ACT/MERC Workshop: Ballast Water Compliance Monitoring Using Fluorometry
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Background:
The international maritime industry, with over 70,000 merchant vessels, is responsible for
transporting approximately 90% of the goods traded in world markets and is a foundation for the
global economy. However, commercial shipping is also inadvertently responsible for introducing
aquatic invasive species to coastal waters worldwide through the transport and discharge of
ballast water. Some of these invasive species have caused enormous ecological and economic
damage. Therefore, the International Maritime Organization (IMO), U.S. Coast Guard (USCG),
and U.S. Environmental Protection Agency (EPA) have developed ballast water discharge
regulations to minimize the spread of aquatic invasive species. These regulations allow for only
very few live organisms to be discharged, including fewer than 10 live organisms per ml within
the 10 to 50 μm in size class (a size class typically dominated by phytoplankton).
Ballast water regulations will be successful at reducing environmental and economic risks only if
treatment systems operate effectively and reliably and if vessel owners and operators comply.
Even small rates of noncompliance can prevent environmental regulations from achieving their
goals. The rate of noncompliance is an important consideration in the case of ballast water
invasive species, where risk factors are difficult to measure accurately and risk reductions from
widespread compliance may not offset the high risks posed by just a few vessels that discharge
ballast water not meeting the standards. Therefore, effective and reliable compliance monitoring
tools are needed, especially those that can be readily implemented by vessel crew on a routine
basis and regulatory inspectors.
To address this issue, vessel compliance monitoring strategies, technologies, and methodologies
are now being developed. Given the complexity and logistical constraints of directly measuring
live organisms in ballast water discharge during normal vessel operations, phased compliance
monitoring approaches have been proposed, which provide increasing levels of confidence. For
example, a tiered monitoring framework might include: (1) Vessel reporting and initial
inspections, followed by expanded inspections utilizing (2) Measures of treatment operations and
performance, (3) Indirect measures of exceedance of the discharge standard, and (4) Direct
detailed measures of compliance with the discharge standard.
While multiple approaches to compliance monitoring will likely be utilized to varying degrees,
indirect measures of exceedance may ultimately be widely adopted for routine monitoring,
provided the tools: (a) can be validated and standardized, (b) are simple to use and tamper-proof,
and (c) provide sufficient confidence that a discharge was not in compliance with discharge
standards. One such suite of tools may be chlorophyll fluorometers and pulsed/modulated
fluorometers, similar to sensors used in shipboard oil content monitors, but adapted and tuned to
provide abundance estimates of live photosynthetic organisms. With support from the US
Maritime Administration (MARAD) and the National Socio-Environmental Synthesis Center
(SESYNC), the Alliance for Coastal Technologies (ACT) and the Maritime Environmental
Resource Center (MERC) are partnering to assess fluorometers as tools for compliance
monitoring of ballast water discharge regulations. The first step in this effort was to hold a
workshop on June 14 - 15, 2012, at SESYNC in Annapolis, MD, to discuss fluorescence-based
assays and instruments in this context. The workshop focused on fluorometric assessment of
biomass and physiological condition to identify exceedance of discharge limits for living
organisms between 10-50 μm in size, nominally “phytoplankton”. Specific questions included:
(a) What are the strengths and limitations of various fluorometric approaches for use in this
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