State/local amalgam separator/BMP programs

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• State/local amalgam separator/BMP programs
• US Navy separator/BMP program
• Regulated Medical Waste vs. Hazardous Waste
  concerns
• US EPA Office of Solid Waste dental school
  initiative
• Dental chairside trap designs
• Hg vapor issues

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New York

• Amalgam separators must be installed by May 2008
• All dental facilities that apply, alter,
  maintain, remove, or dispose of amalgam
• Excludes orthodontists, periodontists,
  prosthodontists, and Oral Surgeons
• Separators must be 99 efficient
• Separator waste must be disposed of within one
  year

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New York

• All dentists must recycle amalgam waste
• Maintain written certification of recycling
• Dentist must notify local sewer authority that
  separator is installed
• New offices must install separators prior to
  opening
• Amalgam waste cannot be disposed of in trash,
  medical waste containers, or sterilized in
  autoclaves
• Pre-encapsulated amalgam only (elemental Hg
  banned)

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Milwaukee, Wisconsin

• Milwaukee Metropolitan Sewerage District (MMSD)
  requiring separators to be installed by February
  1, 2008
• MMSD serves 28 municipalities
• 317 total amalgam using offices in district
• Currently 184 amalgam using offices with
  separators installed (58)
• Point of contact Tom Nowicki, [phone]

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Milwaukee, Wisconsin
Data from Tom Nowicki, Milwaukee County Sewerage
District
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Wisconsin Statewide

• Separators and BMPs required in Dane County
  (Madison) by 12/31/2008
• Seven major Wisconsin municipalities will also
  require separator installations by 2008 (GLWQI
  1.3 ng/L)
• Wisconsin Dental Association is cooperating with
  separator effort
• Contact Randy Case of the Wisconsin DNR for more
  information [phone]

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Gurnee, Illinois NSSD

• NSSD is 2nd largest POTW in Illinois
• No discharge directly to Lake Michigan
• Mandated Pretreatment systems at Naval Base,
  Great Lakes
• Completed survey of all dentists in service area
• Working towards a program requiring BMPs and/or
  separators in near future
• Point of Contact Sharon R. Thieszen (847)
  623-6060

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Minneapolis/St. Paul Metro Area 7 Counties

• Separators or permits required for all dental
  offices placing and/or removing amalgam
• MCES Maintains a list of approved separators
• 99 removal efficiency with ISO 11143
• Testing and certification
• Works closely with Minnesota Dental Association
• Point of Contact Peter Berglund of MCES, (651)
  602-4708

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Duluth, Minnesota

• Voluntary effort organized by Tim Tuominen of the
  WLSSD
• Installed separators in all dental offices
  serviced by WLSSD
• Works with Northeast District Dental Society
  (MDA)
• WWTP influent is down and effluent is approaching
  the GLWQI level of 1.3 ng/L
• Point of Contact is Tim Tuominen [phone]

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Non-Great Lakes States/Areas

• Connecticut (95), Maine (95/98, list of
  approved separators), New Hampshire, Vermont,
  Rhode Island (eastern half of state)
• Massachusetts requires 98 ISO 11143 efficient
  separator or equivalent method acceptable to
  MassDEP
• VT and CT include separators in BMPs and require
  dentists to implement BMPs
• Washington requires installation of ISO 11143
  separators statewide

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Non-Great Lakes States/Areas

• New Jersey is working on a requirement for
  separators
• Montana Draft Bill 1262 would require amalgam
  separators and recycling of amalgam waste
• Warren Air Force Base, Cheyenne, Wyoming required
  to install amalgam separators in dental clinics

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Non-Great Lakes States/Areas

• Wichita, Kansas requires ISO 11143 separators
• San Francisco Bay area
• East Bay Municipal Utility District
• Contra Costa Central Sanitation District
• Union Sanitary District
• Palo Alto Sanitary District
• Toronto (one of earliest requirements)
• Montreal

