MASCO/MWRA Hospital Mercury Work Group

About the Mercury Work Group

The Massachusetts Water Resources Authority (MWRA) currently prohibits the discharge of mercury by industrial facilities to its sewer system and imposes an effective discharge limitation for mercury of 1.0 part per billion (ppb) from its regulated sources, including hospitals and institutions. Meeting the MWRA's standard for sewer discharge presents a formidable challenge for hospitals because of the nature of the testing performed and the type of equipment used by health care providers in their effort to effectively diagnose and treat disease. Key substances used in research and diagnostic work, reagents in particular, often contain trace amounts of mercury that are usually not listed in the content descriptions.

These trace amounts of mercury tend to collect in the organic material (biomass) that may be present in waste piping systems and, as a consequence, can slough off into the wastewater stream at any time. This problem is further complicated by the fact that laboratory testing procedures vary significantly, depending upon the type of testing or research being conducted, making standardization of procedures exceedingly difficult.

Phase I Reports

To address this complex issue, the MWRA established a Mercury Products Work Group in the Fall of 1994 to examine the problem and develop strategies to reduce the amount of mercury being discharged. Hospital participation in this process was coordinated through MASCO (a not-for-profit provider of services and technical assistance to Longwood Medical and Academic Area institutions), and involved the active participation of twenty-eight (28) hospitals.

One of the innovative aspects of this project involved the MWRA's and hospitals' willingness to suspend their usual rules of engagement by moving beyond the traditional use of enforcement mechanisms including fines as the primary means of pursuing compliance. Specifically, the MWRA distributed a memorandum stating that the MWRA would not fine a hospital for mercury violations, so long as they were actively participating in Work Group activities. This not only provided direct economic relief to some of the institutions (prior to formation of the Work Group, one of the members had received a fine in excess of $100,000), but it served to create a climate in which all parties were able to focus more clearly on the search for solutions to the problem at hand. The repercussions of this paradigm shift caused institutions to also consider and change their normal ways of interacting with each other. Rather than competing, as is so often the case these days, the participating institutions focused on bringing their collective resources to the table. The pooling of knowledge and the allocation of staff in this fashion has helped to produce results much more quickly and thoroughly than would have otherwise been possible. In addition, this collective approach to addressing common concerns has thus far saved those institutions more than $2 million through the elimination of duplicate efforts that would have been required as part of individual compliance programs.

The Work Group (with a new name of the MWRA/MASCO Mercury Work Group) approached the problem from three directions:

  • Identify sources of mercury contamination and develop recommendations for their control.
  • Develop guidelines for the removal of residual mercury from wastewater systems.
  • Identify and evaluate potential mercury pretreatment systems. 

In the course of their work, the various Subcommittees of the Work Group drew from public data bases, researched the literature, performed analytical testing of products to assess mercury content, issued letters to chemical manufacturers requesting their support, completed facility audits, reviewed Material Safety Data Sheets (MSDS), conducted interviews with suppliers of wastewater pretreatment systems and technologies, generated new analytical data from actual points of discharge from its members' facilities, and directed a bench-scale feasibility test program with six participating pretreatment technology vendors. As a result of implementing lessons learned during the Work Group process, the average hospital mercury discharge has fallen by 83% since 1994 and from approximately 8 ppb in MWRA FY1997 to less than 4 ppb in FY1998.

In 1997, the MWRA issued another memorandum creating penalty "safe harbors" for those institutions that continued to make progress toward compliance with the mercury discharge prohibition under enforcement orders and schedules. In response, several facilities have been implementing mercury pretreatment systems to bring their discharges into compliance.

A relational database containing information on the mercury content of products used in various facilities, including clinical and research laboratories has been developed and is available on this website. This Mercury Products Database can be accessed via the link on the left navigation menu. Use this tool to get critical mercury content information on products by name or type of use. You can also check to see if there are known mercury-free alternatives. We encourage you to help us improve the database by sharing information you might have on particular products. We can be contacted at

Phase II Reports

During Phase II of this project that began in 1996, the MWRA/MASCO Mercury Work Group produced four important documents. The Facilities Loadings Subgroup Report details what we have learned about the levels of mercury discharge from five types of facilities. The Pretreatment Guidance Manual contains useful information intended to help facilities understand the various steps that may be necessary as part of a comprehensive source reduction program. The Manual pays particular attention to the selection, design, installation, and operation of an industrial wastewater pretreatment system. The Technology Identification Subgroup Report is a companion document to the Pretreatment Guidance Manual and presents information on the chemistry of mercury in wastewater and on the results of bench-scale feasibility tests of six mercury pretreatment technologies on samples of clinical laboratory wastewater.

Recognizing the need to integrate all that we have learned about reducing mercury discharges, the Work Group completed the Mercury Management Guidebook in May 1999. The Guidebook was written to help all types of facilities in overall management of mercury to reduce and control the mercury content of sewer discharges. While directed toward facilities discharging to sewers in the MWRA sewer service area, the Guidebook should be an important resource to any facility in an effort to reduce mercury discharges.

Oustide the MWRA/MASCO Mercury Work Group, MASCO prepared a Generic RFP for the Testing of Mercury Removal Technologies that outlines one approach to pretreatment system vendor selection. This RFP is intended to help institutions that find it necessary to pursue pretreatment options in addition to source reduction.

As a follow-up to the Work Group's bench-scale pretreatment feasibility testing project, the Massachusetts Strategic Envirotechnology Partnership (STEP), operating under the Massachusetts Executive office of Enfironmental Affairs (EOEA), conducted a pilot-scale project of four mercury removal technologies at threee wastewater generating facilities. The STEP project report is expected to be published in late 1999.

For more information, contact us by email at, or by calling 617-632-2860.

Related Links

Toxics Use Reduction Institute - University of Massachusetts Lowell
MWRA Website
EPA PBT Project
EPA Documents on Mercury
Eco Gateway


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