### 1 ATTACHMENT 2: A REVIEW OF THE AVAILABLE DATA ON THE EFFECTIVENESS OF AMALGAM SEPARATORS

I. INTRODUCTION The ADA has collected data on whether amalgam separators reduce effluent mercury from a number of publicly available so urces (including information from the National Association of Clean Water Agencies (“NACWA”) st udy). These results are summarized below. A more systematic review of this data is necessary before definitive conclusions can be drawn,
II. EXECUTIVE SUMMARY Although the database cannot be viewed as definite, several general observations can be made. First, clearly, installation of amalgam sepa rators shifts the primary point at which amalgam is removed from the sewerage treatme nt plant, where professional environmental engineers handle the material, to the dental office (where techni cal experience with mercury is more limited). Second, in general, the levels of mercury in biosolids (see Table 1: Comparison of average biosolids concentrations and EPA bios olid limits in the main ADA comments) and the effluent (see Figures 1 through 13, below) are re latively low. The mercury concentrations in treatment plant effluent, in particular, are of ten barely above the detection limit. The low concentrations and the inherent variation in mercury concen trations in effluent make determination of trends difficult. Given the extremely low levels of total mercury in the treatment plant effluent, the fluctuations may si mply be analytical vari ation or variation in background levels of mercury.

### 2 Third, the data does support the effectiven ess of the treatment plant in removing mercury from influent. Fourth, the data indicates that total mercur y levels in biosolids and treatment plant influent can decrease as a result of the installation of amalgam se parators. The issue (discussed in the body of these comments) is whether further reductions of mercury leve ls in biosolids that are already well below EPA biosolid limits significantly reduces the release of mercury into the environment, specifically the release into surface water. Fifth, a visual review of the effluent data indicates that there is no clear pattern of decreases in treatment plant effluent following th e installation of amalga m separators, and some data may suggest an increase in the effluent. Ne ither the individual presentations that interpreted this municipal data nor the NACWA study correlat ed the change in merc ury concentration over time with separator installations. Sixth, the mercury concentrati ons in treatment plant efflue nt, in particular, is often near to the detection limit. The low concentr ations and the inherent variation in mercury concentrations in effluent make determination of trends difficult. Given the extremely low levels of total mercury in the POTW effluent, the fluctu ations may simply be analytical variation or variation in background levels of mercury. In summary, there are no downward tr end in the mercury concentration of effluent easily observable after installation of am algam separators. However, a more detailed statistical analysis of the existing data (with an attempt to correlate the timing of the institution of the pre-2007 Best Management Practices (“BMPs ”) for amalgam waste, amalgam separators, another mercury reduction activit ies at the sewerage treatment facilities) would probably be useful.

### 3 III. THE MEASURE OF EFFECTIVENESS The issue of whether amalgam separators are effective depends on what measure one uses to define “effectiveness. ” There is no debate that amalga m separators installed in dental offices would prevent more than 6 tons of amalgam from entering sewerage treatment plants annually. As a result, the concen tration of mercury in sewerage treatment plant influent and biosolids (where the vast majority of mercury from amalgam is collected) will decrease after separators are installed, so long as other s ources are much higher th an the dental office contribution, thereby masking any decrease. However (as discussed in Attachment 1 to the ADA Comments), the net benefit to the environment is far less than this 6 tons beca use sewerage treatment plants remove more than 95% of amalgamated mercury. Al so, typically, the protecting th e environment does not include the interior workings of indus trial plants or municipal wast ewater treatment plants (see discussion in the ADA Comments). The ADA considers that the appropriate measure of “effectiveness” for the pretreatment rule is the reduction of the mercury concentration in the effluent from sewerage treatment plants discharged into surface water an d the deposition of mercury into surface water (from mercury that originated in the discharge of amalgam wastew ater into sewerage treatment systems).. The available data on separator effectiv eness reviewed in this Attachment indicates that (1) the amount of mercury in the influent and biosolids decreas e after separators are installed (consistent with the principles of mass balance) and such a decrease should and usually is measurable 1 

### , and (2) there is no observable decreases in the concentration of mercury in effluent following the installation of amalgam separators.

