• 한국식품조리과학회지
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• 제31권1호
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• pp.1-8
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• 2015

Organic acids are known as natural sanitizers. We examined the sanitizing effects of five organic acids (acetic acid, propionic acid, citric acid, malic acid, and lactic acid) and their persistence on three pectinolytic yeast strains isolated from decayed citrus, and the persistence of their sanitizing effects was determined during storage at $4^{\circ}C$ and $16^{\circ}C$. The 7~8 log CFU/mL of the mixed three yeast mixture was exposed to various concentrations of each organic acid for 1 min. The yeast mixtures decreased under detection limit(1 log CFU/mL) in 1% of acetic acid, followed by in 3% of propionic acid with the reduction of 5 log CFU/mL. The citric acid, malic acid, and lactic acid decreased the number of yeasts under detection limit at 7.5%. When treated with deionized water and 1~5% of organic acids were treated on the surfaces of citrus contaminated by yeasts, total numbers of the yeasts decreased under detection limit(3 log CFU) at 5% of acetic acid and 4 log CFU/piece at 5% propionic acid compared with deionized water. When treated with acetic acid and propionic acid on the stem ends of the contaminated citrus, total numbers of the yeasts significantly decreased 0.5 log CFU/piece at 3% of both organic acids. During storage at $4^{\circ}C$ and $16^{\circ}C$ for 20 days, total number of yeasts significantly decreased at 2% acetic acid compared with deionized water. This study suggested that organic acids could be used to sanitize microbial contaminants from citrus for storage and transportation.

• 한국환경과학회지
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• 제15권2호
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• pp.169-175
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• 2006

The changes of contaminants and odor corresponding to anaerobic maturation process of piggery slurry were investigated by applying the additives, such as different kinds of complex microorganism products and deodorants containing microorganism activating agents. The pHs during 20-day anaerobic maturation were operated stably without great change regardless of the additives, although they were rather lower in the case that the additives were contained than the case that they were not contained. The effects of removing CODcr, $NH_3-N$, T-N, and T-S in case that the additives were not contained, were not so great during the 20-day operation and so it would be difficult to remove the organic materials and nitrogen ingredients simply with anaerobic maturation process. However, in case of anaerobic maturation process that the additives were contained, their average removal rates were improved with the values of $49\%,\;63.5\%,\;48.5\%,\;and\;30.7\%$ for above each of items, even if the 20-day of short-term maturation period was applied. Especial1y, odor intensity with the additives was lowered continuously during the operation period and it had more than two times of lowering effect compared to that without those.

• 한국물환경학회지
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• 제22권1호
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• pp.23-29
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• 2006

Biosorption technology was used to remove hazardous materials from wastewater, herbicide, heavy metals, and radioactive compounds, based on binding capacities of various biological materials. Biosorption process can be explained by two steps; the first step is that target contaminants is in contact with microorganisms and the second is that the adsorbed target contaminants is infiltrated with inner cell through metabolically mediated or physico-chemical pathways of uptake. Until recently, no information is available to explain the definitive mechanism of biosorption. The purpose of this study is to evaluate biosorption capabilities of organic matters using activated sludge and to investigate affecting factors upon biosorption. Over 49% of organic matter could be removed by positive biosorption reaction under anoxic condition within 10 minutes. The biosorption capacities were constant at around 50 mg-COD/mg-MLSS for all batch experiments. As starvation time increased under aerobic or anaerobic conditions, biosorption capacity increased since higher stressed microorganisms by starvation was more brisk. Starvation stress of microorganisms was higher at aerobic condition than anaerobic one. As temperature increased or easily biodegradable carbon sources were used, biosorption capacities increased. Consequently, biosorption can be estimated by biological -adsorbed capability of the bacterial cell-wall and we can achieve the cost-effective and non -residual denitrification with applying biosorption to the bio-reduction of nitrate.

