• Journal of the Korean Wood Science and Technology
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• 제42권4호
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• pp.450-459
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• 2014

파쇄한 소나무와 참나무를 수중에서 Pb(II) 제거를 위한 흡착제로서 적용성을 검토하였다. 접촉시간, 초기 Pb(II) 농도, pH, 경쟁이온, 그리고 흡착제 주입량이 Pb(II) 흡착에 미치는 영향을 파악하기 위하여 회분 흡착 실험을 수행하였다. 동역학적 실험 결과, 소나무와 참나무에 Pb(II) 흡착은 유사 1차 모델과 유사 2차 모델 모두 적합한 것으로 나타났다. 평형 흡착 실험 결과는 결정계수가 소나무의 경우 0.956, 참나무의 경우 0.950으로 Freundlich 모델이 적합한 것으로 나타났다. 소나무와 참나무의 Pb(II) 최대 흡착양은 각각 16.853과 27.989 mg/g으로 나타났다. pH가 3에서 9로 증가함에 따라서 소나무와 참나무에 Pb(II) 흡착은 증가하였다. $Na^+$, $Ca^{2+}$, 그리고 $Al^{3+}$와 같은 양이온의 존재는 Pb(II) 흡착을 감소시켰다. Pb(II) 흡착은 증류수 조건에서 보다 해수에서 흡착량이 컸으며, 이는 해수에 존재하는 $CO{_3}^{2-}$와 $OH^-$ 이온이 Pb(II)와 화합물을 형성하기 때문이다. 본 연구를 통해서 Pb(II)로 오염된 물 정화에 소나무와 참나무가 활용될 것으로 판단된다.

• 한국습지학회지
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• 제9권1호
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• pp.107-114
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• 2007

This study aimed to investigate the hexachlorobenzene (HCB) dechlorinating ability of sediment microbes collected from a natural canal receiving secondary effluents from an industrial estate and nearby factories. Nine sites along the stream and one in the estuary in the Gulf of Thailand into which the canal spills were specified and sampling for sediment and water. Preliminary analysis of the sediments showed that the first four sites nearest to the discharging location were contaminated by HCB within the range of 0.18 to 1.25 ppm. Apart from that, 1,3,5-trichlorobenzene which has never been commercially produced or used in any manufacturing processes except for the transformation from higher chlorinated benzene was also identified in the range of 0.16 to 0.24 ppm. This suggested a possibility of sporadically HCB contamination in this stream. Of more important, people in the community along this canal earn their living by coastal fishery; hence, posing a risk of spreading HCB and its less chlorinated congeners via food chain from caught marine creatures to human. As a result, there is an urgent need to understand the behavior of HCB dechlorination in this stream sediment which can lead to a clean-up action in the future. Serum bottles with sediment slurries (sediment to water ratio of 1:1 (v/v) and filtered to remove particles larger than 0.7 mm) from each site were inoculated with 2 mg/l of HCB, kept anaerobically in the dark at room temperature without any nourishment, and analyzed for HCB and its less-chlorinated congeners every 6 days. Total chemical oxygen demand, suspended solids, and volatile suspended solids were in the range of 21,492-73,584, 158,100-518,100 and 6,000-32,700 mg/l, respectively. It was found that all sediment slurries began to dechlorinate HCB in 12 to 30 days and the HCB was completely removed within 42 to 60 days or so. On the other hand, there was no HCB dechlorination occurred in the controlled set which was sterilized by autoclaving prior to the addition of HCB. This implies that the HCB transformation was solely due to microorganisms' activities. HCB was dechlorinated principally via pentachlolobenzene to 1,2,3,5-tetrachlorobenzene and terminated at 1,3,5-trichlorobenzene which is the major pathway as reported by many researchers. Dichlorobenzene has not been detected in any samples within the dechlorination period of 60 days. The results indicate that the microbial matrix in the sediment of this stream has an outstanding capability to dechlorinate HCB. Existing substrates and nutrients which mainly sorbed onto the solid phase and the typical temperature in Thailand were sufficient and suitable to promote the activities of these HCB-dechlorinating microbes.

