ABSTRACT
Fluorescence excitation-emission matrix (EEM) and absorption spectroscopy were applied to study the optical properties of 29 CDOM samples collected from different ballast tanks of nine international route vessels anchored in Xiamen Port between October 2007 and April 2008. The purpose was to examine the feasibility of these spectral properties as a tracer to verify if these vessels follow the mid-ocean ballast water exchange (BWE) regulation. Using parallel factor analysis, four fluorescent components were identified, including two humic-like components (C1: 245, 300/386 nm; C2: 250, 345/458 nm) and two protein-like components (C3: 220, 275/306 nm; C4: 235, 290/345 nm), of which C2 component was the suitable fluorescence verification indicator. The vertical distribution of all fluorescent components in ballast tank was nearly similar indicating that profile-mixing sampling was preferable. Combined use of C2 component, spectral slope ratio (SR) of absorption spectroscopy and salinity may provide reasonable verification if BWE carried out by these nine ships. The results suggested that the combined use of multiple parameters (fluorescence, absorption and salinity) would be much reliable to determine the origin of ballast water, and to provide the technical guarantee for fast examination of ballast water exchange in Chinese ports.
