• Korean Journal of Soil Science and Fertilizer
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• v.47 no.3
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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.

• Journal of the Mineralogical Society of Korea
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• v.26 no.4
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• pp.229-244
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• 2013

Arsenic contamination may be brought about by a variety of natural and anthropogenic causes. Among diverse naturally-occurring chemical speciations of arsenic, trivalent (As(III), arsenite) and pentavalent (As(V), arsenate) forms have been reported to be the most predominant ones. It has been well known that the behavior of arsenic is chiefly affected by aluminum, iron, and manganese oxides. For this reason, this study was initiated to evaluate the applicability of manganese slag (Mn-slag) containing high level of Mn, Si, and Ca as an efficient sorbent of arsenic. The main properties of Mn-slag as a sorbent were investigated and the sorption of each arsenic species onto Mn-slag was characterized from the aspects of equilibrium as well as kinetics. The specific surface area and point of zero salt effect (PZSE) of Mn-slag were measured to be $4.04m^2/g$ and 7.73, respectively. The results of equilibrium experiments conducted at pH 4, 7 and 10 suggest that the sorbed amount of As(V) was relatively higher than that of As(III), indicating the higher affinity of As(V) onto Mn-slag. As a result of combined effect of pH-dependent chemical speciations of arsenic as well as charge characteristics of Mn-slag surface, the sorption maxima were observed at pH 4 for As(V) and pH 7 for As(III). The sorption of both arsenic species reached equilibrium within 3 h and fitting of the experimental results to various kinetic models shows that the pseudo-second-order and parabolic models are most appropriate to simulate the system of this study.

• Journal of Food Hygiene and Safety
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• v.37 no.6
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• pp.385-393
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• 2022

The contamination level of inorganic arsenic, a human carcinogen, was investigated in 87 grains and 66 processed grain foods. Two inorganic arsenic species arsenite (As(III)) and arsenate (As(V)) and four organic arsenic monomethylarsonic acid, dimethylarsinic acid, arsenobetaine, arsenocholine were analyzed using HPLC-ICP/MS with high separation and sensitivity and ICP/MS was used to quantify total arsenic. Inorganic arsenic was detected in all grains. And the total arsenic in grains consists of about 70-85% inorganic arsenic and about 10-20% DMA. The concentration of inorganic arsenic was high in rice and black rice cultivated in paddy soil with irrigated water, while the miscellaneous grain in field was low. Mean concentration of inorganic arsenic in rice germ, brown rice and polished rice was 0.160 mg/kg, 0.135 mg/kg, 0.083 mg/kg, respectively, indicating that rice bran contains more arsenic. In processed grain foods, inorganic arsenic concentration varied according to the kind of ingredients and content, and the detection amount was high in processed food with brown rice and germ. The arsenic content of all samples did not exceed each standard, but the intake frequency is high and it is considered that continuous monitoring is necessary for food safety.

• Resources Recycling
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• v.30 no.3
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• pp.30-40
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• 2021

The present study investigates the bioleaching efficiencies of arsenic via contact and non-contact mechanisms. The attachment of Acidithiobacillus ferrooxidans was restricted by a partition system comprising a semi-permeable membrane with a molecular weight cutoff of 12-14 kDa. The results were compared for two arsenic concentrations in the system (1.0% and 0.5% w/v) to maintain a homogeneous system. The overall bacterial performance was monitored by comparing total arsenic and iron concentrations, Fe ion speciation, pH, and solution redox potentials in flask bioleaching experiments over a period of 10 d. Our results indicated that bacterial attachment could increase arsenic extraction efficiency from 20.0% to 44.9% at 1.0 % solid concentrations. These findings suggest that the bacterial contact mechanism greatly influences arsenic bioleaching from mine tailings. Therefore, systems involving two-step or non-contact bioleaching are less effective than those involving one-step or contact bioleaching for the efficient extraction of arsenic from mine tailings.