• 대한치과보철학회지
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• 제28권2호
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• pp.29-51
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• 1990

This study was designed to compre the tensile bond strength of 4-META containging denture base resin to Co-Cr alloys after various surface treatments. Especially the surface treatment of sandblasting the mental with aluminum oxide and treating in oxidizing solution composed of 3% aqueous sulfuric acid with 1% potassium manganate were compared. Effect of surface roughness on bonding was measured after sandblasting with 50um, 300um aluminun oxide and polishing with emery pater. Also the effects of wax and wax solvent on bonding were observed. According to the type of polymerization process, heat-cured Meta-Dent resin and autopolymerizing Meta-Fast resin were used. For some specimnens, the tensile bond strength were measured agter three pre-conditions : 1day after bonding, immersed in water at $75^{\circ}C{\pm}3^{\circ}C$ for 4weeks, under normal ambient condition for 4weeks. The following results were obtained from this study : 1. The bond strengths of resins containing 4-META were significantly higher than those of conventional denture base resins(p<0.05). 2. Autopolymerizing Meta-Fast resin had higher bond strength than heat-cured Meta-Dent, resin(p<0.05). 3. The bond strengths of Biosil and Nobilium to 4-META containging resins were not significally different(p>0.05). 4. Stable adhesion can be achieved when mechanically roughen the metal surface by snadblasting with $50{\mu}m$ aluminum oxide than treating in an oxidizing soluing with potassium manganate(p<0.05). 5. Once the metal surface is contaminated with wax, the bond srtength decreased greatly in spite of wax wash with boiling water. But the bond strength recovered significantly with the use of wax solvent 6. Meta-Dent resin had higher bond strength when roughen the metal surface with $50{\mu}m$ aluminum oxide than with $300{\mu}m$ aluminum oxide(p<0.05). In case of Meta-Fast, resin, the use of $300{\mu}m$aluminum oxide was a little advantageous of bonding, but was statistically insignificant(p>0.05).

• 핵의학기술
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• 제17권1호
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• pp.3-6
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• 2013

Purpose: The treatment of thyroid cancer patients was continuously increased. According to the increment of thyroid cancer patients, the establishment of iodine therapy site was also increased in each hospital. This treatment involves the administration of radioactive iodine, which will be given in the form of a capsule. Therefore, protections and managements for radioactive source pollution and radiation exposure should be necessary for radiation safety. Among the many problems, the problem of disposing the radioactive wastes was occurred. In this study, The date for self-disposal for radioactive wastes, which were contaminated in clothes, bedclothes and trash, were calculated. Materials and Methods: The number of iodine therapy ward was 15 in Korea Institute of Radiological Medical and Sciences. Recently, 8 therapy wards were operated for iodine therapy patients and others were on standby for emergency treatment ward of any radiation accidents. Radioactive wastes, which were occurred in therapy ward, were clothes, bedclothes, bath cover for patients washing water and food and drink which was leftover by patients. Each sample was hold into the marinelli beaker (clothes, bedclothes, bath covers) and 90 ml beaker (food, drink, and washing water). The activities of collected samples were measured by HpGe MCA device (Multi Channel Analysis, CANBERRA, USA) Results: The storage period for the each kind of radioactive wastes was calculated by equation of storage periods based on the measurement outcomes. The average storage period was 60 days for the case of clothes, and the maximum storage period was 93 days for patient bottoms. The average storage period and the maximum storage period for the trash were 69 days and 97 days, respectively. The leftover foods and drinks had short storage period (the average storage period was 25 days and maximum storage period was 39 days), compared with other wastes. Conclusion: The proper storage period for disposing the radioactive waste (clothes, bedclothes and bath cover) was 100 days by the regulation on self-disposal of radioactive waste. In addition, the storage period for disposing the liquid radioactive waste was 120 days. The current regulation for radioactive waste self-disposing was not suitable for the circumstances of each radioactive therapy facility. Therefore, it was necessary to reduce the leftover food and drinks by adequate table setting for patients, and improve the process and regulation for disposing the short-half life radioactive wastes.

• 지질공학
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• 제14권4호
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• pp.469-485
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• 2004

이 연구는 충북 음성군지역 지하수를 대상으로 모암과 심도에 따른 지하수의 수리화학적 특성을 비교하였다. 그리고 금속광산의 광화대가 지하수의 화학성분에 미치는 영향에 대해서도 알아보았다. 연구지역은 쥬라기 화강섬록암과 백악기 퇴적암층이 단층으로 경계를 이루고 있다. 천부지하수는 쥬라기 화강암지 역에서 개발되어 대부분 농업용수로 사용되는 반면 심부지하수는 백악기 퇴적암을 모암으로 하여 생활용수로 이용되고 있다. 천부 지하수는 전반적으로 약산성화되어 있으며, 전기전도도 값은 $126\~613\;{\mu}S/cm$의 범위를 보인다. 지하수의 화학적 유형은 $Ca-HCO_3$형에서 $Ca-Cl(SO_4,\;NO_3)$ 형까지 넓게 분포한다. 일부 지하수에서는 질산염$(NO_3)$의 농도가 높게 검출되어 농업등 인간활동과 관련된 오염의 특성을 보인다. 일부 지하수는 철(Fe), 망간(Mn), 아연(Zn)등 중금속의 함량이 수 ppm이상의 높은 농도를 보여 금속광산의 광화대 영향을 시사한다. 심부지하수는 중성내지는 알카리성으로 천부 지하수에 비해 높은 전기전도도를 보인다. 그리고 지하수의 화학적 유형은 $Ca-HCO_3$의 특성을 보인다. 광산의 배출수는 산성배수의 특성을 보이지 않지만 황산염과 중금속의 함량이 약간 높은 특성을 보인다. 동위원소 조성에서는 천부지하수에 비해 심부지하수가 보다 결핍된 낮은 수준을 보여 심도에 다른 동위원소의 조성차이가 뚜렷하다. 이상을 종합하면 연구지 역 지하수의 화학성분은 단층을 경계로 화강섬록암, 퇴적암으로 뚜렷이 구분되는 모암성분의 차이, 지하수공 심도차이, 농업활동의 유무, 그리고 광화대의 영향 등이 복합적으로 반영되었음을 알 수 있다.

