• Journal of the Korean Chemical Society
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• v.47 no.6
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• pp.578-584
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• 2003

Polychlorinated biphenyls (PCBs) known as environmental contaminants in soil were analyzed by the soil pollution standard process test and the static supercritical $CO_2$ extraction mode. It was shown that the percent average recoveries of PCBs by the soil pollution standard process test were ranged in 25-35% and the corresponding standard deviations were above 10%. In contrast, the percent average recoveries of PCBs by the static supercritical $CO_2$ extraction mode were 2-2.5 times higher and standard deviations were within 7%. These results indicate that static supercritical $CO_2$ extraction mode may be a useful alternative to sample pretreatment certified by the soil pollution standard process test. The increasing supercritical $CO_2$ pressure from 1130 psi to 1996 psi at $40^{\circ}C$ enhanced the recovery of all PCB congeners from soil. However, at same Tc and Pc, the equilibrium time (5 versus 60 minutes) had no effect on the recovery of each PCB congener. Finally, similar PCB recoveries were obtained under the same extraction condition, regardless of the molecular weight and structure (coplanar versus non-coplanar) of PCB congeners.

• Journal of Environmental Health Sciences
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• v.44 no.4
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• pp.323-329
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• 2018

Objectives: The purpose of this study is to investigate the water quality of 16 golf course ponds located in northern areas Gyeonggi province by investigating residual pesticides, organic matters (BOD, TOC) and nutrients (TN, TP). Methods: The result data for the residual pesticides were used from 2014 to 2017. and other result data were used for April and July in 2017. The residual pesticides analytical method was based on 'Golf course residual pesticides inspection method', The others analytical method was based on 'The water pollution process test standard' Results: Very toxic pesticides and banned pesticides were not detected but general pesticides were detected. In case of the water quality of the golf course pond was applied to the lake water quality standard. In April the average TOC concentration was V grade to 6.46 mg/L, TP V grade to 0.13 mg/L, TN VI grade to 1.6 mg/L, In July TOC average concentration was VI grade to 8.65 mg/L, TP VI grade to 0.17 mg/L, TN V to 1.5 mg/L. All TN and TP concentrations corresponded to eutrophication. Compared with lake water quality monitoring, the concentrations of BOD, TOC and TP were high but the TN concentration was low in April and July. Conclusions: It is considered that water quality managements are necessary for the golf course pond. The first reason is that the pollutants of pond are discarded to river during rainfall and act as pollution sources. The second reason is that the golf course users are uncomfortable because of odor caused by the pollutants of the pond.

• Economic and Environmental Geology
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• v.45 no.3
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• pp.307-315
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• 2012

In this paper, a laboratory model test was conducted to evaluate grouting efficiency of ordinary portland cement(OPC) and micro cement used in MIS(Micro-Injection Process System). For this research, a injection equipment was developed for pressure permeation which can evenly simulate various grouting tests in a laboratory and suggested a standard for the production of the test specimen. Using the injection device, the laboratory injection tests of grouts were prepared with water/cement ratio of 1:1, 2:1, 3:1, 4:1, and 5:1. The analysis of injection test for pressure permeation showed that the efficiency of injection increases linearly as the water/cement ratio increases. Comparison of efficiency of the injection indicates that MIS with a relatively smaller average diameter shows more efficient injection than the OPC. In the low ratio of water/cement as 2:1~1:1, the injection efficiency of OPC was especially poor. Also, a nonlinear grout volume-injection time is represented by a hyperbolic model and grout volume predicted by hyperbolic model was compared with the value measured. From the comparison, it shows that the hyperbolic model has the potential of evaluating the efficiency of grouting.