• 한국지하수토양환경학회지:지하수토양환경
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• 제12권1호
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• pp.1-35
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• 2007

지난 수십년 동안 토양내 수착된 오염물질이 접촉시간(contact time)이 경과함에 따라 생물학적 또는 화학적 이용성의 감소는 일반적으로 인식되어 오고 있다. 이와 같은 aging 또는 격리(sequestration)라 불리는 현상이 위해성에 직접적인 영향을 미친다는 것이 알려져 있다. 이러한 현상은 소수성 오염물질을 중심으로 보고되어 왔으나, 최근 연구결과에 의하면 중금속의 경우에도 이와 같은 현상이 발견되고 있으며, 이는 오염물질의 흡-탈착 이력(hysteresis) 현상, 비가역 흡착, 탈착저항성, 비평형 흡착 등과 직접적으로 연관된 것으로 알려지고 있다. Aging 또는 sequestration에 의한 오염물질의 생이용성(bioavailability)의 감소는 인체에 대한 실질적인 위해성의 감소를 의미한다. 최근 들어 이와 같은 과학적인 증거를 토대로 단순한 오염물질의 농도 측정이 아니라 위해성에 근거한 오염 복원(또는 관리)의 개념이 도입되어 환경친화적인 복원수준의 선정에 적용하고 있다. 이는 토양내 오염물질의 총농도가 아니라 오염물질의 생이용성 또는 독성을 기준으로 하여 정화수준을 결정함으로써 오염부지의 처리비용과 노력의 절감효과를 동시에 기대할 수 있기 때문이다. 토양내 잔류오염물질의 생이용성 또는 독성은 오염물질의 이동 또는 거동 특성에 의해 영향을 받으며 결국 생물체로의 노출 경로와 생체축적에 직접적인 영향을 미친다. 본 논문에서는 토양내 오염물질의 위해성을 평가하여 토양오염복원에 적용시 과학적인 타당성에 대해 살펴보고자 하였다.

• 한국식품위생안전성학회지
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• 제29권4호
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• pp.312-315
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• 2014

페놀은 보통 대기로 배출되며 반감기가 비교적 짧은 물질로서 환경에 농축되는 경우는 드물다. 하지만, 누출사고가 발생되어 수계나 토양에 오염될 경우 페놀에 오염된 농수산물의 안전성을 확보하기 위하여 페놀을 정확하게 검출할 수 있는 시험법을 확립하고자 하였다. 식품 중 페놀을 초음파추출기로 추출하고 GPC로 정제하여 GC/MS로 분석하는 시험법을 확립하였으며, 시험법의 유효성 확인을 위한 실험 결과들이 AOAC 가이드라인에서 제시하는 Criteria를 만족함으로써 시험법의 신뢰성을 확보할 수 있었다. 확립된 시험법은 식품 중 페놀의 오염조사 및 이행률 조사에 활용될 수 있다.

• 농업과학연구
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• 제46권4호
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• pp.869-883
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• 2019

China is currently facing great challenges in protecting its arable soil from contamination by heavy metals, especially Cd in paddy soil. China enacted the first soil environmental quality standards (SEQS) for ten pollutants in 1995, and the Ministry of Ecology and Environment released the results of the first nationwide soil survey in 2014. The soil survey showed that as much as 16% of China's soil and 19% of the agricultural soils were contaminated mainly with heavy metals and metalloids beyond the environmental quality limits. The exceeded rate of the contaminant limits in food crops was widespread in China, and the most severe regions were East and Southwest China. Heavy metals and metalloids accounted for 82.4% of the contaminants in soils while organic pollutants accounted for 17% of the contaminants in the soil. Among the heavy metals and metalloids exceeding the Ministry of Environmental Protection (MEP) limit, cadmium (Cd) was highest at 7.0%, followed by nickel (4.8%), arsenic (2.7%), cobalt (2.1%), mercury (1.6%) and lead (1.5%). However, all the average concentrations of the pollutants were lower than the recommended values for the contaminants except for Cd for three levels of pH (< 6.5, 6.5 - 7.5, and > 7.5). According to the Action Plan on Prevention and Control of Soil Pollution released by the State Council in 2016, 90% of contaminated farmland will be made safe by 2020 with an increase to 95% by 2030. Therefore, it is necessary to improve the soil quality to meet the environmental quality standard for soils and heavy metal standards for food safety.

