• Korean Journal of Soil Science and Fertilizer
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• v.28 no.2
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• pp.176-182
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• 1995

Field and pot experiments were carried to find out the effects of direct application of phosphate rock powder on soybean plant in upland soils with different available P content. In newly reclaimed upland soil with extremely low available P, phosphate rock powder was superior to single superphosphate at the application rate of 400kg-600kg/ha, in the first year particularly. In the second year, however, the reverse was the case excepting at the rate of 200kg/ha. In upland soil with low avialble $P_2O_5$($52mg\;kg^{-1}$), the application of phosphate rock powder at the high appliaction rate(400-600kg/ha) increased the yield of soybean remarkably in the first year and there was residual effect in the second year. The application of phosphate rock at high rate, increased the P and Ca contenl of plant and soil. The concentration of all fractions of P in the soil at the harvest was higher in phosphate rock treatments than in single superphosphate and fused magnesium phosphate treatments. In this soil with low avaiable P the occurrence of different fractions of P was in the order of Org-P>Fe-P>Ca-P>Al-P, in the first year and there was no change in the second year.

• Journal of Soil and Groundwater Environment
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• v.10 no.5
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• pp.61-69
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• 2005

Changes in pyrene binding by dissolved and kaolinite-associated humic substances (HS) due to HS adsorptive fractionation processes were examined using purified Aldrich humic acid (PAHA) at different pH (4, 7 and 9). Irrespective of solution pH, molecular weight (MW) fractionation occurred upon adsorption of PAHA onto kaolinite, resulting in the deviation of residual PAHA MW from the original MW prior to sorption. Variation in $K_{OC}$ by bulk PAHA was observed at different pH due to relative contributions of partitioning and size exclusion effects (i.e., specific interactions). For all pH conditions investigated, carbon-normalized pyrene binding coefficients for nonadsorbed, residual fractions $(K_{OC}(res))$ were different from the original dissolved PAHA $K_{OC}$ value $(K_{OC}(orig))$ prior to contact with the kaolinite suspensions. Positive correlations between pyrene $(K_{OC}(res))$ and weight-average molecular weight $(MW_W)$ for residual PAHA fractions were observed for pH 7 and 9. However, such a positive correlation was not found at pH 4 due to the absence of the dramatic fractionation observed for high pH conditions (i.e., exclusive fractionation with respect to higher MW), suggesting that actual MW distribution pattern is more important for sorption-fractionated HS than the composite MW value. For adsorbed PAHA, conformational changes of PAHA upon adsorption seem to be important for the extent of pyrene binding. At relatively high pH (7 and 9), lower extent of pyrene binding was observed for adsorbed PAHA versus nonadsorbed PAHA. The conformation effects were more pronounced at higher pH.

• Journal of Korea Soil Environment Society
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• v.2 no.1
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• pp.13-20
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• 1997

Usage and residue of pesticide were sureyed for five years from three golf courses which have morethan eighteenholes inKangwon-do from 1992 to 1996. A total of 186 samples(soils, lawns, effluents) were collected from these courses and residual levels of four kinds of organochlorines and twelve kinds of organophosphorus pesticides in each samples were determined by GC-ECD and GC-NPD. The amount of pesticide used in each golf course was 1, 635.6kg a year on the average, and that of pesticide to the green and the fairway were 33g/$\textrm{m}^2$ and 3g/$\textrm{m}^2$, respectively. The pesticide which was not permitted for the management of golf course was detected in 24 of 186 samples and its detection rate was 12.9%. The average pesticide residue in soils was 0.208 ppm for captan, 0.031 ppm for daconil, respectively. Detection rate of the prohibited pesticides has decreased every year since 1992, and there were no residues all the tested samples in 1996.Based on these results, it might be judged investigation methods of pesticide residue should be changed with current using pesticide from the prohibited pesticides and the criteria of residual pesticides in effluents of golf course also should be established.

