• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.05a
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• pp.46-51
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• 2000

Environmental quality regulations are used to establish the maximum permissible concentrations of heavy metals before a site can be deemed to be polluted or contaminated. This paper compares the results obtained by 0.IN HCl extraction and acid extraction method(HNO$_3$+HClO$_4$.HCl). The leaching efficiency of 0.1N HCl extraction is directly proportional to the final pH of leachate, due to the different solubilities of the heavy metals at different pH values, The severe differences between 0.1N HCl-extractable and total metal contents result mainly from the buffering effect of carbonates, present in sediment. samples. Application of sequential extraction experiments to some sediments collected from gully pot in Seoul illustrates a much stronger scavenging effect by Fe and Mn-hydroxides, carbonates and organic phases. As deduced from both sequential extraction and leaching experiments, the relative mobility of heavy metals is found to be: Mn>Zn>>Co>Cd>>Cu>Pb>Cr>Fe, in spite of large differences in heavy metal content and localization. Changes in the physicochemical environments (such as acidification) caused by a traffic accident may result in the severe environmental pollution of heavy metals of surrounding area( surface water and rivers).

• Economic and Environmental Geology
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• v.32 no.3
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• pp.261-271
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• 1999

Mining activity in the Gubong gold mine started in 1908 and lasted up to recent days. Heavy metals derived from the activity may be porentially toxic to human life and envirinment of this area. Because metal toxicity depends on chemical associations into five operationally defined groups: exchangeable, carbonate, reducible, oxidizable, and residual fractions, and the Most of heavy metals have significant little significance (alomost<1%). And Cu is mainly associated with the oxidizable from. Total concentration of heavy metals, pH, and mineralogy affect the chemical forms of the metals. Heavy metal concentrations. Significant amounts of metal elements (5∼65.1% in Pb, 6.2∼39.7% in Zn, 8.7∼54.7% in Cd, and 3.6∼24.7% in Cu) were present in carbonate form from mine wastes, contaminated soils and sediments. High pH value and cerussite (Pb bearing carbonate mineral) in mine wastes, contaminated soils and sediments. High pH value and cerussite (Pb beraring varbonate mineral) in mine waste support this result. Areas with high corbonate bound from would have higher potentoal conamination, however, because elements of carbonate bound forms are easily mobilized under lower pH conditions in the surface envionments due to acid to rain soil acidification.

• Korean Journal of Agricultural and Forest Meteorology
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• v.4 no.4
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• pp.237-247
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• 2002

Air pollution by acid pollutants is problematic in the whole world. Water acidification has already been deteriorating the forest ecosystem. This study was conducted to analyze the acidity and chemical composition of the open precipitation and throughfall at forests with various geographic locations in Korea. The results of this study are as follows; The open precipitation pH was lowest in Seochun. The throughfall pH showed some buffering capacity in only Quercus mongolica stands. In Pinus rigida(Shingal and Seochun) stands, there was little difference from the open precipitation. Chemical composition of the open precipitation for each sampling site showed that $Ca^{2+}$, N $H_{4}$$^{+}$ and S $O_{4}$$^{2-}$ concentrations had higher value than other ions, and except these ions, the small quantity of ions showed different properties to each site. Changes of ion concentrations in the throughfall showed a tendency to increase. ion concentrations of the throughfall increased with washout and nutrient leaching from the trees. In conclusion, the influence was extended to the pure zone, and the frequency of acid rain is increasing. But, if the deposition of pollutants exceeds the capacity of purification, it would damage forest ecosystem. Further investigations are necessary to identify tolerant tree species to acid pollutants.nts.

