Disposing of stains from home microscopy lab

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MikeBradley
Posts: 105
Joined: Sat Sep 22, 2018 4:29 pm
Location: Sunshine Coast, BC, Canada

Disposing of stains from home microscopy lab

#1 Post by MikeBradley » Sat Oct 19, 2019 4:29 am

I wonder how other amateur microscopists manage stain disposal? What are the protocols? My lab is my office and it has no sink or running water. Our waste water goes to a community septic system.

I will soon start using plant stains including safranin, toluidine, meth. blue, eosin and I'd like to set up safe, practical disposal. Do you combine several days/weeks worth together and then take to hazardous waste disposal? Or is it safe to flush in the sink with copious volumes of water? What else? Thanks for any tips.
Michael
Olympus BH2,
AO110
Carl Zeiss Standard WL
Canon 90D

Hobbyst46
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Re: Disposing of stains from home microscopy lab

#2 Post by Hobbyst46 » Sat Oct 19, 2019 11:53 am

Some ideas from my limited experience. I use stains only occasionally.
1. Try to make only a small amount of stock stain solution. The appropriate concentration of the dye (solid/water, weight/volume) is of the order of 0.1% (at the most IMHO). Stock solutions might be of the order of 1%.
2. If one wishes just to make the strongly-colored solution colorless, the way is dropwise addition of home bleach (a solution of hypochlorite). The resulting liquid is still waste, possibly hazardous although the hazard differs from that of the original colored liquid.
3. The way to remove the original dye from solution is by absorption or adsorption onto a solid matrix. There are several potential solid materials for this purpose. I just tried vermiculite. This inexpensive stuff is fluffy grey granules that find use in plant nurseries. Non-toxic, non-corrosive, non-flammable, no expiration date, simple to store at home in a closed bag. It avidly absorbs water and adsorbs the dye from it. Tried it with methylene-blue and neutral-red and it works. The adsorbed dye does not leach back into water (mostly).
Pour the unwanted dye solution onto the vermiculite in a cup or small bowl. Shake to just disperse the liquid among the granules. Action is immediate. The used vermiculite can be dispensed as solid trash (local dump or hazardous waste according to location, habit, local rules etc).
4. When handling stain solutions, protect the surrounding from splashes.
Zeiss Standard GFL+Canon EOS-M10, Olympus VMZ stereo

MicroBob
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Location: Northern Germany

Re: Disposing of stains from home microscopy lab

#3 Post by MicroBob » Sat Oct 19, 2019 12:54 pm

Hi Mike,
It's a good idea to think about this before producing the waste. In my view proper waste disposal is the main reason to limit the use of chemicals in the home lab. Microscopy recipes have been developed without much concern for environmental issues so it is a good idea to think about what is really appropriate today. At the same time I wouldn't make too much fuss about minimal quantities of substances that are released into the environment when at the same time similar substances are released into the environment by industry in huge quantities. So it is always a consideration that should be based on solid information.
When you google for methylene blue: https://de.wikipedia.org/wiki/Methylenblau You get (only in the german version?) the H an P sentences that describe the health and protection recommendations. In this case: Don't swallow it. If you are a rat, don't swallow more than 1,18g per kg, or you will die. So this is not a terribly dangerous subsance and I would release it into the sewer or let it soak into wood chips, sand, kitten litter or as Doron suggested, vermiculite, and throw it into the bin.
In typical microscope recipes you will find really dangerous substances next to harmless substances without any note about the difference. So it is a good idea to make a list of what you intend to use and check.

Bob

Tom Jones
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Re: Disposing of stains from home microscopy lab

#4 Post by Tom Jones » Sat Oct 19, 2019 4:31 pm

Mike,

Go to the manufacturer's (or any manufacturer of the stain) web site and look for the Safety Data Sheets/Material Safety Data Sheets. They contain all of the relevant safety and disposal information.

See for example: https://www.tedpella.com/SDS_html/19451_sds.pdf

The stains mentioned are in use constantly in clinical (hospital) labs and disposed of into the sanitary sewer system.

For confirmation, call your local hospital microbiology and histology labs and ask them. There *might* be a local restriction or two depending on the sewer system, but it's really unlikely.

If you use xylene for anything, that probably won't be okay into the sewer.

Tom

Wes
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Re: Disposing of stains from home microscopy lab

#5 Post by Wes » Sat Oct 19, 2019 4:43 pm

I would filter the stain solutions through activated charcoal. It worked for coomassie brilliant blue so it's very likely to work for you too. You can also add a little bleach or potassium permanganate to oxidize the dyes.

mnmyco
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Re: Disposing of stains from home microscopy lab

#6 Post by mnmyco » Sun Oct 20, 2019 2:42 am

Oxidizing can produce even worse chemicals. For instance, bleach and ethidium bromide makes much worse chemicals than ethidium bromide. California actually allows 9 ng/L of ethidium bromide in the normal sewer system in some cities. I doubt you produce enough to cause any harm however you dispose of them, but I imagine the safest bet is a professional incinerator meant for burying waste chemicals.

Wes
Posts: 630
Joined: Sat Mar 09, 2019 12:58 pm

Re: Disposing of stains from home microscopy lab

#7 Post by Wes » Sun Oct 20, 2019 12:18 pm

mnmyco wrote:
Sun Oct 20, 2019 2:42 am
Oxidizing can produce even worse chemicals. For instance, bleach and ethidium bromide makes much worse chemicals than ethidium bromide. California actually allows 9 ng/L of ethidium bromide in the normal sewer system in some cities. I doubt you produce enough to cause any harm however you dispose of them, but I imagine the safest bet is a professional incinerator meant for burying waste chemicals.
Ethidium bromide is demonized but in reality I have not seen any actual data to suggest it causes cancer and birth defects. I am highly suspicious of biotech supply companies that propagate the myth in order to sell their supposedly safer alternatives, which in reality are way more toxic than ethidium bromide. I do agree with you that bleaching it could generate worse things.

mnmyco
Posts: 144
Joined: Tue Aug 28, 2018 11:03 pm

Re: Disposing of stains from home microscopy lab

#8 Post by mnmyco » Mon Oct 21, 2019 3:13 am

No, it does. There was a paper published on it. If I can find it again I will post a link. I refuse to stop using it. I mean I’ve had to regularly work with KCN and NaCN. If I can protect myself from exposure to those I think I can for EtBr as well.

MikeBradley
Posts: 105
Joined: Sat Sep 22, 2018 4:29 pm
Location: Sunshine Coast, BC, Canada

Re: Disposing of stains from home microscopy lab

#9 Post by MikeBradley » Mon Oct 21, 2019 3:36 am

Thanks everyone for the helpful replies. I had not considered absorbing the stains onto suitable materials for solid disposal but I think that’s the way I will go. The vermiculite suggested by Doron is what I intend to try first. I’m only simple exploring plant sections so I won’t be dabbling in the exotic DNA/RNA or fluorescence stains.
Michael
Olympus BH2,
AO110
Carl Zeiss Standard WL
Canon 90D

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