• Journal of Soil and Groundwater Environment
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• v.10 no.2
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• pp.44-51
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• 2005

Fractional composition and mobility of some heavy metals in sediments from Okdong stream are investigated. The fractional scheme for heavy metals in the sediment was established for five chemically defined heavy metal forms as adsorbed fraction, carbonate fraction, reducible fraction, organic fraction, and residual fraction. The most abundant fraction heavy metals in the sediments is reducible and secondly abundant is organic fraction. Adsorbed fraction is minor part of the total heavy metals. Mobilization of heavy metals in the sediments from Okdong stream occur $19.8{\sim}56.7%$ of total cadmium concentrate. The most abundant fraction of the sediment metal is organic fraction in Cu, Pb metals investigated. Labile fraction of sediment metals are $0.5{\sim}48.5%$ of total Zn, $2.6{\sim}48.1%$ of total Pb, and $0.2{\sim}36.9%$ of total Cu, respectively. Most of labile fraction consists of reducible fraction for Cd, Zn, adsorbed fraction for Pb, reducible fraction for Cu, adsorbed fraction for Ni. The Mobilization of Zn and Cu is most likely to occur when oxygen depletes and that of Pb and Ni occurs when physical impact, oxygen depletion and pH reduction.

• Journal of Applied Biological Chemistry
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• v.64 no.2
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• pp.177-184
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• 2021

While veterinary antibiotics are used only in a part of the dose administered, the rest are excreted as urine or feces. Residual antibiotics enter the adjacent agricultural environments by spraying manure-based composts on farmlands and lead to secondary pollution. Therefore, it is necessary to develop the technique for post management such as regulatory levels of antibiotics in the agricultural environments. This study was conducted to compare by different matrices the amount of residual antibiotics such as tetracyclines and sulfonamides, which are known to be frequently used in Korea and to practice risk assessment by different antibiotics in soils before and after application of composts. Pre-treatment with modified typical method using buffer and solid phase extraction showed the recovery of composts and soils was more than 70% at ppb level and the limits of detection were 0.13-0.46 and 0.05-0.25 ㎍/kg, respectively. Analysis of manure-based composts revealed concentrations from 5.38 to 196.0 ㎍/kg for tetracyclines, from below the detection of limit (BDL) to 259.0 ㎍/kg for sulfonamides. In case of agricultural soils, residual concentrations of selected veterinary antibiotics were ranged 0.30-53.3 ㎍/kg, BDL-4.16 ㎍/kg respectively and the concentration level of tetracyclines, which had higher soil distribution coefficient (Kd) values, was higher than that of sulfonamides. There was a difference in human risk assessment by different antibiotics in soil before and after application of composts. But, it was indicated that detection values of all of 5 antibiotics were very safe on the basis that Hazard Quotient was safe below 1.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.2
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• pp.133-139
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• 2014

Veterinary antibiotics (VAs) in animal compost and organic fertilizer can have adverse effect on ecosystem and eventually human health. The main purpose of this research was to evaluate feasibility of Charm II system for monitoring residuals of VAs in animal compost and organic fertilizer. Four different VAs (Tetracyclines: TCs, Sulfonamides: SAs, Macrolides: MLs, and ${\beta}$-lactams: ${\beta}$-LTs) were analyzed and total of 100 samples were monitored. Results reveled that SAs in animal compost showed the highest detection frequency (64%) with exceeded concentration of criteria. However, very low detection frequency (0-12%) for ${\beta}$-LTs was observed in animal compost and organic fertilizer. Depending on physicochemical properties of each VAs, detection frequency of VAs was determined. In conclusion, charm II system can be utilized to screen if residual of VAs is in animal compost and organic fertilizer. Also, more research is necessary to establish standard method for analysis of VAs in complex matrix and to minimize adverse effect of VAs from source to environment.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.56-63
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• 2003

Fractional composition and mobility of sediments some heavy metals in Okdong stream are investigated. The fractional scheme for sediment heavy metal was made for five chemically defined heavy metal forms as adsorbed fraction, carbonate fraction, reducible fraction, organic fraction, and residual fraction (Tessier et at., 1979). The most abundant fraction of the sediment heavy metal is reducible and secondly abundant organic fraction. Adsorbed fraction is minor part of the total heavy metals. Mobilization of sediment heavy metals in stream Okdong is occur 19.8∼56.7% of total cadmium concentrate. The most abundant fraction of the sediment metal is organic fraction in Cu, Pb metals investigated. Labile fraction of sediment metals are 0.5%∼48.5% of total Zn, 2.6%∼48.1% of total Pb, 0.2∼36.9% of total Cu respectively, Most of labile fraction consists of reducible fraction for Cd, Zn, adsorbed fraction for Pb, reducible fraction for Cu, adsorbed fraction for Ni. The Mobilization of Zn and Cu is most likely to occur when oxygen depletes and that of Pb and Ni occurs when physical impact, oxygen depletion and pH reduction.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.409-412
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• 2003

