Lab Recipes
Read this document first. Although the heavy metal soak protocol consists simply of adding a microliter of heavy metal solution to a crystal drop, you must know the basics of heavy metal handling and disposal BEFORE you reach for your first heavy metal compound. These heavy metal rules are very similar to radioisotope rules. Whether radioisotope or heavy metals, you must be introduced to these materials. For protection of yourself and of everybody around you, you may not spontaneously jump into using them. You might as well read this document starting at item 7 because you can't properly use heavy metals without planning at the outset for their disposal.
Toxicity information is available for just a few of the many heavy metal compounds in our collection. That means that the compounds range from "known to be spectacularly toxic" to "toxicity unknown because nobody ever tasted it." You should use the heavy metal compounds assuming that all of them are insidious toxins, and treat them with great respect.
A listing of heavy metal compounds in our collection is available at
http://www.doe-mbi.ucla.edu/~dha/heavy_metals/heavy_metals.html
but should only be visible from inside the MBI domain.
The compound numbers refer to stickers on the caps.
Please search the list rather than lifting up every bottle.
Lately, most people use heavy metal stock solutions prepared by Cameron Mura or Mike Sawaya, rather than by directly handling the dry reagents as discussed in the following sections. Users of these pre-made solutions should package heavy metal contaminated tips, Kimwipes, etc. as described below (items 7-10). Cam Mura's labelling scheme follows the cap numbers in the above listing. For example, "Hg 40" means mercuric chloride. Return Cam Mura's heavy metals box to Mike Sawaya or Dan Anderson; never leave it lying around just because it's more than 4 Angstroms away from your immediate agenda.
Do not leave anything near the microscopes. Unidentified chemical-looking items left adjacent to the microscopes are assumed to be heavy metals, because that's one of the primary reasons why 1.5 ml centrifuge tubes of chemical-looking contents arrive adjacent to this lab's microscopes. We can't dispose of unidentified chemical-looking items.
Heavy metal handling.
- Do your heavy metal work to completion and without interruption,
including clean-up.
Do not rush through a heavy metal
experiment to get somewhere else or to answer the phone.
Focus your attention on the heavy metal experiment and nothing else.
- You must handle the heavy atom compounds wearing gloves,
lab coat, eye protection, and closed-toe shoes.
Wear gloves even to look at the bottles.
If you must touch doorknobs while handling heavy metals,
take off the gloves, or get somebody to open the doors for you.
UCLA safety rules prohibit walking through hallways wearing gloves.
When you take off the gloves, they go to hazardous waste, not the trash.
Do your work on top of a bench protector sheet, paper side up. The sheet will catch any splatters and drips, same as in radioisotope handling. The bench protector sheet is disposed of as hazardous waste, along with the gloves, pipet tips, etc.
-
Use our dedicated heavy metal spatulas and glassware for heavy metals.
Glassware and spatulas used for heavy metal experiments
are contaminated forever.
Do not return them to general circulation.
Clean the heavy metal spatula with a wet Kimwipe.
The contaminated Kimwipe goes into a plastic bag
as dry waste (see disposal section, below).
Please do heavy atom experiments in well labelled crystallization trays,
whenever possible.
If you must use new glassware, clearly label it,
and keep it completely separate from
non-heavy metal glassware.
If a heavy-metal contaminated item goes into general circulation,
we will have to trash all the beakers and spatulas to make sure that we
eliminated the dirty one. This will shut down the lab for weeks and you
ought to be
fired.
-
Weigh heavy metal compounds on weighing paper, or
into centrifuge tubes on top of weighing paper.
Use the analytical balance (the one with an enclosure),
not the top-loader.
Many of these compounds
are corrosive to the balances, in addition to poisoning
all subsequent experiments and experimentalists.
If you spill any, clean up immediately (or else).
Heavy metal clean-up materials almost always go to heavy metal dry waste
(see disposal sections, below).
- Use only minimal amounts of heavy atom compounds.
