전기분해처리 선박평형수가 해양생물의 성장 및 생존에 미치는 영향

Abstract

Diverse ballast water management systems (BWMSs) have been developed worldwide in order to regulate international transportation of invasive alien species by ship’s ballast water. Among them, an electrolytic method generates active substances and disinfection by-products (DBPs) in ballast water. The DBPs exert apparent toxic effects on marine organisms and have adverse impacts on marine environment. In this study, toxicity experiments were conducted to investigate for effects of eletrolysed ship's ballast water on growth and survival of marine organisms. Experiments were carried out for three marine organisms, i.e., diatom Skeletonema costatum, rotifer Brachionus plicatilis and olive flounder Paralichthys olivaceus at two salinity condition (35 psu and 19 psu). The results revealed that S. costatum was the most sensitive organism that showed apparent effect of growth inhibition to the electrolysed ballast water; it showed no observed effect concentration (NOEC), lowest observable effect concentration (LOEC) and effect concentration of 50% (EC50) values of T25, T50 and T55.7, respectively, at seawater condition (35 psu). And hatching larva (yolk-sac larva) of P. olivaceus showed effects of survival rate at the seawater condition. On the other hand, B. plicatilis and juvenile of P. olivaceus showed no effects at the both salinity conditions. The chemical compounds revealed that electrolysed ballast water contained total residual oxidants (TROs) below 0.03 μg/L and a total of 20 DBPs (297 μg/L) such as bromate, volatile halogenated organic compounds, halogenated acetonitriles, halogenated acetic acids (HAAs) and chloral hydrate at seawater condition. The chemical compounds revealed that electrolysed ballast water contained TROs below 0.03 μg/L and a total of 13 DBPs (271 μg/L) at brackish water condition (19 psu). Among DBPs, total concentration of HAAs showed gap, in seawater and brackish water, that 218.22 and 100.56 μg/L, respectively.