• 한국광물학회지
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• 제21권1호
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• pp.57-65
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• 2008

본 연구에서는 달천광산 토양 내 중금속의 함량을 알아보고 지화학적인 형태를 알아보고자 달천광산의 광미와 인근 저수지의 토양을 채취하여 화학분석법(전함량분석, 연속추출분석)을 적용하였다. 분석결과 달천광산 토양 내 중금속은 철 > 비소 >구리 > 납 > 크롬 순으로 높은 값을 보이며 특히 $63\;{\mu}m$ 이하의 토양에서 가장 높게 나타나 As, Cu, Pb 등 유해 중금속의 거동이 미립질 토양을 구성하는 광물과 연관되어 있음을 알려주었다. 연속추출 분석 결과, 인근 저수지 토양의 경우, $63\;{\mu}m$ 이하의 입도에저 철 > 납 > 구리 > 비소 > 크롬의 순으로 나타났다. 달천랑산 광미에서 측정된 비소는 양이온교환 형태로 존재하는 비율이 다른 형태에 비하여 가장 높은 값을 보이고 따라서 상대적으로 이동이 훨씬 용이한 것으로 추정된다. 광미와 인근 저수지의 토양 내 포함된 중금속의 전함량과 더불어 물리 화학적 결합상태에 따른 중금속의 존재형태를 규명하는 것은 중금속으로 오염된 토양을 복원하기 위한 기초 자료로 매우 중요하다. 더 나아가서 As와 Cr과 같은 독성 유해중금속의 화학종에 따른 유해성 평가를 위한 기초자료로 중요성이 있으며 지표수 및 지하수 환경오염의 정밀 연구를 위해 필수적이다.

• 자원환경지질
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• 제29권1호
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• pp.45-55
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• 1996

Although the Dongjin Au-Ag-Cu mine had been abandoned since about forty years ago, the results of this study on the dispersion patterns and contamination level of heavy metals in the hydrologic system flowing via the waste rump show that the environmental impacts from the mine wastes are still significant. The stream water in the vicinity of the waste rump is severely acidified (pH 3.8 to 4.4) and highly enriched in various dissolved heavy metals. The heavy metal contents of the stream water and stream sediments are systematically attenuated with increasing distance from the mine area. However, it is worth to note that continuous attenuation of heavy metal contents in both media were reenriched in downstream area more than 800 m apart from the mine because it can be acted as a secondary source of heavy metal pollution. The heavy metals, especially Cd, Cu and Zn of polluted downstream sediments mainly occur in Fe-Mn oxides and organic materials, which indicates that these elements are the main pollutants from the waste rump of the Dongjin mine. The heavy metal contents of crops, such as sesame, perilla, red Pepper and brown rice, collected from the polluted farm land in the downstream area are lower than those of land plants from stream sides, but significantly higher in Cd, Cr, Cu and Zn than those from the unpolluted farm land. Especially, almost all of the crops in polluted farm land have been severly contaminated by Cd (>0.4 ppm). On the other hand, the heavy metal contents of the crops collected from refreshed farm land by means of a soil addition method shows significantly lowered level comparing with those of polluted area, which indicates that a soil addition method was effective for the refreshment of polluted farm land by toxic metallic pollutants. Wormwoods from this area showed very high contents in a11 the heavy metals even in unpolluted area (Cd > 1 ppm, Cr > 1 ppm, Cu > 11 ppm, Pb> 4 ppm, Zn > 55 ppm), indicating that a special caution must be payed when one takes ingest them.