### 4 The purpose of the Clean Water Act and sewera ge plants is to prevent releases to surface water. Regulatory action was not requir ed until the Environmental Protection Agency (“EPA”) set the mercury water quality standard of 0.3 milligrams of mercury per kilogram of fish (“mg/kg” or “ppm”) and analytical techni ques allowed measurements of nanogram per liter (“ng/L” or “ppt”) levels of mercury in effluent and it was f ound that fish in many areas contained mercury concentrations in excess of 0.3 ppm. Thus, the proper measure of amalgam separator “effectiveness” is the change, if any, in mercury concentrations in sewerage plant effluent (i.e., the discharge to the surface water in which the fish reside) . As discussed below, the raw data on the impact of amalgam separators on the merc ury concentration in sewerage treatment plant effluent is unclear and likely to small.

IV. MILWAUKEE, WI After working cooperatively with the Greater Milwa ukee and Wisconsin Dental Associations and individual dentis ts to refine the elements of th is program, the District adopted rules in January 2004 requiring the in stallation of amalgam separators. 2 

### This was the first municipality in the Great Lakes region to require separators for amalgam. 3 

### The municipality acknowledged that th e sources being controlled (including dental offices) were “not the only cause for pollutant reductions. Other causes include: the movement of heavy manufacturing to areas with lower costs; the implementation of new, more efficient manufacturing processes; and the increasing amount of self- policing that is occurring as facilities implement environmental management systems.” 4

### 5 The Appendix to this Attachment contai ns the Milwaukee Metropolitan Sewerage District’s August 2007 analysis of its influent, bi osolid, and effluent con centrations. Below are the relevant plots of the concen tration of mercury in effluent versus time from this Appendix. 5

### 6 Figure 1: Milwaukee Metropolita n Sewerage District Mercury Concentration in Effluent Effluent Mercury

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.09/17/0311/17/031/17/043/17/045/17/047/17/049/17/0411/17/041/17/053/17/055/17/057/17/059/17/0511/17/051/17/063/17/065/17/067/17/069/17/0611/17/061/17/073/17/075/17/07ng/L

Jones Island South Shore Linear (Jones Island) Linear (South Shore) 

### Figure 2: Milwaukee Metropo litan Sewerage District Quarterly Average Mercury Concentration in Effluent Effluent Quarterly Averages

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0Dec-03Feb-04Apr-04Jun-04Aug-04Oct-04Dec-04Feb-05Apr-05Jun-05Aug-05Oct-05Dec-05Feb-06Apr-06Jun-06Aug-06Oct-06Dec-06Feb-07Apr-07Jun-07ng/L

Jones Island South Shore Linear (Jones Island) Linear (South Shore)

### 7 Figure 3: Milwaukee Metropolita n Sewerage District Mercury Concentration in Effluent with Alleged Outliers Removed Effluent Concentration with Outliers Removed

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.09/17/0311/17/031/17/043/17/045/17/047/17/049/17/0411/17/041/17/053/17/055/17/057/17/059/17/0511/17/051/17/063/17/065/17/067/17/069/17/0611/17/061/17/073/17/075/17/07ng/L

Jones Island South Shore Linear (Jones Island) Linear (South Shore)

### 8 Figure 4: Milwaukee Metropolita n Sewerage District Mercury Mass in Effluent Jones Island Effluent Mass

0 1 2 3 4 5 6 7 8 99/17/0311/17/031/17/043/17/045/17/047/17/049/17/0411/17/041/17/053/17/055/17/057/17/059/17/0511/17/051/17/063/17/065/17/067/17/069/17/0611/17/061/17/073/17/075/17/07grams/day



### Figure 5: Milwaukee Metropolita n Sewerage District Mercury Mass in Effluent South Shore Effluent Mass

0 1 2 3 4 5 6 7 89/17/0311/17/031/17/043/17/045/17/047/17/049/17/0411/17/041/17/053/17/055/17/057/17/059/17/0511/17/051/17/063/17/065/17/067/17/069/17/0611/17/061/17/073/17/075/17/07grams/day

