• Environmental Analysis Health and Toxicology
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• v.22 no.2 s.57
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• pp.171-175
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• 2007

Indigenous species means a species that is likely, due to historical presence, to occur at a specified site for some portion of its life span. Therefore, indigenous species can be useful as an indicator to assess environmental risk caused by hazardous chemicals in a specific site. So far a few toxicity studies using freshwater species which are indigenous to Korea have been carried out. In this study, a freshwater shrimp (Neocardina denticulata) indigenous to Korea was used for acute toxicity test of heavy metals. Neocardina denticulata were exposed to cadmium chloride $(CdCl_2)$, copper chloride $(CuCl_2)$ and zinc chloride $(ZnCl_2)$ using automatic flow-through system for 96 hours. The 96h LC50s were calculated as 0.043 $(0.042{\sim}0.045)mg\;CdCl_2/L,\;0.104(0.098{\sim}0.113)mg\; CuCl_2/L\;and\;2.021\;(1.633{\sim}2.594)mg\;ZnCl_2/L$. When compaired with some international standard species such as medaka(Oryzias latipes), Neocardina denticulata had high sensitivity. Therefore, this study suggested that Neocardina denticulata have possibilities for a sensitive test species to test heavy metal toxicity in aqua-system.

• Journal of Powder Materials
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• v.5 no.1
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• pp.50-56
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• 1998

A new process using rapid solidification (melt spinning method) followed by pressing and sintering was investigated to produce the n-type thermoelectric ribbons of 90% $Bi_2Te_3$+10% $Bi_2Se_3$ doped with $CdCl_2$. Quenched ribbons are very brittle and consisted of homogeneous $Bi_2Te_3-Bi_2Se_3$ pseudo-binary solid solutions. Property variations of the materials was investigated as a function of variables, such as dopant $CdCl_2$ quantity and sintering temperature. When the process parameters were optimized, the maximum figure of merit was $2.146{\times}10^{-3}K^{-1}$.

• Journal of Environmental Science International
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• v.6 no.3
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• pp.249-258
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• 1997

Mercury- and cadmium-resistant bacteria were Isolated from an Industrial complex wastewater of Taejon area. All of them were motile, gram negative rods. In the results of physicochemical test and VITEK card test. HM1 was Identified with Achetobacter cd- coaceucus, CM3 was Identified 65 Commonas acidovorns, HM2, HM3, CMI , and CM4 were Pseudomonas sp., but HM4 and CM2 were unidenteed. They were tested for subceptlbility to 14 heavy metals. Mercury-resistant bacteria(HM1, HM2, HM3, and HM4) were sensitive to low concentration(100~400ppm) of $Cd^{2+}$, $Co^{2+}$. $Zn^{2+}$, and Ni2+, while cadmium-resistant bacteria(CM1, CM2, CM3, and CM4) showed resistance up to the high concentration(600~ 1, 200ppm) of these metal loons. As a result of resistance spectrum test of mercury-resistant bacteria, HM1 was broad-spectrum strain, HM2. HM3, and HM4 were narrow-spectrum stratas. Transmission electron microscopic examination of cell wall of HM1 culture grown with and without 100ppm of $HgCl_2$ showed remarkably merphological abnormalities. In the result of atomic absorption spectrometric analysis of cadmium-resistant bacteria grown at 200ppm of $CdCl_2$ for 6h, all of them accumulated cadrnium(14ppm~57ppm) In cell. In cadinium-resistant bacteria, CM1, CM2, and CM4 were spared from the Inhibitory effect of $Cd^{2+}$ by the addition of $Mn^{2+}$, CM4 were also spared from the Inhibitory effect of $Cd^{2+}$ by the addition of $Mn^{2+}$ as well as $Zn^{2+}$.

• Current Photovoltaic Research
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• v.3 no.1
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• pp.10-15
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• 2015

Cu doping by copper or $Cu_2Te$ materials enhances p+ formation in CdTe near the back contact interface, allowing better formation of ohmic contact. However, the Cu in CdTe junction is also considered as a principal component of CdTe cell degradation. In this paper, Na-doped ZnTe layer was employed as a back contact material to improve the stability of CdTe solar cells. As a process variable, post $CdCl_2$ treatment of CdS/CdTe film was conducted before or after depositing ZnTe:Na on CdTe. The change of the photovoltaic properties of CdTe cells were investigated with aging time. Low-temperature photoluminescence analysis was conducted to describe the degradation mechanism. The result showed that the CdTe solar cells with better stability compare to Cu contact were achieved using an optimized ZnTe:Na back contact.

