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Mercury
Work Group
Phase I Reports >> Executive Summary
Executive Summary | End-of-Pipe Report |
Operations Report | Infrastructure Report
For more information,
contact David Eppstein by email at
deppstein@masco.harvard.edu,
or by calling 617-632-2860.
MWRA\MASCO HOSPITAL MERCURY WORK GROUP
STEERING COMMITTEE
EXECUTIVE SUMMARY REPORT
June 23, 1995
Introduction
The Massachusetts Water Resources Authority (MWRA) is concerned
about the level of mercury being discharged into Boston Harbor
due to the possible effect elevated levels might have on aquatic
life. Elevated levels of mercury can also affect the quality of
fertilizer pellets manufactured by the MWRA making it more difficult
to market this recycled commodity.
Mercury is discharged in small quantities by a variety of industrial
sources and it is also present in trace amounts in some process
chemicals and household products, such as bleach. MWRA regulations
specifically prohibit the discharge of mercury to the sewer system
and the MWRA currently enforces this prohibition at a level of
five (5) times the method detection limit (MDL) of 0.2 parts per
billion (ppb). This results, at the present time, in an effective
discharge limitation of 1.0 ppb from MWRA regulated sources, including
hospitals and institutions.
For the past year, the MWRA has been working with area hospitals
and MASCO (a consortium of Longwood Medical and Academic Area
Institutions) in a collaborative process that stresses cooperation
and the pooling of resources to identify and address the problem
of mercury contained in hospital and medical facilities' wastewater
streams. This Hospital Mercury Work Group is a unique public-private
partnership that places us ahead of the rest of the country in
the effort to deal effectively with the mercury discharge issue.
The Work Group has approached the problem from three directions.
The Operations Subcommittee has been working to identify sources
of mercury contamination and develop recommendations for their
control. The Infrastructure Subcommittee has focused on developing
guidelines for the removal of residual mercury from hospital wastewater
conveyance systems. The End of Pipe Alternatives Subcommittee
concentrated on the identification and evaluation of potential
mercury pretreatment systems.
The Case of Hospitals
From the outset, hospitals have shared the MWRA's and the public's
concern about the presence of mercury in the wastewater stream,
particularly in light of their roles as health care providers.
Collectively (as part of the Hospital Mercury Work Group) and
individually, area hospitals have contributed enormous amounts
of time and resources to address this problem. Thousands of hours
of hospital staff time have been devoted to this project and more
than $1 million has been spent, to date, in search of solutions.
Meeting the MWRA's standard for discharge presents a formidable
challenge for hospitals because of the nature of the testing and
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, 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 the 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 if not impossible.
At the outset of the process, it was believed that the medical
community was, perhaps, the single largest contributor of mercury
into the MWRA Sewerage System. Some, in fact, had estimated that
up to 20 percent of the current mercury loading to the MWRA's
Deer and Nut Island facilities was being generated by the Hospitals
and Institutions served by the MWRA. Subsequent analysis of historical
flow information augmented by "Real Time" sampling and
documentation of actual flows from several institutions participating
in the Work Group seems to indicate that this initial perception
overstated the hospital problem. The current data base, as compiled
by the Hospital Mercury Work Group in conjunction with the MWRA,
appears to indicate that the hospitals' collective contribution
of mercury to the MWRA sewerage system is actually only 1 to 2
percent of the daily influent mercury loading (estimated by the
MWRA to be 3/4 of a pound). This amount translates to approximately
1/4 of an ounce in 1 million gallons per day of total wastewater
flow from 28 medical institutions participating in the Work Group.
Sources of Mercury
The three Subcommittees were each charged with the responsibility
of developing and implementing their own workplans. One common
objective of the Subcommittees was to document where the mercury
was coming from and how much of it existed. In the course of their
work, the Subcommittees drew from public data bases, performed
analytical testing of products to assess mercurial content, issued
letters to chemical manufacturers requesting their support, completed
facility audits, reviewed Material Safety Data Sheets (MSDS),
conducted interviews of suppliers of wastewater pretreatment systems
and technologies, generated new analytical data from actual points
of discharge from its members' facilities and researched the literature
in an attempt to prepare the most comprehensive database dealing
with mercury discharge problem that is currently available anywhere
in the United States.