### 9 Both a visual observation of the data and the admittedly limited statistical tests performed on the data indicate that “[e]ffluent concentrations do not correlate with influent concentrations” and for both Jones Island and So uth Shore, “the trend line shows a slight increase in effluent con centration with decreasing influent concentration.” 6



### V. 

## WICHITA, KANSAS The City of Wichita, Kansas initiated a pha sed program that resulted initially in 60% of dental community voluntarily complying with the program. 7 

### The program was implemented in October 2001. Presently, 99% of dentists have complied. 8 

### Figure 6: Wichita Loading and Da te of Separator Implementation 9

### 10 Figure 7: Wichita Mercury Concentration in Effluent 10



### The data actually shows an increase in average mercury concentration from 2002 (2.17 ng/L) to 2003 (2.77 ng/L) and that the largest decrease actu ally occurred from 2001 (3.57 ng/L) to 2002 (2.17 ng/L) after requiring BMPs. Despite this cooperation from the local dental community, no clear pattern of a decrease in the mercury concentration in influent to or effluent from the treatment plant is discernible. 11

### 11 VI. DULUTH SEWERAGE TREATMENT PLANT Separators in Duluth, Minnesota were installed from roughly June 1999 through December 2004. Although a pattern of a slight me rcury decrease in sludge is discernible, no such pattern is clear in the treatment plant effluent. Figure 8: Duluth Mercury Concentration in Sludge and Date of Separator Installation 12

### 12 Figure 9: Duluth Mercury Concentration in Effluent 13



### VII. MADISON, WISCONSIN As of 2005, 23 of the 103 dentists in Madison had installed separators. 14 

### The regulatory goal was to have all general practi ce dentists install separators by December 31,
2008. 15 

### Table 1 (below) provides, among other things , the mercury concentration in the effluent from 2004 to 2006.

### 13 Table 1: Madison, Wisconsin Mer cury Concentration in Effluent 16



### The 2004, 2005, and 2006 data show no trend yet, although it may be premature. 17

### 14 VIII. MINNEAPOLIS AREA The Minneapolis Metropo litan Council on Environmen tal Services (“MCES”) launched its voluntary separator pr ogram in January 2003. 99% of general practice dental clinics in the Minneapolis area in stalled separators (724). 18 

### The average concentration of mercury in the MCES Metro Plant effluent over time (through 9/5/07) is: 19 

### 1994: 11 ng/l 2003: 8.4 2004: 5.2 2005: 5.0
2006: 6.2
2007: 3.1 The ADA has not found information on the rate at which amalgam separators were installed in the MCES syst em. Additionally, ther e were strong efforts to implement best management amalgam waste handling practi ces and other mercur y reduction/pollution prevention efforts prior to and after January 2003. This complicates interpretation of the data on average total mercury concentrations (parti cularly the decreases between 1994 and 2003 and between 2003 and 2004 and the further decrease from 2006 to the first part of 2007). Specifically, the decrease in 2007 through August st rongly suggests that other mercury reduction efforts are at play given the likelihood that most of the separators have been installed for some time. Therefore, it is difficult to determine whether the changes in concentration are related primarily to the use of separators.

### 15 IX. PALO ALTO/BAY AREA The Regional Water Quality Control Plant (“RWQCP”) covers dischargers located in Palo Alto, the East Palo Alto Sanitary District service area, Los Altos, and the town of Los Altos Hills. The due date for amalgam se parator installation in this area was March 31,
2005. 20 

### By April 30, 2005, 96 percent of the 132 dent al offices had certifie d that their amalgam separators were installed. 21 

### Figure 10 below plots the mercur y concentrations in the plant’s influent and effluent. Figure 10: Palo Alto (i.e., Regional Water Quality Control Plant (RWQCP)) Mercury Concentration in Effluent 22

### 16 Figure 11: Palo Alto Mercury Concentration in Effluent Different Scale

Two things are immediately apparent from the Palo Alto data. First, the largest decrease in mercury effluent occurred from 1995 to 2000, prior to the installation of separators (see Figures 10 and 11). Second, gi ven the scales of Figures 10 and Figure 11, little change is observable. Nevertheless, the raw data should be examined more care fully with appropriate statistical tools to better understand separator eff ectiveness in Palo Alto.