• The Korean Journal of Ecology
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• v.26 no.3
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• pp.115-121
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• 2003

Leaves of two-week old seedlings of tomato (Lycopersicon esculentum) were treated with various concentrations (0∼100 M) of $CdCl_2$ for up to 9 days and subsequent growth of seedlings, symptoms of oxidative stress and isozyme activities of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and peroxidase (POX) were investigated. Compared with the non-treated control, Cd exposure decreased biomass but increased Cd accumulation, hydrogen peroxide production and lipid peroxidation as malondialdehyde (MDA) formation in leaves and roots. Further studies on the developmental changes of isozyme activities showed that Fe-SOD, Cu/Zn-SOD and one of three APX isozymes decreased and CAT and one of four POX isozymes increased in leaves, whereas Fe-SOD, one of three POX isozymes and two of four APX isozymes decreased and CAT increased in roots, showing different expression of isozymes in leaves and roots with Cd exposure level and time. Based on our results, we suggest that the reduction of seedling growth by Cd exposure is the oxidative stress resulting from the over production of $H_2O_2$ and the insufficient activities of antioxidant enzymes particularly involved in the scavenging of $H_2O_2$. Further, the decreased activities of SOD and APX isozymes of chloroplast origin, the increased activities of CAT and POX and high $H_2O_2$ contents with Cd exposure might indicate that Cd-induced oxidative stress starts outside chloroplast.

• The Korean Journal of Zoology
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• v.23 no.2
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• pp.69-76
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• 1980

Mice were dosed with $HgCl_2$ (5, 10 and 20 mg per kilogram body weight) and $CdCl_2$ (10, 15 and 20 mg per kilogram body weight) by the abdominal injection. Acid phosphatase activites of the liver at 24, 48 and 72 hours following the injection were measured by the Mundry colorimetric method using disodium p-nitrophenyl phosphate as the substrate, and the following results were obtained. The enzyme activities measured were 3.47 mg Pi/ml/0.5 hr at 24 hr and 5.00mg/ml/0.5 hr at 72hr respectively following the injection of 5 mg/kg body weight of $HgCl_2$ and 6.79 mg Pi/ml0.5 hr at 24 hr and 3.47 mg Pi/ml/0.5 hr respectively following the injection of 20 mg/kg body weight of the mercury compound, as compared with the activity of 8.3 mg Pi/ml/0.5 hr for the control. With the cadmium treatment, about 50% of the animals injected with 10mg/kg body weight, and none of the animals injected with 15 and 20mg/kg body weight, survived. Of the surviving animals, the sublethal concentration of cadmium was shown to activate the enzyme: the activities at 24, 48 and 72hr following the injection were around 11.2 mg Pi/ml/0.5 hr as compared with 8.63 mg Pi/ml/0.5 hr for the control.

• Journal of Microbiology and Biotechnology
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• v.27 no.1
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• pp.155-160
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• 2017

The dye decolorization rate in a cell-free culture broth of the white-rot fungus Trametes versicolor CBR43 was studied, including the effects of inhibitors of NaCl, Zn(II), and Cd(II) on dye decolorization activity. The maximum rates of dye decolorization in cell-free culture broth were 1,410, 44.7, 41.2, and $0.19{\mu}mol{\cdot}l^{-1}{\cdot}min^{-1}$ for Acid Blue 62, Acid Black 175, Reactive Blue 4, and Acid Red 114, respectively. The inhibition effects of NaCl, Zn(II), and Cd(II) on dye decolorization were quantitatively compared using the half maximal inhibition concentration ($IC_{50}$), which indicates the concentration of an inhibitor required for 50% inhibition. Based on $IC_{50}$ values, dye decolorization in the cell-free culture broth of CBR43 was most potently inhibited by Cd(II), whereas the inhibitory effect of NaCl was relatively low. The dye decolorization rates and $IC_{50}$ data can be used in the design and development of a dye-wastewater treatment process using T. versicolor CBR43 and its operating factors.

