Environmental Engineering Reference
In-Depth Information
nonprofi t organizations in the United States, Canada, and
Europe convened during a workshop in Pensacola, Florida,
in September 2003. The workshop's aim was to identify
suitable Hg indicators and to propose a national (North
American) monitoring and assessment network to measure
and document the changes in atmospheric loading result-
ing from changes in Hg emissions in the United States and
their impact on aquatic biota MeHg. A holistic, multime-
dia monitoring approach was designed, as this is needed
to detect change across a diverse and complex system.
Products of this workshop were a paper published in 2005
(Mason et al., 2005) and a more detailed topic (Harris
et al., 2007a), which expanded the ideas of the paper and
put forward a detailed plan and approach for such a moni-
toring network.
Since the workshop and the publication of the topic,
there have been a series of meetings in the United States
with federal offi cials from the United States Environmental
Protection Agency (EPA) and other agencies and for U.S.
congressional staff. This resulted in the introduction of two
bills by Congress to support the formation and structure
of a comprehensive national monitoring network. These
bills have not been acted on, but activities are ongoing to
continue to promote and develop the monitoring network.
In this regard, EPA and other Federal agencies organized
a workshop in Annapolis, Maryland, in May 2008 to fur-
ther a comprehensive and integrated monitoring network
(MercNet; http://nadp.sws.uiuc.edu/mercnet).
In addition to the efforts in North America, there are a
number of international efforts to develop an integrated
global monitoring network and regional initiatives in
Asia and elsewhere. Such initiatives are focused on evalu-
ating the current information and reassessing Hg emis-
sions and cycling in the atmosphere and the importance
of long-range transport (Pirrone and Mason 2009), as well
as on coordinating monitoring efforts. The various activi-
ties have been coordinated through the United Nations
Environmental Program Global Partnership for Mercury
Air Transport and Fate Research (UNEP-MFTP) (Pirrone and
Mason, 2009; UNEP, 2009) and the Hemispheric Transport
of Air Pollutants (HTAP) Task Force (HTAP, 2010). An HTAP
report on hemispheric transport of air pollutants, including
mercury, is in its fi nal stages of preparation (HTAP, 2010).
In addition, the notion of a global Hg network has been
incorporated into the Global Earth Observation System of
Systems (GEOSS) program as Sub-Task HE-09-02d. The sub-
task initiates the development of:
regional and global atmospheric mercury models for use in
evaluations of different policy options for reducing mercury
pollution impacts on human health and ecosystems. Build
upon the contributions of, among others, the UNEP Mercury
Programme, the Hemispheric Transport of Air Pollutants
Task Force (TF HTAP), and the European Monitoring and
Evaluation Program (EMEP). Moreover, this sub-task will
build upon the US MercNet initiative and international
monitoring and modelling efforts undertaken by Italy, Japan
and South Africa (Global Earth Observation System of
Systems [GEOSS], 2009).
Policy and Management Requirements
A monitoring and assessment network must be developed
with a clear understanding of the policy and manage-
ment requirements, and with knowledge of the current
situation in order to inform policy development, includ-
ing answers to policy questions such as: (1) What further
Hg reductions are needed to improve human and ecosys-
tem health? (2) What sources should the agencies focus on
fi rst in terms of Hg control? and (3) What regulation will
be the most cost-effective? Any network will be developed
and initiated during a time (Schmeltz et al., 2011), when
regulations are already being implemented; therefore the
monitoring information that is being gathered may need to
be modifi ed to ensure its relevancy and its ability to assess
the impact of Hg changes on human and ecosystem health.
In addition, suffi cient information must be available for
all areas so that scientists and policymakers can accurately
assess the environmental benefi ts and effectiveness of Hg
control, as this is not the case at present.
Currently, much research is being conducted in an unco-
ordinated and nonstandard manner, and this is insuffi cient
for determining spatial and temporal trends in environmen-
tal contamination. Also, there is insuffi cient information to
establish the baseline concentrations in multiple ecosystem
compartments that are needed to assess the effectiveness of
future Hg emission reductions or other changes in emission
distribution globally. Comprehensive Hg monitoring infor-
mation is needed to assess progress on mandated Hg reduc-
tions of controllable anthropogenic inputs to the atmosphere,
as well as the impact of changes in emissions due to natural
variability and human-induced climate change.
Modeling Requirements
a global observation system for mercury by harmonizing
standard operating procedures for monitoring mercury and
its compounds in air, atmospheric deposition, water, soil,
sediments, vegetation and biota. The sharing of data from
this network, allowing access to comparable and long-term
data from a wide array of locations, will help understand
temporal and spatial patterns of mercury transport and
deposition to, and evasion from, terrestrial and aquatic eco-
systems. The data produced will support the validation of
In designing the network, it is crucial to incorporate the
needs of models/modelers (Keeler et al., 2009) and to
understand the role of these models in a national Hg assess-
ment and their limitations. The data collected must be
suffi cient to allow for the testing and validation of model
parameters; this includes the need for long-term datas-
ets (Ryaboshapko et al., 2007a; Bullock and Jaegle, 2009;
Keeler et al., 2009) and for data collected simultaneously