X. EAST BAY MUNICIPAL UTILITY DISTRICT In the East Bay Municipal Utility District (“EBMUD”), separators were installed between January 2004 and September 2005. 23 

### More than 96% of permitted dental facilities have installed amalgam separators. 24 

### Figure 12 shows the mercury con centrations in the influent and effluent from the plant.

.

### 17

### 18 Figure 12: EBMUD Comparison of Mercury Concentration in Influent and Effluent 25



### Given the scale, no increase or decrea se can be observed, although there is no noticeable decrease.

XI. OTHER SEWERAGE TREATMENT PLANTS This brief review of the mercury concentr ation in effluent data available on line did not uncover other effluent data. In some cases (such as Narragansett Bay 26 

### ), there are tables showing mercury concentration data for effluent for limited periods of time. 27 

### In the case of Narragansett Bay, voluntary separators were inst alled from 2004 through the end of 2005, but the weekly mercury concentration in effluent data for 2005 suggests no downward trend. However, more information and a statistical analysis would be needed to reach a scie ntifically sound conclusion concerning the trends..

### 19 XII. NACWA SEPARATOR EFFECTIVENESS STUDY Samples of influent wastewater, treated e ffluent, and biosolids were collected and analyzed for total mercury concentrations, and some influent and effluent samples were analyzed for dissolved mercury concentrations. In addi tion, flow rates, total suspended solids, and turbidity were measured. The only publicly available summary of the study is a Power Point presentation that generally plots effluent mercury against th e different sewerage tr eatment plants or the number of dental offices per million gallons of flow (i.e., this presentation did not plot the mercury concentrations in effluent before, during, and after instal lation of separators). 28 

### Although the ADA reviewed a written copy of the re port, the ADA has not seen or reviewed the raw data. The ADA conclusions are as follows: First, the NACWA study adds signifi cantly to the body of knowledge on the effectiveness of separators and collects the data in one location. Second, some of the treatment plants we re implementing mercury reduction well before the NACWA study was initiated. As a result, we suspect that some of the data gathering may have limitations that might not exist in a prospective study. Third, the ADA is unable to determine when the separators were installed in the case of each treatment plant, making it difficult ascer tain the true “effect” of the installations. In other words, an “effect” (i.e., a change in a treatment plant’s e ffluent mercury ), by definition, must be causally linked to the timi ng of the separator installations. Fourth, the draft report reviewed by the ADA did not take into account that some chemicals like sodium hypochlorite, which can ha ve very high concentrations of mercury (e.g., Clorox® and Comet® can have microgram per kilogram levels of mercury), could be contributing significant amounts of mercur y to treatment plant effluents.

### 20 Fifth, the trends in mercury concentrati on in effluent must be understood in the context of the overall mercury reduction progr ams implemented by the municipality. For example, most treatment plants th at have historic data show a more dramatic decrease in the mercury concentration in influent , biosolids, and in effluent prior to the installati on of separators. Both prior to and during the installation of separators, other signifi cant mercury reduction program have been instituted nationwide. For ex ample, the majority of dental offices that initially implemented the pre-2007 ADA Best Ma nagement Practices are contributing to significant reductions that are now intermingled with any reductions from the separators. Thus, any analysis of the impact of separators must take into account these other confounding factors. Sixth, the NACWA analysis includes attempts to correlate the number of dentists per million gallons of treatment plant flow. The information available on the plants is very limited. The data suggests that two of the twelve plants (treatment plants A and L) had higher concentrations of mercury in the e ffluent compared to the other plan ts. It is not discernible from the Power Point, whether any or all of this data was taken before, during or after separators were installed. Some figures suggest a higher mercury concentration with a incr ease in the number of dentists per million gallons of flow. However, th e higher concentrations on these figures seem to be associated with treatment plant L and A, which were anomalous. Finally, this analysis is not based on accepte d statistical methods (as far as can be determined from the publicly available informati on). More importantly, th e mere existence of a high number of dentists per million gallons of fl ow does not fairly indicate a given dental community’s contribution to mercury in treatment plant effluent. Indeed, a number of dental offices in a community are highly correlated w ith high population and an urban setting. Thus, the mercury in the influent and effluent may be more a function of the la rger number people, the