• Journal of Nutrition and Health
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• v.27 no.8
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• pp.828-836
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• 1994

A low level exposure experiment was conducted on growing rats to investigate the accumulation and organ distribution of protein bound cadmium compared with cadmium chloride. Male Sprague-Dawley rats were fed for 21days with one of the semisynthetic diets, which contains cadmium as either bovine liver- or kidney meal bound cadmium, cadmium chloride with uncontaminated liver meal or cadmium chloride without organ meal, in the levels of ca. 0.5, 1 and 1.5mg/kg diet, respectively. After 21days of exposure cadmium was accumulated in liver, kidney and gastrointestinal tracts depending upon cadmium levels in diet. Inspite of very low cadmium accumulation in whole blood, it tends also to increase with dietary cadmium levels. The blood cadmium concentration of animals fed organ meal containing diets was about 4-7 fold higher than that without organ meal, regardless of cadmium was intrinsically bound to protein or not. However, significant effects of organ protein on cadmium accumulation in liver, kidney and digestive tracts were not detectable, when cadmium was supplemented as cadmium chloride. On the other hands, animals fed diet containing ca. 1.5mg Cd/kg as organ bound cadmium retained more cadmium in liver, kidney and digestive tracts compared to cadmium chloride with organ meal, whereby the increase of cadmium concentration in kidney was greater then in liver. However, when the concentration of protein bound cadmium was<1mg/kg diet, organ bound cadmium was not significantly different from cadmium chloride in bioavailability and organ distribution. From this result it is suggested that the intestinal absorption of protein bound cadmium is influenced of the amount of cadmium bound in protein. When cadmium concentration in protein is relatively low, protein bound cadmium seems to be absorbed in the same way as cadmium ions are absorbed. However, when the concentration is high, at least a small amount of intact protein bound cadmium could be absorbed and accumulated selectively in kidney.

• Journal of Environmental Health Sciences
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• v.20 no.2
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• pp.64-72
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• 1994

Tolerance to toxic effects of cadmium (Cd), including lethality has been shown following pretreatment with cadmium and zinc. This study was designed to determine if tolerance also develops to Cd-induced hepatotoxicity and renal toxicity. Three groups of rats (A, B, C), each consisting of 108 rats, were studied and each group was divided into three subgroups (1, 2, 3), 12 rats for each subgroup. Rats were subcutaneously pretreated with saline (A), CdCl$_2$ (0.5 mg/kg, B), and ZnCl$_2$ (13.0 mg/kg, C) during time periods of 5 days. At the end of the period, rats were challenged with CdCIa (3.0 and 6.0 mg/kg) by intraperitoneal injection. As for the cadmium levels in rat tissues after pretreatments, it was highest in the liver. Then kidney, heart, blood and muscle followed it in that order. After 24, 48 and 96 hours of intraperitoneal injection by challenge doses the concentration of cadmium in liver and kidney increased proportionally to the increase of challenge dosage. However metallothioneins in liver and kidney were increased by the pretreatment of cadmium and zinc. These data indicate the liver is a major target organ of acute Cd poisoning, and suggest that cadmium induced hepatic injury, via release of Cd-MT, may play and important role in the nephrotoxicity observed in response to short-term exposure to cadmium. This result suggests that increasing cadmium concentrations, gradually accumulating in liver and kidney as the result of the pretteatmerit, served to induced the synthesis of metallothionein, thus making them resistant to the challenge from cadmium.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.6
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• pp.631-642
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• 1998

Fall-out particles were collected by the modified British deposit gauges at 35 sampling sites in Suwon area from January to November, 1996. Twenty chemical species (Al. Ba, Cd, Cr, K, Pb, Sb, Zn, Cu, Fe, Ni, V, F-, Cl-, NO3-, 5042-, Na+, NH4+, Mg2+, and Ca2+) were analyzed by AAS and If. The purposes of this study were to estimate qualitatively various emission sources of the fell-out particle by applying multivariate statistical techniques such as factor analysis, multiple regression analysis, and discriminant analysis. During the study, outlier sites were determined by a z-score method. Cl-, Na+, Mg2+, and SO42- were highly correlated due to their common marine related source. Wind speed was the most influential factor for the deposition fluxes of the particle itself and all the chemical species as well. When applying the factor analysis, 8 source patterns were qualitatively obtained, such as marine source, soil source, oil burning source, Cr related source, tire source, Cd related source, agriculture source, and F- related source. As a result of the multiple regression analysis, we could suggest that some chemical compounds may possibly exist in the form of CaSO4, NaN03, NaCl, MgC12, (NH4)2SO4, NaF, and CaCl2 in the fall-out particles. Finally, spatial and seasonal classification study performed by a discriminant analysis showed th.at SO42-, Ca2+, Cl-, and Fe were dominant in the group of spatial pattern; however, SO42-, Cl-, Al, and V were in the group of seasonal pattern.