• 한국토양비료학회지
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• 제47권3호
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• pp.213-216
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• 2014

Arsenic is a known hazardous metalloid not only to the animals but also to plants. With high concentrations, it can impede normal plant growth and cause even death of plants at extremely high levels. A known plant response to stress conditions such as toxic levels of metal (loids) is the production of stress ethylene, causing inhibitory effect on root growth in plants. When the effect of various arsenic concentrations was tested to maize plant, the stress ethylene emission proportionately increased with increasing concentration of As(V). The inoculation of two arsenic tolerant bacteria; Pseudomonas grimonti JS126 and Pseudomonas taiwanensis JS238 having respective high and low 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity reduced stress ethylene emission by 59% and 30% in maize grown in arsenic polluted soils. The result suggested the possible use of Pseudomonas grimonti JS126 for phytoremediation of arsenic polluted soils.

• 한국토양비료학회지
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• 제44권1호
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• pp.58-66
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• 2011

Arsenic pollution is a serious global concern which affects all life forms. Being a toxic metalloid, the continued search for appropriate technologies for its remediation is needed. Phytoremediation, the use of green plants, is not only a low cost but also an environmentally friendly approach for metal uptake and stabilization. However, its application is limited by slow plant growth which is further aggravated by the phytotoxic effect of the pollutant. Attempts to address these constraints were done by exploiting plant-microbe interactions which offers more advantages for phytoremediation. Several bacterial mechanisms that can increase the efficiency of phytoremediation of As are nitrogen fixation, phosphate solubilization, siderophore production, ACC deaminase activity and growth regulator production. Many have been reported for other metals, but few for arsenic. This mini-review attempts to present what has been done so far in exploring plants and their rhizosphere microbiota and some genetic manipulations to increase the efficiency of arsenic soil phytoremediation.

• Asian Pacific Journal of Cancer Prevention
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• 제13권1호
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• pp.187-190
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• 2012

Background: High incidence of gallbladder cancer (GBC) is reported from North India, with elevated concentrations of heavy metals in water and soil. This Indo-Japan collaborative study compared presence of heavy metals in gallbladder tissues. Methods: Heavy metal concentrations were estimated in Indian GBC and cholecystitis tissues and compared with Japanese GBC and cholecystitis tissues. Spectrophotometry was done for 13 Indian gallbladder tissues (8 GBC, 5 cholecystitis) and 9 Japanese (5 GBC, 4 cholecystitis). Transmission electron microscopy (TEM) thin foil element analysis was done in 10 Indian samples (6 GBC, 4 cholecystitis). Results: Chromium, lead, arsenic and zinc were significantly high in Indian GBC compared with Japanese GBC. Chromium, lead and arsenic were significantly high in the Indian cholecystitis tissues compared to the Japanese. TEM of Indian tissues demonstrated electron dense deposits in GBC. Conclusion: Heavy metals-chromium, lead, arsenic and zinc are potential carcinogens in Indian GBC from endemic areas. This preliminary study links presence of heavy metals in gallbladder cancer tissues in endemic areas.

• 한국토양비료학회지
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• 제47권6호
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• pp.518-524
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• 2014

Heavy metal pollution in agricultural field near at the abandoned metal mines has been a critical issue in Korea. In particular, bioaccumulation in plants can have detrimental effect on human health. Main objective of this research was to examine arsenic (As) concentration in soil with varied extraction methods and to determine bioaccumulation and biological transfer factor in different crops. Results showed that bioaccumulation ratio of As for total contents in soil was ordered leafy and stem vegetables (1.19%) > fruit bearing vegetables (0.79%) > pulses (0.40%) > root vegetables (0.36%) with different crop species. Among 6 different extraction methods, all of extraction methods showed high correlation ($R^2=0.87-0.97$) except DTPA ($R^2=0.25$) when comparing As concentration in soil extracted with different extractants and As concentration in each crops. Calculated biological transfer factor was ranged 0.002-0.018 depending on crop species. Overall, concentration of As in crops can be varied and best management practice for minimizing bioaccumulation of As should be considered depending on crop species.

• Toxicological Research
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• 제35권4호
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• pp.311-317
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• 2019

The transport systems for metals play crucial roles in both the physiological functions of essential metals and the toxic effects of hazardous metals in mammals and plants. In mammalian cells, Zn transporters such as ZIP8 and ZIP14 have been found to function as the transporters for Mn(II) and Cd(II), contributing to the maintenance of Mn homeostasis and metallothionein-independent transports of Cd, respectively. In rice, the Mn transporter OsNramp5 expressed in the root is used for the uptake of Cd from the soil. Japan began to cultivate OsNramp5 mutant rice, which was found to accumulate little Cd, to prevent Cd accumulation. Inorganic trivalent arsenic (As(III)) is absorbed into mammalian cells via aquaglyceroporin, a water and glycerol channel. The ortholog of aquaporin in rice, OsLsi1, was found to be an Si transporter expressed in rice root, and is responsible for the absorption of soil As(III) into the root. Since rice is a hyperaccumulator of Si, higher amounts of As(III) are incorporated into rice compared to other plants. Thus, the transporters of essential metals are also utilized to incorporate toxic metals in both mammals and plants, and understanding the mechanisms of metal transports is important for the development of mitigation strategies against food contamination.

