Failure of the public health testing program for ballast water treatment systems

Andrew N. Cohen, Fred C. Dobbs

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


Since 2004, an international testing program has certified 53 shipboard treatment systems as meeting ballast water discharge standards, including limits on certain microbes to prevent the spread of human pathogens. We determined how frequently certification tests failed a minimum requirement for a meaningful evaluation, that the concentration of microbes in the untreated (control) discharge must exceed the regulatory limit for treated discharges. In 95% of cases where the result was accepted as evidence that the treatment system reduced microbes to below the regulatory limit, the discharge met the limit even without treatment. This shows that the certification program for ballast water treatment systems is dysfunctional in protecting human health. In nearly all cases, the treatment systems would have equally well "passed" these tests even if they had never been turned on. Protocols must require minimum concentrations of targeted microbes in test waters, reflecting the upper range of concentrations in waters where ships operate.

Original languageEnglish
Pages (from-to)29-34
Number of pages6
JournalMarine Pollution Bulletin
Issue number1
StatePublished - Feb 15 2015


  • Ballast water
  • Microbes
  • Public health
  • Ships
  • Vibrio cholerae
  • Water treatment


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