Draft Document – EPA Region 8 cam Industrial Pretreatment Program 4/28/05 

1

This DRAFT is being circulated for comment. Comments are due 

no later than June 15, 2005. Please send comments to the email 

address or physical address shown below. 

DRAFT 

May 9, 2005 

POTW MERCURY CONTROL STRATEGY 

Addendum to the Region 8 Strategy for the Development of Local Limits 

U.S. EPA Region 8, Industrial Pretreatment Program 
Draft Document – EPA Region 8 cam Industrial Pretreatment Program 4/28/05 

2

DISCLAIMER

The mention of trade names, commercial products, or organizations does not 

imply endorsement by the U.S. Government. The statements in this document are 

intended to provide technical support and guidance on the development of Local Limits 

to protect the POTW and implement provisions of the Clean Water Act, 40 CFR Part 

403, and the POTW’s NPDES permit for POTWs in EPA Region 8. This document is 

not intended, nor can it be relied on, to create any rights enforceable by any party in 

litigation with the United States. This document may be revised without public notice to 

reflect EPA policy and regulations. 

EPA wishes to thank all of the reviewers for their technical review and input in the 

revision of this document. 

This is intended as a working document. As the science improves and additional 

information becomes available, this document will be modified. Updates will be made 

available at: http://www.epa.gov/region08/pretreatment

 For further information, you may contact Curt McCormick (8P-W-P), USEPA Region 

8, Suite 300, 999 18th Street, Denver, CO 80202 or email the pretreatment program at: 

mccormick.curt@epa.gov
Draft Document – EPA Region 8 cam Industrial Pretreatment Program 4/28/05 

3

POTW MERCURY CONTROL STRATEGY 

Addendum to the Region 8 Strategy for the Development of Local Limits 

I. Summary

This Strategy has been developed to provide assistance to POTWs in addressing situations 

where mercury has been identified as a pollutant where controls are needed to reduce 

discharges to a Publicly Owned Treatment Works (POTW). POTWs, with or without an 

approved pretreatment program, are required to develop and implement local limits to address 

pollutant problems and protect their POTW (see 40 CFR Section 403.5 and the POTWs NPDES 

permit). Many POTWs have developed local limits for Significant Industrial Users (SIUs) and 

other non-SIUs. Region 8 has modified the Local Limits Strategy to provide specific guidance 

for developing local limits for all non-domestic users for those pollutants of specific concern to 

POTWs from the commercial (non-SIU) sectors. 

In the past, POTWs had a method available for mercury that would quantify mercury 

concentrations at or above 200 parts per billion (μg/L). EPA has approved an analytical method 

that is used to measure mercury concentrations in the parts per trillion range (ng/l). This 

advance in the science of testing has allowed POTWs to generate low level, quantifiable 

mercury data. The new mercury data will result in some POTWs needing to revise local limits 

and implement controls to reduce mercury discharges to POTWs. 

Region 8 details three approaches addressing mercury discharges where mercury is identified 

as a problem (see Section II. B.). The first approach is a traditional process of including 

numeric local limits in an enforceable control mechanism. The second approach allows the 

discharger to demonstrate through analytical data that it has adequately controlled its discharge 

for the pollutant. The third approach is the use of Best Management Practices (BMPs). The 

use of BMPs is at the POTW discretion and shall not be an expectation of any non-domestic 

user. 

If a POTW is required to develop and implement an enforceable BMP program, the POTW will 

be required to specify how it intends to implement activities to identify and reduce POTW 

mercury loadings from the various sources. The goal of the mercury control program is to 

reduce POTW influent mercury loading and effluent mercury discharge to a level that assures 

the underlying NPDES permit limit and/or state water quality standard or other limiting criterion 

or standard is met. 

This Strategy focuses on general and specific approaches to controlling mercury. While this 

document is intended as a source of information for POTWs in Region 8 developing and 

implementing mandatory mercury control programs, this Strategy also provides useful 

information that could be used in the implementation of voluntary programs. In addition, this 

Strategy is written with a focus on approved pretreatment programs. However, many POTWs 

without approved pretreatment programs will find the information and concepts in this Strategy 

useful. The reader is directed to Section VI of this document for references used in the 

development of this Strategy. 
Draft Document – EPA Region 8 cam Industrial Pretreatment Program 4/28/05 

4

II. Mercury Program Evaluation

A. Applicability 

Voluntary Programs

Many POTWs are evaluating whether to implement a voluntary or mandatory mercury control 

program. Voluntary programs are strongly supported and encouraged by Region 8 to address 

mercury before it becomes a problem. Voluntary mercury control programs may be developed 

and implemented where: 

1. The POTW has no projected or actual violations of its mercury NPDES permit limit (interim or 

final limit); 

2. The POTW does not have a compliance schedule in its NPDES permit for meeting a mercury 

limit; 

3. The POTW influent monitoring is less than 90% of the MAHL; 

4. The Water Quality Standard for the receiving water is not being exceeded (based upon 

calculations or observation); or 

5. No other limitation (etc. Biosolids) or standard is being exceeded. 

As a note: All non-domestic users are required to comply with all Pretreatment Standards and 

Requirements established by the POTW. If the POTW implements a voluntary program under 

the conditions specified above, the non-domestic user must comply with what the POTW 

requires. 

Mandatory Programs

Mandatory POTW mercury control programs will be implemented where: 

1. Projected or actual violations of its mercury NPDES permit limit (interim or final limit); 

2. The POTW has a compliance schedule in its NPDES permit for meeting a mercury limit; 

3. Influent monitoring is 90% or greater of the MAHL; 

4. The water quality standard for the receiving water is being exceeded (based upon 

calculations or observation); or 

5. A limitation or standard (e.g. Biosolids) is being exceeded. 
Draft Document – EPA Region 8 cam Industrial Pretreatment Program 4/28/05 

5

B. Approaches to Controlling a Pollutant of Concern 

EPA, Region 8 recognizes the following general approaches to controlling mercury for nondomestic dischargers: 

1. Issue a control mechanism to dischargers. This is the process that POTWs have 

used to control discharges from Significant Industrial Users (SIUs) and specific nonSIUs. The requirement to control non-domestic users through the use of permits or 

orders is an existing pretreatment program regulatory requirement and an approved part 

of local programs. The permitting process establishes limits for specific pollutants, and 

requires sampling and reporting to the POTW. Permits can also contain other 

requirements that the POTW deems necessary for a particular discharger. Permit 

violations are enforced by the POTW according to its legal authority and implementing 

procedures for compliance. 

