• Journal of Plant Biotechnology
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• v.3 no.1
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• pp.13-17
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• 2001

A Chromium (VI)[Cr(VI)] reductase gene from heavy metal reducing bacteria Pseudomonas aeruginosa HP014 was used to transform tobacco plant cells. A chimeric construct containing the Cr(VI) reductase gene was transfered to tobacco leaf disks using an Agrobacteriun tumefaciens binary vector system. From the leaf disks, transformed plantlets were regenerated. Hybridization experiments demonstrated that the Cr(VI) reductase gene was inserted into and expressed in the regenerated plants. The Cr(VI) reduction activity showed that the transgenic plants may be a another possible tool to reduce the pollution of the toxic Cr(VI) in soil.

• Journal of Environmental Science International
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• v.23 no.7
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• pp.1269-1275
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• 2014

Ecotoxicity assessments with the physiochemical water quality items and the bioassay test using Daphnia magna were conducted for 18 selected effluents of 6 industrial types (metal processing, petroleum refining, synthetic textile manufacturing, plating, alcohol beverage manufacturing, inorganic compound manufacturing) being detected toxicity from industrial effluent in Ulsan city, and the interrelationship between total toxic unit (${\Sigma}TU$) and concentrations of Water Quality Conservation Act in Korea were investigated. The average toxic unit(TU) of effluents for 6 industrial types displayed the following ascending order: petroleum refining (0.2) < synthetic textile manufacturing (0.6) < alcohol beverage manufacturing (0.9) < metal processing (1.3) ${\leq}$ inorganic compound manufacturing (1.3) < plating (3.0). These values were less than effluent permission standard. Based on the result of substances causing ecotoxicity, the correlation analysis was not easy because most of heavy metals were not detected or were less than effluent permission standard. Toxicological assessment of industrial effluent was suitable for the evaluation of the mixture toxicity for pollutant. The whole effluent toxicity test using a variety of species was needed for the evaluation of industrial wastewater.

• Korean Journal of Soil Science and Fertilizer
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• v.11 no.2
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• pp.119-126
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• 1979

Rice seeds, suweon 264, were germinated under 5 levels of toxic heavy metals, Cd(0, 0.05, 0.5, 5, 20ppm), Cu(0, 0.05, 0.5, 5, 20, ppm), Cr(0, 0.5, 1, 5, 10ppm), Ni(0, 0.5, 1, 5, 10ppm), Co(0, 0.5, 1, 5, 10ppm), Zn(0, 0.5, 5, 20, 40, ppm), Pb(0, 0.5, 5, 20, 40ppm) and Mn(0, 1, 10, 25, 50, ppm) in culture solution, and then grown with supplying culture solution contained respective concentrations. Germination and growth response to the toxic heavy metals were studied. Results obtained are as follows : 1) The germination injury of rice seeds by excess concentration of toxic heave metal in culture solution occured in Cd and Cu; below 0.05 ppm, Ni; below 0.5 ppm, Mn; below 1.0 ppm, Co and Cr; 0.5-1.0 ppm, and 0.5-5 ppm, Zn and Pb. Thereby, in the order of degrees of the elements toxicity to germination, they were arranged as follows : Cd>Cu>Ni>Co>Cr>Mn>Zn$$\geq_-$$Pb. 2) Toxic heavy metal concentrations in culture solution, which result in decreasing dry weight due to the injury of excess concentration of treated elements, were Cd: below 0.05 ppm, Ni, Cr and Co; below 0.5 ppm, Cu and Zn; 0.5-5 ppm, Pb; 5-20 ppm and Mn; 10-25 ppm. The order was Ni>Cd>Cr>Co>Cu$$\geq_-$$Zn>Pb>Mn. 3) The critical contents of Cd, Ni, Pb, Cu, Zn, Mn, and Co in dry matter, Which result in decreasing dry weight, were considered to be 0.05-15.5, 1.50-25.0, 24.0-28.0, 26.5-62.5, 470-645.0, 231.0-500.0 and below 15.0 ppm, respectively. 4) The contents of Cr, Co, Cd, Pb, Ni, Cu and Zn in dry matter by 0.5 ppm treatment concentration of each heavy metals was trace, 15.0, 17.5, 24.0, 25.0, 84.5 and 470.0 ppm, respectively. Thereby, in the order of each element to uptaked by rice seedlings, they were arranged as follow; Zn>Cu>Ni>Pb>Cd>Co>Cr. 5) The hazardous concentrations of root activity by toxic heavy metals in culture solution were Cd; below 0.05, Cu; 0.05-0.5, Cr; below 0.5, Ni; 0.5-1.0, Co; 0.5-1.0, Zn; above 0.5, Pb; 0.5-5.0 and Mn; 1.0-10.0 ppm. The hazardous degree of root activity by toxic heave metals was in the order of Cd>Cu>Cr>Zn>Ni>Co>Pb>Mn.