### 21 greater use of mercury-containing products, a nd a greater likelihood of industrial and other nondental commercial contribution. Finally, some of the samples were com posites and others were grab samples, which may make comparisons more difficult.

XIII. CONCLUSION Although amalgam separators do increas e the amount of amalgam that is recycled, the data does not demonstrate the effec tiveness of amalgam sepa rators in reducing the amount of mercury that is releas ed to the environment. Aside from the lack of clear data on effluent effects, most of the data is from nonpeer reviewed repor ts and presentations, which is insufficiently robust to demonstrate whether me rcury concentrations in sewerage treatment plants significantly decrease, increase or rema in the same after the installation of amalgam separators in dental offices. The ADA urges EPA and/or NACWA to perform a more systematic statistical analysis of this data (a nd any other data that is available).#9134446 v2 

## APPENDIX TO ATTACHMENT 2: MILWAUKEE METROPOLITAN SEWERAGE DISTRICT MERCURY DATA SUMMARY

### 1 

# Milwaukee Metropolitan Sewerage District Mercury Data Summary
August 31, 2007
Sample results show mixed outcomes, as shown in the following graphs. Influent and Milorganite show desirable resu lts. At both Jones Island and South Shore, influent mercury concentrations and masses are decreasing. Fo r both Jones Island and South Shore, a Kendall Trend Test identifies decreasing tr ends at a 95% confidence level. Milorganite concentrations are decreasing, but a Kendall Trend Test identifies a decreasing tre nd at only a 90% confidence level. In contrast, at both Jones Island and South Shore, effl uent mercury concentrations and masses are increasing. Even when outliers are elim inated, the trend is increasing or stable. For the purpose of this analysis, outlie rs were defined as results more than two standard deviations from the average. Agri-Lif e concentrations are stable. Effluent concentrations show a correlation with flow and total suspended (TSS) concentrations. A possible explanation is that mercury perfor mance is related to TSS performance and TSS removal tends to decrease as flows increase. In contrast, influent concentration does not correlate with flow. Effluent concentrations do not correlate with in fluent concentrations. For both Jones Island and South Shore, the trend line shows a slight incr ease in effluent concen tration with decreasing influent concentration.

### 2 Influent Mercury

0 100 200 300 400 500 600 7009/17/0311/17/031/17/043/17/045/17/047/17/049/17/0411/17/041/17/053/17/055/17/057/17/059/17/0511/17/051/17/063/17/065/17/067/17/069/17/0611/17/061/17/073/17/075/17/07ng/L

Jones Island South Shore Linear (Jones Island) Linear (South Shore)

Influent Quarterly Averages

0 50 100 150 200 250 300 350 400 450Dec-03Feb-04Apr-04Jun-04Aug-04Oct-04Dec-04Feb-05Apr-05Jun-05Aug-05Oct-05Dec-05Feb-06Apr-06Jun-06Aug-06Oct-06Dec-06Feb-07Apr-07Jun-07ng/L

Jones Island South Shore Linear (Jones Island) Linear (South Shore)

### 3 Jones Island Influent Mass

0 20 40 60 80 100 120 140 160 1809/17/0311/17/031/17/043/17/045/17/047/17/049/17/0411/17/041/17/053/17/055/17/057/17/059/17/0511/17/051/17/063/17/065/17/067/17/069/17/0611/17/061/17/073/17/075/17/07grams/day