• 한국토양환경학회지
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• 제3권1호
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• pp.55-63
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• 1998

본 연구에서는 광산 인근 토양에서 산성비를 비롯한 침출수에 의한 지하 환경 오염 메카니즘을 검토하고, 오염 방지 및 교정과 대안의 효과를 정량화 하기 위한 방안을 고찰하였다. 이를 위하여 중금속인 비소의 오염도가 높은 토양을 대상으로 인위적 산성용액에 의한 비소의 용출을 실험적으로 검토하였다. 한편, 산성 침출오염수에 의한 지하 환경의 오염을 방지하기 위하여 석회석을 활용한 토양의 안정화방법의 효과를 살펴 보았다. 오염된 시료토양에 포함된 비소는 pH 1이하의 강산성 용액일수록 격렬히 용출되었으며, pH 값이 낮아질 수록 최대 용출량은 증가되는 것으로 나타났다. 석회석에 의한 토양 안정화방안은 매우 효과적이었으며, 석회석에 의한 산성용액의 중화반응 특성식은 미반응 핵 모델중에서 화학반응이 속도지배인 특성식에 잘 부합되는 것으로 보여진다.

• 한국토양비료학회지
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• 제47권6호
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• pp.540-546
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• 2014

Acid mine drainage sludge (AMDS) has been classified as mine waste and generally deposited in land. For this reason, studies have been conducted to examine the possibility of recycling AMDS as an amendment for heavy metal stabilization in soil. The main objective of this study was to evaluate heavy metal stabilization efficiency of AMDS comparing with the widely used lime stone. Also, optimum mixing ratio was evaluated for enhancing heavy metal stabilization. AMDS and limestone were mixed at the ratio of 0:100, 25:75, 50:50, 75:25, and 100:0 with five different heavy metal solutions ($100mg\;L^{-1}$ of $NaAsO_2$, $CdCl_2$, $CuCl_2$, $Pb(NO_3)_2$, and $ZnSO_4{\cdot}7H_2O$). The amendments were added at a rate of 3% (w/v). In order to determine the stabilization kinetics, samples were collected at different reaction time of 0, 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024 minutes. The heavy metal stabilization by AMDS was faster and higher than those of limestone for all examined heavy metals. While limestone showed only 20% of arsenic (As) stabilization after 1,024 minutes, 96% of As was stabilized within 1 minute by AMDS. The highest effect on the stabilization of heavy metal (loid) was observed, when the two amendments were mixed at a ratio of 1:1. These results indicated that AMDS can be effectively used for heavy metal stabilization in soil, especially for As, and the optimum mixing ratio of AMDS and lime was 1:1 at a rate of 3% (w/v).

• Journal of Microbiology and Biotechnology
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• 제28권2호
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• pp.323-329
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• 2018

In Escherichia coli, the transcription of genes related to metal homeostasis is activated by the presence of target metals. The promoter regions of those genes can be fused with reporter genes to generate whole-cell bioreporters (WCBs); these organisms sense the presence of target metals through reporter gene expression. However, the limited number of available promoters for sensing domains restricts the number of WCB targets. In this study, we have demonstrated an alternative method to generate novel WCBs, based on the notion that since the sensing mechanisms of WCBs are related to metal transportation systems, their properties can be modulated by disrupting metal homeostasis. Mutant E. coli strains were generated by deleting the znt-operon genes zntA, which encodes a zinc-export protein, and zntR, which encodes a znt-operon regulatory protein, to investigate the effects on the metal-sensing properties of WCBs. Deletion of zntA increased the sensitivity but abolished the selectivity of cadmium-sensing WCBs, whereas arsenic-sensing WCBs gained sensitivity toward cadmium. When zntR was deleted, cadmium-sensing WCBs lost the ability to detect cadmium, and this was recovered by introducing exogenous zntR. In addition, the metal-binding site of ZntR was genetically engineered to modulate metal selectivity. This study provides a valuable platform for the development of novel E. coli-based WCBs.

• Asian Pacific Journal of Cancer Prevention
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• 제15권7호
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• pp.2965-2970
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• 2014

Background: To evaluate association of lung cancer with arsenic and cadmium levels measured in tumor tissue. Materials and Methods: Ninety-five patients with lung cancer tumor tissue obtained surgically were included in this study. Arsenic and cadmium levels were measured and levels of metals were compared among types of lung cancer and with reference to patient data. Results: The histopathologic diagnoses of the 95 cases were SCC, 49, adenocarcinoma, 28, large cell, 11 and SCLC, 1. Mean tumor arsenic and cadmium levels were $149.3{\pm}129.1{\mu}g/kg$ and $276.3{\pm}219.3{\mu}g/kg$, respectively. Cadmium levels were significantly associated with smoking (p=0.02), histopathologic type (p=0.005), and TNM staging (r=0.325; p=0.001), although arsenic was not related to any parameter (p>0.05). There was no relation between metal levels and mortality (p>0.05). Conclusions: We found a significant association between tumor cadmium levels of patients with lung cancer and smoking, histopathologic type and staging, although there was no relation with arsenic levels.

• 상하수도학회지
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• 제18권4호
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• pp.493-499
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• 2004

Rejection characteristics of heavy metals by nanofiltration membranes were investigated. Nanofiltration membranes rejected heavy metals much better than chloride, sulfate and TOC, of which concentration in synthetic wastewater was higher than that of heavy metals. To consider rejection characteristics of various metals by nanofiltration membranes, separation coefficient, which is the ratio of the metal permeation rate to the chloride ion or TOC permeation rate, was introduced. In spite of different materials and different nominal salt rejection of nanofiltration membrane used, the separation coefficients of metals were nearly the same. In particular, the separation coefficient of arsenic against chloride ion and TOC was larger than any other separation coefficient of heavy metals. These phenomena were observed in the relationship between the molar conductivity and the separation coefficient for heavy metals.