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• Navy is installing separators in all dental
  treatment facilities
• US, overseas, and ships
• Installing systems that remove both particulate
  and dissolved Hg
• Also installing chairside filtration systems that
  remove particulate and protect downstream
  plumbing lines
• Working on non-mercury filling materials

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• Disposable filter elements are housed inside
  reusable chambers
• Filter elements are made from spun polypropylene
• 6 inch filter element has a vendor claimed
  surface area of 2.2 square feet (depth
  filtration)
• Cost of a disposable filter element is less than
  2.00 a piece

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Pore Size 50 ?m 15 ?m 1 ?m 0.5 ?m
Mean Hg 79.13 23.55 17.68 4.25
Sample Size 50 50 50 50
SD 71.40 23.25 17.35 6.35

• Baseline Hg levels without any chairside
  filtration system averaged 1,087.38 mg (n50,
  SD993.92)
• Units are in mean mg of Hg per dental chair per
  day

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Pore Size 50 ?m 15 ?m 1 ?m 0.5 ?m
Removal 92.72 97.83 98.86 99.61

• Calculated removal efficiencies (B Hg F Hg /
  B Hg) x 100 where B Hg is the baseline Hg level,
  F Hg is the amount of particulate Hg collected
  after the chairside filter)
• Baseline Hg levels without any chairside
  filtration system averaged 1,087.38 mg (n50,
  SD993.92)

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Empty Full Pass ISO
0.5?m 97.5 96.8 Yes
15?m 94.8 96.1 No

• The 0.5 ?m filter passed at 96.8
• The 15 ?m filter failed at 94.8
• Currently testing the 1.0 and 5.0 ?m filters with
  the ISO protocol
• ISO 11143 protocol is currently up for revision
  to close the loophole of flow rate and other
  changes (The threshold for maximum testing will
  be 1 liter/minute, where there was no threshold
  before)

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• Reusable filter chambers require periodic
  cleaning to remove debris
• A disposable unit has been developed to address
  this issue

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• Chairside filtration systems substantially reduce
  Hg emissions into wastewater
• Low cost and minimal maintenance
• 0.5 ?m filter passed ISO 11143 protocol
• Location at the chair protects downstream
  plumbing lines from amalgam debris
• Minimal impact on vacuum levels at the HVE tip
•  

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• In some locations amalgam waste is both a
  regulated medical waste (Potentially Infective
  Medical Waste, PIMW) and a hazardous waste
• In Illinois teeth, contiguous bond and gum are
  excluded from PIMW classification
• Some recyclers require a certificate of
  disinfection before they will accept dental
  waste
• Medical waste is routinely incinerated or
  autoclaved which would release Hg to atmosphere

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• EPA is seeking to partner with US Dental Schools
  to develop a curriculum based dental recycling
  program
• Student dentists
• Practicing dentists though CE
• Gray Bag program (ANSI/ADA Specification 109)
• Point of contact is David Carver, USEPA OSW (703)
  308-8603

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• Standard procedure to collect, store, and prepare
  amalgam waste for shipment to recyclers
• Disinfecting of wastes (if required by recyclers)
• Keep written records mass, name and address or
  recycler, etc.
• Wastes include extracted teeth with amalgam
  fillings

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• Scrap amalgam
• Contact
• Non Contact
• Used capsules
• Chairside traps
• Extracted teeth with amalgam fillings
• Amalgam from amalgam separators and vacuum pump
  filters

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• Landfills vs. Retorting Facilities
• Need for the disinfection of amalgam waste?
• Universal Waste Laws
• Ease regulatory burdens
• Promote proper recycling, treatment, or disposal
• Provide for collection opportunities

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• Most dental chairs have built in chairside traps
• While not originally designed to function as
  amalgam separators, chairside traps remove
  substantial amounts of amalgam waste
• There is confusion in the literature concerning
  pore sizes of traps
• This project used image analysis to obtain more
  accurate estimates of trap pore sizes from four
  selected chairside traps