• Korean Journal of Ecology and Environment
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• v.41 no.1
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• pp.66-72
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• 2008

Total metals, soluble metals, and bioavailable metals were monitored at the sediments of urban lakes located in Seoul, Korea during spring season 2006. The metals measured were zinc, arsenic, chromium, copper, nickel, and cadmium, which are known to be toxic to human health and ecosystems. The main sources of heavy metals in the lakes were urban runoff and atmospheric deposition associated with air pollution in urban areas. Extraction by using a weak electrolyte solution (0.1 M $Ca(NO_3)_2$) was used to predict bioavailability of the metals. Among the six heavy metals studied, copper was the most bioavailable, based the weak electrolyte extraction techniques. Since metal toxicity is related to metal bioavailability, the results were consistent with the high ecotoxicity of copper, compared to other heavy metals. Overall results suggest that there was no direct relationship between total and bioavailable metal concentration, although zinc, copper and cadmium show some relationships.

• Economic and Environmental Geology
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• v.29 no.1
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• pp.45-55
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• 1996

Although the Dongjin Au-Ag-Cu mine had been abandoned since about forty years ago, the results of this study on the dispersion patterns and contamination level of heavy metals in the hydrologic system flowing via the waste rump show that the environmental impacts from the mine wastes are still significant. The stream water in the vicinity of the waste rump is severely acidified (pH 3.8 to 4.4) and highly enriched in various dissolved heavy metals. The heavy metal contents of the stream water and stream sediments are systematically attenuated with increasing distance from the mine area. However, it is worth to note that continuous attenuation of heavy metal contents in both media were reenriched in downstream area more than 800 m apart from the mine because it can be acted as a secondary source of heavy metal pollution. The heavy metals, especially Cd, Cu and Zn of polluted downstream sediments mainly occur in Fe-Mn oxides and organic materials, which indicates that these elements are the main pollutants from the waste rump of the Dongjin mine. The heavy metal contents of crops, such as sesame, perilla, red Pepper and brown rice, collected from the polluted farm land in the downstream area are lower than those of land plants from stream sides, but significantly higher in Cd, Cr, Cu and Zn than those from the unpolluted farm land. Especially, almost all of the crops in polluted farm land have been severly contaminated by Cd (>0.4 ppm). On the other hand, the heavy metal contents of the crops collected from refreshed farm land by means of a soil addition method shows significantly lowered level comparing with those of polluted area, which indicates that a soil addition method was effective for the refreshment of polluted farm land by toxic metallic pollutants. Wormwoods from this area showed very high contents in a11 the heavy metals even in unpolluted area (Cd > 1 ppm, Cr > 1 ppm, Cu > 11 ppm, Pb> 4 ppm, Zn > 55 ppm), indicating that a special caution must be payed when one takes ingest them.

• Journal of the Korean Ceramic Society
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• v.43 no.2 s.285
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• pp.136-141
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• 2006

The stabilizing behavior of heavy metals in the silicate glass containing Electric Arc Furnace dust (EAF dust) were studied by the Toxic Characterization Leaching Procedure (TCLP) test, and the change of crystalline phase and glass network structure were investigated as a function of EAF dust content added. The glass containing EAF dust of $30\;wt\%$ an oxygen/network former ratio(R) of $2\~3$ allowing a fairly stable network structure thus showed much lower heavy metal leaching concentration than that for containing EAF dust above $50\;wt\%$ at TCLP test. For the glass containing EAF dust $50\~60\;wt\%$, however, the R was over 3, which weakened the glass network structure and increased the heavy metals leachate. Adding the EAF dust to a glass decreased the degree of Si-O-Si symmetry and increased the number of non-bridging oxygen, which decreased the chemical durability of glasses. When the dust content in a glass was over $70\;wt\%$, the Zn and Fe ions reacted to form the spinel crystal rather than to bind to network structure of glass and leaching concentration of those ions from the specimen decreased, so the spinel phase could be attributed to lowering a heavy metal leaching.

• Korean Journal of Food Science and Technology
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• v.26 no.6
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• pp.745-749
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• 1994

Animal experiments were conducted to confirm the suppressive effect of green tea on the intestinal absorption and tissue accumulation of toxic heavy metals in rats. When drinking water contaminated with 500 and 5000 times level of water quality standard for lead or cadmium was administrated to rats for 3 weeks, feed intake and body weight gain were not significantly differrent among all groups except for high cadmium group. In the relative weights of target organs, kidney and femur showed a significant difference by heavy metal administration and green tea did not influence on the weights. Green tea showed a suppressing effect on the accumulation of heavy metals in target organs, in which the reducing effect in femur was $25{\sim}45%$ for lead, and 42% for cadmium. As calcium content of femur decreased by heavy metal administration was increased in green tea group, it was concluded that heavy metal accumulation in femur was interrupted by tea beverage.