### South Shore Influent Mass

0 50 100 150 200 250 300 3509/17/0311/17/031/17/043/17/045/17/047/17/049/17/0411/17/041/17/053/17/055/17/057/17/059/17/0511/17/051/17/063/17/065/17/067/17/069/17/0611/17/061/17/073/17/075/17/07grams/day

### 4 Effluent Mercury

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.09/17/0311/17/031/17/043/17/045/17/047/17/049/17/0411/17/041/17/053/17/055/17/057/17/059/17/0511/17/051/17/063/17/065/17/067/17/069/17/0611/17/061/17/073/17/075/17/07ng/L

Jones Island South Shore Linear (Jones Island) Linear (South Shore)



### Effluent Quarterly Averages

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0Dec-03Feb-04Apr-04Jun-04Aug-04Oct-04Dec-04Feb-05Apr-05Jun-05Aug-05Oct-05Dec-05Feb-06Apr-06Jun-06Aug-06Oct-06Dec-06Feb-07Apr-07Jun-07ng/L

Jones Island South Shore Linear (Jones Island) Linear (South Shore)

### 5 Effluent Concentration with Outliers Removed

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.09/17/0311/17/031/17/043/17/045/17/047/17/049/17/0411/17/041/17/053/17/055/17/057/17/059/17/0511/17/051/17/063/17/065/17/067/17/069/17/0611/17/061/17/073/17/075/17/07ng/L

Jones Island South Shore Linear (Jones Island) Linear (South Shore)

### 6 Jones Island Effluent Mass

0 1 2 3 4 5 6 7 8 99/17/0311/17/031/17/043/17/045/17/047/17/049/17/0411/17/041/17/053/17/055/17/057/17/059/17/0511/17/051/17/063/17/065/17/067/17/069/17/0611/17/061/17/073/17/075/17/07grams/day



### South Shore Effluent Mass

0 1 2 3 4 5 6 7 89/17/0311/17/031/17/043/17/045/17/047/17/049/17/0411/17/041/17/053/17/055/17/057/17/059/17/0511/17/051/17/063/17/065/17/067/17/069/17/0611/17/061/17/073/17/075/17/07grams/day

### 7 Jones Island Flow Versus Influent Concentration

0 50 100 150 200 250 300

0 100 200 300 400 500 600 700 Concentration (ng/LFlow (MGD)



### South Shore Flow Versus Influent Concentration

0 50 100 150 200 250 300

0 100 200 300 400 500 600 700 Concentration (ng/L)Flow (MGD)

### 8 Jones Island Flow Versus Effluent Concentration

0 50 100 150 200 250 300

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 Concentration (ng/L)Flow (MGD)



### South Shore Flow Versus Effluent Concentration

0 50 100 150 200 250 300

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 Concentration (ng/L)Flow (MGD)

### 9 Jones Island Effluent TSS and Mercury

0 2 4 6 8 10 12 14 16 18

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 Mercury (ng/L)TSS (mg/L)



### South Shore Effluent TSS and Mercury

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 Mercury (ng/L)TSS (mg/L)

### 10 Jones Island Influent Versus Effluent

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0

0 100 200 300 400 500 600 700 Influent (ng/L)Effluent (ng/L)



### South Shore Influent Versus Effluent

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0

0 100 200 300 400 500 600 700 Influent (ng/L)Effluent (ng/L)

### 11 Agri-Life Mercury Concentrations

0 0.5

1 1.5

2 2.5

39/8/0311/8/031/8/043/8/045/8/047/8/049/8/0411/8/041/8/053/8/055/8/057/8/059/8/0511/8/051/8/063/8/065/8/067/8/069/8/0611/8/061/8/073/8/075/8/07mg/kg



### Milorganite Mercury Concentrations

0 0.2 0.4 0.6 0.8

1 1.29/7/0311/7/031/7/043/7/045/7/047/7/049/7/0411/7/041/7/053/7/055/7/057/7/059/7/0511/7/051/7/063/7/065/7/067/7/069/7/0611/7/061/7/073/7/075/7/07mg/kg

### 12 ENDNOTES TO ATTACHMENT 2 TO THE ADA COMMENTS

1 There may be treatment plants where the concentration of mercury from othe r sources are so elevated that they may mask any reduction in mercury concentrations in influent or biosolids.