• 자원환경지질
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• 제41권6호
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• pp.673-683
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• 2008

본 연구에서는 만경강에 의해 형성된 충적대수층에서 나타나는 고비소지하수를 지구화학적으로 고찰하였다. 연구지역에서는 조사된 관정 29개 중 15개에 해당하는 총 52%가 WHO의 비소 먹는물기준치($10{\mu}g/L$)를 초과하는 것으로 조사되었다. 비소가 부화된 지하수는 다른 지하수에 비하여 낮은 Eh값과 낮은 $NO_3$ 및 $SO_4$농도, 그리고 높은 pH, alkalinity와 Fe, $NH_4$ 및 $PO_4$농도를 보였다. 이는 세계최대의 비소오염지역인 벵갈만 충적층지역에서 흔히 관찰되는 비소용출기작인 철, 망간수산화물의 환원적 용해현상과 일치하는 수질특성이며, 국내의 충적층 지하수도 비소오염으로부터 자유롭지 못함을 지시하는 결과이기도 하다. 특히, 연구지역에서는 농업기원화학종인 $NO_3$와 $SO_4$의 존재가 비소 농도를 낮추는데 크게 공헌함으로써 농업활동이 비소의 농도를 낮추는 역할을 하였다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제15권3호
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• pp.44-51
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• 2010

Contamination of groundwater from point and non-point sources is one of major problems of water resource manangement in Jeju island. This study characterized groundwater and soil contamination in Hallim area which is one of the areas of significantly contaminated soil and groundwater in Jeju Island. The amount of loaded contaminant (ALC) of Jeju area was estimated as 13,212 ton N/yr and 3,210 ton P/yr, The ALC of Hallim area was amounted to 2,895 ton N/yr and 1,102 ton P/yr, which accounted for 21.9% and 34.3% of the Jeju's ALC, respectively. The soil pH values (5.6-5.9) were not much different in land use areas. By contrat, average cation exchange capacity (CEC) of 14.1 $cmol^+/kg$ was high comparing to the nationwide range of 7.7-10.9 $cmol^+/kg$. Further, Sodium adsorption ratios (SARs) of horse ranch, pasture, and cultivating land for livestock were as high as 0.19, 0.17, and 0.16 respectively, comparing to the other landuse areas. Nitrate nitrogen at 22.2% of total groundwater wells exceeded 10 mg/L (the criteria of nitrate nitrogen for drinking water), averaginged 6.62 mg/L with maximum 28.95 mg/L. Groundwater types belonged to Mg-$HCO_3$, Na-$HCO_3$, Ca-$HCO_3$, and Na-Cl, among which Mg-$HCO_3$ type occupied more than 70% of the total samples, indicating the presence of anthropogenic sources. The concentration of nitrate nitrogen was negatively related to altitude and well depth, and positively related to the concentration of Ca, Mg, and $SO_4$ which might originate from chemical fertilizer. The ratio of nitrogen isotopes was estimated as an average of 8.10$^{\circ}/_{\circ\circ}$, and the maximum value of 17.9$^{\circ}/_{\circ\circ}$. According to the nitrogen isotope ratio, the most important nitrogen source was assessed as chemical fertilizer (52.6%) followed by sewage (26.3%) and livestock manures (21.1%).

• 한국물환경학회지
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• 제32권5호
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• pp.419-432
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• 2016

이 연구의 목적은 응천에서 채집한 담수 붕어(Carassius auratus)의 산화적 스트레스와 조직병리학적 손상을 분석하여 하수처리장 방류수의 영향을 평가하는 것이다. 방류수 혼합 지점과 하류 지점에서 채집한 붕어의 아가미, 간, 콩팥의 과산화수소 분해효소(catalase)의 활동도는 상류 지점과 비교하여 더 높은 것으로 나타났다. 또한, 혼합 지점의 아가미와 간의 글루타치온 S-전이효소(glutathione-S-transferase)의 활동도는 상류 지점과 비교하여 유의하게 높았으며(p < 0.05), 상류 지점보다 유의하게 더 증가된 간의 지질 과산화(lipid peroxidation)가 혼합 지점에서 관찰되었다. 붕어의 조직병리학적 손상의 정도는 간 > 콩팥 > 아가미순으로 나타났다. 이 결과는 간이 방류수의 영향을 가장 크게 받는다는 것을 의미한다. 붕어의 조직 손상도(degree of tissue changes)는 혼합 지점에서 채집한 시료(30.98 ± 5.40)에서 가장 컸으며, 그 다음은 하류 지점 시료(19.28 ± 4.31)이고 가장 낮은 것은 상류 지점 시료(4.83 ± 2.67)로 나타났다. 이러한 결과는 혼합 지점에서 채집한 붕어가 방류수에 가장 큰 영향을 받았다는 것을 의미하며, 산화적 스트레스와 조직병리학적 지표들이 방류수로 오염된 하천을 모니터링하는데 유용하다는 것을 나타낸다.