A quick method of testing ballast water discharge for compliance may be possible thanks to research from well-known BWMS scientist, Cees van Slooten, whose PhD dissertation examined current methods and suggested a viable alternative
Cees van Slooten currently heads the BWMS type-approval testing projects at Control Union Certifications in Rotterdam, but prior to this, he was a researcher at the Royal Netherlands Institute for Sea Research where he examined current ballast water discharge regimes and developed a ready-to-use technique for quickly testing whether harmful organisms were discharged via ballast water.
In 2004, the International Marine Organization (IMO), part of the United Nations, introduced a standard for the discharge of living organisms that led to a mandatory disinfection of ballast water for most cargo ships.
“However”, said Mr van Slooten, “it was not until 2016 that enough member states agreed to the standard and ratified it. After that, it will be several more years before all those ships are provided with a treatment system. In September 2024, almost all ocean-going vessels should comply with the discharge standard.”
During his PhD-research that lasted from 2010 to 2014, Mr van Slooten tested whether a treatment substance (DDAC) is suitable for ballast water treatment. DDAC appears unsuitable as a ballast water treatment substance because the required neutralisation method using bentonite clay raises practical objections.
Secondly, his research demonstrated that heterotrophic bacterial plate counting is not correlated with alternative methods like flow cytometry and qPCR. Therefore, he suggested reassessing the use of plate-counting during ballast water testing.
His research continued to focus on indicative compliance tools. The FlowCAM instrument automatically photographs water-entrained particles and conducts automated image-analysis to classify organisms. However, in UV-treated seawater, the FlowCAM was unable to automatically distinguish between living and dead organisms. Therefore, it was not considered a promising tool for indicative compliance testing.
The main result of Mr van Slooten’s PhD-research is the technique he developed for a – by now often used – method for compliance and enforcement of ballast water disinfection by local authorities.
Mr van Slooten said, “In the discharge standard, IMO has stated that less than 10 microscopic algae cells may remain in each millilitre of water. For zooplankton, with sizes of at least 50 µm, like amphipods, that standard is 1M times stricter: less than 10 specimens in every 1,000 litres of water are allowed.”
The authorities need to be able to enforce those values. Mr van Slooten said, “There are techniques, but are they sensitive enough? Such a technique is only suitable for enforcement if it is quick, simple and still accurate in measuring ballast water.”
“I developed a pipette-free and ready-to-use concentration method – SIMPLE-ATP – for use in an existing analysis of ATP, the ancient energy molecule of all living organisms. With luminous enzymes of fireflies, you can determine the presence of ATP. The more luminous, the more ATP, the more living cells.”
“Normally, ATP analysis does not work in salt water but SIMPLE-ATP removes the salt while simultaneously concentrating the organisms that are relevant to the discharge standard.”
Mr van Slooten defended his dissertation at the University of Groningen last June. His promotor is Prof Anita Buma.
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