• 한국산업보건학회지
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• 제20권1호
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• pp.63-69
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• 2010

This study was conducted to compare the concentration of various air contaminants in nine different laboratories during routine activities. Volatile organic compounds (VOC) were sampled and analyzed using NIOSH Method 1500 and asbestos fibers were sampled and analyzed using NIOSH Method 9002 and 7400. Detectable levels of acetone, toluene and ethanol were found in all the laboratories and xylene and n-hexane were detected in eight of the nine laboratories. All the VOC concentrations were well below the Korean Ministry of Labor's Exposure Limit and American Conference of Governmental Industrial Hygienists' (ACGIH) Threshold Limit Values (TLVs). Total VOC concentrations at the university laboratories were significantly higher than those at governmental agency laboratories. Airborne fiber concentrations were below 0.01 fibers/cc, while the concentration of chrysotile was 2% in insulation materials sprayed on the ceiling of one laboratory. While all the governmental agency laboratories (n=4) had fume hoods, two out of the five university laboratories did not have fume hoods. The capture velocity of half of the fume hoods were below the maintenance standard(0.4 m/sec). In conclusion, the study suggests that the current controls in place at both university and government agency laboratories are not sufficient in limiting exposure to harmful chemicals to non-detectable levels, though they appear to be adequate in protecting workers to levels below applicable occupational exposure limits. The study also suggests that researchers working in university laboratories may be exposed to greater levels of contaminant than those working in government agency laboratories.

• 한국물환경학회지
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• 제37권6호
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• pp.501-509
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• 2021

In 2018, total 263 micro and emerging contaminants were selected as target substances by the Ministry of Environment, and 80 of them were first-class substance including endocrine disruptors, residual Pharmaceuticals and Personal Care Products (PPCPs), residual organic pollutants, pesticides and heavy metals. In this study, in order to evaluate the Hazard Quotient (HQ) of the 80 types in the domestic water environment the concentration of discharged effluent and nearby water environment reported by Korean institutes since 2010 was investigated. There were 45 substances reported to be detected, and Measurement Environment Concentration (MEC) were obtained by collectively converting them into water environment concentration. For biotoxicity, half maximal Effective Dose (EC50) to Daphnia magna, a water fleas species widely adopted in Material Safety Data Sheet (MSDS) was applied. As for the biotoxicity level, the Predicted No-Effect Concentration (PNEC) was obtained by applying the Assessment Factor (AF) and the HQ was derived by dividing it from the MEC. As a result of calculating the HQ, more than 1 substances were Cabamazepine, Mefenamic acid, Acetaminophen, Ibuprofen, Nonylphenol, Nickel, Erythromycin, Acetylslic acid, etc. Meanwhile, perfluorinated compounds were identified as hazardous substances in the water env ironment, with 5 out of 14 species included in the 20 ranks of first-class substance.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 추계학술발표회
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• pp.330-333
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• 2003

Recently electrokinetic process is known to be a promising remediation technology for the contaminated soils with heavy metals, radionuclides, organic matters, and so on. The contaminants in electrokinetic technology are removed mainly by three mechanisms; electroosmosis, electromigration, and electrophoresis. When direct current is introduced between two electrodes planted in soil, a large amount of hydrogen ions is formed and moves from anode to cathode with the other cations contained in electrolyte. The water flow caused by tile movement of cations is called as electroosmosis. Especially for non-ionic pollutants, the electroosmotic flow(EOF) is the most important removal mechanism among them and transports contaminants from anode to cathode along the water flow. In this study, characteristics of electroosmotic flow was investigated according to the resistance state of soil. The decrease, maintenance, and increase of soil resistance could be obtained by controlling ions in soil. When the resistance of soil was decreasing or maintained, the EOF is proportional to electric current and voltage, respectively and when the resistance was increasing, the EOF is proportional to only electric current not voltage.

• 한국토양환경학회지
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• 제2권2호
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• pp.95-103
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• 1997

유기화합물로 오염된 지반을 정화하는 방법 가운데 화학약액을 주입하는 흙세척 방법은 매우 효과적인 것으로 알려져 있다. 이를 실험실에서 재현하는 경우에는 일반적으로 연성벽체의 주상실험을 실시하게 된다. 이때 유기화합물로 오염된 시편을 화학약액으로 세척하는 과정 중에서 일부의 유기화합물은 연성벽체를 통하여 확산되고, 확산된 양은 화학약액에 의한 세척효율 산정시 반드시 고려하여야 할 것으로 나타났다. 연성벽막을 통한 확산량을 조사하고자 다섯가지의 유기화합물(페놀, 아닐린, 나이트로벤젠, 퀴놀린, 및 2나프톨)을 이용하여 breakthrough 시험을 실시하였다. 나이트로벤젠은 75% 이상이 벽막을 통하여 확산되었다. 나머지의 유기화합물은 25%이하의 확산량을 보였다. 실험중 생분해 효과는 관찰되지 않았다.