• Journal of Nutrition and Health
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• v.29 no.9
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• pp.958-970
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• 1996

This study was performed to investigate the effect of dietary calcium level on cadmium and lead toxicity in rats. Fifty-four male rats of Sprague-Dawely strain weighing 152$\pm$12g were blocked into 9 groups according to body weight, and were raised for 30 days. Nine experimental diets different with cadmium(0%, 0.04%), lead (0%, 0.071%) and calcijm(0.5%, 1.0%, 1.5%) levels were prepared. The results are summarized as follow. Weight gain, F.E.R.(food efficiency ratio), and weights of liver, kidney and femur were lower in cadmium exposed groups than those of heavy metal free groups. Weight gain F.E.R. and ash weight of lead groups were lower than those of heavy metal free groups. But, these were increased with increasing dietary calcium level. Cadmium and lead concentrations in blood, liver, kidney and femur were lower in rats fed 1.5% calcium than 0.5% calcium diet. Fecal cadmium and lead excretions were remarkably increased in 1.5% calcium groups, and cadmium and lead retention rates were decreased in 1.5% calcium groups. Metallothionein concentrations in liver, kidney and small intestine were higher in rats exposed to cadmium and lead. Calcium content in blood, femur and daily urinary and fecal calcium excretion were decreased by cadmium and lead additions, and increased in 1.5% calcium groups. Creatinine clearance were decreased with cadmium administratino and calcium addition. In conclusion, weight gain and organ weights were decreased with cadmium or lead administration. But, cadmium administration was more toxic than lead adminstration. Cadmium or lead toxicity was alleviated by increasing dietary calcium level. Especially, lead toxicity was alleviated in proportion to dietary calcium level.

• Toxicological Research
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• v.33 no.2
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• pp.119-124
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• 2017

Hexavalent chromium is a bio accumulative toxic metal in water and fish. It enters aquaculture ponds mainly through anthropogenic sources. Hexavalent chromium concentrations and its effects on the morphology and behavior of Clarias gariepinus were investigated from four aquaculture ponds for 12 weeks. Chromium was measured using diphenyl carbohdrazide method; alkalinity and hardness were measured using colometric method and analyzed with Bench Photometer. Temperature and pH were measured using pH/EC/TDS/Temp combined tester. Temporal and spatial replications of samples were done with triplicates morphological and behavioural effects of the metal on fish were observed visually. Chromium ranged from no detection to 0.05 mg/L, alkalinity 105 to 245 mg/L, hardness 80 to 165 mg/L, pH 6.35 to 8.03 and temperature 29.1 to $35.9^{\circ}C$. Trend in the chromium concentrations in the ponds is natural > earthen > concrete > collapsible. There was a significant difference (P < 0.05) in chromium, alkalinity, water hardness, pH and temperature among the four ponds. Significant positive correlation also existed between alkalinity, water hardness, pH, with chromium. Morphological and behavioural changes observed in the fish include irregular swimming, frequent coming to the surface, dark body colouration, mucous secretion on the body, erosion of gill epithelium, fin disintegration, abdominal distension and lethargy. High chromium concentration in natural pond was due to anthropogenic run-off of materials in to the pond. Acidic pH, low alkalinity, low water hardness also contributed to the high chromium concentration. Morphological and behavioural changes observed were attributed to the high concentrations, toxicity and bio accumulative effect of the metal. Toxicity of chromium to fish in aquaculture could threaten food security. Watershed best management practices and remediation could be adopted to reduce the effects of toxicity of chromium on pond water quality, fish flesh quality and fish welfare.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.11a
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• pp.196-201
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• 2000

The influence of adsorption on cadmium toxicity to soil microorganisms in smectite-rich soils and sediments was quantified as a function of solution and sorbent characteristics. Adsorption and surface complexation experiments were conducted to infer Cd sorption mechanisms to a reference smectite and three fractions of a Veritsol soil, and to elucidate the effects of the surface complexation on Cd bioavailability and toxicity in soils and sediments. Cadmium adsorption isotherms conformed to the Langmuir adsorption model, with adsorptive capacities of the different samples dependent on their characteristics. Equilibrium geochemical modeling (MINTEQA2) was used to predict the speciation of Cd in the soil suspensions using Langmuir and Triple Layer surface complexation models. The influence of adsorption and surface complexation on cadmium toxicity to soil microorganisms was assessed indirectly through the relative change in microbial hydrolysis of fluorescein diacetate (FDA) as a function of total Cd concentration and sorbent characteristics. Adsorption decreased the toxicity of Cd to soil microorganisms. Inner-sphere complexation is more effective than outer-sphere complexation in reducing the bioavailability and toxicity of heavy metals in soils and sediments.

• Proceedings of the KSEEG Conference
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• 2004.12a
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• pp.1-8
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• 2004

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.10 no.S_4
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• pp.189-196
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• 2001

The blue green alga, Microcystis aeruginosa, was found to accumulate proline under the stressful concentration of cupric ions. The changes of proline level in Microcystis aeruginosa in response to copper(Cu) have been monitored and the function of the accumulated proline was studied with respect to its effect on Cu uptake. Exposure of Microcystis aeruginosa elevated concentrations of Cu led to accumulation of fee proline depending on the concentrations of the metal in the external medium. The greater the toxicity or accumulation of the metal, the higher the amount of proline in algal cells were found. When proline was exogenously supplied prior to Cu treatment, the absorption of Cu was markedly reduced. When exogenous proline was supplied after Cu treatment, it resulted in a remarkable desorption of the adsorbed Cu immediately after the addition of proline. Pretreatment of Microcystis aeruginosa with proline counteracted with metal-induced lipid peroxidation. The results of the present study showed a protective elect of proline on metal toxicity through inhibition of lipid peroxidation and suggested that the accumulation of proline may be related to the tolerance mechanism for dealing with Cu stress.