2. Monitoring to demonstrate no discharge of concern. POTWs routinely gather 

pollutant information from non-domestic users to allow the POTW to determine whether 

specific pollutants need to be controlled. Typically, the POTW and/or non-domestic 

users monitor the discharge at a frequency sufficient to characterize the discharge. For 

highly variable discharges, the POTW may require a specific number of samples to be 

collected to account for differences in operations. This evaluation is also coupled with a 

review of raw materials used and waste management practices. 

3. Require specific BMPs. POTWs may issue a control mechanism that defines the 

BMPs that a non-domestic user must implement as a condition of discharge to the 

POTW. For many non-SIUs, this may be effective at addressing specific pollutant 

contributions from individual waste streams. BMPs, by themselves, would require that 

the POTW and/or discharger demonstrate that the BMPs are effective at reducing the 

pollutant discharge. Where BMPs result in a zero discharge status for the pollutants of 

concern, no further analytical sampling is required. Similarly, where the BMPs include 

installation of adequate treatment on the pollutants of concern, additional effluent 

monitoring by the discharger may not be required. 

All of the options listed above may be components of a mercury control program for the POTW. 

The POTW will make the decision of whether treatment is required for a discharger to meet 

limits and requirements, as it is required to do under its approved pretreatment program. A 

POTW is not required to adopt the BMP approach. This Strategy is not intended to interfere 

with existing POTW pretreatment program procedures and is not intended to suggest that a 

POTW must allow any option that is not part of its approved pretreatment program. 
Draft Document – EPA Region 8 cam Industrial Pretreatment Program 4/28/05 

6

III. Mercury Control Program

There are some general components to be considered when designing a mercury control 

program: 

A. Define whether there is a problem. Monitor the POTW’s influent, effluent, domestic 

contribution, non-domestic contribution and Biosolids; 

B. Develop adequate legal authority and SOPs (submit to the Approval Authority as 

required); 

C. Allocate adequate resources and staffing needed to implement the mercury control 

program; 

D. Identify sources of mercury that contribute to POTW influent loadings; 

E. Implement control measures for identified sources; 

F. Public education program; and 

G. Track and report mercury source reduction. 

The following questions should be considered: 

▪ What is the extent of the mercury loading problem, if any? 

▪ Do you have adequate legal authority (ordinance or rules and regulations)? 

▪ What changes to local limits need to be made to allow you to address non-SIU 

discharges? 

▪ Do you have the necessary Standard Operating Procedures (SOPs), forms, etc? 

▪ Do you have appropriate monitoring/reporting requirements developed? 

▪ Do you have good data on commercial, domestic and influent mercury levels? 

▪ Are you going to use permits, enforcement orders, or other control mechanisms for nonSIUs? 

The following figure provides a timeframe that the POTW can use when designing its program. 
Draft Document – EPA Region 8 cam Industrial Pretreatment Program 4/28/05 

7

Begin Hg Program Development

0-8 mo: Complete Legal Authority Changes (submit for Approval), Local Limits, SOPs, and resource allocation 

0-12 mo: Focus on Training and Outreach 

0-6 months Complete Additional Hg Monitoring

6 mo 12 mo 18 mo 

8-12 mo: Issue BMP controls and incorporate BMPs into existing Permits 

0-6 mo: Use existing IWS procedures to identify potential sources of Hg 

Evaluate Hg loading to the POTW. Hold public meeting or update regulated entities and public via written communication. 

0-7 mo. Approval Authority Review

BMP Program Implementation 

Where a POTW is required to implement a mandatory mercury control program, the POTW will be requiimplementation of its source reduction strategies and conduct the specified monitoring. The POTW shogeneral timeframes for development and implementation of the mercury control program. Where the POpermit or other Standards, the individual steps should be completed in the shortest time possible. Many adequate legal authority in-place which would accelerate implementation of a program. The use of this 

an affirmative defense. It is provided as a tool for the POTW to use for design and implementation of a 
Draft Document – EPA Region 8 cam Industrial Pretreatment Program 4/28/05 

8

A. Define the Problem – Data Review and Collection

The POTW must have the data on which to base its decisions. The most significant decision is 

whether there is a mercury problem to address. The POTW must ensure that its monitoring 

program (influent, effluent and biosolids) is completed with proper sampling and analysis 

procedures. POTWs with approved pretreatment programs and other major POTWs without 

approved programs already have a requirement to monitor for mercury in their influent and/or 

effluent. Depending on the disposal option, POTWs will also be monitoring biosolids for 

mercury. 

Many POTWs have used a test method (245.1) that is generally not sensitive enough to allow 

the POTW to make a determination as to whether there is a mercury problem. The POTW 

needs reliable and accurate data to determine the appropriate removal efficiency for the POTW. 

The POTW is required to use the most sensitive analytical method necessary to allow the 

POTW to evaluate compliance. 

If the POTW demonstrates through analytical data that no mercury loading problem exists, there 

is no need for a mandatory mercury control program, though the POTW has the option of 

implementing one. The POTW should continue to monitor and evaluate mercury influent and 

effluent data and opt to implement a voluntary program. 

A couple of notes on mercury monitoring should be considered: 

1. The frequency of monitoring must be adequate to evaluate mercury contributions to the 

POTW. Most POTWs will be looking most critically at the headworks loading to 

characterize contributions within the sewerage system. If the POTW performs sewer 

system monitoring, the POTW is encouraged to use sewer maps supported by on-site 

verification to assure that assumptions on contributors to a specific sampling point are 

correct. 

2. Depending on the disposal option for biosolids, the POTW may have to initiate sampling 

to evaluate the level of mercury in the biosolids. The POTW should characterize the 

mercury in biosolids since removal efficiencies indicate that the majority of mercury 

received by the POTW are partitioned to the Biosolids. 

 

3. The POTW should carefully evaluate whether a MDL of <0.2 ug/L is adequate. More 

POTWs are realizing that they must use Method 1631 (currently approved under 40 CFR 

Part 136) or Method 245.7 (expected to be approved) for mercury analyses. Failure to 

use these more sensitive methods may result in significant re-sampling requirements to 

obtain a definitive value for mercury. 
Draft Document – EPA Region 8 cam Industrial Pretreatment Program 4/28/05 

9

4. The POTW should sample commercial and domestic contributions. The latter is 

especially important since the domestic contribution is generally considered 

uncontrollable under 40 CFR Part 403. POTW influent monitoring plus domestic 

monitoring plus SIU monitoring would allow the POTW to also calculate the contribution 

from the non-SIU sectors. However, if the POTW does not sample the domestic and 

commercial contributions, then the mass-balance for mercury loading at the POTW will 

be less useful. Targeting specific commercial dischargers or lift stations is most 

commonly done. See Section III.D. for more information on potential sources. 

