• Korean Journal of Soil Science and Fertilizer
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• v.48 no.5
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• pp.397-403
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• 2015

Heavy metals reduce the photosynthetic efficiency and disrupt metabolic reactions in a concentration-dependent manner. Moreover, by replacing the metal ions in metalloproteins that use essential metal ions, such as Cu, Zn, Mn, and Fe, as co-factors, heavy metals ultimately lead to the formation of reactive oxygen species (ROS). These, in turn, cause destruction of the cell membrane through lipid peroxidation, and eventually cause the plant to necrosis. Given the aforementioned factors, this study was aimed to understand the physiological responses of rice to cadmium (Cd) and arsenic (As) toxicity and the effect of essential metal ions on homeostasis. In order to confirm the level of physiological inhibition caused by heavy metal toxicity, hydroponically grown rice (Oryza sativa L. cv. Dongjin) plants were exposed with $0-50{\mu}M$ cadmium (Cd, $CdCl_2$) and arsenic (As, $NaAsO_2$) at 3-leaf stage, and then investigated malondialdehyde (MDA) contents after 7 days of the treatment. With increasing concentrations of Cd and As, the MDA content in leaf blade and root increased with a consistent trend. At 14 days after treatment with $30{\mu}M$ Cd and As, plant height showed no significant difference between Cd and As, with an identical reduction. However, As caused a greater decline than Cd for shoot fresh weight, dry weight, and water content. The largest amounts of Cd and As were found in the roots and also observed a large amount of transport to the leaf sheath. Interestingly, in terms of Cd transfer to the shoot parts of the plant, it was only transported to upper leaf blades, and we did not detect any Cd in lower leaf blades. However, As was transferred to a greater level in lower leaf blades than in upper leaf blades. In the roots, Cd inhibited Zn absorption, while As inhibited Cu uptake. Furthermore, in the leaf sheath, while Cd and As treatments caused no change in Cu homeostasis, they had an antagonist effect on the absorption of Zn. Finally, in both upper and lower leaf blades, Cd and As toxicity was found to inhibit absorption of both Cu and Zn. Based on these results, it would be considered that heavy metal toxicity causes an increase in lipid peroxidation. This, in turn, leads to damage to the conductive tissue connecting the roots, leaf sheath, and leaf blades, which results in a reduction in water content and causes several physiological alterations. Furthermore, by disrupting homeostasis of the essential metal ions, Cu and Zn, this causes complete heavy metal toxicity.

• ALGAE
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• v.26 no.3
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• pp.265-275
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• 2011

This study examined the bioaccumulation of the heavy metals copper (Cu) and zinc (Zn) by the giant kelp, Macrocystis pyrifera, by exposing meristematic kelp tissue to elevated metal concentrations in seawater within laboratory aquaria. Specifically, we carried out two different experiments. The first examined metal uptake under a single, ecologically-relevant elevation of each metal (30 ppb Cu and 100 ppb Zn), and the second examined the relationships between varying levels of the metals (i.e., 15, 39, 60, 120, 240, and 480 ppb Cu, and 50, 100, 200, 300, 500, and 600 ppb Zn). Both experiments were designed to contrast the uptake of the metals in isolation (i.e., when only one metal concentration was elevated) and in combination (i.e., when both metals' concentrations were elevated). Following three days of exposure to the elevated metal concentrations, we collected and analyzed the M. pyrifera tissues using inductively coupled plasma atomic emissions spectroscopy. Our results indicated that M. pyrifera bioaccumulated Cu in all treatments where Cu concentrations in the seawater were elevated, regardless of whether Zn concentrations were also elevated. Similarly, M. pyrifera bioaccumulated Zn in treatments where seawater Zn concentrations were elevated, but this occurred only when we increased Zn alone, and not when we simultaneously increased Cu concentrations. This suggests that elevated Cu concentrations inhibit Zn uptake, but not vice versa. Following this, our second experiment examined the relationships among varying seawater Cu and Zn concentrations and their bioaccumulation by M. pyrifera. Here, our results indicated that, as their concentrations in the seawater rise, Cu and Zn uptake by M. pyrifera tissue also rises. As with the first experiment, the presence of elevated Zn in the water did not appear to affect Cu uptake at any concentration examined. However, although it was not statistically significant, we observed that the presence of elevated Cu in seawater appeared to trend toward inhibiting Zn uptake, especially at higher levels of the metals. This study suggests that M. pyrifera may be useful as a bio-indicator species for monitoring heavy metal pollution in coastal environments.