• Journal of the Korea Organic Resources Recycling Association
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• v.19 no.1
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• pp.79-85
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• 2011

A study on characteristics for removal of arsenic ion using phosphorylated pine needles was performed. The surface condition of phosphorylated pine needles was confirmed by FT-IR, SEM(Scanning Electron Microscopy) and EDX(Energy Dispersive X-ray). The removal rate of arsenic ion was the highest as about 98% at pH 7. Most absorption for arsenic ion was also completed within 30min and decreased with time and pH of arsenic solution from 6.5 to 2.4.

• Microbiology and Biotechnology Letters
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• v.51 no.1
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• pp.1-9
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• 2023

Arsenic (As), which is ubiquitous throughout the environment, represents a major environmental threat at higher concentration and poses a global public health concern in certain geographic areas. Most of the conventional arsenic remediation techniques that are currently in use have certain limitations. This situation necessitates a potential remediation strategy, and in this regard bioremediation technology is increasingly important. Being the oldest representativse of life on Earth, microbes have developed various strategies to cope with hostile environments containing different toxic metals or metalloids including As. Such conditions prompted the evolution of numerous genetic systems that have enabled many microbes to utilize this metalloid in their metabolic activities. Therefore, within a certain scope bacterial isolates could be helpful for sustainable management of As-contamination. Research interest in microbial As(III) oxidation has increased recently, as oxidation of As(III) to less hazardous As(V) is viewed as a strategy to ameliorate its adverse impact. In this review, the novelty of As(III) oxidation is highlighted and the implication of As(III)-oxidizing microbes in environmental management and their prospects are also discussed. Moreover, future exploitation of As(III)-oxidizing bacteria, as potential plant growth-promoting bacteria, may add agronomic importance to their widespread utilization in managing soil quality and yield output of major field crops, in addition to reducing As accumulation and toxicity in crops.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.3
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• pp.157-162
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• 2006

Objective of this research was to evaluate optimal conditions of arsenic adsorption in water by zero-valent iron (ZVI). Batch experiment showed that adsorption of arsenic by ZVI followed a Langmuir isotherm model. The masses of As(V) adsorbed onto ZVI were increased as decreasing pH of the reacting solution (pH 3: 2.05, pH 5: 1.82, pH 7: 1.24, pH 9: 1.03 mg As/g $Fe^0$) and as increasing the temperature ($15^{\circ}C$ : 1.59, $25^{\circ}C$ : 1.81, 35 : $1.93^{\circ}C$ mg As/g $Fe^0$). The SEM and EDS (energy dispersive X-ray spectrometer) analysis of morphology and structure of ZVI before and after reacting with arsenic in water revealed that a relatively smooth and large surface of ZVI was transformed into a coarse and small surface particle after the reaction. The EDS spectra on the chemical composition of ZVI demonstrated that arsenic was incorporated into ZVI by adsorption mechanism. The XRD analysis also identified that the only peak for $Fe^0$ in the ZVI before the reaction and confirmed that $Fe^0$ was transformed into $Fe_2O_3$ and FeOOH, and As into $FeAsO_4{\cdot}2H_2O$.

• Journal of the Mineralogical Society of Korea
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• v.22 no.3
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• pp.177-189
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• 2009