2 Milwaukee Metropolitan Sewer District, Source Reduction E ffectiveness Analysis at 6 (May 2005), available at http://www.mmsd.com/docs/wastewatertreatment/ 05-067_Source_Red_Eff_Analysis_Report.pdf

.
3 Milwaukee Metropolitan Sewer District, Source Reduction E ffectiveness Analysis at 6 (May 2005), available at http://www.mmsd.com/docs/wastewatertreatment/ 05-067_Source_Red_Eff_Analysis_Report.pdf

.

.
4 Milwaukee Metropolitan Sewer District, Source Reduction E ffectiveness Analysis at 6 (May 2005), available at http://www.mmsd.com/docs/wastewatertreatment/ 05-067_Source_Red_Eff_Analysis_Report.pdf

..
5 Milwaukee Metropolitan Sewerage Dist rict, Mercury Data Summary at 4 to 6 (August 31, 2007) (Appendix 1 to this Attachment).

6 Milwaukee Metropolitan Sewerage Dist rict, Mercury Data Summary at 2 (Aug ust 31, 2007) (Appendix 1 to this Attachment).

7 Wichita Silver and Mercury BMP Program, Jamie G. Beld en, Pretreatment Specialist, Power Point Presentation, available <www.kansas.gov/uaa/sbcs/p resentations/belden%20jamie%20p2%20case%20studies.pdf> at 12 of 34.

8 Wichita Silver and Mercury BMP Program, Jamie G. Beld en, Pretreatment Specialist, Power Point Presentation, available <www.kansas.gov/uaa/sbcs/p resentations/belden%20jamie%20p2%20case%20studies.pdf> at 12 of 34.

9 Wichita Silver and Mercury BMP Program, Jamie G. Beld en, Pretreatment Specialist, Power Point Presentation, available <www.kansas.gov/uaa/sbcs/p resentations/belden%20jamie%20p2%20case%20studies.pdf> at 18 of 34.

10 Wichita Silver and Mercury BMP Program, Jamie G. Beld en, Pretreatment Specialist, Power Point Presentation, available <www.kansas.gov/uaa/sbcs/p resentations/belden%20jamie%20p2%20case%20studies.pdf> at 18 of 34.

11 An Assessment of Mercury in the Form of Amalgam in De ntal Wastewater in the United States. Jay A. Vandeven and Steve L. McGinnis, Water, Air, and Soil Pollution (2005) 164: 349–366, Springer 2005 (“2005 Vandeven/McGinnis Article”).

12 Mercury in Municipal Wastewater. Tim Tuominen, WLSSD, Rebecca Flood, MCES (September 19, 2007) available at < http://www.mnei.org/policy/images/HgTMDLmee tinginfo/WastewaterTreatment.pdf > at 16 of 35.

13 Mercury in Municipal Wastewater. Tim Tuominen, WLSSD, Rebecca Flood, MCES (September 19, 2007) available at < http://www.mnei.org/policy/images/HgTMDLmee tinginfo/WastewaterTreatment.pdf > at 17 of 35.

14 Madison Metropolitan Sewerage District, Mercury Pollu tant Minimization Program at 4 (PMP), available at <http://www.madsewer.org/ ProgramsAndInitiatives/Mer cury/MercuryPMP.pdf>.

15 Madison Metropolitan Sewerage District, Mercury Pollu tant Minimization Program at 4 (PMP), available at <http://www.madsewer.org/Pr ogramsAndInitiatives/Mercu ry/MercuryPMP.pdf>).

16 Madison Metropolitan Sewerage District, Mercury Po llutant Minimization Program at Appendix C (PMP).

17 Madison Metropolitan Sewerage District, Mercury Pollu tant Minimization Program at Appendix C (PMP) ), available at <http://www.madsewer.org/Progr amsAndInitiatives/Mercu ry/MercuryPMP.pdf>.