• Journal of Applied Biological Chemistry
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• v.42 no.4
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• pp.169-174
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• 1999

Arabidopsis AHL gene contains 4 exons encoding a putative protein highly homologous to the yeast salt-sensitive enzyme HAL2, a 3'(2'),5'-bisphosphate nucleotidase involving in reductive sulfate assimilation. AHL cDNA complemented yeast met22 (hal2) mutant. AHL fusion protein expressed in E. coli exhibited $Mg^{2+}$-dependent, 3'-phosphoadenosine 5'-phosphate (PAP)-specific phosphatase activity. $Li^+,\;Na^+,\;K^+$ and $Ca^{2+}$ ions inhibit the enzyme activity by competing with $Mg^{2+}$ for the active site of the enzyme. The enzyme activity was also sensitive to ${\mu}M$ concentrations of toxic heavy metal ions such as $Cd^{2+},\;Cu^{2+}$ and $Zn^{2+}$, but was not recovered by addition of more $Mg^{2+}$ ions, suggesting that these ions inactivate the enzyme with a mechanism other than competition with $Mg^{2+}$ ions. Inhibition of the AHL enzyme activity may result in accumulation of PAP, which is highly toxic to the cell. Thus, the AHL enzyme could be one of the intial targets of heavy metal toxicity in plants.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.6
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• pp.644-650
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• 2016

In soil-to-plant transfer of heavy metals, the amount absorbed and accumulated varies depending on the environment conditions. The absorption rate of cadmium (Cd) in plants differs considerably depending on the bioavailability of Cd in the soil, while usage by various organic matters is also reported to affect absorption patterns. Therefore, this study aimed to identify the difference in the transfer of essential metal ions and Cd to various plant parts when rice straw compost was used to cultivate soybean (Glycine max L. cv. Daepung). In the two-leaf stage of soybean cultivated in a greenhouse, Cd was mixed in the soil, after which the Cd and essential metal ions contents, and physiological changes of soybean seedlings were studied on the 15th and 25th day. The Cd toxicity in the plant was reduced with the use of rice straw compost. Further, the Cd content varied with the plant part, and was higher in young leaves (3rd and 4th leaf) than in the stem. When analyzed by leaf age, the Cd transfer was highest in young leaves (3rd and 4th leaf), followed by mature leaves (1st and 2nd leaf). While there was no significant difference between plant tissues in the absorption rate of copper (Cu) and zinc (Zn) when rice straw compost was used against Cd toxicity, the absorption rate of manganese (Mn) and iron (Fe) showed a significant decline in both the control and rice straw compost treatment conditions, as well as a significant difference between leaf ages. Therefore, these results confirm that the use of rice straw compost against Cd toxicity is effective, and implies that the rate of Cd transfer in the soybean plant varies significantly with leaf age.

• Journal of the Korean Applied Science and Technology
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• v.26 no.1
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• pp.69-73
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• 2009

Copper alloy metal fiber was incorporated into the conventional water-soluble metal working fluids to increase the antimicrobial activity. Fluid treated by copper alloy metal fiber is shown that bacteria is disappeared whereas that untreated metal fiber is increased bacteria as increasing the life time. When the electrochemical potential of Cu/Zn ion is -268mV, radicals with molecular oxygen are easily made. Especially, hydroperoxide radical shows strong toxicity to the strains, leading to the conformational change of plasma membrane. As a result antimicrobial activity of copper alloy metal fiber in metal working fluid is superior to that of copper fiber.

• Journal of Korean Ophthalmic Optics Society
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• v.1 no.1
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• pp.115-118
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• 1996

The study on the cytotoxicities of heavy metals, metal-metal and metal-chelator combinations was carried out to evaluate the cytotoxic effect of those on mouse L929 fibroblasts. The colorimetric assays (NR and MTT) were conveniently carried out in 96-well microtiter plates. The rank order was Cd > Zn Ni > Cr(III) for the heavy metals tested. Examination of the effect of metal-metal interaction on cytotoxicity showed a moderate reduction of cadmium toxicity by zinc. The colorimetric assays were also effectively used to investigate the effect of the chelators, ethylenediamine tetra acetic acid (EDTA) and chitosan. Reduction of heavy metal toxixity by chelator was efficient.

• Journal of the Korean Applied Science and Technology
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• v.24 no.3
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• pp.233-237
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• 2007

This study is focused on the possibility of copper alloy metal fiber for an antimicrobial activity in the water soluble metal working fluids. Electrochemical potential of Cu/Zn ion is -268mV, and easily makes radicals with molecular oxygen. Especially, hydroperoxide radical shows strong toxicity to the strains. Plasma membrane causes conformational change when hydroperoxide radical binds to plasma membrane. Elution of copper ion from copper alloy metal fiber is detected in metal working fluid. As a result antimicrobial activity of copper alloy metal fiber in metal working fluid is superior to that of copper fiber.