• Journal of agriculture & life science
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• v.45 no.5
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• pp.73-80
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• 2011

Fifty substances of pesticide were selected for analysis through the historical investigation of pesticides detected from environmental-friendly agricultural soil, and the environmental-friendly agricultural soils in Gyeongnam area were collected and then were accepted Anve (accelerated solvent extraction) and SPve (solid-phase extraction) as multiresidue extraction and clean up methods suitable to the soils. The pesticide residues were analyzed by using GC/vCD/NPD, HPLC/UV/FL, GC/MSD, or HPLC/MSD. 50 kinds of pesticides for the soils were an average of 95.5% from retrieval ratio of the 72 to 118% range, and the average of 3.0% for CV (%). Among 40 samples of soil, 20 components were detected from pesticide residues of 21 samples, and average amounts detected for these components were 0.035 for endosulfan, 0.043 for ethoprophos, 0.020 for chlorpyrifos, 0.023 for chlorfenapyr, 0.047 for flufenoxuron, 0.070 for fenvalerate, 0.266 for cypermethrin, 0.016 for lufenuron, 0.022 for bifenthrin, 0.025 for fenobucarb/BPMC, 0.043 for difenoconazole, 0.059 for fenarimol, 0.020 for kresoxim-methyl, 0.026 for tetraconazole, 0.039 for isoprothiolane, 0.017 for iprobenfos, 0.014 for nolrimol, 0.156 for fluquinconazole, 0.047 for tebuconazole, and 0.045 mg/kg for oxadiazon. Therefore it is infered that the establishment of pesticide residues limit for environmental-friendly agricultural soil is needed as soon as possible.

• Journal of Soil and Groundwater Environment
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• v.16 no.5
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• pp.67-73
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• 2011

Groundwaters were sampled from 730 wells being used for drinking purposes during 2007-2009. These samples were analysed using a gas-flow type GPC (Gas Proportional Counter) according to the USEPA method (900.0). We obtained a gross-alpha counting TDS (total dissolved solid) efficiency curve (Y = 0.0017X2 - 0.3122X + 19.165, X = TDS, Y = efficiency, $R^2$ = 0.9734) using natural uranium standard to get gross ${\alpha}$ value of the samples. The gross alpha values ranged from MDA (minimum detectable activity) to 14.88 pCi/L and 429 samples showed values higher than MDA (< 0.9 pCi/L). Correlations of the uranium values with the total alpha values and the gross-alpha values indicate that uranium values have high impacts on gross-alpha values. Groundwater samples of study areas were classified into four regions according to the rock types; plutonic (granite) rock region (427 areas), metamorphic rock region (181 aeras), sedimentary rock region (70 areas), volcanic rock region (52 areas). Groundwater of Cretaceous granite presented the highest gross-alpha value. Gross alpha in groundwaters showed no relationship with uranium in terms of the geological ages, rocks and minerals.

• Environmental Engineering Research
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• v.13 no.4
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• pp.216-223
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• 2008

An efficient method for the simultaneous determination of eleven phenolic endocrine-disrupting chemicals (EDCs) present in wastewater influent samples was described. The 11 phenolic EDCs including alkylphenols, chlorophenols, and bisphenol A were determined by gas chromatography/mass spectrometry-selected ion monitoring (GC/MS-SIM) following two work-up methods for comparison; isobutoxycarbonyl (isoBOC) derivatization and tert-butyldimethylsilyl (TBDMS) derivatization. The wastewater influent samples containing the 11 EDCs were adjusted to pH 2 with $H_2SO_4$ and then cleaned up with n-hexane. Next, they were subjected to solid-phase extraction (SPE) with XAD-4 resin and subsequently converted to isoBOC or TBDMS derivatives for sensitivity analysis with gas chromatography/mass spectrometry-selected ion monitoring (GC/MSSIM). Following isoBOC derivatization and TBDMS derivatization, the recoveries were 86.6-105.2% and 97.6-142.7%, the limits of quantitation (LOQ) for the 11 phenolic EDCs for SIM was 0.001-0.050 ng/mL and 0.003-0.050 ng/mL, and the SIM responses were linear with the correlation coefficient varying by 0.9717-0.9995 and 0.9842-0.9980, respectively. When these methods were applied to five selected wastewater influent samples, for isoBOC derivatization and TBDMS derivatization the ranges of concentration detected were 0.2-99.6 ng/mL and 0.4-147.4 ng/mL, respectively.