5. If Infiltration and Inflow (I&I) are of concern or significant, the POTW should design 

sampling programs for specific sewer lines that will allow an evaluation of the 

contribution from this source. These contributions are generally viewed as 

uncontrollable under the pretreatment program and reductions in I&I the sole 

responsibility of the POTW through infrastructure improvements and will not be a 

consideration in delaying or abandoning the adoption of local limits. 

6. If the POTW has not been monitoring mercury in the influent and effluent, or doing so 

infrequently, EPA strongly suggests that the monitoring frequency be increased to a 

level of 6 influent/effluent samples over a six week period (alternating days) to better 

characterize the POTW influent mercury loading. The removal efficiency can have a 

major impact on the ultimate local limit that is calculated. 
Draft Document – EPA Region 8 cam Industrial Pretreatment Program 4/28/05 

10

Mercury Methods and Source Characterization (8) (16) (17)(19) (20)(21) 

Source Typical Concentration Method Options 

POTW wastewater influent 21 - 500 ng/L 

1631 (dilution) 

1631 modified (245.7) 

POTW wastewater effluent 1 – 51 ng/L 1631 

POTW sludge or biosolids 

0.2 – 30 mg/Kg (dry weight) – 

Generally on the lower end SW846: 7471B 

POTW Collection System 50 - 1000 ng/L 

1631 (dilution) 

1631 modified (245.7) 

1631 modified (CVAAS) 

245.1 (optimized & dedicated 

instrument) 

Industrial Effluent - SIUs 138 ng/L 

1631 

1631 modified (245.7) 

1631 modified (CVAAS) 

Commercial Effluent 489 ng/L 

1631 modified (245.7) 

1631 modified (CVAAS) 

1631 (dilution) 

245.1 

Residential 

38 ng/L 

1631 

1631 modified (245.7) 

1631 modified (CVAAS) 

Trucked and Hauled Waste 3057 ng/L

1631 (dilution) 

1631 modified (245.7) 

1631 modified (CVAAS) 

245.1 (optimized & dedicated 

instrument) 

Surface Water 0.2 - 10 ng/L 1631 

Dental office discharge 

(without separator treatment 

and no dilution by sanitary 

wastewater) 

episodic discharges ranging to 

> 5,000,000 ng/L 

245.1 

1631 modified (CVAAS) 

1631 modified (245.7) 
Draft Document – EPA Region 8 cam Industrial Pretreatment Program 4/28/05 

11

POTW Mercury Contributions 

Several POTWs have evaluated the relative contribution of mercury at their POTW headworks 

and at several sources within their sewer systems. Below is an analysis of the broad categories 

of mercury sources that were identified. The following data is intended to provide a general 

understanding, not a definitive headworks loading evaluation. Many of these numbers could be 

prefaced by placing the qualifier “up to” before these values. Region 8 expects that POTWs will 

be generating site-specific data for their POTWs. 

Sources (1)(8)(16)(20)(21)(22) % of POTW Headworks Loading 

Dental Offices 60.2 Up to 53% 62.2 

Human waste, human 

waste with amalgam, 

and residential 

products 

26.5 14 

 

18.4 

Hospitals, Dentists, 

Universities 

 44 

Permitted Industry 

(incl University) 

7 8 0.9 

Stormwater: 4 

Other (Groundwater, 

I&I) 0.4 

 

Trucked and Hauled 

Septage 

 0.36 

Commercial Sector 18 

Uncharacterized 34 
Draft Document – EPA Region 8 cam Industrial Pretreatment Program 4/28/05 

12

B. Legal Authority 

There are a number of areas of the POTW legal authority that must be reviewed. The POTW 

needs to have authority to implement local limits and BMPs for non-SIU contributors. The 

POTW can convert all non-SIU mercury contributors to SIUs and apply local limits through 

individual control mechanisms, though this may be resource intensive. POTWs have the 

general authority to control all non-domestic users through their ordinance and rules. More 

specific authority may be needed in the legal authority to specifically address: 

 1. Issuance of control mechanisms to non-SIUs. POTWs may adopt a variety of 

measures to control non-SIUs. Individual permits are generally limited to SIUs 

because of the resources involved in the SIU permitting process. The most 

common approach has been the use of “Specific Notice of Authorizations” (a 

letter based format), and “General Permits” (a permit that establishes similar 

conditions for all users that fall into a specific sector or business type). 

 2. Application of local limits and/or BMPs to all IUs. Some POTWs may adopt 

specific local limits or specific BMP requirements into their legal authorities for 

non-SIUs. 

 3. Enforceability of the controls. Depending on how the POTW chooses to 

implement its legal authority, the POTW may make modifications to its 

enforcement authority or procedures. The current enforcement, including penalty 

authority in approved programs, should be adequate to address violations of 

Pretreatment Standards and Requirements by all non-domestic dischargers. 

The POTW should consult with their attorney and the Approval Authority on this issue if there 

are any questions. These changes may be a substantial modification to the POTWs legal 

authority. 

C. Resources and Staffing

POTW pretreatment staff should carefully evaluate the resources and staffing necessary to 

carry out this program. The inclusion of an NPDES limit in a permit or a water quality standards 

related issue generally drives the POTW to look at mercury reductions. Pretreatment staff 

should coordinate with the city or district office that works with the state NPDES permits 

program. It is critical that the POTW Pretreatment Program not try to absorb increased costs 

and staffing needs without a careful evaluation. Discarding existing pretreatment requirements 

or activities may be critically scrutinized by the Approval Authority. It is strongly suggested that 

the POTW work closely with their management in addressing needed resources. EPA is 

available to provide support in these discussions (where EPA is the Approval Authority). As 

with other program activities, the POTW should evaluate whether cost recovery be considered 

for newly identified dischargers. 
Draft Document – EPA Region 8 cam Industrial Pretreatment Program 4/28/05 

13

D. Identification of Mercury Sources

The Mercury Control Program requires that the POTW have a systematic approach for 

identifying and evaluating sources of mercury discharged to the POTW. There are numerous 

potential sources of mercury highlighting the need for the POTW to have a good database on 

commercial and industrial discharges to the POTW. The database typically already in-place for 

approved programs as a part of the Industrial Waste Survey procedures. Without a thorough 

industrial waste survey, the POTW may find it very difficult to develop and implement a 

sampling plan, interpret mercury data, or otherwise develop an overall strategy for controlling 

commercial businesses or sectors. 

Note: Do not rely solely on MSDS for the purpose of defining components of commercial 

products (or any other activities that are designed to evaluate low level contaminants). MSDS 

are useful only for chemical constituents down to about 1%. The POTW/IU is strongly urged to 

perform direct chemical analyses on wastewaters or raw materials where the pollutant would be 

of concern at a level below 1%. For raw materials used by specific facilities a Certificate of 

Analysis will provide a more thorough and useful evaluation of chemical contaminants. 

