Seong-Dae Moon

Monitoring toxicity of polycyclic aromatic hydrocarbons in intertidal sediments for five years after the Hebei Spirit oil spill in Taean, Republic of Korea

Ecotoxicological monitoring of intertidal sediments was performed for 5 years after the Hebei Spirit oil spill in Taean, Korea. Sediment toxicity was observed on most of the beaches 4 months after the spill and later decreased rapidly to nontoxic levels 8 months after the spill. The concentrations of total polycyclic aromatic hydrocarbons (TPAHs) in the sediments ranged from 2 to 530,000 ng/g during the monitoring. More than half of the samples exhibited significant toxicity 5 years after the Hebei Spirit oil spill. Using a logistic regression model, the median lethal concentration of TPAHs to amphipod Monocorophium uenoi was estimated to be 36,000 ng/g. From the 63 chemistry and toxicity data, the effect range-low, effect range median, threshold effect level, and probable effect level were derived to be 3190, 54,100, 2480, and 29,000 ng/g, respectively. The relative compositions of the PAH groups indicated that the weathering process is still ongoing.

Cellular Energy Allocation of a Marine Polychaete Species (Perinereis aibuhitensis) Exposed to Dissolving Carbon Dioxide in Seawater

An experiment was conducted to evaluate the biochemical adverse effect of increased carbon diox- ide in seawater on marine polychaete, Perinereis aibuhitensis. We measured the available energy reserves, Ea (total carbohydrate, protein, and lipid content) and the energy consumption, Ec (electron transport activity) of Perinereis aibuhitensis exposed for 7-d to a range of CO2 concentration such as 0.39 (control =390 ppmv), 3.03 (=3,030 ppmv), 10.3 (=10,300 ppmv), and 30.1 (=30,100 ppmv) CO2 mM, respectively. The cellular energy allocation (CEA) methodology was used to assess the adverse effects of toxic stress on the energy budget of the test organisms. The results of a decrease in CEA effect of increased carbon dioxide in seawater from all individ- ual in Ea and Ec. Increase of carbon dioxide reduced pH in seawater, significantly. The chemical changes in sea-

Chronic Effect Exposed to Carbon Dioxide in Benthic Environment with Marine Invertebrates Copepod(Tisbe sp.) and Amphipod (Monocorophium acherusicum)

Chronic effects such as reproduction and population dynamics with elevated CO2 concentration were evaluated using two representative marine benthic species, copepod (Tisbe sp.) and amphipod (Monocorophium acherusicum) adopting long-term exposure. Juvenile copepod and amphipod individuals were cultivated in the seawater equilibrated with control air (0.395 mmol CO2/air mol) and high CO2 air having 0.998, to 3.03, 10.3, and 30.1 mmol CO2/air mol during 20 and 46 days, respectively. After the exposure period, the number of benthic invertebrate was counted with separate larval and juvenile stage such as naupliar, copepodid and adult for copepod, or neonate and adult for amphipod, respectively. The individual number of both test species at each life-stage was significantly decreased in seawater with 10.3 mmol CO2/air mol or higher. Recently, the technology of marine CO2 sequestration has been developed for the reduction of CO2 emission, which may cause climate change. However, under various scenarios of CO2 leaks during the injection process or sequestrated CO2 in marine geological structure, 1)

Initial recolonization of benthic fauna in defaunated sediment contaminated with octylphenol: Field microcosm exposure study

