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binding site capacity by dissolved seawater components; this may require future sensor designs
to incorporate flushing and cleaning/chelating functionality in the analytical system. Again
coupling this sensor transduction base with IS coating may offer
in situ
performance
enhancements.
Breakout Session I.
This breakout session sought to develop sector-specific viewpoints on the following aspects of
in
situ
metal monitoring:
I.
WHAT ARE THE CURRENT MONITORING NEEDS
(target prioritization,
regulatory metrics)?
II.
WHAT IS THE CURRENT STATUS OF METAL SENSOR DEVELOPMENT
FOR APPLICATION IN ENVIRONMENTAL MONITORING
(strength and
weaknesses regarding application to coastal environmental research, monitoring and
management)?
Management Viewpoint: Group Chair, Michael Lyons; Rapporteur, Keith Maruya
Participants representing the management sector felt that from a regulatory perspective the
following metals should be priority targets for development of
in situ
or on site analytical
systems: Hg, Se, As, Cu, Pb, Ag, Cr, Cd, Ni. These elements already have defined WQ criteria
goals and impact water resources globally (Table 1). In terms of development of new metal
sensor technologies, this group felt that desirable performance features of such analytical systems
should include the capacity to measure not only total metal concentrations, but also provide
information on metal speciation. Identification of the proportion of total metal content present in
the labile or dynamic dissolved metal fraction which would serve as a better proxy for bioactivity
than the current total dissolved concentration measures targeted by WQ criteria. Desirable
performance features would include sub- parts per billion (ppb) limits of detection, functionality
in a range of aquatic environments (i.e., freshwater to marine). The participants felt that
availability of portable, low cost and rugged on site analytical systems would greatly enhance
their WQ monitoring efforts by enabling them to increase temporal sampling frequency and
spatial resolution. A critical point for adoption of new technologies into their monitoring
programs would be whether they enabled more efficient allocation of resources for targeted lab-
based metal analysis required to support regulatory decisions regarding compliance (e.g., TMDLs
and MDELs), drinking water supply monitoring, waste processing management, storm water
source tracking and ambient recreational water quality.
S
UMMARY OF
B
REAKOUT
G
ROUP
D
ISCUSSIONS
ACT Workshop on Trace Metal Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11