Total extraction of stream sediments in the Kwangyang mine area shows their significant pollution with most trace metals such as Cr, Co, Fe, Pb, Cu, Ni, Zn and Cd, due to sulfide oxidation in waste dumps. Calculations of enrichment factor shows that Chonam-ri creek sediments are more severely contaminated than Sagok-ri sediments. Using the weak acid (0.1N HCl) extraction and sequential extraction techniques, the transport and sediment-water partitioning of heavy metals in mine drainage were examined for contaminated sediments in the Chonam-ri and Sagok-ri creeks of the Kwangyang Au-Ag mine area. Calculated distribution coefficient (Kd) generally decreases in the order of Pb $\geq$Al > Cu > Mn > Zn > Co > Ni $\geq$ Cd. Sequential extraction of Chonam-ri creek sediments shows that among non-residual fractions the Fe-Mn oxide fraction is most abundant for most of the metals. This indicates that precipitation of Fe hydroxides plays an important role in regulating heavy metal concentrations in water, as shown by field observations.

• The Korean Journal of Soil Zoology
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• v.4 no.2
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• pp.75-80
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• 1999

Two years-study with litter bag (mesh size : 0.4 mm, 1.7 m) was carried out from Nov., 1996 to Sept., 1998 to investigate the soil microarthropod community in the process of needle leaf secomposition of Korean pine (Pinus koraiensis) forest in Namsan and Kwangreung, where were supposed to be under different environmental selective pressures. Soil arthropoda collected from litter bags were sorted into suborders or higher taxa. Acari and Collembola were dominant groups, which were 61-68% and 27-35% of total soil arthropod in their numbers, respectively. Among Acari, Oribatida was major group, and Gamasida and Actinedida were minor groups. Abundance of Acari was a little higher in Kwangreng than in Namsan. But there was not significant difference between the arthropod community structure of Namsan and Kwangreng forest. And the different mesh sizes (0.4 mm and 1.7 mm) of litter bags could not make significantly different community structures in the litter bags. One taxon showed different pattern of population dynalics from another. But Oribatida, Gamasida and Collembola showed peak density in July, 1997. All taxa showed lower population densities in cold season i.e. Nov., Jan. and March. There was not significant difference in decomposition rate between Namsan and Kwangreng forest, and between mesh sizes of litter bags. % residual mass of needle leaf was about 40% at 22 months after litter fall.

• Korean Journal of Environmental Agriculture
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• v.14 no.3
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• pp.302-311
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• 1995

Benfuresate or oxolinic acid, as an experimental pesticide, was applied to the different textural paddy or upland soil respectively under the field condition and the residual concentrations were determined. Six kinetic models were employed to characterize the best-fit kinetic model describing the residual pattern of benfuresate or oxolinic acid and the $t\frac{1}{2}$ estimated from each model was comparatively assessed. All of the six models explained significantly the residual patterns of the pesticides but the empirical models such as PF, EL, and PB were not recommendable for the $t\frac{1}{2}$ estimation. Among theoretical models, the residual patterns were followed in the orders of the second-order(SO)>first-order(FO)>zero-order(ZO) kinetics, judging from the size and significance of coefficient of determination and standard error. However, the multiple FO model, consisting of the fast and slow decomposition steps, was better than the single FO model for the residual pattern and the $r^2$ in this case became similar to that of SO kinetic model. Thus the multiple FO and SO models were represented as the best fit model of the experimental pesticide. The $t\frac{1}{2}$ of benfuresate estimated from the single FO kinetic model in Weolgog and Cheongwon series was 49 and 63 days, respectively, which were 20 and 13% longer than the respective $t\frac{1}{2}$ from the SO kinetic model. The $t\frac{1}{2}$ of oxolinic acid from the FO model in Yonggye and Ihyeon series were 87 and 51% longer than those from the SO kinetic model, respectively. These results demonstrated that the best-fit model representing the residual pattern of a pesticide and the resultant $t\frac{1}{2}$ might be variable with the kinds of pesticides and the environmental conditions. Therefore it is recommended that the half-life of a pesticide be assessed from the best-fit model rather than from the FO kinetic model uniformly.