Clinical & Research Laboratories
Some of the more obvious sources of mercury were readily identified,
such as thermometers, manometers and chemicals identified by their
MSDS to contain mercury. A bit more work was involved in identifying
mercury present in certain reagents, stains, immunodiagnostics,
disinfectants and cleaning solutions. Based on actual sampling
results, some bleaches, soaps/cleaners, x-ray photographic chemicals,
hematoxylins and acid zinc formalin were also identified as containing
mercury. It was also surprising to discover that "significant
levels" were found in laboratory petri dishes, wastewater
pretreatment chemicals and several saline solutions and T3 kits
containing Thimerisol. In addition, embedded tissues which had
been fixed in mercury containing fixatives were found to leach
mercury that contaminated other areas of the histology laboratories.
To date, the Operations Subcommittee has compiled an electronic
database of some 5,504 products used by the hospitals and institutions
participating in the survey. Of these, approximately 781 have,
thus far, been confirmed to contain some level of mercury. There
are 72 records which indicate a mercury content of between 1 -
10 ppb and 469 records noting a concentration above 10 ppb.
An additional 75 of the most commonly used products from the database
suspected of containing mercury have been selected for analysis.
This data, and other product information submitted by hospitals
and institutions will be added to the electronic database. This
"work in progress" will be updated semi-annually and
copies will be provided to active participants of the MASCO Hospital
Mercury Work Group in either the dBase III Plus Format, dBase
III Plus Hg Application, or the ASCII Format. An attempt is also
being made to work with the suppliers to identify suitable mercury
free alternatives to products currently being used. However, progress
on this front is complicated due, primarily, to the lack of known
suitable substitutes and people's concern over the liability of
using new (and often untested) alternatives.
Medical Waste Incinerators
In an effort to help minimize the impact of off-site solid waste
disposal, many institutions have installed and routinely operate
medical waste incinerators. The "Red Bag" wastes disposed
of in these units may contain syringes, blood products, tissues,
bags and other materials which may contain residual quantities
of mercury. Disposal of obvious sources of mercury, such as thermometers
or mercury bearing stains can also occur if proper waste management
directives are not followed.
These medical waste incinerators are typically supplied with
fume scrubbing capabilities which help to reduce the amount of
mercury, along with other regulated contaminants, from entering
the ambient air environment through the incinerator stack. These
contaminants may reenter the water phase via the recirculating
scrubber liquor and, subsequently, enter the sewer system via
the scrubber bleed-off discharge (typically 0.1 gallon per minute
per 1,000 scfm of exhaust capacity). Though not having the same
wastewater characteristics as the heavily organic laden clinical
and research laboratory wastewaters, the fume scrubber discharge
stream can be a significant source of mercury contamination to
the sewer system.
Infrastructure
Perhaps the most intriguing source of mercury discovered (and
possibly the most difficult to deal with) is the presence of mercury
contained in a facility's infrastructure piping system. By this,
we mean in the network of traps, pipes and tanks installed within
the building between a facility's laboratory sinks and the point
at which these liquid wastes would leave the building and enter
the sewer system. Several institutions have found mercury of
various forms in numerous conveyance plumbing locations. It is
not uncommon for a 10-15 year old trap, when removed, to contain
elemental mercury (Hg0) which is easily identified as a pool of
silvery liquid within the base of the trap. Elemental mercury
usually gets into laboratory sinks and floor drains as a result
of broken laboratory equipment. Some elemental mercury sources
included old mercury thermometers, thermostats and blood pressure
manometers.
A more significant finding than the presence of elemental mercury
in traps was that organic material present in the wastewater discharged
to a facility's "Special Waste" system, would encourage
the development and growth of biological material (biomass) within
the infrastructure itself where mercury would either settle out,
be physically adsorbed or, in the presence of bacteria living
in the piping, undergo a transformation to methyl mercury after
which it becomes adsorbed into the biomass. Many of the older
institutions were able to document the presence of mercury in
biomass growth from discharges that began over 50 years ago. Testing
performed by the Infrastructure Subcommittee documented a mercury
concentration of nearly 1,000 parts per million (ppm) in the biomass
removed from one Institution's infrastructure.