• Journal of the Mineralogical Society of Korea
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• v.16 no.3
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• pp.201-213
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• 2003

The adsorption property and ability of domestic zeolites for some heavy metal ions (Ag, Pb, Cr, Cu, Zn, Mn), which may cause a serious environmental problem in industrial wastewater, were evaluated on ore unit through a series of adsorption experiments together with careful examinations of mineral composition and properties of the zeolites. Though the adsorption behavior basically took place in the form of a cation exchange reaction, the higher CEC value does not necessarily to imply the higher adsorption capacity for a specific heavy metal. A general trend of the adsorption selectivity for heavy metals in the zeolites is determined to be as follow: $Ag\geq$Pb>Cr,Cu$\geq$Zn>Mn, but the adsorption properties of heavy metal ions somewhat depend on the species and composition of zeolite. Clinoptilolite tends to adsorb selectively Cu in case of Cr and Cu, whereas heulandite prefers Cr to Cu. A dominant adsorption selectivity of the zeolite ores for Ag and Pb is generally conspicuous regardless of their zeolite species and composition. The zeolite ores exhibit a preferential adsorption especially for $Ag^{+}$ so as not to regenerate when treated with $Na^{+}$ . In the adsorption capacity for heavy meta ions, the zeolites differ in great depending on their species: ferrierite>clinoptilolite>heulandite. Considering the CEC value of mordenite, the mordenite-rich ore appears to be similar to the clinoptilolite ore in the adsorption capacity. The adsorption capacity for heavy metals is not positively proportional to the CEC values of the zeolites measured by the exchange reaction with ammonium ion. In addition, the adsorption capacity roughly tends to depend on the zeolite contents, i.e., the grade of zeolite ore, but the trend is not consistent at all in some ores. These may be caused by the adsorption selectivity for some specific heavy metals, the presence of possible stacking micro-faults and natural cations such as K hardly to exchange in the zeolite. Considering the economic availability and functional effectiveness as natural zeolite resources, clinoptilolite ores could be applicable to utilize the domestic zeolites for the removal of heavy metals.

• The Korean Journal of Ecology
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• v.23 no.6
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• pp.445-452
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• 2000

The effects of sludge and fertilizer application on germination and seedling growth of woody plants on heavy metal mine tailings were evaluated by greenhouse experiment. Two different mine tailings (Lead-zinc mine tailings from Kwangmyong, Kyonggi-do and tungsten mine tailings from Sangdong. Kangwon-do). four fertilizer treatments (N +P +K: 20, 40, 60, and 80 kg/m$^3$), and four sewage sludge treatments (5.5, 11, 22.5, and 45 Mg/m$^3$) were used in the experiment. Tested plants were Pinus densiflora, Larix leptolepis, Amorpha fruticosa, and Alnus hirsuta. There were three replicates for each treatment. In addition, vermiculite was used instead of mine tailings to determine the effect of physical amendments. Fifty seeds of a species were sown in a pot (upper diameter 13.5 cm, depth 10 cm) and seedling emergence were recorded daily for 30 days. The highest germination rate was 53% for all treatments. Germination rate of Larix leptolepis was lowest among the four species studied. One month later after seeding, seedlings were thinned and only 5 seedling were left in each pot, and fertilizer and sewage sludge were applied once again. Growth of seedlings were determined for 10 weeks since then. Most plants grew very poorly or died within 5 weeks on lead/zinc mine tailings from Kwangmyong. The analysis of heavy metal contents by the total dissolution method showed that heavy metals generally increased in the order of tungsten mine tailings from Sangdong < sewage sludge from Puchon < lead/zinc mine tailings from Kwangmyong. Growth of woody plants was improved significantly by the fertilizer treatments on tungsten mine tailings. In contrast. survival and growth of woody plants were not affected significantly by the sewage sludge treatment on both tailings. This study shows that fertilizer applied to established seeded stands may provide some benefits in terms of increased ground cover in the field. It is suggested that reclamation should be proceeded by the study of the physico-chemical and biological characteristics of mine tailings.