### 13 18 Mercury in Municipal Wastewater. Tim Tuominen, WLSSD, Rebecca Flood, MC ES (September 19, 2007) available at < http://www.mn-ei.org/policy/images/HgTMD Lmeetinginfo/WastewaterTreatment.pdf > at 27 of 35.

19 Mercury in Municipal Wastewater. Tim Tuominen, WLSSD, Rebecca Flood, MC ES (September 19, 2007) available at < http://www.mn-ei.org/policy/images/HgTMD Lmeetinginfo/WastewaterTreatment.pdf > at 31 of 35.

20 Clean Bay Pollution Prevention Plan 2007: The Pollution Pr evention Plan for the City of Palo Alto's Regional Water Quality Control Plant at 35 (February 2007), available at < http://www.city.paloalto.ca.us/civica/filebank/blobdload.asp?BlobID=7149 >at 49 of 231.

21 City of Palo Alto, Advanced Mercury Source Control Study, 2004 Annual Report of Activity at page 3 of 22 (February 2005), available at <http ://www.city.palo-alto.ca.us/civica/f ilebank/blobdload.asp?BlobID=3741>.

22 Clean Bay Pollution Prevention Plan 2007: The Pollution Pr evention Plan for the City of Palo Alto's Regional Water Quality Control Plant at 34 (February 2007), available at < http://www.city.paloalto.ca.us/civica/filebank/blobdload.asp?BlobID=7149 > (48 OF 231 of the pdf).

23 EBMUD Wastewater Department, 2006 Pretreatment and Pollution Prevention Report at 3-18 (2006), , available at http://www.ebmud.com/wastewater/industrial_&_commerci al_permits_&_fees/pollution_prevention_program/annu al_report/ww_pollution_prevention_annualreport_2006.pdf (page 37 of 142 in the pdf) and BUD, Mercury Control at Dental Facilities – A Cost-Effective Model, NACWA 2006 National Pretreatment and Pollution Prevention Workshop at 16 of 18, available at <http://archive .nacwa.org/getfile.cfm?fn=2006pret-b.horenstein.ppt>. Unfortunately, the Power Point presentation does not illustrate the effluent data.

24 EBMUD Wastewater Department, 2006 Pretreatment and Pollution Prevention Re port at 6-7 (2006), available at <http://www.ebmud.com/wastewater/industrial_&_commerc ial_permits_&_fees/pollution_prevention_program/ann ual_report/ww_pollution_prevention_annualreport_2006.pdf>.

25 East Bay Municipal Utility Distri ct (“EBMUD”) Wastewater Department, 2006 Pretreatment and Pollution Prevention Report at 3-18 (2006), available at <http://www.ebmud.com/wastewater/industrial_&_commerc ial_permits_&_fees/pollution_prevention_program/ann ual_report/ww_pollution_prevention_annualreport_2006.pdf>.
26 Installation of separators resulted, according to the Narragansett Bay Commission resulted in 17% and 23% reductions in influent mercury at Field’s Point and Bucklin Point respectively. Narragansett Bay Commission, Protecting the Environment with Pa ssion an d Integritty, ANNUAL REPORT | 2005 (2006), available at <http://www.narrabay.co m/Documents/PDFs/NBC_Annual_Report_FY05.pdf>.

27 Narragansett Bay Commission, Environmental Monitoring and Data Analysis, 2005 Monitoring Data at 40-42 and 47-49 of 111 (October 2006), availa ble at <http://www.narrabay.com/Docu ments/EMDA/Attachments%20All.pdf> at 42-44 and 49-51 of 111.

28 Some of the preliminary results of the NACWA study were presented at the NACWA 2007 Pretreatment meeting. See Managing Mercury, Other Metals, and More, Elizabeth Toot-Levy – Moderator, Northeast Ohio Regional Sewer District, available at < http://www.nacwa.org/images/ stories/public/07pret/2007pret-e.toot-levy.pdf >..