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Mercury Reduction Case Studies St. Mary's Medical Center, Duluth, Minnesota |
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The following information is from: Western Lake Superior Sanitary District (March 1997), "Blueprint for Mercury Elimination: Mercury Reduction Project Guidance for Wastewater Treatment Plants," page 18. St. Mary's Medical Center is a 326-bed hospital located in Duluth, Minnesota. Western Lake Superior Sanitary District (WLSSD) staff began the mercury reduction project by meeting with Hospital management to ensure their interest and commitment. Once support was assured, an existing team of Hospital employees worked with WLSSD staff on the project. Representatives from maintenance and purchasing departments were particularly important to the team. The maintenance staff is familiar with the inner workings of the Hospital, which is helpful when conducting monitoring. Purchasing department involvement is necessary because toxics reduction projects often involve changes in the types of products purchased and used. As a first step, the mercury reduction team completed a survey on mercury use provided by WLSSD (see survey at the end of this case study). The survey disclosed that St. Mary's had already replaced some mercury-containing items, such as thermometers and blood pressure cuffs, with alternative electronic devices. In addition, mercuric chloride, a common reagent used in the pathology lab, was being captured and handled as hazardous waste instead of being flushed to the wastewater treatment plant. A wastewater monitoring plan was then developed to try to pinpoint mercury sources within the Hospital. Older buildings, such as hospitals, often have several discharge points to the sanitary sewer system. Meeting with maintenance staff to review old blueprints was found to be essential before beginning the monitoring program. The use of dye tablets may be needed to verify sewer flow and route connection information, especially in facilities that have undergone expansion. Monitoring results found mercury concentrations varying from 0.3 ppb to 1.2 ppb. The monitoring also identified days on which mercury concentrations were high, and where it came from in the Hospital. In this case, the information was valuable in educating the reduction team. The team felt they had already solved their mercury problem and didn't anticipate additional discharges. Once they saw the numbers, however, a "can do" attitude quickly developed. In 1997, the remaining mercury in the wastewater appeared to be coming from the Hospital laboratories and laundry services. Reagents and bleach are the suspected sources. These products are being investigated and, where possible, alternatives will be substituted. Historic sources are also under investigation. Mercury from items such as broken thermometers may have been disposed of down the drain in older buildings. The mercury accumulates in waste traps and discharges in small amounts each time water is used. Traps in nursing stations and in the labs are being cleaned and inventoried as part of the reduction effort. WLSSD continues to work with St. Mary's on mercury reduction and has initiated similar projects with the other hospitals in Duluth. These following actions are essential first steps for any hospital beginning a mercury reduction project:
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Case Studies Mercury Reduction R E G I S T E R G L O S S A R Y F E E D B A C K S I T E M A P H O M E |
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