Try to keep heavy metal experiments far below 1ml,
using at most a few milligrams of heavy metal compound in a stock
solution.
The volume of toxic solution and disposal bulk (that we have to pay for) may be minimized by
soaking the crystals on the tops of Micro Bridges or in drops hanging
from cover slips, rather than in the wells of crystallization plates.
- Special handling:
Moderately volatile mercury compounds such as methyl mercuric chloride are stored in a sealed box. Open that box in the hood and handle these compounds in the hood as much as possible. That means crossing the hallway carrying an unopened but probably externally contaminated box of mercurials. This is easiest done by two people, one operating the doorknobs without gloves. Methyl mercuric chloride leaks through vacuum grease, so don't inhale adjacent to the soak container.We no longer have dimethylmercury or tetraethyllead (probably permanently), but we still have separate documentation for them, for the old capillary mount method:
http://www.doe-mbi.ucla.edu/local/recipes/DMM.html
Osmium tetroxide is also volatile, and should be stored in the same kind of vials as dimethylmercury (Pierce Chemical/Thermo "Reactivials" with teflon cap liners).
Uranium and thorium compounds are radioactive, not just toxic. They are available for use only through negotiation with me (Dan Anderson), and I am going to micromanage your experiment.
Disposal of and planning for disposal of heavy metal wastes.
- The current heavy metal segregation rule says to
keep mercury and lead compounds separate.
If you do a binding assay
via native gel shift,
don't put lead and
mercury into the same gel.
Keep track of how much of each heavy metal
reagent is in each container.
Each compound has to be individually listed on the disposal tag;
you may not just say "mercurials."
To minimize disposal costs, segregate the concentrated wastes
such as stock solutions from trace contamination wastes such as Kimwipes.
-
Whatever form the wastes take, one of us with the password and
hazardous waste disposal training certificate have to fill in the blanks
on an online "Hazardous Waste ID Tag"
and attach the tag to each bottle,
tube or bag.
We have 90 days to dispose of the waste after the first
atom goes in the waste container. The spirit of this regulation
is that disposal has to happen while somebody living remembers what it is.
-
Collect liquid heavy metal wastes into
screw-cap containers
to take to hazardous waste disposal.
Lead and mercury should not be in the same container.
Stock solutions in 1.5 ml centrifuge tubes may be placed inside
larger screw-cap tubes (such as 50 ml Falcon-style tubes)
for disposal.
- Heavy metals in crystallization plates.
If the heavy metals are on cover slips on crystallization plates, place the cover slips into 50 ml conical Falcon-style centrifuge tubes (lead and mercury separate).
If the heavy metals are in MicroBridges, pull out the bridges and place them into zip-lock plastic bags (lead and mercury separate).
Disposal of an entire crystallization plate containing heavy metal in the wells is quick and easy but expensive because of the bulk. If a heavy metal tray has already dried out at the time of disposal, it qualifies as "dry waste", so put it into a zip-lock bag, close the bag, then double-bag. -
Disposal of dry soft things:
Weighing paper, paper towels, gloves, and other dry non-sharp wastes
contaminated by tiny amounts of heavy metals
should be placed into zip-lock bags (lead and mercury separate).
Mark the bag with what's in it.
This sort of waste can usually be tagged as "solid waste 99%,
mercuric chloride 1%"
if that describes it.
If a Kimwipe has 2 grams of mercuric chloride,
it has to be tagged accordingly; be accurate.
Disposal of dry sharp things: Contaminated sharp things such as needles and cover slips should be placed in heavy metal sharps containers such as 50ml screw-cap centrifuge tubes. Do not place anything toxic in the regular sharps containers. -
Uranium and Thorium compounds are radioactive and toxic.
They should be packaged for disposal as for the other metals,
but their contents identified with isotope
tags, and given to the Radiation Safety Office, not to the usual
hazardous waste disposal people.
RSO still requires segregation, so don't mix uranium and thorium.
Next: About this document ... Thomas Holton 2001-09-05
