 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
2
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
3
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)
4
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, (414)
225-2275
5
Milwaukee, Wisconsin
Influent Mercury
700
Mercury (ng/L)
600
500
400
300
200
100
Jones Island
South Shore
Linear (South Shore)
11/17/06
9/17/06
7/17/06
5/17/06
3/17/06
1/17/06
11/17/05
9/17/05
7/17/05
5/17/05
3/17/05
1/17/05
11/17/04
9/17/04
7/17/04
5/17/04
3/17/04
1/17/04
11/17/03
9/17/03
0
Linear (Jones Island)
Data from Tom Nowicki, Milwaukee County Sewerage District
6
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 (608) 2677639
7
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
8
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
9
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 (218) 7404815
10
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
11
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
12
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
13
 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
14
 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
15
Pore Size
50 m
15 m
1 m
0.5 m
Mean Hg
Sample Size
79.13
50
23.55
50
17.68
50
4.25
50
SD
71.40
23.25
17.35
6.35
 Baseline Hg levels without any chairside
filtration system averaged 1,087.38 mg
(n=50, SD=993.92)
 Units are in mean mg of Hg per dental chair
per day
16
Pore Size
50 m
% Removal 92.72
15 m
97.83
1 m
98.86
0.5 m
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 (n=50, SD=993.92)
17
0.5m
15m
Empty
97.5%
94.8%
Full
96.8%
96.1%
Pass ISO
Yes
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)
18
 Reusable filter chambers require periodic
cleaning to remove debris
 A disposable unit has been developed to
address this issue
19
 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
20
 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
21
 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
22
 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
23
 Scrap amalgam


Contact
Non Contact
 Used capsules
 Chairside traps
 Extracted teeth with amalgam
fillings
 Amalgam from amalgam separators
and vacuum pump filters
24
 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
25
26
 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
27
Uncovered type trap
Covered trap
Trap used in new ADEC Dental chairs
28
Example of an inline chairside trap
after 5 days of use
29
SEM of amalgam waste from removal of
amalgam restorations. Note that the
particles have high aspect ratios.
30
Table 1: Mean and Standard Deviations
(SD) from Traps with Square Pores
Length,μm
Width,μm
Feret’s 1,μm
Aspect 2
Trap 1
n=99
1156.76
1121.51
1348.95
1.03
(108.81)
(103.51)
(21.56)
(1.01)
Trap 2
n=110
1126.61
1038.54
1239.74
1.41
(233.73)
(293.90)
(242.77)
(4.56)
Trap 3
n=200
749.18
600.44
889.45
1.43
(77.79)
(122.99)
(87.36)
(1.44)
1 Feret’s
Diameter is the greatest dimension between
any two points along the boundary
2 Aspect
is the ratio of the longest dimension to shortest
dimension
31
Table 2: Mean and Standard Deviations
(SD) Trap with Round Pores – Trap 4
Diameter,μm Diameter,μm Diameter,μm
Trap 4
n=199
(max)
(min)
(mean)
936.18
(29.07)
894.63
(79.55)
918.84
(55.00)
Roundness
3
1.37
(1.96)
3 Roundness
is a measure of how far the pore
shape differs from a circle
32
Trap 1 – DentalEZ
33
Trap 2 – Pinnacle Products, Inc.
34
Trap 3 – Pinnacle Products, Inc.
35
Trap 4 – Parts Warehouse, Inc.
36
 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
37
 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
38
39
OSHA PELA
NIOSH RELB
ACGIH TLVC
Federal
8-Hour TWA
0.1 mg/m3
8-Hour TWA
0.05 mg/m3
8-Hour TWA
0.025 mg/m3
(100,000 ng/m3)
(50,000 ng/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
40
Location
Hg Vapor Levels
Open Oceans
1-2 ng/m3
Urban Atmosphere
2-20 ng/m3
Coal-Fired Power Plants
(Combustion zone)
Great Lakes, IL, USA
1,000-20,000 ng/m3
13.2 ng/m3
41
 We’ve 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
42
Clinic I
Clinic II
Clinic III
(110 chairs)
(30 chairs)
(2 chairs)
Hg, ng/m3
45,316
73,737
35,421
ng of
Hg/min
532,684
131,353
18,079
43
 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 coalfired power plants
44
45
46
47