Following is a list of potential sources of mercury. 

Identified Mercury Sources

Algae sample preservative 

Auto salvage 

Batteries: Hearing aids, pacemakers, defibrillators, fetal monitors, Hofler monitor, pagers, 

picker caliber, spirometer alarm, telemetry transmitter, temperature alarm, blood analyzer 

Blood pressure cuffs (if they are not digital, they may contain mercury) 

Boilers: commercial and industrial boiler maintenance 

Cathodes 

Chemicals: acetic acid, acetone, aldehyde, ammonia, arsenic, bleach, buffers, barbital, 

chloride, chlorine, citric acid, CO in gas, cystine, glucose, HCN, iron, ferric chloride, ferrous 

chloride, glucose, Kjeldahl nitrogen, manganese, mercury, mercury chloride, nitric acid and 

Utrex, organomercury catalysts, phenyl mercuric acetate, sodium hydroxide, standard mercury 

solutions, thiophene, vanadium, wine coloring, zinc. 

Chlor-alkali industry: mercury cell processes: production of chlorine, caustic soda, sodium 

hydroxide and products manufactured with these raw materials. 

Coloring: colored papers, horn, inks, linen, plastics, rubber, sealing wax, stain for wood 

(discontinued), mordant in dye for beaver and rabbit pelts. 

Commercial Labs (5 ppb) 

Contact lens solution, nasal spray containing preservative Thimerosal 

Crematories: Ash Disposal 

Dental offices, Dental amalgam 

Disinfectants: phenyl mercuric acetate, thimerosol, Merthiolate, Mercurochrome 

Electroplating Al 
Draft Document – EPA Region 8 cam Industrial Pretreatment Program 4/28/05 

14

Etching steel/iron, fire gilding, blackening brass 

Extracting Au from Pb and extraction of Au and Ag from Ore 

Fish meat/waste 

Fuel Oil – Eastern US Residential and Commercial 

Fungicide/pesticides: paper mill slimicide, seed protectant, snow mold control at golf courses, 

root maggot control, imported undyed textiles, gold porcelain paint, corrugated cardboard glue. 

Hospital: clinical, incinerator, laundry and research facilities discharge (0.3 to 5.4 ppb) 

Household switches, industrial switches, mercury thermocouple, motion switches 

Human Waste (ingestion of mercury containing foods and liquids) and leaching of mercury from 

dental amalgam fillings. 

Incinerators: solid waste, medical waste, sewage sludge, cremation, coal, oil, natural gas, 

wood. 

Industrial Laundries 

Instruments/equipment – Medical/Scientific: barometers, hydrometers, manometers, 

pyrometers, sphygmomanometer, thermometers, defibrillators, esophageal dilators, cantor 

tubes, Miller Abbot tubes, feeding tubes, microwave ovens, nursing incubators, room 

temperature controls, refrigerators, Analytical instruments using mercury chloride as a reagent, 

electron microscope uses it as a vibration dampener. 

Laboratories – commercial and testing: premixed tubes for COD analysis. Also see Chemicals

Lamps: fluorescent, high pressure sodium, mercury arc or vapor lamps, metal halide, neon, UV 

disinfectant, cathode ray tubes (CRT) 

Landfill leachate – may range from 0.7 to 2 ppb 

Laundry Gray water 

Medical Laboratories: Thimerosal and Mercuric Chloride (preservatives in many reagents used 

in medical testing). Reagents containing these: Merthiolate, Mercury Nitrate, Mercury Iodide, 

Buffer, Mucolex, Stabilur Tablets, Immu-sal, Camco, B5 Fixitive, Zenker’s Solution, Helly, 

Ohlamacher, Carnoy-Lebrum, Shardin, Mercuric Oxide, Mercurochrome, Mercurophyline, 

Mercury Sulfate, Millon’s Reagent, Nessler’s Solution, Phenol Mercuric Nitrate, Takata’s 

Reagent, Gram Iodine, Carbol-Fuchin, Carbol Gentian Violet, Gomori’s, Cajal’s, Alum 

Hematoxylin (Solution A), Golgi’s 

Mining: Hg mines and where Hg is a secondary product 

Paint – Latex – pre-1990 and some older marine paints 

Petroleum Refining 

Pharmaceuticals: anesthetic, antiseptic, antineoplastic agent, antisyphilitic, cathartic, diuretic, 

purgative. 

Phosphate fertilizer production 

Plastics: catalyst for curing; fireworks: Pharaoh’s serpents and Bengal green lights; 

Photography intensifier (discontinued). 

Pottery/Arts: up to 31 ppb; some ceramic glazes up to 41 ppb. 

Preservatives: tanning, embalming (discontinued), anatomical specimens 

Rectifiers, batteries (alkaline, button (Hg-Zn and Hg-Cd)). 

Recycling: facilities doing fluorescent lamp recycling and thermostat recycling. 

Residential (uncontrollable through 40 CFR Part 403) 

Scrubber Water – 200 to 20 ppb (before and after treatment, respectively 

Septage Haulers, portable toilets (62 ppb) 

Spiritist Use: asogue, precipitado rojo (HgO), precipitado amarillo (HgO), precipitado blanco 
Draft Document – EPA Region 8 cam Industrial Pretreatment Program 4/28/05 

15

(Hg2Cl2) 

Stain used in laboratory slide preparation 

Stormwater, Infiltration, groundwater 

Switches: Silent wall switches (prior to 1991), wall-mounted office thermostats, airflow/fan 

limits, building security systems, pressure control, torque-arm alarm switches, float control (used 

for sump pumps). 

Toys and games 

Universities (labs, medical) 

Veterinary (labs, treatment) broken thermometers and chemicals 

Vaporization: landfill gas, petroleum refining, POTWs, smelting and roasting at mining 

operations. 

Volcanos, cinnabar (mineralized bedrock). 