• Journal of Environmental Impact Assessment
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• v.15 no.5
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• pp.299-308
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• 2006

To utilize a closed municipal solid waste landfill site in environmentally secure conditions, it is necessary to verify the stabilization level of landfill leachate. To assess leachate stabilization of an open-dumping municipal solid waste landfill site (Salmi Landfill) which is located at the vicinity of Chungju Reservoir which flows into Paldang Reservoir utilized as Seoul Metropolitan water supplies, the landfill history and surrounding characteristics of the landfill site were surveyed. In this investigation, waste, leachate, groundwater and surfacewater samples from this landfill were physically and chemically analyzed, and the analysis results were evaluated by 'The Criteria of Landfill Waste Stabilization (CLWS)', 'Discharge Criteria of Landfill Leachate', 'The Criteria of Domestic Use in Groundwater Quality', and 'The Criteria of Domestic Use in Surfacewater Quality' that promulgated by Korean Ministry of Environment. From the analysis results on the Salmi open-dumping landfill, C/N ratio was 18.9 and $BOD/COD_{Cr}$ ratios in leachate were higher than 1/10. Based on the CLWS, this results seemed to imply that the process of leachate stabilization at this landfill was still proceeding.

• Journal of Environmental Impact Assessment
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• v.14 no.6
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• pp.365-375
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• 2005

For managing and utilizing a closed municipal solid waste landfill site in environmentally secure conditions, it is necessary to verify the stabilization level of landfill gas(LFG) and waste. For assessing LFG and waste stabilization of an open-dumping municipal solid waste landfill (Salmi Landfill) which is located at the vicinity of Chungju Reservoir which flows into Paldang Reservoir that has been used for Seoul Metropolitan water supplies, the history and the surrounding characteristics of the landfill site were surveyed. In this study, waste and LFG samples obtained from landfill site were physically and chemically analyzed, and then the analysis results were evaluated on the basis of 'The Criteria of Landfill Waste Stabilization(CLWS)' that were promulgated by Korean Ministry of Environment. Based on LFG composition of Salmi landfill, $CH_4$ was as high as 68%. In CLWS regulation, the stabilization criteria of $CH_4$ should be lower than 5%, and the criteria of C/N ratio should also be lower than 1/10. The result showed that C/N ratio of landfilled waste ranged 17.4~24.7. From this results, it was concluded that the LFG and C/N ratio stabilization level of this landfill based on the CLWS were still actively proceeding.

• Environmental Engineering Research
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• v.17 no.3
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• pp.145-150
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• 2012

Pb-contaminated soil at a clay shooting range was analyzed by the sequential extraction method to identify metal binding properties in terms of detrital and non-detrital forms of the soil. Most of the metals in the soils existed as non-detrital forms, exchangeable and carbonate-bound forms, which could be easily released from the soil by a washing method. Therefore, the characteristics of Pb desorption for remediation of the Pb-contaminated soil were evaluated using hydrochloric acid (HCl) by a washing method. Batch experiments were performed to identify the factors influencing extraction efficiency. The effects of the solid to liquid (S/L) ratio (1:2, 1:3, and 1:4), soil particle size, and extraction time on the removal capacity of Pb by HCl were evaluated. Soil samples were collected from two different areas: a slope area (SA) and a land area (LA) at the field. As results, the optimal conditions at 2.8 to 0.075 mm of particle size were 1:3 of the S/L ratio and 10 min of extraction time for SA, and 1:4 of the S/L ratio and 5 min of extraction time for LA. The characteristics of Pb desorption were adequately described by two-reaction kinetic models.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.2
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• pp.75-83
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• 2013

