Development for assessment of risks arising from the wastes based considering in-water hull cleaning systems

Abstract

Vessel fouling, a well-known pathway for the introduction and subsequent spread of marine nonindigenous species (NIS), has potential risks of biosecurity and chemical contaminants when vessel in-water cleaning is applied to reduce hull fouling and improve vessel operating efficiency. There remain uncertain risks in the un-recovered effluent release from vessel in-water cleaning, consisting of reactive in-water cleaning and capture (RICC) with post-treatment system. RICC can cause large quantities of uncaptured effluent release into recipient waters during cleaning operation of equipment having a variety of performance efficacy. However, cumulative release of specific biocides and fouling associated with vessels were not assured for now as a result of shortage of information which could be generated from the released effluent into the recipient waters during cleaning. In this regard, areas expecting frequent in-water cleaning of vessels should be managed in terms of identification, regrowth possibility of propagules and marine pathogen of foreign species as well as environmental risks of toxic substances including metals and booster biocides in dislodged wastes. This viewpoint can contribute to develop management practices for controlling marine NIS through vessel fouling in line with the guideline of International Maritime Organization.