Ballast Waters

Ships’ ballast waters (BW) are a recognised vector through which potentially invasive organisms are released into the environment. The introduction of allochthonous species into new ecosystems can displace established communities and cause very profound changes in the new ecosystem, causing severe losses of biodiversity and other natural and unnatural damage. Ballast water discharges from one harbour to another may cause dramatic damage in the global ecosystems due to contamination by foreign species. The International Marine Organization (IMO) has attempted to mitigate the problem by proposing a new regulation (D-1 and D-2 IMO 2004). The International Convention for the Control and Management of Ship’s Ballast Water and Sediments (IMO, 2004) came into force in 2017. It establishes the maximum accepted limits on contents of bacteria, algae, and zooplankton in ballast water before discharging in new areas by implementation of recommended water treatment procedures. D-2 compliance standard requires that discharged water does not have exceeded limits of total phytoplankton below 50 micron size, zooplankton and toxicogenic bacteria as Vibrio cholera, Escherichia coli and intestinal Enterococci. 

The typical method of analysis is to use standard culture, fluorimetry or microscopy, all laboratory methods to quantify specific bacteria or phytoplankton with sufficient reliability to meet regulations, but such methods provide only a few millilitres for each test and take between 1 and 12 days to get the results.