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Uncovered type trap
Trap used in new ADEC Dental chairs
Covered trap
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Example of an inline chairside trap after 5 days
of use
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SEM of amalgam waste from removal of amalgam
restorations. Note that the particles have high
aspect ratios.
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Table 1 Mean and Standard Deviations (SD) from
Traps with Square Pores
Length,µm Width,µm Ferets 1,µm Aspect 2
Trap 1 n99 1156.76 (108.81) 1156.76 (108.81) 1121.51 (103.51) 1348.95 (21.56) 1.03 (1.01)
Trap 2 n110 1126.61 (233.73) 1126.61 (233.73) 1038.54 (293.90) 1239.74 (242.77) 1.41 (4.56)
Trap 3 n200 749.18 (77.79) 749.18 (77.79) 600.44 (122.99) 889.45 (87.36) 1.43 (1.44)
1 Ferets Diameter is the greatest dimension
between any two points along the boundary 2
Aspect is the ratio of the longest dimension to
shortest dimension
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Table 2 Mean and Standard Deviations (SD) Trap
with Round Pores Trap 4
Diameter,µm (max) Diameter,µm (min) Diameter,µm (mean) Roundness 3
Trap 4 n199 936.18 (29.07) 894.63 (79.55) 918.84 (55.00) 1.37 (1.96)
3 Roundness is a measure of how far the pore
shape differs from a circle
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Trap 1 DentalEZ
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Trap 2 Pinnacle Products, Inc.
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Trap 3 Pinnacle Products, Inc.
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Trap 4 Parts Warehouse, Inc.
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• All traps had at least one dimension greater than
  700µm
• When traps are the only Hg abatement mechanism,
  our findings suggest greater potential for Hg
  emissions than was previously assumed
• Manufacturers have the opportunity to contribute
  to the reduction of environmental Hg
  contamination
• Covered traps help prevent waste amalgam from
  entering plumbing lines

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• Recycling means that more amalgam waste is
  stored in dental treatment rooms
• May result in Hg vapor levels exceeding human
  exposure limits
• Another issue is Hg vapor levels in exhaust air
  from dental vacuum systems

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Federal OSHA PELA 8-Hour TWA 0.1 mg/m3 (100,000 ng/m3)
NIOSH RELB 8-Hour TWA 0.05 mg/m3 (50,000 ng/m3)
ACGIH TLVC 8-Hour TWA 0.025 mg/m3 (25,000 ng/m3)

• A Permissible Exposure Limit for Hg vapor is a
  time weighted average for an 8-hour workday and a
  40-hour workweek. This is the legally enforceable
  limit for the workplace
• B Recommended Exposure Limit for Hg vapor for up
  to a 10-hour workday and 40-hour workweek
• C Hg threshold limit value as a time weighted
  average for an 8-hour workday and a 40-hour
  workweek

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Location Hg Vapor Levels
Open Oceans 1-2 ng/m3
Urban Atmosphere 2-20 ng/m3
Coal-Fired Power Plants (Combustion zone) 1,000-20,000 ng/m3
Great Lakes, IL, USA 13.2 ng/m3
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• Weve surveyed a number of dental operatories
• Hg vapor levels in breathing zone is well below
  OSHA/NIOSH/ACGIH exposure levels
• Hg vapor levels inside recycling containers can
  exceed exposure levels
• Care should be taken when opening containers

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Clinic I (110 chairs) Clinic II (30 chairs) Clinic III (2 chairs)
Hg, ng/m3 45,316 73,737 35,421
ng of Hg/min 532,684 131,353 18,079
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• Mean for all three clinics and both methods was
  51,684 ng/m3
• Exhaust air form dental vacuum systems contains
  3,915 times more Hg than ambient air samples
• Exhaust air from dental vacuum systems had
  2.6-to-51.7 times higher concentration of Hg than
  flue gas from combustion zones in coal-fired
  power plants

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