• Journal of Ginseng Research
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• v.45 no.2
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• pp.218-227
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• 2021

Background: Panax ginseng is one of the most important medicinal plants and is usually harvested after 5 to 6 years of cultivation in Korea. Heavy metal (HM) exposure is a type of abiotic stress that can induce oxidative stress and decrease the quality of the ginseng crop. Siderophore-producing rhizobacteria (SPR) may be capable of bioremediating HM contamination. Methods: Several isolates from ginseng rhizosphere were evaluated by in vitro screening of their plant growth-promoting traits and HM resistance. Subsequently, in planta (pot tests) and in vitro (medium tests) were designed to investigate the SPR ability to reduce oxidative stress and enhance HM resistance in P. ginseng inoculated with the SPR candidate. Results: In vitro tests revealed that the siderophore-producing Mesorhizobium panacihumi DCY119^T had higher HM resistance than the other tested isolates and was selected as the SPR candidate. In the planta experiments, 2-year-old ginseng seedlings exposed to 25 mL (500 mM) Fe solution had lower biomass and higher reactive oxygen species level than control seedlings. In contrast, seedlings treated with 10⁸ CFU/mL DCY119^T for 10 minutes had higher biomass and higher levels of antioxidant genes and nonenzymatic antioxidant chemicals than untreated seedlings. When Fe concentration in the medium was increased, DCY119^T can produce siderophores and scavenge reactive oxygen species to reduce Fe toxicity in addition to providing indole-3-acetic acid to promote seedling growth, thereby conferring inoculated ginseng with HM resistance. Conclusions: It was confirmed that SPR DCY119^T can potentially be used for bioremediation of HM contamination.

• Advances in environmental research
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• v.6 no.4
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• pp.241-254
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• 2017

This study was conducted to investigate the levels of heavy metals in twelve species of vegetables and assessment of health risk. Samples were analyzed using inductively coupled plasma mass spectrometer (ICP-MS). The ranges of Cr, Ni, Cu, As, Cd and Pb in vegetables species were 0.37-5.4, 0.03-17, 0.35-45, 0.01-2.6, 0.001-2.2, and 0.04-8.8 [mg/kg, fresh weight (fw)], respectively. The concentrations of As, Cd and Pb in most vegetable species exceeded the maximum permissible levels, indicating unsafe for human consumption. Health risks associated with the intake of these metals were evaluated in terms of estimated daily intake (EDI), and carcinogenic and non-carcinogenic risks by target hazard quotient (THQ). Total THQ of the studied metals from most of the vegetables species were higher than 1, indicated that these types of vegetables might pose health risk due to metal exposure. The target carcinogenic risk (TR) for As ranged from 0.03 to 0.48 and 0.0004 to 0.025 for Pb which were higher than the USEPA acceptable risk limit (0.000001) indicating that the inhabitants consuming these vegetables are exposed to As and Pb with a lifetime cancer risk. The findings of this study reveal the health risks associated with the consumption of heavy metals through the intake of selected vegetables in adult population of Bangladesh.

• Journal of Food Hygiene and Safety
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• v.38 no.4
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• pp.255-263
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• 2023

The standards for heavy metal levels in crustaceans are 0.5 mg/kg and 1.0 mg/kg or lower for lead and cadmium, respectively. Further, the contamination levels of arsenic, mercury, methyl mercury, and tin are being continuously investigated, considering their current exposure levels. Shrimps are potentially exposed to heavy metals because they inhabit areas with abundant organic matter, such as sandy or muddy shores, places with a lot of seaweed, and estuaries. This study measured the monetary value of reducing consumer anxiety and increasing consumer confidence if the government prohibits the sale of shrimp species that exceed the threshold for specific heavy metals and of the top shrimp species for which no threshold for heavy metals is specified. We derived consumer willingness-to-pay (WTP). Combining the estimated WTP with the number of households in the country, the total value of benefits was estimated to be 363.9 billion won. The results of this study will provide an important empirical finding, showing to what extent specific policies regarding heavy metals in seafood can alleviate consumer anxiety and provide psychological reassurance.