• Korean Journal of Environmental Agriculture
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• v.17 no.3
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• pp.234-238
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• 1998

Anaerobic degradation characteristics of dewatered liquid of household food waste including methane conversion efficiency and degradation kinetics were studied in an anaerobic batch reactor of 5 L volume. The ultimate methane production for dewatered liquid of household food waste tested was over 0.31L $CH_4/L{\cdot}dewatered$ liquid of household food waste. The kinetic constant of dewatered liquid of household food waste tested was $0.223d^{-1}/L$. The kinetic behavior of anaerobic degradation was described as a first order series reaction. The determinant of rate-limiting step(DR) that is balanced out from the rates of reaction steps was defined by the logarithmic difference of the maximum acidification rate and the maximum methanation rate. Anaerobic degradation characteristics of organic materials were evaluated by the value of DR. The DR of dewatered liquid of household food waste tested was 1.17.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.19 no.6
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• pp.1-17
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• 2016

The study was aimed to understand the ecological status of the Maebongsan urban forest in Cheongju-si through investigating the vegetation, soil characteristics, and soil microarthropods. Phytosociological analysis for twenty plots revealed that the plant communities were classified into Pinus rigida community, Robinia pseudoacacia community, Castanea crenata community, Quercus acutissima community, Pinus strobus community, Pinus koraiensis community, and Larix kaempferi community. The importance value showed that afforestation tree species like Castanea crenata, Robinia pseudoacacia, and Pinus rigida dominate the urban forest. DBH analysis indicated that although the plant communities seem to be under the succession to Quercus forest, the dominance of Castanea crenata and Robinia pseudoacacia might still persist for several more decades. The properties of soils from the plant communities showed that loamy sand and sandy loam in soil texture, low organic matters, and severe acidification. The abundance of soil microarthropods were not different among the plant communities except Castanea crenata community and Pinus koraiensis community. The two communities showed especially low abundance of collembola and acarina. Thus, we can say that Castanea crenata community and Pinus koraiensis community seem to have been influenced strongly by anthropogenic activities.

• Journal of Korean Society for Atmospheric Environment
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• v.8 no.1
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• pp.45-51
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• 1992

A study on acidity in fog, dew and frost was carried out. Samples were taken during May 1990-February 1991 at two sites in Chongwon, Choongbook. The acidity of dew and of fog collected from grass at site A was 4.89 and 5.46, respectively. Dew in summer showed very strong acidity. The volume of dew deposited on grass was much less than the volume of rain, but dew is effective to diffuse acid predursors and acid materials. Dew and fog can remove more effectively atmospheric acid materiasl deoposited on grass by diurnal turbulent motion rather than direct absorption of acid predursors and materials in the atmosphere. In a polluted area, acidic dew and fog can be occurred by the direct absorption and oxidation of acidic predursors in the atmosphere as well as the role of wet removal on grass surface. Acidity of frost collected on teflon surface showed little difference to acidity of dew and fog on teflon surface. This suggests a similar absorption mechanism of atmospheric precursors and materials into dew and frost in the atmosphere. Strong acidity in dew, fog and frost appeared to occur from local pollution sources of several ten kilometres. In particular, strong acidity in dew, fog, and frost together with acid rain can accelerate a damage in ecosystems. Discussion is made on scientific analyses and seasonal variations of acidity of fog, dew and frost. A mechanism on acidification of fog, dew and frost is also discussed.

• Journal of Microbiology and Biotechnology
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• v.16 no.7
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• pp.1125-1131
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• 2006

A kan'::luxCDABE fusion strain that was both highly bioluminescent and responsive to benzoic acid was constructed by transforming E. coli strain W3110 with the plasmid pUCDK, which was constructed by digesting and removing the 7-kb KpnI fragment from the promoterless luxCDABE plasmid pUCD615. Experiments using buffered media showed that this induction was dependent on the pH of the media, which influences the degree of benzoic acid protonation, and the expression levels seen are likely due to acidification of the cytoplasm by uncoupling of benzoic acid. Consequently, the sensitivity of this strain for benzoic acid was increased by nearly 20-fold when the pH was shifted from 8.0 to 6.5. Benzoic acid derivatives and several phenolics also resulted in significantly increased bioluminescent signals. Although these compounds are known to damage membranes and induce the heat-shock response within E. coli, bacterial strains harboring mutations in the fadR and rpoH genes, which are responsible for fatty acid biosynthesis during membrane stress and induction of the heat-shock response, respectively, showed that these mutations had no effect on the responses observed.