Water supply; water supply residuals from treatment 

Wood burning, esp bark 

WWTP trickling filter arm 

References for the table above include: 

1. New Hampshire Mercury Reduction Strategy. www.des.state.nh.us

2. Blueprint for Mercury Elimination, 1997. Western Lakes Superior Sanitary District. 

http://www.wlssd.duluth.mn.us/

3. Massachusetts Water Resources Authority, MASCO Mercury Working Group www.masco.org and see Harvard 

University: www.uos.harvard.edu/ehs/

4. Palo Alto Regional Water Quality Control Plant, Mercury Pollution Prevention Plan, October 1997. 

http://www.city.palo-alto.ca.us/cleanbay/

5. Mercury in Massachusetts. 1996. Department of Environmental Protection. www.state.ma.us/dep/

6. Wastewater Practices: Mercury Discharge. www.uos.harvard.edu/ehs/

7 EPA Region 8 Pretreatment Program and POTWs. 

8. Vermont Department of Environmental Conservation. Mercury Education and Reduction. 

http://www.anr.state.vt.us/dec/ead/mercury/merc.htm

9. Al Garcia, Littleton/Englewood Pretreatment Program. Evaluation of the Sources, Impacts, and Controls of 

Mercury. 2002. http://www.ci.englewood.co.us/wwtp/departments/PT/PT.htm

10. EPA. Mercury in Medical Facilities. http://www.epa.gov/seahome/mercury.html
Draft Document – EPA Region 8 cam Industrial Pretreatment Program 4/28/05 

16

E. Implement Control Measures 

40 CFR Part 403 requires that enforceable local limits be developed and implemented for the 

control of any pollutant of concern. Section II.B. discusses the various approaches. Some 

pollutants may be effectively controlled through the implementation of Best Management 

Practices (BMPs). Region 8 supports the use and implementation of enforceable BMPs. The 

approved pretreatment POTW is required to use permits or orders if the discharger is classified 

as a SIU. Where the discharger is a non-SIU, the POTW may require specific controls through 

permits, orders, discharge authorizations, or other legally enforceable controls. The POTW 

should obtain a legal review from its attorney and adoption of these procedures and changes to 

the legal authority (ordinance or rules) may require approval from the Approval Authority (see 

Section III.B.). 

Local Limits

The POTW shall use the latest revision of the Region 8 Local Limits Strategy and appendices 

for developing local limits where the POTW identifies the need to modify or develop local limits 

for mercury. EPA has also put out some general guidance for local limits (July 2004) that may 

also be of use. The following items will drive the development or modification of existing local 

limits: 

1. The POTW only adopted a local limit for SIUs: Most POTWs originally developed local 

limits around this concept. The approved local limits package was approved and has 

additional loading data for non-SIUs. EPA Region 8’s latest Local Limits Strategy moves 

away from this SIU-only approach to one that encourages POTWs to develop separate 

local limits for SIUs and Non-SIUs, the MAIL and MACL, respectively. In some cases, 

the POTW may choose to adopt a MAL and allocate the loading to all regulated users in 

lieu of adopting a separate MAIL and MACL. 

2. The POTW used a less sensitive analytical method and had to rely on assumptions on 

the level of mercury (default data), including compliance with existing water quality 

standards. 

3. The POTW has no local limit for mercury. Mercury is determined to be a pollutant of 

concern and a local limit is required to be developed. The POTW is required to apply 

the local limit as appropriate. 

4. The state has adopted new or revised water quality standards for the receiving water for 

mercury (including a TMDL). 

5. The POTW wants to use BMPs. Region 8 is requiring that the POTW adopt a local limit 

for mercury as the underlying, supporting limit for implementing BMPs (without 

treatment) or a monitoring-only approach for the non-SIU sector. POTWs will generally 

adopt a local limit for SIUs as a concentration (mg/L) or mass-based (lbs/day) limit. The 

local limit for non-SIUs should generally be in a mass based form (lbs/day). 

Concentration-based limits have been adopted for non-SIUs in limited cases (e.g. the 

silver program requiring the use of treatment technologies). 
Draft Document – EPA Region 8 cam Industrial Pretreatment Program 4/28/05 

17

6. The POTW has been issued a permit that has more protective limits for mercury, either 

as an effective limit or a delayed limit. 

7. The POTW wants to implement a voluntary program to avoid the mandatory program 

requirements (see Objectives of the Pretreatment Program at 40 CFR Section 403.2 and 

Applicability section of this Strategy). 

BMPs

BMPs need to establish specific action items and specific dates that describe what activities 

need to be completed and/or reported. BMPs developed by POTWs to prevent Pass Through 

and Interference would be enforceable Pretreatment Standards under 40 CFR 403.5, where the 

POTW adopts the legal authority for BMPs and makes them enforceable through the issuance 

of a permit and/or other control mechanism. 

POTWs usually implement BMP controls by three different approaches: 

1. IU self reporting on BMP implementation; 

2. POTW on-site inspections and site visits to verify compliance ; and 

3. A combination of these approaches 

Effectively requiring and managing BMP implementation for a specific discharger requires that 

the POTW be very explicit on what is being required. The POTW is urged to go over the 

requirements with the person responsible for compliance. Procedural and technical issues that 

should be addressed where appropriate include: 

1. Specific Notice to IUs of requirements and enforceability 

2. Installation of adequate treatment/wastewater prohibitions where necessary 

3. BMPs addressing adequate O&M of treatment unit(s)* where required. 

4. BMPs addressing all sources of mercury discharge 

5. Reporting (or records retention) for O&M, monitoring and other activities 

6. Certification of compliance by the IU (report to POTW) 

7. Re-opener for a permit and local limits should a BMP approach be ineffective; and 

8. Inclusion of other BMPs/requirements as determined by POTW. 

* O&M procedures are based upon the type of treatment system used per the manufacturer’s 

specifications. The approved type of treatment will depend on the form, concentration and 

physical characteristics of the mercury and the characteristic and volume of wastewater to be 

treated. 
Draft Document – EPA Region 8 cam Industrial Pretreatment Program 4/28/05 

18

F. Public Education Program 

Many POTWs have been implementing education programs for mercury and other pollutants 

(e.g. mercury thermometer collection programs, IU training, newsletters, household hazardous 

waste collection, etc). External groups also provide technical information on how to manage 

waste. The most up-to-date information can be identified by doing an Internet search for these 

activities (through common Internet search engines). EPA also has various programs for 

mercury waste management (www.epa.gov and search for mercury). 

 

G. Tracking Reductions and Reporting to the Approval Authority (states or EPA) 

Updates to mercury control efforts will be required to be submitted to the Approval Authority as 

part of the POTW Pretreatment Annual Report where the POTW is on a mandatory mercury 

control program. For other POTWs, the POTWs should report to the Permitting Authority and 

EPA as required in the POTW NPDES Permit or other control mechanism or regulatory 

reporting requirement. The content of the reports may include: 

 1. A summary of all mercury monitoring performed during the reporting period; 

 2. A summary of all legal authority changes made and a program description (if these 

were not previously provided to the Approval Authority); 

 3. A listing of resources being dedicated to the program; 

 4. A listing of actual/potential sources of the pollutant that have been identified; 

 5. A summary of all source control activities; 

 6. A graph showing mercury influent loadings to date (e.g. last three years); and 

 7. Other information as required by the Approval Authority. 

The graph of influent loading over time (may also include effluent loading) is particularly 

important to allow the POTW to gauge the on-going effectiveness of its mercury control 

program. Specifically, the POTW should institute a data tracking and evaluation system that 

allows the POTW to evaluate changes in mercury loadings over time. This data will provide 

feedback on whether: (1) the mercury control program is effective; (2) increases in monitoring 

and/or inspections on IUs are needed; (3) enforcement is needed; or public education programs 

are needed. 