• Journal of Environmental Health Sciences
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• v.47 no.6
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• pp.530-539
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• 2021

Background: In South Korea, areas around abandoned metal mines are designated as regions with high arsenic (As) contamination. However, studies assessing urinary As exposure, As metabolism, and relevant genetic polymorphisms in residents of these metal mine areas are lacking. Objectives: To identify factors associated with As exposure and evaluate the effects of MTHFR, As3MT, and GSTO1 genetic polymorphisms on As metabolism in residents of abandoned metal mine areas by measuring urinary As species. Methods: Urinary As species (arsenite [As³⁺], arsenate [As⁵⁺], monomethyl arsonic acid, and dimethylarsinic acid) were isolated using high-performance liquid chromatography in combination with inductively coupled plasma mass spectrometry (HPLC-ICP-MS). Four genetic polymorphisms (MTHFR A222V, MTHFR E429A, GSTO1 A140D, As3MT M287T) were analyzed in 144 residents of four areas around abandoned metal mines. Results: The study sample was comprised of 34.7% men and 65.3% women, with a mean age of 70.7±10.9 years. The urinary inorganic As concentration was higher among those consuming more than half locally produced rice (0.31 ㎍/L) than those consuming less than half such rice (0.18 ㎍/L). The urinary dimethylarsinic acid concentration was higher in the group that had consumed seafood in the past day (31.68 ㎍/L) than in those who had not (22.37 ㎍/L). Furthermore, individuals heterozygous in the MTHFR A222V and GSTO1 A140D polymorphism had higher urinary arsenic species concentrations than did individuals with a wild type or homozygous for the variant allele. Conclusions: Consumption of locally produced rice was associated with inorganic As exposure, whereas seafood consumption was associated with organic As exposure among residents of abandoned metal mine areas. There was no clear association between MTHFR A222V and GSTO1 A140D polymorphisms and As metabolism.

• Journal of Korean Society on Water Environment
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• v.28 no.2
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• pp.171-177
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• 2012

This research investigates how using algae as an ecotoxicological test species is easier than using daphnia for identifying toxic causative substances. From the results of the ecotoxicity measurements on the Shihwa lake and its tributaries, heavy metals were considered as one of major factors in causing toxicity. The algae ecotoxicity value was 9.6 while the daphnia ecotoxicity value was 0.8 in the Jeongwang stream. By using algae as the test species, we could identify the toxicity that causes heavy metals which might otherwise have been missed with only daphnia. The results from the EDTA addition test showed that zinc and copper were the main toxic causative substances in the Jeongwang stream and Gunja stream.

• Journal of the Korean Geotechnical Society
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• v.24 no.6
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• pp.17-25
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• 2008

Permeable reactive barriers (PRBs) technology can be applied to contaminated groundwater remediation. It is necessary to select adequate reactive material according to contaminant characterization. In groundwater. In this research, the reaction between reactive material and heavy metal contaminants was estimated through batch test. Reactive material was slag, which has been produced in Gwangyang power plant, and heavy metal contaminants were cadmium, lead and copper. Batch test consisted of two testes: 1) sorption equilibrium test and 2) sorption kinetic test. Sorption equilibrium test was performed for estimating slag sorption capacity against contaminants. And sorption kinetic test was performed for slag sorption rate with contaminants species, contaminants initial concentration and sulfate. Sorption capacity and sorption rate were affected by contaminant species. Sorption rate increased with increasing initial concentration in lead and copper but decreased with increasing initial concentration in cadmium. Sorption rate increased in existing sulfate. In low concentration, film diffusion was domain mechanism, and in high concentration, particle diffusion was domain mechanism.