thiosulphate that is part of the formulae. Presumably, as the fixer oxidizes or otherwise dies, so too will the speed of toning?

    Bob.
     
  9. ann

    ann Subscriber

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    things are relative, we use a lot of selenium so i would rather error on the conversative side. I have heard of using the "spent" toner on the roses, and i trust Donald and his informtion.

    There are a lot of products on the market that we use daily that contain selenium with no side effects; however, toners contain very toxic chemicals so better safe than sorry.

    Do i worry if i splash some selenium on my person; of course not, but i do use and expect my students to wear nitile gloves.
     
  10. Bob Carnie

    Bob Carnie Subscriber

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    I agree with Ann , do not dump selenium down the drain.
    As a matter of fact when my lab was checked by the city environmental officers , selenium was not advised to be dumped even into the recovery systems. The company that recovers the silver from our unit has given us separate bottles for selenium capture which they take away.

    This topic always comes up and I for one would love to hear the straight goods on photographic disposal.
    There seems to be quite a few brainiacs on this forum with degrees in chemistry . Would not one of our esteemed experts take on a project to sort out the do"s and don'ts of chemical removal .
    I am not one of these experts , but since using a large volumne of chemistrys I would like to know more. I think I am disposing saftley but I am not totally sure.
    I do wear gloves with selenium (I do not know why) and I don't in Dectol (once again I do not know why).
    I think a list of our common ingredients and theirproper usage and disposal for printing negatives and toning would an excellent article.
     
  11. Jorge

    Jorge Inactive

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    The do's and dont's of disposal have nothing to do with safety and more to do with local environmental regulations. If you are a bussiness (as is the case of Bob) you are most likely SOL. You have to arrange for proper disposal. If you are a hobbiest, then you most likely fall under the household excemption. As others noted above selenium is a wonderful fertilizer in small quantities, but most importantly you have to remember that selenium toner has other ingredients like Ammonia and sulfur, also good for your plants.

    Selenium toner will last for years, so it can be used even after 2 years of storage. Ann's suggestion is a good one, with one modification, the print has to be exposed and developed and then placed in the toner to exhaust the selenium.

    In Holly's case, since this is an university, it is most likely that it is governed by environmental laws just as any bussiness. If so the two choices are to arrange for disposal (which most likely there is already a program in place, contact your chemistry department) or trying to exhaust the selenium and then dump the remaning solution. If it was me, I would try to avoid hassles and cover my ass and would contact the chemistry deparment and would ask them what are they doing with their chemical waste, I am sure they already have a program in place for disposal and most likely will take the jug of selenium toner off your hands.
     
  12. avandesande

    avandesande Member

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  13. Ole

    Ole Moderator Staff Member Moderator

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    Selenium is already in the environment, and is a necessary trace mineral. So are cobalt, molybdenum, copper, arsen, and just about every other element. Like all other trace nutrients, selenium is poisonous in high concentrations. If you look a bit more closely at the link provided, it deals with ppm and ppb of selenium, not per cent. Confusing these terms can be very, very dangerous.

    It's not a question of how much you dump, but how well you disperse it.
     
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  15. avandesande

    avandesande Member

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    The average family puts 500,000 # of water down the drain each year. If you dump a pound of selenium(that is a LOT of toner) down the drain that is 2ppm. Probably only 1 in 1,000 people have a darkroom in their house. I stand by my statement about a darkroom (at least a home one) not effecting the environment. I am not confused by PPM.
     
  16. Ole

    Ole Moderator Staff Member Moderator

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    Provided you dump it gradually over the full year.

    I'm not saying you shouldn't pour selenium toner down the drain, I'm just saying you should think about where it's going and how it gets there.

    There are still lots of houses where waste water goes to infiltration in the ground, or through (small) local septic tanks. I wouldn't say that selenium is "harmless" in any of those cases.

    But with large central sewage treatment plants, or even unprocessed to sea, it won't do (much) harm.
     
  17. avandesande

    avandesande Member

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    from kodaks papers...

    Note: Observe the precautionary information on all
    chemical packages. The active ingredient in Rapid Selenium
    Toner is a sulfite salt that has a concentration of less than 2
    percent. Working solutions of the toner generally contain
    less than 1⁄2 percent selenium sulfite. These selenium
    concentrations are not considered hazardous when you
    handle the solutions under normal conditions. However, we
    recommend that you use print tongs and wear clean rubber
    gloves when you use this toner. If toner splashes onto your
    skin, wash immediately with plenty of water.
    If the prints you plan to tone are already dried, rewet them by
    immersing them in a fixing bath, and then rewash them.
    Otherwise, staining may occur.


