Environmental Engineering Reference
In-Depth Information
that mercury-added products be labeled; that the sales of
many specifi c mercury products for which alternatives
exist be phased out; that manufacturers notify the states
about mercury-added products they are selling; and that
manufacturers and government institutions enhance the
collection and recycling of end-of-life mercury products.
The Interstate Mercury Reduction and Education
Clearinghouse (IMERC) was established by the states to col-
lect and manage the data submitted under legislative mer-
cury product notifi cation requirements. IMERC also helps in
the implementation of other aspects of state mercury-prod-
ucts laws. IMERC data are currently the only source of infor-
mation on total mercury use and trends in use in products in
the United States. Manufacturer notifi cations indicate that,
concurrent with the implementation of state mercury-prod-
ucts legislation, mercury use in fabricated and formulated
products decreased nationally by about 11%, or about 14 tons
per year, between 2001 and 2004 (NEWMOA, 2008e).
Many other mercury pollution-prevention initiatives have
also been implemented across the region. Details of these
efforts can be found at the respective state agency websites.
These include legislation requiring manufacturer-funded recy-
cling programs targeting thermostats (Maine and Vermont)
and vehicle mercury switches (Maine and Massachusetts).
Programs to educate students and teachers about mercury and
to conduct school mercury cleanouts have also been imple-
mented across the region and have resulted in the removal of
several thousand pounds of mercury from the region's high
schools and middle schools. Several states (Massachusetts,
Connecticut, and Vermont) have also implemented statewide
mercury thermometer exchange programs, which have col-
lected over 150,000 mercury fever thermometers.
The region has also taken the lead in addressing mercury
pollution from the dental sector attributable to the instal-
lation, shaping, and removal of amalgam fi llings, which
contain approximately 50% mercury. All jurisdictions under
the MAP have implemented initiatives to reduce this source
using pollution prevention and control approaches. Regional
emission inventory estimates indicated that sewage sludge
incinerators (SSI) were responsible for a signifi cant share of the
region's mercury emissions (NESCAUM, 2005). To address this
sector the Mercury Task Force has focused on efforts to reduce
mercury inputs to wastewater. This approach was viewed as
preferable to mercury emission control requirements on SSIs
because additional release pathways related to the handling
and treatment of wastewater and treated sludge would also be
addressed. The benefi cial reuse of treated biosolids, discharge
of untreated wastewater during high-fl ow storm events, emis-
sions during wastewater and sludge treatment, and discharge
of treated wastewater all result in releases of mercury. Reducing
mercury inputs to wastewater addresses all these pathways.
Considerable research demonstrates that the dental sec-
tor has been a signifi cant contributor to mercury loadings
in municipal wastewater (Arenholt-Bindslev and Larsen,
1996; Andersen, 2001; Cain et al., 2004). The Massachusetts
Water Resources Authority estimated that dentists
accounted for 13-79%, with a midpoint estimate of 46%,
of mercury inputs to its system in the 1990s (Massachusetts
Water Resources Authority, 1997). Other studies suggest
values in the range of 30% to
60%.
Goals for the dental sector were established under the
MAP in 2005. These stipulated that 75%, by 2007, and 95%,
by 2010, of the region's dentists who generate mercury-
containing wastewater from dental amalgam would have
amalgam separator pollution controls installed and be
using other Best Management Practices (BMPs) to mini-
mize mercury pollution. Amalgam separators are devices
that rely on a number of relatively simple technologies to
capture mercury amalgam particulates and, in some cases,
soluble mercury. Units typically cost from $500 to $2,000
and can reduce mercury discharges from dental practices
to wastewater by 95-99% (Agedembo et al., 2002; Strategic
Envirotechnology Partnership, 2003). BMPs minimize mer-
cury pollution by stipulating proper waste amalgam han-
dling and disposal practices be followed.
The jurisdictions have pursued a variety of approaches
to achieve the MAP goals for this sector. The Canadian
provinces are implementing the Canada-wide Standard for
Mercury in Dental Amalgams, which was adopted in 2000
(Canadian Council of Ministers of the Environment, 2000).
Under this policy, mercury releases from the dental sector
were to be reduced by 95% by 2005 through the voluntary
use of best management practices and amalgam separators.
Several New England States also initially tried voluntary
approaches to encourage the use of amalgam separators, but
by 2007, all had adopted legislation and or regulations requir-
ing their use. Overall, these efforts have been very success-
ful. By 2007,
53%
in the Canadian provinces were estimated to have appropri-
ate amalgam separators installed. For the region as a whole,
approximately 9054 dentists (2038 in the Canadian provinces
and 7016 in the New England states), or 78% of the total, had
installed amalgam separators in their offi ces, exceeding the
2007 regional goal of 75%. As the overall Canadian result falls
short of the reduction target established under the Canada-
wide Standards, the provinces are considering next steps,
which may include installation requirements.
Although the American Dental Association (ADA) had
opposed state and national regulations requiring the use of
amalgam separators for many years, instead favoring volun-
tary approaches, amalgam separators were included in the
Association's recommended “Best Management Practices
for Amalgam Wastes” (American Dental Association, 2004).
To date, purely voluntary efforts by the states to encourage
amalgam separator use have not met with great success,
and as a result, as of 2009 amalgam separator requirements
had been adopted in 11 states.
91% of dentists in New England and
OUTREACH AND EDUCATION
Most of the pollution-prevention efforts in the region have
also included outreach components to educate consumers,
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