Experiences in Mercury Spill Clean-up at UCLA

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Experiences in Mercury Spill Clean-up at UCLA

• Presented to
• the American Chemical Society
• April 3, 2001
• Joe Raab, CIH
• University of California, Los Angeles

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The Mercury Haz Mat StoryWhen a Good Element
Goes Bad

• Overview of mercury
• Examples of mercury spill clean-ups
• Mercury clean-up tools
• Absorbents and indicators
• Determining how clean is clean
• Mercury reduction steps

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Mercury

• Elemental / organic / inorganic compounds.
• Liquid rather than solid at room temperature.
• Low vapor pressure (evaporates slowly) but often
  produces significant vapor at room temp.
• Mostly absorbed through the lungs or sometimes
  through damaged and broken skin.
• Usually a lack of acute symptoms, chronic affects
  to CNS.
• Bio-accumulates in the food chain.

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Items which Contain Mercury

• Gauges, manometers barometers, and vacuum gauges,
• Blood pressure sphygmomanometers
• Mercury switches and relays
• Thermometers

• Mercury containing thermostat probes.
• Dental amalgam
• Hospital equipment
• Laboratory solutions
• Fluorescent high intensity discharge (HID) lamps

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Types of Mercury Spills at UCLA 1997-1999
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Mercury Incidents at UCLA Center for Health
Sciences vs. Campus
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Calculating the Costs (1999 data)

• Disposal cost (assuming 80 due to haz mat
  events)
• Disposal cost 34.65/lb.
• 1,437 lbs.
• Total cost 39,833
• Haz Mat Response Cost
• Labor hours 280.59
• Personnel cost 100/hr.
• Total cost 28, 059

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Office Spill from Mercury Above-Ceiling

• The problem trapped mercury in plumbing lines
  above the ceiling
• During demolition of the floor above, approx.
  0.25 liters of mercury hit the tiles and
  contaminated the office below.

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Office Spill from Mercury Above-Ceiling

• Contaminated Materials
• Ceiling tiles and light fixtures
• Leased office copier
• Carpet
• files
• Etc.
• Phase II from trapped mercury in a light
  fixture !!!!!

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Pathology Laboratory

• B5 fixative (6.6 mercuric chloride 2.3 sodium
  acetate solution)
• Was placed into aluminum container and corroded
  through onto the floor.

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Pathology Laboratory

• Air and bulk samples revealed extensive
  contamination of the floor.
• Many attempts made to clean the floor until
  finally the decision was made to remove it.
• Additional contamination found in sinks and
  plumbing systems

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Pathology Laboratory

• Floor was ultimately removed and drummed.
• Accomplished using trained abatement workers
  using jack hammers and controls similar to lead
  abatement.

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Blood Pressure Sphygmomanometers

• Many recent incidents.
• Contamination of care giver and patient is
  common.
• Pressure applied results in large dispersal of a
  large volume of mercury.
• Very difficult clean ups.

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Mercury Thermometers

• Can be well contained or dispersed.
• Drop height increases dispersion.
• Often in ovens, incubators, carts, refrigerators
  and other difficult areas.
• Haz Mat Size up steps are very important.

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Mercury Clean-up Tools

• Vacuum Cleaners
• Mercury spill kits and pumps
• Absorbent sponges
• Direct Reading Instruments
• Personal Protective Equipment

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Vacuum Cleaners

• Advantages
• Easy pick up of bulk materials.
• Different styles and sizes available.
• Disadvantages
• May not work on some contamination.
• Need routine maintenance and parts replacement.
• May create vapor during clean-up.
• Expensive

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Mercury Spill Kits and Hand Pumps

• Advantages
• Good for small spills and individual drops.
• Provide access to difficult areas.
• Disadvantages
• Not efficient for large spills.
• Requires repetitive action.
• May miss small droplets.
• Eye fatigue.

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Mercury Sponges

• Wetted sponge with amalgam on one side.
• Advantages
• Best when used with small spills to accumulate
  and amalgamate small droplets.
• Disadvantages
• May spread drops around.
• Sometimes does not amalgamate well.
• Can be messy.
• Amalgam can look like Hg.

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Direct Reading Instruments Jerome Mercury
Monitor

• Direct reading instrument which deposits mercury
  vapor on gold film and reads concentration based
  on change in electrical resistance.
• LOD 0.003 mg/m3.

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Direct Reading Mercury Instruments

• Advantages
• Accurate real time monitoring of mercury vapor.
• Good for tracking down areas of contamination.
• Aids in the selection of appropriate PPE.
• Aids in identification of contaminated items.

• Disadvantages
• Direct reading is not directly comparable to PEL.
• Background may be high during clean-up.
• LOD limitations. May give a false sense of
  security.
• Can become saturated.

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Personal Protective Equipment (PPE)

• Respirator
• Typically tight fitting half or full face with
  mercury vapor cartridges.
• End of Service Life Indicator.
• Protective Suit
• Booties
• contamination of shoes is common
• Gloves

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Mercury Absorbents and Indicators

• Typically applied after some effort has been made
  to take up the bulk material.
• Many require significant application time to
  absorb the mercury.
• The characteristics of the contaminated surfaces
  will determine their success.
• Reapplication or additional agitation may be
  necessary.

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Hg Absorb

• Typically granular zinc and citric acid.
• Acid slightly agitates and frees up the mercury
  to be absorbed.
• Requires additional clean-up.
• Contact with Hg contamination is important.
• Not good on porous surfaces.

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Mercury Indicator Powder

• Sulfur, Silicon Dioxide, Proprietary
  ingredient.
• Sprinkle over spill and wait at least 24 hours.
• Color change from dull yellow to rust.
• Very helpful in identifying problem areas of
  contamination.

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Liquid Absorbents

• Liquid mixture containing copper sulfate, calcium
  chloride, potassium iodide, sodium thiosulfate.
• Apply with sprayer, leave for 24 hours and rinse
  off.
• Forms mercury sulfide.
• Better on porous surfaces than solid absorbents.

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Determining How Clean is Clean?

• Direct reading instrument mercury measurements of
  non-detect.
• NIOSH Method 6009 using hopcalite tubes and
  atomic absorption analysis
• Estimated method LOD 0.3 ?g
• What do you compare result to (PEL, 1/10 PEL?)
• Mercury indicator powder - no color change.
• Swipe samples.
• Hazardous waste leachate testing methods.

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Mercury Reduction Steps

• Non-mercury alternatives
• (i.e. Replacement of blood pressure
  sphygmomanometers)
• Literature campaign
• Substitute chemicals (i.e. zinc chloride
  fixatives)
• Secondary containment for existing sources
• Future mercury round-ups

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Conclusions

• Mercury spills are disruptive, expensive, time
  consuming, etc.
• Mercury spills can be very difficult to clean,
  requiring a variety of tools and well trained haz
  mat crews.
• Always check personnel in the area of the spill
  for contamination on their person.

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Conclusions (continued)

• Mercury absorbents and indicators can be
  essential after the initial clean-up to rid the
  area of trace material.
• Sometimes a successful clean-up requires the
  removal of contaminated materials (i.e. carpet).
• Consult waste managers about the disposal of
  contaminated materials.

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Conclusions (continued)

• Determining the extent of the contamination is
  difficult and can require a combination of
  analytical methods.
• Consider long term exposures prior to clearing
  an area.
• The best method for dealing with mercury spills
  is to prevent them in the first place by using
  mercury reduction methods.

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