폐기물 배출해역 퇴적물이 해양생물에 미치는 독성영향

Abstract

In 1998, South Korea adopted its own ocean dumping policy, with two sites in the East Sea (East Sea-Jung and East Sea-Byung) and one site in the Yellow Sea (Yellow Sea-Byung) serving as dumping sites. After gradually reducing the level of ocean dumping to prevent deterioration of marine environment due to such dumping, the practice of ocean dumping was officially banned starting from January 2016. For the purpose of remediation and restoration of these waste dumping sites, the present study evaluated the toxic effects of waste deposits in waste dumping sites on marine benthic organisms. As the methods for identifying the biological toxicity of benthic ecosystem sediments, the present study used 10-day survival rate test on benthic amphipods (Monocorophium acherusicum) and 30-minute luminescence inhibition in luminescent bacteria (Vibrio fischeri), which are methods that have been widely used in Korea and abroad in various studies. Calculation of relative average survival rate and relative luminescence inhibition based on the toxicity test showed results of -2.5∼25.0 % and -21.9∼0.6 %, respectively. Therefore, toxicity was not detected in the experimental organisms based on the Korean Standard Method for Marine Environment (section on waste disposal, 2013). However, t-test for investigation of significant differences between the experimental and control groups showed that toxicity was not detected in the luminescent bacteriatoxicity test, just as in the Korean Standard Method for Marine Environment, but seven specimens (DB-085, DB-092, YBR-004, YB-008-1, DJR-009, DJ-2013-2, DJ-2014-2) showed significant differences against the control group in the benthic amphipod test. The specimen that showed the highest toxicity was DB-085 from the East Sea-Byeong dumping site, with average survival rate of 65% and relative average survival rate of 25%. In the heavy metal analysis on DB-085 specimen, the results showed Cr, Zn, and Cd detection of 297.4 mg/kg, 165.7 mg/kg, and 0.67 mg/kg, respectively, which represented the highest concentrations of these heavy metals among all specimens, while DB-085 also showed the second highest concentration of Pb (53.3 mg/kg) and Cu (57.1 mg/kg), behind only DB-092. In the correlation analysis between Cr concentration and relative average survival rate of East Sea-Byung specimens, the results showed correlation coefficient (R) of 0.9489, indicating a strong correlation between Cr concentration and relative average survival rate. Therefore, it is inferred that high concentration of Cr in DB-085 acted as the cause of toxicity in M. acherusicum.