Recolonization of benthic fauna in defaunated sediment contaminated with octylphenol (OP) has been investigated by the use ofin situ microcosm exposure study. Trays with defaunated sediment (control) and those treated with five OP concentrations (0.59, 5.4, 7.6, 66, and 660 μg g−1, sediment dry weight (DW)) were exposed at the subtidal (ca. 10 m), in the southern coast of Korea, over two months. The initial response (after one-month exposure) of macrozoobenthos at the trays of control and three lower OP (0.59–7.6 μg g−1 DW) showed rapid colonization of macrozoobenthos with high diversity and abundance. However, the species number sharply decreased after two-month exposure, particularly at the tray of greatest OP (660 μg g−1 DW) treated with species number from 15 (after 30-days) to 3 (after 70-days). Other univariate indices such as abundance and biomass of benthic macrofauna also showed concentration-and time-dependent declines, indicating a potential adverse effect of OP on benthic community recolonization. Further, the multi-dimensional scaling (MDS) analysis that clearly separated two distinct faunal groups of macrobenthos during exposure supported the concentration-dependant recolonization followed by succession at the OP concentration of >7.6 μg g−1 DW. Similar to macrofauna, the meiofaunal abundance significantly decreased at the OP concentration of >7.6 μg g−1 DW, indicating certain threshold of OP between 7.6–66 μg g−1 DW that caused adverse effect on benthic community recolonization. Although the critical adverse OP concentration found in community level was relatively high compared to the environmental concentrations (ppb levels) reported in coastal sediments, it should be pointed out that certain species could be influenced by the exposure of lower OP concentrations.

Development of water quality criteria of ammonia for protecting aquatic life in freshwater using species sensitivity distribution method

Ammonia is deemed one of the most important pollutants in the freshwater environment because of its highly toxic nature and ubiquity in surface water. This study thus aims to derive the criteria for ammonia in freshwater to protect aquatic life because there are no water quality criteria for ammonia in Korea. Short-term lethal tests were conducted to perform the species sensitivity distribution (SSD) method. This method is widely used in ecological risk assessment to determine the chemical concentrations to protect aquatic species. Based on the species sensitivity distribution method using Korean indigenous aquatic biota, the hazardous concentration for 5% of biological species (HC5) value calculated in this study was 44mg/L as total ammonia nitrogen (TAN). The value of the assessment factor was set at 2. Consequently, the criteria for ammonia were derived as 22mg/L at pH7 and 20°C. When the derived value was applied to the monitoring data nationwide, 0.51%, 0.09%, 0.18%, 0.20%, and 0.35% of the monitoring sites in Han River, Nakdong River, Geum River, Youngsan River, and lakes throughout the nation, respectively, exceeded this criteria. The Ministry of Environment in Korea has been considering introducing water quality standard of ammonia for protecting aquatic life. Therefore, our results can provide the basis for introducing the ammonia standard in Korea.