• Journal of Microbiology and Biotechnology
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• v.13 no.1
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• pp.90-98
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• 2003

In vivo $^31p$ Nuclear Magnetic Resonance ($^31p$NMR) and metabolic studies were carried out on an acetic acid tolerant mutant, Zymomonas mobilis $ZM4/Ac^R$, and compared to those of the parent strain, Z. mobilis ZM4, to evaluate possible mechanisms of acetic acid resistance. This investigation was initiated to determine whether or not the mutant strain might be used as a suitable recombinant host far ethanol production from lignocellulose hydrolysates containing various inhibitory compounds. $ZM4/Ac^R$ showed multiple resistance to other lignocellulosic toxic compounds such as syringaldehyde, furfural, hydroxymethyl furfural, vanillin, and vanillic acid. The mutant strain was resistant to higher concentrations of ethanol or lower pH in the presence of sodium acetate, compared to ZM4 which showed more additive inhibition. in vivo $^31p$ NMR studies revealed that intracellular acidification and de-energization were two mechanisms by which acetic acid exerted its inhibitory effect. For $ZM4/Ac^R$, the internal pH and the energy status were less affected by sodium acetate compared to the parent strain. This resistance to pH change and de-energization caused by acetic acid is a possible explanation for the development of resistance by this strain.

• Journal of Microbiology and Biotechnology
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• v.20 no.1
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• pp.179-186
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• 2010

In biological wastewater treatment, high lipid concentrations can inhibit the activity of microorganisms critical to the treatment process and cause undesirable biomass flotation. To reduce the inhibitory effects of high lipid concentrations, a two-phase anaerobic system, consisting of an anaerobic sequencing batch reactor (ASBR) and an upflow anaerobic sludge blanket (UASB) reactor in series, was applied to synthetic dairy wastewater treatment. During 153 days of operation, the two-phase system showed stable performance in lipid degradation. In the ASBR, a 13% lipid removal efficiency and 10% double-bond removal efficiency were maintained. In the UASB, the chemical oxygen demand (COD), lipid, and volatile fatty acid (VFA) removal efficiencies were greater than 80%, 70%, and 95%, respectively, up to an organic loading rate of 6.5 g COD/l/day. No serious operational problems, such as significant scum formation or sludge washout, were observed. Protein degradation was found to occur prior to degradation during acidogenesis.

• Environmental Engineering Research
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• v.13 no.4
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• pp.210-215
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• 2008

The present study investigates the effect of oxidation-reduction potential (ORP) and organic compounds on specific anaerobic ammonium oxidation activity (SAA) using batch experiments. The batch tests were based on the measurement of nitrogen gas production. The relationship between ORP and dissolved oxygen (DO) concentration was found to be ORP (mV) = 160.38 + 68 log [$O_2$], where [$O_2$] is the DO concentration in mg/L. The linear relationship obtained between ORP and SAA ($R^2$ = 0.99) clearly demonstrated that ORP can be employed as an operational parameter in the Anammox process. At ORP value of -110 mV, the SAA was $0.272{\pm}0.03\;g\;N_2-N\;(g\;VSS)^{-1}\;d^{-1}$. The investigation also revealed inhibitory effect of glucose on the SAA while acetate concentration up to 640 mg COD/L (corresponding to 10 mM) had stimulating effect on the SAA. However, acetate concentration beyond 640 mg COD/L had inhibitory effect on the Anammox activity. The results indicated that nitrogen rich wastewaters containing low level organic matter could be better treated by Anammox microorganisms in real-world conditions after some acidification process.