Since methyl mercury is readily concentrated in living tissue,
some facilities found that even minimum, or non detectable levels
of one form of mercury going down the pipe would, after a period
of time, show up in the biomass at significant concentrations.
As bits of these biosolids periodically break off and are flushed
out of the systems, they carry the concentrated mercury with them.
It is these elevated levels of mercury contained in the biosolids
that are frequently detected during compliance sampling.
Locating and removing this biomass from the pipes can prove to
be quite difficult due to the inaccessibility of much of the
system. This biomass formation is very difficult to remove and
control due to its location within the piping in locations and
lengths sometimes within institution walls. Consequently, it
is not uncommon to have the biomass build up to a point where
it restricts or prevents flow. When this occurs, there are only
two options:
1. Remove the piping and literally cut and scrap the biomass away
or
2. Replace the piping with new materials.
For less severe situations, the Infrastructure Subcommittee has
developed a Maintenance Guidebook that contains some recommended
procedures for the control of this biomass growth; these include
trap cleaning, powerwashing and chemical cleaning.
Approaches to the Problem
End-of-Pipe Alternatives
Complexities in hospital laboratory wastewater composition and
variations in hydraulic loading require a multiple technological
approach to the design of any end-of-pipe pretreatment system.
Designing systems to achieve a "non-detect" limit presents
additional problems since any time effluent monitoring data confirms
the presence of mercury, the Professional Engineer who designed
the system {MGL 21, Section 27 (13) and 248 CMR 2.13} could lose
his or her license. A system designed to remove mercury from a
hospital wastestream would also have to be able to remove nearly
all other pollutants from the wastestream as well, due to deleterious
impacts of both conventional and non conventional contaminants
upon pretreatment system components. For example, chlorine bleach,
used as a hospital disinfectant, can cause a rapid deterioration
of the membranes used in nanofiltration and reverse osmosis based
systems. Oil and grease can cause an almost immediate failure
of ion exchange media. The organic material and biological activity
present in the raw wastewater will use activated carbon as a food
source, in turn, causing premature failure of the media.
Equipped with that knowledge, the End of Pipe Alternatives Subcommittee
proceeded to evaluate the following technologies for potential
application to the mercury problem:
-
Simple Filtration
-
Reverse Osmosis
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Chemical Reactions
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Disinfection
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Membrane Microfiltration
-
Ion Exchange
-
Absorption
-
Evaporation
Over the course its fifteen (15) meetings, the Subcommittee heard
presentations of these technologies by engineers, equipment manufacturers/suppliers
and application specialists. From these interviews, it became
apparent that not very much historical case study information
was available so the Subcommittee attempted to solicit information
from preliminary field trials being completed by some of the equipment
suppliers at both Member and Non-Member Institutions.
Infrastructure Maintenance
In Massachusetts, "Special Wastes" include, but are
not limited to, organisms containing recombinant DNA molecules,
chemicals, nuclear, radioactive, acids, alkalines, perchloric
solvents and other such wastes that could be considered detrimental
to the public sewer system and which do not comply with limitations
established by the Publicly Owned Treatment Works such as the MWRA. All "Special Wastes" must be conveyed in a separate
waste and vent piping system. These systems are to be constructed
of approved code materials. The design, methods, materials, type
of neutralization, testing, and inspections required for "Special
Waste" piping systems serving laboratories and industrial
activities are governed under 248 CMR 2.13 of the Massachusetts
State Plumbing Code. All plans and specifications for "Special
Waste" piping and pretreatment systems shall be prepared
by a Registered Professional Engineer for submission to the local
Plumbing Inspector, MWRA, DEP or other authorities for review
and approval.