Effects of PAHs on the early life stages of aquaculture fishes

M oil spill accidents give a variety of adverse influences on aquaculture organisms for a long time. Polycyclic aromatic hydrocarbons (PAHs), one of the major crude oil constituents, have been reported to induce developmental inhibition, morphological deformity, histopathological effects and genetic damage on fishes. In this study, we evaluated the impact of the PAHs on early life stages of three aquaculture fishes (red sea-bream, Pagrus major, rock bream, Oplegnathus fasciatus, and olive flounder, Paralichthys olivaceus) using pyrene, 2-methylnaphthalene, and phenanthrene. Embryonic development and larval morphology were investigated for each species. The median effect concentration (EC50) was not estimated for pyrene, and phenanthrene for all test species. The EC50s for 2-methylnaphthalene of Pagrus major, Oplegnathus fasciatus, and Paralichthys olivaceus were 12.8, 10.9 and 18.0 μmol/L, respectively. The no observed effect concentrations (NOECs) for pyrene of Pagrus major, Oplegnathus fasciatus and Paralichthys olivaceus were 99, 99, 0.013 μmol/L, respectively. The NOECs for 2-methylnaphthalene of Pagrus major, Oplegnathus fasciatus and Paralichthys olivaceus were 5.5, 5.5 and 3.5 μmol/L, respectively. The NOECs for phenanthrene of Pagrus major, Oplegnathus fasciatus and Paralichthys olivaceus were 7.0, 224, 0.96 μmol/L, respectively. There was no morphological deformity in the hatched larvae of Pagrus major exposed three PAHs. The spinal curvature and fin deformity were observed in Oplegnathus fasciatus at 11 μmol/L of 2-metylnaphthalene. Pericardial edema, ocular development inhibition, spinal curvature and fin deformity were observed in Paralichthys olivaceus exposed to 0.013 μmol/L of pyrene, 3.5 μmol/L of 2-metylnaphthalene, and 1.0 μmol/L of phenanthrene. It was considered that Paralichthys olivaceus to be more sensitive than Pagrus major and Oplegnathus fasciatus to PAHs. Some embryo of Paralichthys olivaceus successfully hatched in lower concentrations, while morphological deformity was observed in these concentrations. PAHs seem to have large effects on the early life stages of aquaculture fishes.B biofertilizers are those plant growths promoting rhizobacteria applied in the field to promote crop growth and to reduce the use of synthetic fertilizers. However, in conventional agriculture, the applying pesticides is a routine practice and is unavoidable to achieve reasonable profit. Thus, to develop effective bacterial biofertilizers, the effect of pesticides on plant growth promoting rhizobacteria (PGPR) should be considered before application. In this study, bacterial strains with both PGP traits and pesticide tolerant ability were isolated for selection as potential bacterial biofertilizers. Rice (Oryza sativa) seedlings were planted in the soils with high dose of fungicide etridiazole, metalaxyl, and tricyclazole applied. Endophytes were isolated from rice roots, and 16S rDNA sequence and related plant promoting characteristics including the potential nitrogen fixation, phosphorus solubilizing and indoleacetic acid (IAA) production ability for those endophytic bacteria were determined afterward. A total of seventeen different strains were isolated. Among them, five strains with both nitrogen fixation potentials and IAA production ability were identified. The species isolated included Rhizobium larrymoorei E2, Bacillus aryabhattai E7, Bacillus aryabhattai MN1, Pseudomonas granadensis T6, and Bacillus fortis T9. Except for T9, four strains out of five were even capable of tolerating two or more fungicides without retarding the growth rates. We inoculated the above four endophytic bacteria to the rice roots and confirmed that they were all equipped with rice growth promoting abilities. We applied recommendation rates of etridiazole and metalaxyl on the growth medium in Bacillus aryabhattai MN1 and found out that MN1 can produce high rates of IAA with fungicides applied. The bacteria strains isolated from this study presented PGP traits upon high rates of fungicides application and can be viewed as potential members in bacterial biofertilizers for sustainable agriculture application.

Effect on Early Life Stage of Three Freshwater Fish (Carassius auratus, Cyprinus carpio, Oryzias latipes) Exposed to Suspended Solids.

본 연구에서는 부유토사로 인한 탁도 증가가 어류에게 미치는 영향에 대해 실험실 모의실험을 수행하였다. 국내 강 또는 호소에서 출현 비율이 높은 붕어, 잉어, 송사리를 대상으로 수정란 부화율 평가를 수행한 결과 붕어, 잉어는 4,040 NTU 수준까지 수정란 부화에 미치는 영향이 없었지만, 송사리는 254 NTU 이상의 구간에서 부화율이 저해되는 영향을 보였다. 붕어, 잉어, 송사리 치어의 4일간 노출 결과 생존에 미치는 영향은 없었다. 반면 성장률 결과에서 잉어와 붕어는 7일, 14일, 21일 모두 143 NTU 구간부터 성장저해 영향을 보였다. 송사리는 14일 노출 시 254 NTU, 21일간 노출 시 501 NTU 구간부터 성장저해 영향을 보였다. 따라서 강 또는 호소에서 143 NTU 이상의 탁도가 발생할 경우 붕어, 잉어의 성장을 저해시킬 수 있고, 250 NTU 이상의 탁도는 송사리와 같이 민감 어종의 부화율이 저해될 수 있을 것으로 사료된다. 【To assess the adverse effects of suspended solids on fishes, the hatching rate of embryo, and survival and growth of larvae were measured with common fish species of river such as crusian carp (Carassius auratus), common carp (Cyprinus carpio) and medaka (Oryzias latipes). Bioassay on hatching rate of embryo was conducted with a range of turbidity as 10 levels from 0.2 to 8,080 NTU. Another bioassay on 4-day larval survival and 21-day larval growth were also conducted with a range of turbidity as 8 levels from 0.1 to 8,260 NTU, and 6 levels from 0.7 to 2,030 NTU, respectively. The hatching rate of C. auratus was not significantly different from that of control at turbidity below 4,040 NTU, whereas it decreased when turbidity was 8,080 NTU (p】