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Concentrations were measured three times from 2006 to 2013 at major harbors and marine areas along the Korean coast. The Cu concentration in seawater and sediments increased, while the Zn concentration first decreased and then increased. The pattern of increase in Cu concentration with time was consistent with the increased total tonnage of ships moored at the sampling area and with the increased discharge of organic antifouling agents. To confirm the relationship between seawater and marine sediments in heavy metal pollution, all data were arrayed and compared depending on concentrations. The results revealed that the slope of Cu between seawater and marine sediment rapidly decreased, attributed to the increase in the application of copper-based antifouling agents to vessels after the ban on the use of tributyltin in 2008, rather than the contamination caused by industrial areas.

Since the ban of tri-butyl tin, other various alternative antifouling agents have been used. In this study, the contamination levels from these antifouling agents were examined in the main harbors in Korea. The sampled harbors were classified into four types and the levels of contamination from the antifouling agents were analyzed. The highest degree of contamination was found in the big harbors, followed by the fishing harbors, harbors near agricultural areas, and military and coast guard harbors. In addition, an increase in the number of ships that entered the ports significantly influenced the contamination by the antifouling agents. Correlation analysis was conducted to characterize the alternative antifouling agents. The results revealed strong correlations between the dichlofluanid and chlorothalonil, and between the chlorothalonil and TCMTB, because unlike Irgarol 1051 and SEA-NINE 211, which are used only as antifouling agents, chlorothalonil, dichlofluanid, and TCMTB are also used in agriculture.

Since the ban on tributyltin (TBT) in 2008, dozens of alternative antifouling agents have been used instead. Unfortunately, these alternative antifouling agents contain diverse toxic components, which have contaminated the coasts. From 2006 to 2013, the concentration of chlorothalonil, dichlofluanid, and Irgarol 1051 were monitored continuously, and their mean concentrations increased due to the increase in maritime cargo and consequent increase in the incoming and outgoing ships in harbors. An analysis of the sampling points according to harbor type showed that the contamination was more severe in fishing and big harbors, where there are more incoming and outgoing ships. A correlation analysis indicated a high correlation between chlorothalonil and dichlofluanid. Unlike Irgarol 1051, which is only used as an antifouling agent, the other two substances are used as agricultural chemicals as well, which could explain the high correlation. This study suggests that these alternative antifouling agents should be tracked continuously.

The use of tributyltin (TBT) has been banned in Korea since 2003. In this study, changes in butyltin compound concentration from 1992 to 2009 were examined by area. The number of ships, which greatly influences butyltin compound contamination, continuously increased, but butyltin compound concentration decreased. Results indicated that the regulation of TBT is effective in Korea. The increase in the concentration was caused by military and coast-guard ships, ballast water, and the illegal use of materials. According to port distribution characteristics along the Korean coasts, the level of butyltin compound contamination was high along the west and south coasts in 1992, whereas it was high along the south and east coasts since 2006. We found that overall butyltin compound concentrations decreased in Korea, but concentrations remained high in some regions.

Diverse new antifouling agents are being used as replacements for the organotin compounds that are currently being banned. A comprehensive study on Korea's major seaports was conducted between 2006 and 2009 to assess the concentrations of butyltin compounds and new antifouling agents (chlorothalonil, dichlofluanid, Irgarol 1051). The constituents of the pollution due to antifouling agents in major seaports on the Korean peninsula are shifting from butyltin compounds to new antifouling agents. Also, the distribution of traditional butyltin compounds has centered on the east and west coasts, and the new antifouling agents have polluted the south and east coasts. With the results of this study, our lab was able to identify key locations within Korea where focused pollution control of antifouling agents is necessary.

There are many disposal and treatment methods for contaminated dredged sediments, depending on their properties. In this study, treatment methods for the remediation of dredged sediments as well as the reduction of pore water generated from dredged sediments were optimized. The efficiency of separation using hydrocyclone as the pre-treatment increased with greater inflow velocity of hydrocyclone, deeper insertion of the vortex finder, and smaller hydrocyclone diameter. In the post-treatment of hydrocyclone overflow, the chemical coagulation and membrane filtration methods had high efficiency with regard to the removal of solid and organic compounds, but the former was less feasible, due to its excessive operation and sludge disposal costs. The membrane filtration was easily applicable in the field, based on its convenience of installation and lower cost of operation despite low removal efficiency of trace organic contaminants.