Neutralizing sumps or tanks (chip tanks) can be used for the pretreatment
of wastewaters containing dilute acids and alkalines from laboratory
sinks. These sumps are not allowed to adjust the
pH for wastewater generated by biomedical laboratories. These
sumps similarly cannot be used in facilities discharging significant
quantities of organic materials into the "Special Waste"
System or the biomass which is found will coat the marble chips
rendering the media useless.
As previously explained, mercury accumulation within "Special
Waste" conveyance piping systems containing biomass growth
with mercury creates a complicated wastewater compliance issue.
Two techniques through institution efforts have proved to be
very successful with biomass removal and mercury sources identification
are trap cleaning and conveyance pipe powerwashing.
Trap cleaning and removal will accomplish the following objectives:
trap location / identification, removal of elemental mercury (Hg0)
and removal of biomass growth. Trap cleaning procedures require
that all traps be located and identified so that, prior to cleaning,
a notification to the building occupants, explaining the details
of the cleaning procedures, can be provided. The cleaning procedures
simply require that a trap be removed, the contents be collected
for off-site disposal and the trap then cleaned with a rag or
brush prior to being placed back into operation.
The powerwashing procedure is a way to provide a physical scouring
effect on the accumulated biomass adhered to plumbing and piping
infrastructure. Powerwashing is an effective, but not permanent,
method for removing biomass and preventing biosolids from appearing
in the effluent discharges. Powerwashing techniques are most
efficient when performed on glass piping but, with thermoplastic
piping, some technique modification is required. Powerwashing
activities are usually, at a minimum, using a two (2) person team;
an operator of the powerwasher and a observer of the nozzle and
hose as it moves through the conveyance piping.
Since trap cleaning and conveyance pipe powerwashing will not
permanently remove biomass, periodic cleanings will be necessary
to help ensure recurring growth is removed. As a result of compliance
sampling, several institutions have proven the effectiveness of
trap cleaning and powerwashing.
Source Control
It is extremely difficult to determine which products actually
contain mercury. MSDS are not required to list any compound present
at less than a 1% (or 0.1% for carcinogens) concentration or component
of the product. For mercury, this means that a product might contain
up to 10,000 ppb and the MSDS would not have to indicate its presence.
The easier way to discover which products should be controlled
due to their mercury content requires a good faith effort by manufacturers
and suppliers of reagents to the medical community to step forward
and voluntarily report the actual concentrations of mercury present
in their products, regardless of whether or not they are above
the MSDS listing threshold. Toward this end, 153 questionnaires
were issued to the major suppliers of chemical reagents and immunodiagnostics
to the medical community asking them to voluntarily divulge the
mercury content of their products. To date, 61 responses have
been received containing various degrees of useful information.
Due to the voluntary nature of such a request, the results were
as expected.
Analytical testing is the other means that can be used to identify
the mercury content of a product. This can be very expensive,
time consuming and complicated. Work on this front is proceeding
but progress will be slow.
Public Awareness Training
Protocol and training efforts are critical components of the mercury
equation. Many areas have seen dramatic reductions in end-of pipe
concentrations through an initial information session explaining
to the general workforce of what impacts certain procedures have
on discharge limits. The 80/20 rule may apply here (meaning that
the initial 20% of effort applied will achieve an 80% reduction).
One errant disposal, however, can negate all progress made.
The protocol and training task force effort put forth by the Operations
Subcommittee has developed an outline for hospitals and institutions
to follow when educating their employees. The document contains
an introduction, problem statement, identification of goals, an
explanation of prohibited substances and an explanation of discharge
limitations. The mercury identification process flow diagram explains
the importance of a good chemical inventory control system. The
section on management of mercury sources includes identification,
reduction, and substitution initiatives. Mercury contamination
and sampling is also discussed as well as educational approaches,
training programs, and educational resources.