We applied a sensitive method based on on-line solid-phase extraction (SPE) and liquid chromatography/mass spectrometry (LC/MSD) using an electrospray interface for the determination of eleven perfluorinated compounds (PFCs) in water. The on-line connection suppressed the target loss by keeping the cartridge from drying, which resulted in improvement of the recovery and saving of the analytical time. For the on-line solid-phase extraction of 10 mL water samples, recoveries were between $80.4{\pm}5.2%{\sim}109.5{\pm}1.4%$ and limit of quantification (LOQ) were 3.6~15.9 ng/L for the PFCs. The total PFCs concentrations of the tributaries and main stream of Nakdong River water samples were in the range of $8.0{\sim}678.6{\mu}g/L$.

• Journal of Environmental Health Sciences
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• v.23 no.1
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• pp.66-73
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• 1997

This procedure describes the method for gas chromatographic determination of 31 organophosphorus and 28 organochlorine pesticides in 10g of spinach, tomato and onion. After the pesticides were extracted with several solvents, the amount of coextractives and recovery rates of acephate and methamidophos were calculated. Samples for organochlorine pesticides were cleaned up with florisil solid phase extraction columns. NaBH$_4$ was added to onion extracts, which contained sulfur compound. All the concentrated extracts were analyzed by gas chromatography with ECD and NPD. The smallest amount of coextractives resulted from the spinach samples extracted with 5% MeOH in ethyl acetate. 5% EOH in ethyl acetate had the highest extractability for acephate and methamidophos and gave the best overall performance as an extraction solvent. The ability of 5% EOH in ethyl acetate to extract various organophosphorus and organochlorine pesticides from spinach, tomato and onion was examined. Recovery of 59 insecticides ranged from 58.0% to 110.5%. The average recoveries of fortified spinach, tomato and onion were 90.08%, 94.54% and 84.90%, respectively.

• Environmental Analysis Health and Toxicology
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• v.26
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• pp.2.1-2.7
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• 2011

Objectives: N-Nitrosodimethylamine (NDMA) is classified as a probable human carcinogen by the United States Environmental Protection Agency (US EPA) and is formed during the chlorination of municipal drinking water. In this study, selected nitrosamines were measured in chlorinated drinking water collected from Chuncheon, Kangwon-do, Republic of Korea, and a risk assessment for NDMA was conducted. Methods: Twelve water samples were collected from 2 treatment plants and 10 household taps. Samples were analyzed for 6 nitrosamines via solid-phase extraction cleanup followed by conversion to dansyl derivatives and high-performance liquid chromatography-fluorescence detection (HPLC-FLD). Considering the dietary patterns of Korean people and the concentration change of NDMA by boiling, a carcinogenic risk assessment from ingestion exposure was conducted following the US EPA guidelines. Results: NDMA concentrations ranged between 26.1 and 112.0 ng/L. NDMA in water was found to be thermally stable, and thus its concentration at the end of boiling was greater than before thermal treatment owing to the decrease in water volume. The estimated excess lifetime carcinogenic risk exceeded the regulatory baseline risk of $10^{-5}$. Conclusions: This result suggests that more extensive studies need to be conducted on nitrosamine concentration distributions over the country and the source of relatively high nitrosamine concentrations.

• Analytical Science and Technology
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• v.23 no.3
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• pp.261-268
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• 2010

This study was performed to evaluate the PCBs-containing wastes using official test method. Ninety samples of transformer oil and various solid waste were collected to assess the analytical results. In the analysis of PCBs-containing wastes, the PCBs levels were detected in the range of 7.6 mg/kg to 23.8 mg/kg for transformer oils, $0.02\sim0.54\;{\mu}g/100cm^2$ for plat solid wastes, and 0.01~0.071 mg/kg for amorphous solid waste. In the cupper wire waste of the transformer with oil concentration level of 23 mg/kg, the analytical result exceed PCBs regulation level of 0.04 mg/kg. The new proposed analytical method for PCBs containing waste can be forced to effective management of the wastes.