• Journal of Korean Society on Water Environment
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• v.33 no.4
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• pp.460-473
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• 2017

In order to certificate the contamination assessment of heavy metals in surface sediments from the Nakdong river. Surface sediments were collected of 24 sampling sites (main 14st., tributary 10st.) and analyzed for grain size heavy metals contents. Study area mainly composed of sand (avg. 94.1%) and mean grain size was $1.46{\Phi}$ on average. Heavy metals contents (avg. Al: 12.5%, Zn; 74.4, Cr: 45.3, Li: 26.0, Pb: 17.1, Ni: 10.5, Cu: 7.8, Cd: 0.22 mg/kg) were relatively high contents in the composed of fine sediments. In addition, the results of pearson's correlation coefficient showed that most heavy metals and grain size (silt and clay) were highly correlated. The contents of Zn (6st.) and Ni (1st.) evaluated as moderately polluted, Zn (6st.) evaluated as LEL when compared with sediment quality standard of USEPA and Ontario sediment quality guidelines. Most heavy metals contents were I levels that dose not affected the benthos when compared with sediment pollution evaluation standard of NIER. The results of EX, EF, Igeo and CF showed the contents of Zn, Pb and Cd exceed the background contents and distributing of anthropogenic pollution and evaluated as moderately polluted level. And Nm-08 were relatively high level of contamination in the study area. However as results of PLI (less than 1), all sampling sites were evaluated unpolluted level.

• Journal of Environmental Science International
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• v.20 no.9
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• pp.1069-1078
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• 2011

The environmental changes related to hypoxic water mass were investigated at Gamak bay in summer times, June, July and August 2006. The hypoxic water mass was found, in first, at the northern area of Gamak bay on 27 June. This water mass has been sustained until the end of August and disappear on 13 September. In Gamak bay, the hypoxic water mass was closely related to geography. During the formation of oxygen deficiency, changes in dissolved nutrients was studied and found that on surface layer and lower layer, DIN were 0.80 ${\mu}M$~19.8 ${\mu}M$(6.03 ${\mu}M$) and 1.13 ${\mu}M$～60.83 ${\mu}M$(10.66 ${\mu}M$), and DIP were 0.01 ${\mu}M$～0.92 ${\mu}M$(0.24 ${\mu}M$), and 0.01 ${\mu}M$～3.57 ${\mu}M$(0.49 ${\mu}M$), respectively, far higher distribution on lower layer of the water where hypoxic water mass was occurred. The configuration of phosphorus was analyzed to figure out the possibility of release of phosphorus from sediments. It was found that the Labile-Phosphorus, which is capable of easy move to water layer by following environmental change was found more than 70%. Therefore, in Gamak bay, it was found that the possibility of large amount of release of soluble P into the water, while hypoxic water mass was occurred in deep layer was higher. It is suggested that DIP in the northern sea of Gamak bay mainly sourced from the soluble P from lower layer of the waters where hypoxic water mass was created more than that from basin. However, existence form of phosphorus in sediments during normal times, not during creation of hypoxic water mass, needs further study.

• Economic and Environmental Geology
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• v.39 no.6 s.181
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• pp.739-752
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• 2006

Deep-sea surface sediments acquired by multiple corer from 69 stations in the Clarion-Clipperton fracture zone of the northeast equatorial Pacific, were examined to understand the correlation of mass physical properties and sedimen-tological processes. The seabed of the middle part ($8-12^{\circ}N$) of the study area is mainly covered by biogenic siliceous sediment compared with pelagic red clays in the northern part ($16-17^{\circ}N$). In the southern part ($5-6^{\circ}N$), water depth is shallower than carbonate compensation depth (CCD). The mass physical properties such as grain size distribution, mean grain size, water content, specific grain density, wet bulk density, void ratio, and porosity of sediments are distinctly different among the three parts of the study area. Surface sediments in northern part are characterized by fine grain size and low water contents possibly due to low primary productivity and high detrital input. Conversely, sediments in the middle part are characterized by coarse grain size and high water contents, which might be caused by high surface productivity and deeper depth than CCD. The sediments show low water contents and high density in the southern part, which can be explained by shallower depth than CCD. Our results suggest that the variations in mass physical properties of sediments are influenced by combined effects including biogenic primary productivity of surface water, water depth, especially with respect to CCD, sedimentation rate, detrital input, and the geochemistry of the bottom water (for example, formation of authigenic clay minerals and dissolution of biogenic grains).