Accomplishments
Increased awareness and application of some of the lessons learned
through the Hospital Mercury Work Group process have already
led to a significant reduction in the amount of mercury being
discharged to the MWRA sewerage system by institutions participating
in the Work Group. An analysis of historical testing data from
the MWRA's files shows that there has been a 70% reduction
in the total mass of mercury being discharged into the system
(2.36 to 0.47 ounces per day) by these institutions and that the
average discharge concentration of mercury coming from the membership
has been similarly reduced by more than 80% during the past year
(21.4 to 4.3 ppb). Notably, only 15% of the 76 recorded discharge
locations currently remain at concentration levels that exceed
the aggregate membership average of 4.3 ppb.
Interpretation of the data after substituting current flow information
and removing analytical Non-Detects (NDs), yields an even more
positive measure of performance. The aggregate mass of mercury
being discharged by the Membership is reduced by 87% to only 0.31
ounces per day. Clearly this data is significant and demonstrates
the dramatic impact that source reduction and infrastructure measures
have had upon the overall mercury discharge issue.
The Infrastructure Subcommittee has been able to document the
presence of significant levels of mercury in the pipes, traps
and conveyance systems of the hospitals. Procedures for the methodical
identification, removal and cleaning of these systems have been
compiled and presented in the Subcommittee's Infrastructure
Maintenance Guidebook which can be followed by any facility
in the event that a problem is identified. The collaborative
efforts employed by the members of this Subcommittee in preparing
this manual have led to the development of a practical, "hands
on" approach to helping institutions remove biomass from
their infrastructure systems.
The Operations Subcommittee has sought to determine the mercury
content in the most commonly used chemicals and reagents. With
the cooperation of the MWRA, manufacturers and suppliers, the
Subcommittee has compiled an electronic database of more than
5,000 products. Using this information, the Subcommittee is urging
mercury source reduction by the substitution of products wherever
possible as well as stressing education, awareness and training
for both suppliers and users within the hospitals. Training aids
presented in the final report can assist hospitals in developinh
their own source reduction programs.
Conclusions
The End of Pipe Alternatives Subcommittee has concluded that not
one of the technologies investigated is individually or collectively
capable of reducing the concentration of mercury in a facility's
discharge to below 1.0 part per billion on a consistent or sustainable
basis. Some of the technologies have demonstrated abilities in
removing 99.7% of the total mercury from the wastestream prior
to discharge but the treated effluent still has a mercury content
at the 3 to 5 ppb level. Most of the technologies should be viewed
as polishing systems only and, as a result, initial pretreatment
is required before these advanced techniques can be applied; all
of which requires a significant amount of space and money to be
installed.
In an attempt to place some perspective on these costs as a function
of our membership's relative size according to flow rate, the
Subcommittee developed the following "Order of Magnitude"
table of costs for an End of Pipe solution which, according to
our research, cannot meet a stipulated effluent discharge standard
of 1.0 ppb:
|
Rank
|
Flowrate gpd
|
Capital Cost, $
|
Operating Cost, Expressed as a % of Capital/yr
|
|
Large
|
>20,000
|
1 to 2 Million
|
50%
|
|
Medium
|
5,000 to 10,000
|
Hundreds of Thousands
|
100%
|
|
Small
|
<1,000
|
Tens of Thousands
|
200%
|
The findings of the Infrastructure Subcommittee clearly indicate
that there are things an institution can do to help reduce the
residual presence of mercury in the wastewater conveyance system.
The Subcommittee's guidelines for maintaining and cleaning systems
provide practical and specific information on how to address the
residual mercury problem, once it has been detected. Bear in mind,
however, that the introduction of new sources that contain even
trace amounts of mercury can quickly erase all progress made on
this front.
Consequently, source reduction, through product identification
and employee/user education and training, has been identified
as the best means of effectively reducing the overall amount of
mercury being discharged from our wastewater systems. Product
manufacturers and distributors have also assisted us in this effort
by supplying mercury content information on specific products
and, in some cases, by helping us to identify mercury free alternatives.
The database of products used by hospitals that has been developed
by the Operations Subcommittee is the centerpiece of the Work
Group's efforts to identify products containing mercury and the
continued testing of products contained in that database will
make it easier for all of us to practice effective source control.
