• Journal of Microbiology and Biotechnology
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• 제13권6호
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• pp.1001-1007
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• 2003

Metal ions contamination may inhibit microorganisms involved in the biodegradation of organic compounds and affect biodegradation rates. Therefore, it is likely that bioremediation of xenobiotics-contaminated soils and waste will require inoculation with efficient biodegrading microbial communities, with capabilities of being resistant to heavy metals as well. Two different transconjugants (Pseudomonas sp. KMl2TC and P. aeruginosa TC) were constructed by conjugation experiments. Results on MIC, induction and growth inhibition strongly indicated that arsenic-resistant plasmid, pKM20, could be mobilized, and the newly acquired phenotype of pKM20 was not only expressed but also well regulated, resulting in newly acquired resistances to $As^{5+},\;As^{3+},\;and\;Sb^{3+} in\;addition\;to\;Cd^{2+},\;Zn^{2+},\;and\;Hg^{2+}$. The phenol- degradation efficiencies of Pseudomonas sp. KMl2TC were maintained significantly even at high heavy metal concentrations at which these efficiencies of P. aeruginosa TC were completely impaired. The results in this study on the effects of heavy metals on phenol degradation, especially after conjugation, are the first ever reported. All the results described in this study encourage to establish a goal of making "designer biocatalysts" which could degrade certain xenobiotics in the area contaminated with multiple heavy metals.

• 한국산업보건학회지
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• 제21권4호
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• pp.193-200
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• 2011

Objectives: Blood lead and hyperhomocysteinemia have been found to be associated with cardiovascular disease. The objective of the present study was to assess the relationship of lead biomarkers on plasma homocysteine and blood pressure. Methods: To evaluate the effect of lead biomarkers including blood lead on plasma homocysteine and blood pressure in retired lead workers, 66 retired lead workers without any occupational exposure to organic solvent, mercury and arsenic were agreed to participate this study. For the control subjects 42 controls were recruited from same area of retired lead workers with consideration of demographic characteristics. Results: The mean levels of blood lead and ZPP of retired lead workers were significantly higher than control group. There were positive significant correlations between blood lead and plasma homocysteine, also systolic and diastolic blood pressure. The multiple linear regression analysis also reveled that plasma homocysteine was significantly associated with blood lead after adjusting for age, gender, body mass index, lead exposure, smoking and drinking. Diastolic blood pressure was significantly associated with blood lead, plasma homocysteine, and total cholesterol; whereas, systolic blood pressure was significantly associated with plasma homocysteine only. Conclusions: Blood lead showed significant association with plasma homocysteine and blood pressure even after more than mean 10 years from their retirements.

• 한국산업보건학회지
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• 제26권1호
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• pp.1-10
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• 2016

Objectives: The aim of this study is to review the results of exposure to chemicals and to extremely low frequency(ELF) magnetic fields generated in wafer fabrication operations in the semiconductor industry. Methods: Exposure assessment studies of silicon wafer fab operations in the semiconductor industry were collected through an extensive literature review of articles reported until the end of 2015. The key words used in the literature search were "semiconductor industry", "wafer fab", "silicon wafer", and "clean room," both singly and in combination. Literature reporting on airborne chemicals and extremely low frequency(ELF) magnetic fields were collected and reviewed. Results and Conclusions: Major airborne hazardous agents assessed were several organic solvents and ethylene glycol ethers from Photolithography, arsenic from ion implantation and extremely low frequency magnetic fields from the overall fabrication processes. Most exposures to chemicals reported were found to be far below permissible exposure limits(PEL) (10% < PEL). Most of these results were from operators who handled processes in a well-controlled environment. In conclusion, we found a lack of results on exposure to hazardous agents, including chemicals and radiation, which are insufficient for use in the estimation of past exposure. The results we reviewed should be applied with great caution to associate chronic health effects.

• Environmental Engineering Research
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• 제21권1호
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• pp.29-35
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• 2016

This study evaluated the fertilizing value of struvite deposit recovered from swine wastewater in cultivating lettuce. Struvite deposit was compared to complex fertilizer, organic fertilizer and compost to evaluate the fertilizing effect of struvite deposit. Laboratory pot test showed that the struvite deposit better enhanced lettuce growth in comparison to commercial fertilizers. It was revealed that the growth rate of lettuce was simultaneously controlled by phosphorus (P) and magnesium (Mg). Moreover, nutrients such as nitrogen (N), P, K, calcium (Ca) and magnesium (Mg) were abundantly observed in the vegetable tissue of struvite pot. Meanwhile, struvite application led to the lower accumulation of mercury (Hg), lead (Pb), chromium ($Cr^{6+}$) and nickel (Ni). In addition, no detection of cadmium (Cd), arsenic (As) and nickel (Ni) in the lettuce tissue was observed in struvite application pots. The experimental results proved that the optimum struvite dosage for lettuce cultivation was 0.5 g struvite/kg soil. The column experiments clearly showed that ammonia nitrogen was more slowly released from struvite deposit than from complex fertilizer. Consequently, it was concluded that the struvite deposits recovered from swine wastewater were effective as a multi-nutrient fertilizer for lettuce cultivation.