 
Draft Document – EPA Region 8 cam Industrial Pretreatment Program 4/28/05 

19

IV. Dental Specific Information

This strategy is not requiring the POTW to treat dental dischargers any differently than other 

dischargers for mercury. Region 8 EPA is not requiring any POTW to mandate BMPs in lieu of 

issuing a control mechanism with specific limits. However, where a POTW opts to implement a 

BMP program for dental discharges, the following information should be reviewed. 

If POTWs require BMPs + Treatment at dental facilities that use or discharge mercury, these 

controls are equivalent to a traditional permit (limits, monitoring, reporting). Where BMPs plus 

treatment are appropriately implemented, additional monitoring for mercury on dental facility 

discharges is not being required. 

A. BMPs for a BMP Control Approach – Dental Facilities 

Dental facilities BMP controls may be similar to other sources, except that treatment and 

management of wastes have been fairly well characterized. Control mechanisms for the 

Implementation of BMPs may include: 

1. Specific notice to dentists regarding requirements and enforceability of the BMP controls; 

2. Installation of treatment (e.g. an amalgam separator). (Note: Treatment other than an 

amalgam separator may be adequate. This decision must be based on analytical data 

for that treatment system and appropriate O&M procedures); 

3. Specific requirement for adequate O&M of treatment unit(s) if treatment is required; 

4. Specific requirements for applying BMPs to the discharge of mercury waste through other 

wastewater generating activities (e.g. sinks or other drains). Note: Dentists may be able 

to achieve compliance with limitations and requirements through the use of BMPs only. 

Monitoring mercury discharges will determine whether BMPs alone will be successful; 

5. Reporting (or records retention) for O&M, monitoring and other activities 

6. Certification of compliance by the dentist; 

7. Re-opener for a permit and local limits at the POTWs discretion; and 

8. Inclusion of other BMPs/requirements as determined by POTW. 

B. Dental Amalgam 

Dental amalgam is formed by the reaction of mercury with amalgam alloy (Ag, Sn, Cu) with a 

particle size of 0.1 micron to 3.15 microns. Amalgam may typically contain 50% metallic 

mercury, 35% silver, 9% tin, and 6% copper. 

Average amalgam may contain as much as 450 mg Hg (mixed or prepared for placement). 

Excess amalgam is estimated at 25% or 112.5 mg/Hg. About 9% of mercury in amalgam 

placement is released to wastewater. Mercury in amalgam removal is about 300 

mg/Hg/removal. 90% will be released to dental wastewater or 270 mg (22). 
Draft Document – EPA Region 8 cam Industrial Pretreatment Program 4/28/05 

20

C. Dental Related Waste Streams that may Contain Mercury 

Cuspitor (spit bowl) – Gravity flow – filter: chairside trap 

Cuspitor – Liquid Ring vacuum – filter: chairside trap and vacuum filter 

Cuspitor – Dry Vacuum – filter chairside trap and air/water separator 

Saliva Ejector – Liquid Ring Vacuum – filter: chairside trap and vacuum filter 

Saliva Ejector – Dry Vacuum – filter chairside trap and air/water separator 

Mixing and tool cleaning wastes 

Elemental or bulk mercury 

Used amalgam caught on the chair-side trap (Contact Amalgam) 

Amalgam sludge that settles in a vacuum pump trap 

Non-contact amalgam (scrap) 

Amalgam capsules 

D. Separator Technology 

Separators are manufactured by a number of companies and are the most commonly available 

commercial treatment systems used by dentists. The efficiency requirements for amalgam 

separators and their general acceptability are determined by a number of factors. This includes 

sizing of the units for the wastewater flow and whether the units have been certified by the test 

procedure (ISO 11143) developed by the International Organization for Standardization 

(American National Standards Institute – ANSI is the U.S. member) or ISO. The ISO does not 

oversee or certify labs conducting the test procedure nor does the ISO get involved with 

choosing or installing a separator. 

E. Mercury Removal and Practices 

Type of Treatment 

Chair side traps 60-75% 

Vacuum filters: 12-20% 

Chair Side trap + Vacuum Filter: 72-95% 

*Sedimentation, filtration and adsorption (non-detect using 1631) 

*Filtration and ion exchange (95-96%) 

*Sedimentation, filtration, ion exchange and adsorption (non-detect using std methods) 

*Filtration and adsorption (chelation) 99.99% 

* These are generally considered the best available treatment for amalgam removal that 

have been reviewed. Costs: Separators: $0-$4000 per dental facility; O&M annual cost: 

$300-$1800 per dental facility. 
Draft Document – EPA Region 8 cam Industrial Pretreatment Program 4/28/05 

21

F. Miscellaneous BMP/Considerations* 

Install ISO 11143 certified amalgam separator 

Do not rinse screens or traps into the sewer 

Keep records of amalgam waste shipments 

Use of Air-Water separators for larger amalgam particles 

Proper installation and O&M is required. 

Collected waste shall be disposed of properly. 

Certifications: certifies to proper installation. ID mfg and model, describe and show location, 

describe and show sampling point, ID owner and facility where unit was installed; ID the max 

flow the separator is designed to treat. 

Use pre-capsulated alloys 

Recycle used amalgam capsules and non-contact amalgam 

Salvage amalgam pieces from restorations and recycle 

Recycle trap, filters and separator waste 

Recycle extracted teeth with amalgam restorations (after disinfection). 

Don’t put amalgam waste in biohazard/infectious waste bags (incineration and air release) 

* These were provided by reviewers of previous drafts of this Strategy and other general 

sources (3)(10)(11)(15). These are provided for informational purposes only. 

Authors note 1: While exemptions for dentists that process 3 or fewer amalgams per year is 

being considered by some programs, serious complications of verifying the information (record 

reviews) may occur due to doctor-patient confidentiality.
Draft Document – EPA Region 8 cam Industrial Pretreatment Program 4/28/05 

22

Section V Q&A’s

The following are questions generated from the comments and questions received from various 

entities. 

Q: When are mercury control programs mandatory? 

A: In situations where mercury concentrations exceed the calculated amount of mercury that 

can be safely accepted, the POTW must take steps to reduce the mercury contributions. All 

non-domestic sources are potentially subject to mandatory control measures as determined by 

the POTW. 

Q: Does Region 8 allow voluntary programs? 