Recommendations
The Hospital Mercury Work Group has developed the following recommendations:
Recommendation Number 1:
Read and use the information contained in the Operations and Infrastructure
Subcommittee Reports to help reduce the level of mercury contained
in an institution's discharge. The MWRA should publicize and make available the Hospital
Mercury Work Group Reports. For their part, institutions should:
-
Practice source reduction through education and training of hospital
personnel when purchasing and using products containing mercury
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Use the products database as an aid to identifying potential
sources of mercury
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Work with vendors, doctors, lab personnel and others to explore
the use of mercury free substitutes wherever possible
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If a problem develops and cleaning is indicated, follow the procedures
(clean traps, powerwash pipes, inspect/clean tanks) recommended
in the Infrastructure Maintenance Guidebook.
-
Review the efficacy of limestone chip neutralization tanks and
replace with active neutralization systems when and where appropriate
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Develop accurate flow information at points of discharge. If
this includes the installation of flow meters, work to ensure
their compatibility with MWRA sampling equipment
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Install MWRA approved sampling taps following "Special Waste"
collection and neutralization systems. Ensure that no inappropriate
(sanitary, NCCW, etc) waste sources enter the "special waste"
piping systems.
-
Prevent the discharge of identified mercury bearing stains,
reagents, chemicals, etc. to the "Special waste" system
and dispose off-site as regulated waste.
Recommendation Number 2:
Procedures governing the issuance of Notices of Violation (NOV)
for mercury should be revised to reflect the following principles:
-
Compliance schedules should be established to allow an institution
to demonstrate a good faith effort of implementing the recommendations
contained in the Subcommittees' Reports
-
Sample testing during the compliance period should only be used
to monitor the effectiveness of remedial actions taken and not
serve as the trigger for additional enforcement action
-
The Memorandum of Understanding (MOU) developed by the MWRA regarding
the issuance of fines arising from mercury violations should remain
in effect for the duration of the compliance schedule
Recommendation Number 3:
Representatives from the Hospital Mercury Work Group should continue
to work with the MWRA on the establishment of a more appropriate
discharge limit (both interim as well as long term) for mercury.
Recommendation Number 4:
Continue this MWRA/Hospital Mercury Work Group partnership by
establishing an exchange program that would include visits to
each other's facilities for more than compliance purposes.
Acknowledgments
This Report and the work it summarizes was truly a collaborative
effort involving scores of people from the participating hospitals,
their consultants and the MWRA. All who participated in the process
deserve congratulations for a job well done. Special thanks go
to those people listed below in recognition of the leadership
they provided:
Gary Cousin, Steering Committee Chair - Newton-Wellesley Hospital
David Eppstein, Staff - MASCO
Robert Gingras, Technical Consultant - Earth Tech
Rudman Ham, Work Group Chair - Children's Hospital
David Hathaway, Steering Committee - Mount Auburn Hospital
Phil Kenney, Operations Co-Chair - Quincy Hospital
"Kip" McClelland, Steering Committee Chair - Deaconess
Hospital
Bruce McCoy, Steering Committee - Deaconess Hospital
Kevin McManus, Director TRAC - MWRA
Daniel Murphy, Infrastructure Co-Chair - Beth Israel Hospital
Karen Rondeau, TRAC - MWRA
James Segel, Legal Consultant - Hale & Dorr
Anand Seth, Infrastructure Co-Chair - Massachusetts General Hospital
Charles Storella, End of Pipe Chair - Dana-Farber Cancer Institute
MASCO Hospital Mercury Work Group Contributors
Beth Israel Hospital
Brigham and Womens's Hospital
Boston University Medical Center
Children's Hospital
Dana-Farber Cancer Institute
Deaconess Hospital
Deaconess Glover Hospital
Harvard Medical School
Joslin Diabetes Center
Lahey Clinic
Massachusetts College of Pharmacy and Allied Health Sciences
Massachusetts General Hospital
Melrose Wakefield Hospital
Milton Hospital
Mount Auburn Hospital
Quincy Hospital
New England Medical Center
Newton-Wellesley Hospital
Quincy Hospital
St. Elizabeth's Hospital
South Shore Hospital
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