while also meeting criteria for safety, compatibility with ship operations, and environmental acceptability. Thus, the degree of effectiveness of treatment technologies needs to be measured, particularly during the evaluation of prototype systems. Monitoring ballast water before and after treatment will permit a quantitative assessment of treatment effectiveness. Ultimately treatment effectiveness will be tailored to meet the levels for ballast water discharge defined by regulatory authorities. Monitoring is also important as a research tool to enhance the present limited understanding of the biology of introductions, thereby facilitating the development of effective ballast water management strategies, including a plan for managing ballast water. For example, the presence of dense populations of one or more nonindigenous species of concern could indicate to the master that ballast should not be taken on unless absolutely necessary. Monitoring will also aid in assessing the effectiveness of regulations and guidelines for managing ballast water.
This chapter provides a discussion of the issues associated with monitoring ballast water, whether for auditing or R&D purposes. As with ballast water treatment, shipboard monitoring appears to offer the greatest flexibility, although other possibilities are addressed. Opportunities exist to measure a wide range of ballast water parameters—in addition to salinity—that might be helpful for monitoring purposes. The committee has identified promising approaches, both near term and long term, and has also considered levels of monitoring that might be needed in conjunction with different options for managing ballast water.
Many monitoring procedures and approaches appear promising, but none has yet been used routinely on board ships. Like the candidate technologies for treating ballast water discussed in Chapter 4, shipboard application of monitoring systems introduces additional requirements and constraints on equipment and its operation in comparison with land-based industrial applications. The characteristics of an effective shipboard monitoring system for supporting strategies of managing ballast water can be summarized as follows:
allows rapid data collection
permits unambiguous detection of unwanted biological material or indicator organisms
is safe, rugged, and relatively inexpensive to install and operate
occupies minimum space, allowing monitoring to be performed in situ aboard ships without impeding other onboard operations
allows the necessary monitoring to be performed as quickly as possible, so as not to put undue burden on the ship's crew
permits effective monitoring by personnel with minimum training
requires a minimum of complex procedures, such as chemical extraction
These characteristics may not be realized in a single automated procedure, and some compromises may be necessary to achieve a workable monitoring method. As discussed below, the monitoring method in any given situation will