A: Region 8 supports and strongly encourages voluntary mercury reduction programs. There 

are a number of POTWs in Region 8 that are opting to control mercury through voluntary efforts 

before it becomes a pollutant of concern requiring mandatory controls. 

Q: Is Region 8 requiring that dentists install amalgam separators? 

A: No. The determination as to whether treatment is required is based upon the POTWs 

mercury control program, analytical monitoring data, and compliance with pretreatment 

standards. Amalgam separators are the most common, commercially available treatment 

systems currently available for dentists (see the note at Section IV.F). Region 8 allows for 

demonstration of other treatment where a discharger wishes to utilize another type of treatment 

system. This demonstration would require specific data on the treatment system (e.g. removal 

efficiency, O&M requirements, etc). 

Q: Is this Strategy consistent with the National approach on local limits? 

A: Yes. This Strategy is consistent with the National local limits. 

Q: The mercury in a dental discharge may be in the range of 5 – 15 mg/L mercury in dental 

waste waters when working with new amalgam or removals of old amalgam. This seems to 

exceed the characteristic hazardous waste definition. Shouldn’t these dental facilities be 

required to report under 40 CFR Part 403.12(p)? 

A: The TCLP mercury maximum concentration for a characteristic hazardous waste is 0.2 mg/L 

(40 CFR Section 261.24). The pretreatment regulations require reporting where a discharge is 

greater then 15 kg/month. If the wastewater TCLP test exceeded the 0.2 mg/L level AND the 

facility discharges over 15 kg (approximately 4 gallons) in the month, then the facility is required 

to report under 40 CFR Section 403.12(p). 
Draft Document – EPA Region 8 cam Industrial Pretreatment Program 4/28/05 

23

Q: Shouldn’t EPA be required to consider cost-effectiveness of requiring treatment and 

minimize impacts on dentists? 

A: POTWs are designed to treat domestic wastewater. To the extent non-domestic sources of 

wastewater can safely be handled, the POTW may agree to accept the wastewater. Costeffectiveness to an industrial user of a POTW is not a factor when controls are needed to 

prevent discharges to a POTW that may cause pass through of pollutants to the receiving water, 

interfere with POTW operations, cause adverse impacts to worker health and safety, or interfere 

with the ability to recycle or reclaim solids. 

Q: Isn’t the problem with mercury in surface waters due to air deposition and runoff from 

historic mining activities and not dental offices? 

A: The pretreatment program develops and implements local limits based upon, in part, water 

quality standards and NPDES permit limits. The setting of water quality standards and NPDES 

permit limits are established prior to the development of local limits by a POTW by states. The 

presence or absence of mercury from air deposition or mining sources is site specific and may 

be addressed when water quality standards are established. 

Q: Isn’t the discharge from dental offices highly variable? Aren’t sampling costs high? 

A: The discharge from dental offices and other businesses may be variable. However, POTWs 

have successfully identified mercury levels reflective of the various operating conditions at 

dental offices. POTWs commonly deal with non-domestic users that have variable discharges. 

If the discharger opts to sample a highly variable discharge, the sampling and analysis costs will 

be higher than for a facility that has a more consistent discharge. If the discharger opted to 

sample their effluent data on a daily basis for a year, the sampling costs would be significant 

reflecting the need to obtain a sample that is representative for the pollutant being discharged 

and not targeting sampling when the discharger knows that the pollutant would not be expected 

to be present. The sampling and analysis costs should be evaluated by the discharger and 

compare with the costs of keeping the pollutant out waste stream from the beginning. 

 

Q: There is no legal basis for mandatory requirements for mercury limits on discharges into 

POTWs. What is the basis for requiring controls on internal waste streams? 
Draft Document – EPA Region 8 cam Industrial Pretreatment Program 4/28/05 

24

A: 40 CFR Part 403 specifically sets requirements for discharges by non-domestic users into 

POTWs. Local Limits and categorical standards (40 CFR parts 405-699), specifically establish 

limits and prohibitions that apply to discharges to POTW sewerage systems. The term “internal 

waste stream” is more commonly used in the direct discharge NPDES program. POTWs have 

the authority to specifically limit or prohibit the discharge of any pollutant from any process that 

is ultimately discharged to the POTW. Most regulated users opt to treat waste water at the 

source of generation, rather than installing a treatment system to treat the entire wastewater 

discharge. Most POTWs would allow either option. 

Q: Why isn’t methyl mercury specifically addressed? 

A: Current water quality standards are set for mercury. If states adopt water quality standards 

for methyl mercury for the NPDES program, EPA will incorporate an evaluation of methyl 

mercury into its local limits process. 

 

Q: States are not reporting that mercury water quality standards (20-50 ug/L are common in 

Region 8) are being exceeded so why is EPA addressing mercury from POTWs? 

A: Dischargers have only recently begun to implement a method to measure mercury in 

effluents below 0.2 ug/L. Therefore, data showing the levels of mercury in effluents has not 

been well characterized. With the implementation of the more sensitive test method, more data 

on actual mercury concentrations in effluents and surface waters will be reported. Region 8 

agrees that many POTWs will not have effluent concentrations of mercury that require action. 

However, others will, and the Strategy is developed to assist those POTWs in addressing any 

problems. 

 

Q: Why is EPA requiring amalgam separators over the ADA’s BMPs and voluntary efforts? 

A: Region 8 is not requiring amalgam separators over ADA BMPs and voluntary efforts. 

Region 8 agrees with the ADA’s efforts to provide technical assistance to dischargers on BMPs 

to reduce mercury. Region 8 also supports and strongly encourages voluntary programs. 

However, where BMPS and other actions cannot effectively reduce the discharge of a pollutant, 

treatment is used to further reduce effluent levels. 

Q: Distribution of the Region 8 Strategy has prevented interested parties from commenting on 

the draft. 
Draft Document – EPA Region 8 cam Industrial Pretreatment Program 4/28/05 

25

A: Initial drafts of the Strategy were distributed to Region 8 POTWs and states, on two 

occasions, to identify implementation barriers. State and POTWs are co-regulators in the 

pretreatment program. The ADA was supplied with the draft document upon request. It was 

also sent to the state dental associations. 

The final draft of the document is targeted for spring, 2005, and is intended for distribution to a 

broader audience, including the dental contacts. The draft will be posted on the Region 8 

website for pretreatment (www.epa.gov/region08/pretreatment) for download. 

Q: How can Region 8 require pretreatment programs and dentists to install amalgam 

separators though this guidance document? 

A: Pretreatment programs in Region 8 have the existing legal authority and procedures to 

address mercury discharges from all non-domestic users through the use of permits, monitoring 

and reporting. This Strategy does not require POTWs or dentists to do anything, but rather 

provides guidance to allow non-traditional approaches (e.g. BMPs) to effectively control mercury 

discharges where needed. 