Iron (oxyhydr)oxides commonly form as secondary minerals of high reactivity and large surface area resulting from alteration and weathering of primary minerals, and they are efficient sorbents for inorganic and organic contaminants. Accordingly, they have a great potential in industrial applications and are also of substantial interest in environmental sciences. Goethite (${\alpha}$-FeOOH) is one of the most ubiquitous and stable forms of iron (oxyhydr)oxides in terrestrial soils, sediments, and ore deposits, as well as a common weathering product in rocks of all types. This study focused on adsorption reaction as a main mechanism in scavenging arsenic using goethite. Goethite was synthesized in the laboratory to get high purity, and a variety of mineralogical and physicochemical features of goethite were measured and related to adsorption characteristics of arsenic. To compare differences in adsorption reactions between arsenic species, in addition, a variety of experiments to acquire adsorption isotherm, adsorption edges, and adsorption kinetics were accomplished. The point of zero charge (PZC) of the laboratory-synthesized goethite was measured to be 7.6, which value seems to be relatively higher, compared to those of other iron (oxyhydr)oxides. Its specific surface area appeared to be $29.2\;m^2/g$ and it is relatively smaller than those of other (oxyhydr)oxides. As a result, it was speculated that goethite shows a smaller adsorption capacity. It is likely that the affinity of goethite is much more larger for As(III) (arsenite) than for As(V) (arsenate), because As(III) was observed to be much more adsorbed on goethite than As(V) in equivalent pH conditions. When the adsorption of each arsenic species onto goethite was characterized in various of pH, the adsorption of As(III) was largest in neutral pH range (7.0~9.0) and decreased in both acidic and alkaline pH conditions. In the case of As(V), the adsorption appeared to be highest in the lowest pH condition, and then decreased with an increase of pH. This peculiarity of arsenic adsorption onto goethite might be caused by macroscopic electrostatic interactions due to variation in chemical speciation of arsenic and surface charge of goethite, and also it is significantly affected by change in pH. Parabolic diffusion model was adequate to effectively evaluate arsenic adsorption on goethite, and the regression results show that the kinetic constant of As(V) is larger than that of As(III).

• Environmental Engineering Research
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• v.14 no.3
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• pp.153-157
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• 2009

Arsenic at abandoned mine sites has adversely affected human health in Korea. In this study, the feasibility of using cationic surfactant-modified activated carbon (MAC) to remove As(V) was evaluated in terms of adsorption kinetics, adsorption isotherms, and column experiments. The adsorption of As(V) onto MAC was satisfactorily simulated by the pseudo-second-order kinetics model and Langmuir isotherm model. In column experiments, the breakthrough point of AC was 28 bed volumes (BV), while that of MAC increased to 300 BV. The modification of AC using cationic surfactant increased the sorption rate and sorption capacity with regard to As(V). As a result, MAC is a promising adsorbent for treating As(V) in aqueous streams.

• Journal of Environmental Health Sciences
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• v.46 no.6
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• pp.655-666
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• 2020

Objectives: The purpose of this study was to evaluate urinary arsenic concentrations by arsenic species and to identify related factors among local residents near abandoned metal mines in Korea. Methods: Among the subjects of the Health Survey of Residents Near Abandoned Metal Mines for 2013-2017, 664 people were enrolled in this study. Urinary arsenic species analysis was performed using ICP/MS. Result: The geometric means (95% Confidence Interval) by urinary arsenic species were 0.15 (0.13-0.17) ㎍/L for AsIII, 0.64 (0.55-0.75) ㎍/L for AsV, and 1.21 (1.05-1.40) ㎍/L for inorganic arsenic. The geometric means of urinary MMA and DMA were 1.58 (1.35-1.86) ㎍/L and 77.93 (72.61-83.63) ㎍/L, respectively, and that of organic arsenic was 83.15 (77.80-88.88) ㎍/L. The concentration of inorganic arsenic in the group using groundwater as drinking water was 1.36 (1.13-1.64) ㎍/L, which was statistically significantly higher than the 1.00 (0.80-1.25) ㎍/L in the other drinking water groups. Regarding rice consumption, the concentration of inorganic arsenic in urine in the group whose consumption was more than half rice produced in the residential area was 1.32 ㎍/L, which was statistically significantly higher than that of the 1.12 ㎍/L for the group whose consumption was less than half. Conclusion: In the analysis of the factors affecting the urinary inorganic arsenic concentration of the residents of the abandoned metal mine area, the use of groundwater as drinking water and consumption of rice produced in the residential area were considered related factors.