• 한국산업보건학회지
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• 제22권1호
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• pp.52-59
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• 2012

Objectives: The purpose of this study was to evaluate the exposure possibility of by-products during the semiconductor manufacturing processes. Methods: The authors investigated types of chemicals generated during semiconductor manufacturing processes by the qualitative experiment on generation of by-products at the laboratory and a literature survey. Results: By-products due to decomposition of photoresist by UV-light during the photo-lithography process, ionization of arsine during the ion implant process, and inter-reactions of chemicals used at diffusion and deposition processes can be generated in wafer fabrication line. Volatile organic compounds (VOCs) such as benzene and formaldehyde can be generated during the mold process due to decomposition of epoxy molding compound and mold cleaner in semiconductor chip assembly line. Conclusions: Various types of by-products can be generated during the semiconductor manufacturing processes. Therefore, by-products carcinogen such as benzene, formaldehyde, and arsenic as well as chemical substances used during the semiconductor manufacturing processes should be controlled carefully.

• 대한화장품학회지
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• 제47권3호
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• pp.185-191
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• 2021

환경오염은 인간의 건강, 삶의 질 또는 생태계의 자연적 기능을 방해하는 물질로 지구 환경을 오염시키는 것으로 정의된다. 환경 스트레스 요인에 장기간 반복적으로 노출되면 피부의 정상적인 방어 잠재력을 초과할 때마다 피부 장벽 기능에 장애가 생겨 다양한 피부 질환이 발병하게 된다. 피부에 영향을 미치는 주요 대기오염물질은 다환 방향족 탄화수소, 휘발성 유기화합물, 질소산화물, 미세먼지, 담배 연기, 중금속, 비소 등이다. 이들 물질의 피부 흡수는 피부 표면의 대기오염물질의 침적, 표피 지질 구성, 표피를 통한 혈관 확산에 의해 이루어진다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제12권4호
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• pp.78-85
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• 2007

본 연구에서는 화학회사에서 발생되는 연마분진 폐기물의 흡착제로서의 재이용성을 평가하였다. 연마분진을 $550^{\circ}C$에서 하소시킴으로서 유기불순물을 제거하였다. 연마분진내의 주요 무기물은 Al이었으며 하소 후 Al 함량은 29.09%에서 52.73%로 증가되었다. 하소 후 시료의 안정성 평가를 실시한 결과 pH 2.0의 강한 산성조건에서도 모든 중금속들의 용출량은 0.3 mg/L 이하로 나타났다. pH 변화에 따른 As(V) 흡착실험에서 As(V)의 흡착효율은 전형적인 음이 온형 흡착경향을 보였다. 하소된 연마분진의 주입량 변화에 따른 As(V)의 등온흡착 실험결과는 Freundlich 등온흡착식이 Langmuir 등온흡착식보다 상대적으로 잘 표현되는 것으로 나타났다. Freundlich 등온흡착상수 K와 1/n은 각각 4.2442와 0.3161로 얻어졌다. Langmuir 등온흡착식으로 얻어진 하소된 연마분진의 최대 As(V) 흡착량은 13.25 mg/g이었다. 이러한 연구결과, 하소된 연마분진은 안정도 및 As(V) 흡착능을 고려하였을 때 재이용성이 양호한 흡착제로 나타났다.

• 자원환경지질
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• 제45권2호
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• pp.121-135
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• 2012

본 연구에서는 자력선별 토양정화기술 공정에 적합한 토양의 최적 분산 조건을 도출하기 위하여 토성이 다른 중금속 오염토양 2종의 시료(US, JIK)를 대상으로 분산특성 및 중금속 용출 특성을 파악하였다. 분산제로는 인산염(pyrophosphate, hexametaphosphate, orthophosphate), 계면활성제(sodium dodecyl sulfate, SDS)가 사용되었으며, pH = 9~12와 농도변화(1~200 mM)에 따른 토양입단의 분산특성 및 중금속 함량을 파악하고, 효율적인 분산조건을 도출하였다. 분산용액의 pH변화에 따른 토양분산 특성은 입도변화 결과를 통하여 파악할 수 있는데, 분산용액의 pH가 12에 가까워질수록 현탁액의 점토함량이 증가하였다. 이는 pH가 상승함에 따라 PZC(point of zero charge)이상의 pH가 유지되면서 점토입자들이 분산된 상태로 유지된 것으로 여겨진다. 농도변화에 따른 토양분산 실험 결과, 농도가 증가함에 따라서 높은 점토함량을 나타내었는데, 이는 산화철, 산화망간의 PZC보다 높은 분산용액의 pH조건과 분산제의 흡착에 기인한 것으로 판단된다. 토양입자의 분산에 따른 중금속 용출은 pyrophosphate, hexametaphosphate, orthophosphate는 50 mM 이상의 농도에서, SDS의 경우 100 mM이상의 농도에서 비소 용출량이 일정하게 나타났다. 또한, 분산용액의 pH가 증가함에 따라 비소 용출량도 증가하였다. 인산염은 비소와 유사한 화학구조를 지니고 있어 토양입자표면에서 흡착경쟁을 하여 비소의 탈착을 유발하고, 계면활성제는 토양입자표면에 흡착하여 비소가 탈착되는 것으로 파악된다. 분산용액에 따른 분산효과는 pyrophosphate > hexametaphosphate > SDS > orthophosphate의 순으로 나타났다. 결과적으로 분산효율 및 비소용출량을 고려한 최적의 토양분산용액 조건은 pH 11, 10 mM pyrophosphate로 판단된다. 이러한 결과들은 고구배 자력선별 기술을 이용한 토양정화 공정을 최적화하는데 활용될 수 있을 것으로 기대된다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제11권1호
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• pp.54-64
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• 2006