Q: Why isn’t Region 8 implementing variances for mercury water quality standards similar to 

that in the Great Lakes that take into account costs of requiring use of amalgam separators? 

A: States set water quality standards. As with Region 5’s mercury control guidance, Region 8 

uses the water quality standards that are in effect for a specific receiving water when developing 

local limits. Where a variance exists, the POTW would use that state issued (and EPA 

approved) variance. POTW Pretreatment programs do not have the legal authority to apply 

variances to water quality standards. The Great Lakes Initiative addresses conditions unique to 

Region 5. 

Q: Why does the strategy show two years for a POTW to implement mercury program controls? 

A: Region 8 believes that mercury control programs at most POTWs can be fully implemented 

sooner than two years. However, two years was seen as a reasonable time frame where the 

POTW had to develop the program from scratch. It should be noted that most approved 

pretreatment programs already have most of the components in-place to address mercury. 

It should be noted that where the POTW is required to implement mercury controls, the POTW 

will be implementing the program efficiently to avoid violations of its NPDES permit or other 

standards that may have implications to industrial users that are causing or contributing to these 

violations. 

Q: Discharges from dental facilities to POTWs is a minor source of mercury to the nation’s 

surface waters. Why waste the resources? 
Draft Document – EPA Region 8 cam Industrial Pretreatment Program 4/28/05 

26

A: Where mercury is not a problem at the POTW, the POTW is not required to do anything 

(though Region 8 supports voluntary programs). The contribution of mercury to a POTW and 

the receiving water may be significant in some cases. Where a discharge is above that level 

allowed by the underlying water quality standard, the mercury in the discharge must be reduced. 

The Pretreatment Program addresses these sources while other environmental programs 

address other sources of mercury. Implemented together, the various environmental programs 

will reduce the overall mercury load to the environment 

Q: Amalgam separators may be less efficient than what the Strategy describes. 

A: Region 8 acknowledges that individual treatment systems may be less efficient than 

currently described in the Strategy. However, implementation of BMPs plus treatment is highly 

effective at reducing mercury discharges to POTWs. A properly operated treatment unit will 

achieve removal efficiencies comparable with the treatment technologies outlined in the 

Strategy. 

Q: Setting numerical limits for dental offices is infeasible. 

A: Setting specific limits for non-SIU sectors is relatively straightforward. These limits are 

established on specific analytical data and standards. POTWs have extensive experience with 

calculating how much of a pollutant that they can accept from non-domestic users. This is 

completed by taking the maximum that a POTW can accept based upon the underlying 

standard, receiving water, and POTW operations. This maximum allowable headworks loading 

is further refined by subtracting out the residential (domestic-only) contribution. This maximum 

allowable non-domestic load is then divided up among the significant industrial users and the 

non-SIU (commercial) sectors. The non-SIU portion is then divided up among the commercial 

sectors of interest. 

 
Draft Document – EPA Region 8 cam Industrial Pretreatment Program 4/28/05 

27

VI. References 

(1) City of Palo Alto, CA: Mercury Headworks Analysis for 2002. March 2001, revised 

January 2002 and “Advanced Mercury Source Control Study”, November 7, 2003, snf 

many other documents. Palo Alto, CA (http://www.city.palo-alto.ca.us/cleanbay/) 

(2) Blueprint for Mercury Elimination, 1997. Western Lakes Superior Sanitary District. 

http://www.wlssd.duluth.mn.us/

(3) American Dental Association (www.ada.org) 

(4) Bill Johnson, EIP Associates. Mercury Amalgam Treatment Technologies for Dental 

Offices. July 10, 2000. Technical Memorandum for Palo Alto Regional Water Quality 

Control Plant. 

(5) Keith J. Linn. National Mercury Issues. Northeast Ohio Regional Sewer District. 

Presented at the AMSA/EPA Pretreatment Coordinators Workshop. November 21, 

2003. 

(6) Massachusetts Water Resources Authority, MASCO Mercury Working Group 

www.masco.org and see Harvard University: www.uos.harvard.edu/ehs/

(7) Peter Berglund. Metropolitan Council Environmental Services, St. Paul, MN. Use of the 

ISO Test Procedure to Evaluate Amalgam Separators. Presentation at AMSA/EPA 

Pretreatment Coordinators Workshop. November 19-21, 2003. 

(8) Al Garcia, Littleton/Englewood, CO., Pretreatment Program. Evaluation of the Sources, 

Impacts, and Controls of Mercury. 2002. 

(9) Mercury Study Report to Congress. EPA, 1997. http://www.epa.gov

(10) New Hampshire Mercury Reduction Strategy. www.des.state.nh.us

(11) Palo Alto Regional Water Quality Control Plant, Mercury Pollution Prevention Plan, 

October 1997. http://www.city.palo-alto.ca.us/cleanbay/

(12) Mercury in Massachusetts. 1996. Department of Environmental Protection. 

www.state.ma.us/dep/

(13) Wastewater Practices: Mercury Discharge. www.uos.harvard.edu/ehs/

(14) EPA Region 8 Pretreatment Program and POTWs, personal communications and 

POTW Annual Reports. 
Draft Document – EPA Region 8 cam Industrial Pretreatment Program 4/28/05 

28

(15) Vermont Department of Environmental Conservation. Mercury Education and 

Reduction. http://www.anr.state.vt.us/dec/ead/mercury/merc.htm

(16) Wisconsin Department of Natural Resources and EPA Region 5 Draft Mercury Pollutant 

Minimization Guidance, NPDES Program Branch, February 2004. 

(17) Stone, M., Pederson, E., Jones, R., et al. 2000. "Evaluation of an Integrated System 

to Remove Mercury from Dental-Unit Wastewater." Journal of Dental Research, 79:545, 

3216.

(18) EPA. Mercury in Medical Facilities. http://www.epa.gov/seahome/mercury.html

(19) EPA Region 8, Biosolids Program. 

http://www.epa.gov/region08/water/wastewater/biohome/biohome.html

(20) City of Fort Collins, Colorado. Industrial Pretreatment Program. David Meyer. 

dmeyer@fcgov.com

(21) EPA, Region 5, Mercury Pollutant Minimization Program Guidance. 

www.epa.gov/region05/

(22) American Dental Association. November 16, 2004. Letter to EPA providing comments 

on the draft Region 8 Mercury Control Strategy. Reports that were provided include: 

Assessment of Mercury in the Form of Amalgam in Dental Wastewater in the United 

States, November 14. 2003; and, Laboratory evaluation of amalgam separators, Fan, 

P.L. et. al.; and, Amalgam in dental office wastewater, author not shown.