    So your working solution is already down to 200ppm(roughly corrected by MW). As it is exhausted I am sure that it is much less than that. So your tray has 50ppm when you dump it down the drain.

    Ole is correct in stating that each situation is different and it should be handled with respect. I just hate the blanket statements that we are killing the environment when we dump spent toner down the drain.
     
  18. Mongo

    Mongo Member

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    Two points:

    First, I never mix fresh selenium toner. As my toner gets exhausted I just keep adding concentrate as necessary. About once every six months I drip the solution through a paper coffee filter. This method has worked fine for me so far.

    Second, regarding pouring spent toner down the drain. Comparing the ppm of the toner that one (or several) home darkroom workers pour down the drain as a part of the overall waste that's put down the drain by the entire community over a year is, at best, an unrealistic way to determine the impact you'll have when you dump your toner. The question you should ask is: Will pouring a given volume of toner at a given concentration down the drain cause a problem for my local sewage treatment facility or with my personal sewage system (i.e., septic system)? Unless someone here is a specialist in one of these fields, I think we should leave the determination of the impact to the experts. But you can always avoid the problem by just continuously replenishing your toner.
     
  19. ann

    ann Subscriber

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    i am not sure where the "blanket statement that we are killin the environment" is coming from, i must have gotten lost in the comments.

    I know i did not say that, what i said was i didn't think it was such a good thing to do, and this is based on the situation i am in with a teaching environment.

    I made the decison to deplet the selenium by placing prints in the tray and letting themd sit for a week; the amounts we are using are not the norm that one person would have in a small 1 person darkroom.
     
  20. SkipA

    SkipA Member

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    ann, what then do you do with the selenium-impregnated prints? If it goes in the garbage and into the landfill, doesn't it still get into the environment eventually?

    I just dump my spent selenium toner down the drain, but if your method is really better, I'll start doing it that way. Or dump it on my rose bushes. I use so little of it, though, that it may not make a difference one way or the other.
     
  21. Tom Stanworth

    Tom Stanworth Member

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    At the end of the day, if some people take a very cautious approach that cannot be a bad thing......
     
  22. AllanD

    AllanD Member

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    I don't like the idea of selenium on the garden. If in years to come someone grows cabbages or one of the many other types of brassica on this plot, then these will draw the selenium out of the soil and concentrate it in a food crop. Brassicas are used in this way to clean up old industrial sites. In certain places (Stroud in the UK for instance, although it is cadmium in this case), residents are advised not to grow these crops for fear of concentrating naturally occurring poisonous metals in their food crop. The problem is that this kind of contamination can remain in the soil for years.
     
  23. Tom Stanworth

    Tom Stanworth Member

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    Yes fair point in theory, but it is a matter of concentrations and total quantity. The concentrations of toxic substances in the soil in industrial sites as well as the quantity over the whole site as a whole can be absolutely enormous! I dont think a private user dumping a few lites of working solution every 3 months into the hundreds of tonnes of soil in his back garden can be compared. Wouldn't the selenium would distribute istself far and wide and thus become even more dilute than it already is? We need an industrial land reclamation expert!
     
  24. ann

    ann Subscriber

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    Skip,
    that is a good question. The prints are washed after the selenium has stopped working and thrown away.
    The selenium converts the silver to silver selenide, so it isn't the same as just tossing out active selenium.

    I think the whole question comes down to how much selenium is being discarded, not that it is discarded.

    As with most other things in life, one makes a decision based on their own experiences, and their beliefs . Which means there just isn't one way to do things.

    Holly asked a good question about something she knew nothing about, she nows has a variety of answers which should help her decide what she needs to do.

    As tom suggest "if some people take a very cautious approach that cannot be a bad thing" . That is the road we take at our lab. Is it for everyone? That is up to the users.
     
  25. Bob Carnie

    Bob Carnie Subscriber

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    I agree with being careful with spent chemistrys and pass these onto the reclamation experts.
    Volumes of chemistry seems to be a problem here. I have a lab enviornment, therefore I would assume I use more chemistry than most. But in the GTA (toronto) there are numerous private darkrooms in homes , surrounding me. If lets say 4 of these darkrooms are active on a weekend and start producing shows or portfolios for themselves , they then would be producing more spent chemistry than my lab. Is it ok to dump since each darkroom is a hobby enthusiast ??
    Any one working with our craft chemicals should be fully aware of any potential harm that these chemicals can cause inside and outside of their darkrooms. Sadly there are so many different arguments for or against dumping.
    I will say this , my Honey is a gardener and printer, if she starts dumping the spent selenium on our radishes I think Im out of here.
     
  26. Jose A Martinez

    Jose A Martinez Member

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    how you know when selenium toner is exhausted?

    How?