This study developed a biological risk assessment protocol for in-water cleaning of ship hull biofouling to evaluate the potential spread of non-indigenous species (NIS) in port environments. A Korea-Infection Modes and Effects Analysis (K-IMEA) framework was established to assess biological risks associated with in-water cleaning. The evaluation considered four risk pathways: R1 (introduction/establishment before cleaning), R2 (escape during cleaning), R3 (introduction/establishment after cleaning), and R4 (establishment via effluent water). Response experiments were conducted using in-water cleaning wastes (R2, R4) and artificial fouling collector (AFC) plates (R1, R3).
Results indicated that biological risks were present across all pathways but differed in their controllability. In R1, diverse prokaryotes and microalgae showed regrowth potential, suggesting that prolonged port residence time before cleaning increases the likelihood of establishment. In R2, prokaryotes and macroalgae, particularly Ulva species, survived and reattached when capture efficiency was insufficient. In R3, residual organisms remaining on hull surfaces after incomplete cleaning demonstrated regrowth potential. In R4, viable prokaryotes, microalgae, and macroalgal fragments were detected even after 5 μm filtration.
R1 and R3 represent risks that are difficult to mitigate solely through technological improvements, as they depend on operational conditions such as port residence time and cleaning coverage. Therefore, administrative and regulatory measures, including limiting port residence time and requiring post-cleaning inspection, are necessary. In contrast, R2 and R4 can be reduced through technological improvements, including enhanced capture efficiency and additional post-treatment processes. Since organisms passed through 5 μm filtration, secondary treatment such as ultraviolet (UV) irradiation or electrolysis is required. These findings highlight the need for an integrated approach combining regulatory measures and technological development to minimize biological risks during in-water cleaning.

 

Ship hull biofouling,In-water cleaning,Non-indigenous species,Biological risk assessment,Korea-Infection Modes and Effects Analysis