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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.

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Presentation on theme: "State/local amalgam separator/BMP programs US Navy separator/BMP program Regulated Medical Waste vs. Hazardous Waste concerns US EPA Office of Solid Waste."— Presentation transcript:


2 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

3 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 New York 3

4 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) New York 4

5 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 Milwaukee, Wisconsin 5

6 Data from Tom Nowicki, Milwaukee County Sewerage District 6

7 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) 267- 7639 Wisconsin Statewide 7

8 NSSD is 2 nd 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 Gurnee, Illinois NSSD 8

9 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 Minneapolis/St. Paul Metro Area 7 Counties 9

10 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) 740- 4815 Duluth, Minnesota 10

11 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 Non-Great Lakes States/Areas 11

12 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 Non-Great Lakes States/Areas 12

13 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 Non-Great Lakes States/Areas

14 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

15 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

16 Pore Size50  m15  m1  m0.5  m Mean Hg79.1323.5517.684.25 Sample Size50 SD 71.4023.2517.356.35 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

17 Pore Size50  m15  m1  m0.5  m % Removal92.7297.8398.8699.61 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

18 EmptyFullPass ISO 0.5  m97.5%96.8%Yes 15  m94.8%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) 18

19 Reusable filter chambers require periodic cleaning to remove debris A disposable unit has been developed to address this issue 19

20 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

21 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

22 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

23 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

24 Scrap amalgam Contact Non Contact Used capsules Chairside traps Extracted teeth with amalgam fillings Amalgam from amalgam separators and vacuum pump filters 24

25 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

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27 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

28 Uncovered type trap Trap used in new ADEC Dental chairsCovered trap 28

29 Example of an inline chairside trap after 5 days of use 29

30 SEM of amalgam waste from removal of amalgam restorations. Note that the particles have high aspect ratios. 30

31 Length,μmWidth,μmFeret’s 1,μmAspect 2 Trap 1 n=99 1156.76 (108.81) 1121.51 (103.51) 1348.95 (21.56) 1.03 (1.01) Trap 2 n=110 1126.61 (233.73) 1038.54 (293.90) 1239.74 (242.77) 1.41 (4.56) Trap 3 n=200 749.18 (77.79) 600.44 (122.99) 889.45 (87.36) 1.43 (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 Table 1: Mean and Standard Deviations (SD) from Traps with Square Pores 31

32 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 n=199 936.18 (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 32

33 Trap 1 – DentalEZ 33

34 Trap 2 – Pinnacle Products, Inc. 34

35 Trap 3 – Pinnacle Products, Inc. 35

36 Trap 4 – Parts Warehouse, Inc. 36

37 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

38 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

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40 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 Federal OSHA PEL A 8-Hour TWA 0.1 mg/m 3 (100,000 ng/m 3 ) NIOSH REL B 8-Hour TWA 0.05 mg/m 3 (50,000 ng/m 3 ) ACGIH TLV C 8-Hour TWA 0.025 mg/m 3 (25,000 ng/m 3 ) 40

41 LocationHg Vapor Levels Open Oceans1-2 ng/m 3 Urban Atmosphere2-20 ng/m 3 Coal-Fired Power Plants (Combustion zone) 1,000-20,000 ng/m 3 Great Lakes, IL, USA13.2 ng/m 3 41

42 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

43 Clinic I (110 chairs) Clinic II (30 chairs) Clinic III (2 chairs) Hg, ng/m 3 45,31673,73735,421 ng of Hg/min 532,684131,35318,079 43

44 Mean for all three clinics and both methods was 51,684 ng/m 3 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 44

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