Presentation on theme: "Experiences in Mercury Spill Clean-up at UCLA"— Presentation transcript:
1Experiences in Mercury Spill Clean-up at UCLA Presented tothe American Chemical SocietyApril 3, 2001Joe Raab, CIHUniversity of California, Los Angeles
2The Mercury Haz Mat Story: “When a Good Element Goes Bad” Overview of mercuryExamples of mercury spill clean-upsMercury clean-up toolsAbsorbents and indicatorsDetermining “how clean is clean”Mercury reduction steps
3Mercury 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.
4Items which Contain Mercury Gauges, manometers barometers, and vacuum gauges,Blood pressure sphygmomanometersMercury switches and relaysThermometersMercury containing thermostat probes.Dental amalgamHospital equipmentLaboratory solutionsFluorescent & high intensity discharge (HID) lamps
6Mercury Incidents at UCLA Center for Health Sciences vs. Campus
7Calculating the Costs (1999 data) Disposal cost (assuming 80% due to haz mat events)Disposal cost = $34.65/lb.1,437 lbs.Total cost = $39,833Haz Mat Response CostLabor hours =Personnel cost = $100/hr.Total cost = 28, 059
8Office Spill from Mercury Above-Ceiling The problem = trapped mercury in plumbing lines above the ceilingDuring demolition of the floor above, approx liters of mercury hit the tiles and contaminated the office below.
9Office Spill from Mercury Above-Ceiling Contaminated Materials:Ceiling tiles and light fixturesLeased office copierCarpetfilesEtc.+ Phase II from trapped mercury in a light fixture !!!!!
10Pathology LaboratoryB5 fixative (6.6% mercuric chloride & 2.3% sodium acetate solution)Was placed into aluminum container and corroded through onto the floor.
11Pathology LaboratoryAir 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
12Pathology Laboratory Floor was ultimately removed and drummed. Accomplished using trained abatement workers using jack hammers and controls similar to lead abatement.
13Blood 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.
14Mercury 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.
16Vacuum Cleaners Advantages: Disadvantages: 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
17Mercury 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.
18Mercury 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.
19Direct 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 = mg/m3.
20Direct 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.
21Personal Protective Equipment (PPE) RespiratorTypically tight fitting half or full face with mercury vapor cartridges.End of Service Life Indicator.Protective SuitBootiescontamination of shoes is commonGloves
22Mercury 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.
23Hg 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.
24Mercury 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.
25Liquid AbsorbentsLiquid 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.
26Determining “How Clean is Clean?” Direct reading instrument mercury measurements of non-detect.NIOSH Method 6009 using hopcalite tubes and atomic absorption analysisEstimated method LOD = 0.3 gWhat do you compare result to (PEL, 1/10 PEL?)Mercury indicator powder - no color change.Swipe samples.Hazardous waste leachate testing methods.
28ConclusionsMercury 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.
29Conclusions (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.
30Conclusions (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.