목재 방부제인 chromated copper arsenate(CCA)는 박테리아, 곰팡이 및 곤충에 의한 공격으로부터 목재 제품을 보호할 목적으로 널리 사용되어 왔다. 그렇지만, CCA의 유해 성분인 크롬, 구리 및 비소가 사용 중에 목재로부터 환경으로 배출되어 인간 및 생태계에 영향을 줄 수 있기 때문에 많은 나라에서 사용을 금지하거나 제한된 용도로만 사용하도록 하고 있다. 이 연구는 두 개의 목재 시설물에 인접한 토양에서 크롬, 구리 및 비소의 분포를 알아보고자 실시하였다 연못 진입시설물에 대해서는 계단 바로 인접한 지점에서부터 0, 0.5 및 1m의 수평 거리에서 10개의 표토(0-2.5 cm) 시료를, 그리고 데크 바로 아래 지점에서는 9개의 표토 시료를 채취하였다. 방음벽에서는 시설물로부터 0, 1 및 2 m 거리에서 9개의 표토를 채취하였다. 각 구조물에 대해 배경농도를 측정하기 위한 토양시료도 채취하였다. 토양시료는 pH, 전기전도도, 유기물 함량, 입도 등의 물리화학적 성질에 대해 분석하였다. 시료는 microwave oven을 사용하여 추출한 후에 크롬, 구리 및 비소에 대해 분석하였다. 세 성분 모두 구조물과 인접한 지역에서 배경 지역에 비해 농도가 증가하여 사용 중에 목재로부터 용출되는 것을 알 수 있었다. 용출된 성분은 계단과 방음벽 시설물에서 모두 1m 이내의 거리까지 수평 이동하였다. 약 7개윌 된 데크 시설물에서 세 성분의 용출된 양은 서로 비슷하였으나 (배경 보정 농도: 크롬, 5.01 mg/kg; 구리 5.50 mg/kg; 비소 4.19 mg/kg), 방음벽 바로 아래(0 m)에서는 데크에 비해 더 높은 농도로 비소(49.7 mg/kg)>구리(44.7 mg/kg)>크롬(52.5 mg/kg)의 순서로 측정되었다. 이 때 배경농도는 비소, 구리 및 크롬에 대해 각각 9.88, 30.8 및 46.5 mg/kg이었다. 이 연구 결과를 통해 CCA 구성 성분은 방부목재로부터 환경 중으로 용출되는 것을 알 수 있었으며 그 성분들이 인간과 생태계에 미칠 악영향을 평가할 필요가 있음을 시사하였다.

• 한국산업보건학회지
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• 제20권3호
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• pp.156-167
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• 2010

To evaluate the effect of lead biomarkers including bone lead on neurobehavioral test in retired lead workers, 131 retired lead workers without any occupational exposure to organic solvent, mercury and arsenic were agreed to participate this study. For the control subjects 56 non-occupationally lead exposed subjects were recruited from same area of retired lead workers with consideration of demographic characteristics. The mean levels of blood and bone lead of retired lead workers were significantly higher than control group and there were significant correlation among other lead biomarkers. Compared with controls without occupational lead exposure, lead exposured subjects had worse performance on 10 tests out of 12 neurobehavioral tests, but only two tests(Purdue pegboard nondominant and both hand) showed statistical significance of differences. In multiple linear regression analysis of neurobehavioral tests with lead biomarkers and demographic and lifestyle variables, age was associated negatively with 11 neurobehavioral tests, whereas log-transformed ZPP was associated with Purdue pegboard(both hand) and Santa Ana manual dexterity(non-dominant hand). On the other hand, tibia lead was associated Pursuit aiming test(correct) and Purdue pegboard(dominant hand) and calcaneal lead was associated with Purdue pegboard(dominant hand). This study confirmed that among all relevant variables age was most significantly associated with the poor performance of neurobehavioral tests. The blood lead did not have any significant association with neurobehavioral tests, but tibia and calcaneal bone lead and blood ZPP showed significant association with a few tests even after more than mean 9 years from their retirements.