• Bulletin of the Korean Chemical Society
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• v.28 no.11
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• pp.1985-1992
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• 2007

Ordered mesoporous silica (MCM-41) materials with different textural properties were prepared using alkyl (dodecyl, cetyl, eicosane) trimethyl ammonium bromide (DTAB, CTAB, ETAB, respectively) as structure directing surfactants, functionalized with amine groups and used as adsorbent for the toxic metal ions, Cr (VI), As (V), Pb (II) and Hg (II). Amino functionalization of mesoporous MCM-41 was achieved by cocondensation of N-[3-(trimethoxysilyl)-propyl] aniline with tetraethyl orthosilicate. Adsorption isotherm and adsorption capacity of the amine functionalized materials for Cr (VI), As (V), Pb (II) and Hg (II) ions were followed by inductively coupled plasma mass spectrometry (ICP-MS). Results demonstrate that amine functionalized MCM-41 prepared with ETAB showed higher adsorption capacity for Cr (VI), As (V), Pb (II) and Hg (II) ions in comparison to MCM-41 prepared with CTAB and DTAB. The higher adsorption capacity for MCM-41(ETAB) was correlated with amine content in the material (determined by CHN analysis) and relative decrease in pore volume and pore diameter. X-ray diffraction (XRD) analysis, nitrogen adsorptiondesorption measurements and Fourier Transform infrared spectrometry (FTIR) were used to follow the changes in the textural parameters and surface properties of the mesoporous materials as a result of amine functionalization to correlate with the adsorption characteristics. The adsorption process was found to depend on the pH of the medium.

• Journal of Environmental Health Sciences
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• v.15 no.1
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• pp.33-49
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• 1989

Pollution in the rivers has received considerable attention in recent years, particullary with reference to the effect due to increasing concentration of heavy metals. The metals are toxic to the ecosystem as a whole and to man in particular, since he is at the end of a variety of food chains by virture of his varigated diet. In addition, numerous laboratory tests have established that certain metals, such as Cd, pose a threat to a wide variety of aquatic organisms at concentrations as low as a few $\mu$g/1. Before the biological effects of heavy metals in impacted ecosystems can be completely assessed, however it is necessary to provide data on the concentration of heavy metals in such systems. This study was performed to investigate the concentration level of heavy metals in water, fish and sediments from upstream ($S_1-S_4$) to downstream ($S_5-S_9$) of the Mankyung river. Samples of water, fish, and sediments were collected along the tributaries of the Mankyung from September to October in 1987 and analyzed for lead, cadmium, copper, and zinc by atomic absorption spectrophotometer. From the data presented in this study, we can infer that the concentrations of the heavy metals investigated both in water and sediments are similar to those found in literature for unpolluted regions. The results obtained from the analysis of the edible tissue of the C. auratus show low concentration levels of the four heavy metals investigated. We conclude that the area is still relatively unpolluted and recommended continuing the monitoring of heavy metal concentrations to improve our understanding of their cycle in the river environment.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1997.05a
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• pp.8-11
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• 1997

Current methods of evaluating soil contamination by heavy metals rely on analyzing samples for total contents of metals or quantities recovered in various chemical extracting solutions. Results from these approaches provide only an index for evaluation because these methodologies yield values not directly related to bioavailability of soil-borne metals. In addition, even though concentrations of metals may be less than those required to cause toxic effects to biota, they may cause substantial effects on soil chemical parameters that determine soil quality and sustainable productivity. The objective of this research was to characterize effects of Cu or Cd additions on soil solution chemistry of soil quality indices, such as pH, EC, nutrient cation distribution and quantity/intensity relations (buffer capacity). Metals were added at rates ranging from 0 to 400 mg/kg of soil. Soil solution was sequentially extracted from saturated pastes using vacuum. Concentrations of Cu or Cd remaining in soil solutions were very low as compared to those added to the soils, warranting that most of the added metals were recovered as nonavailable (strongly adsorbed) fractions. Adsorption of the added metals released cations into soil solution causing increases of soluble cation contents and thus ionic strength of soil solution. At metal additions of 200~400 mg/kg, EC of soil solution increased to as much as 2~4 dS/m; salinity levels considered high enough to cause detrimental effects on plant production. More divalent cations (Ca+Mg) than monovalent cations (K+Na) were exchanged by Cu or Cd adsorption. The loss of exchangeable nutrient cations decreased long-term nutrient supplying capacity or each soil. At 100 mg/kg or metal loading, the buffering capacity was decreased by 60%. pH of soil solution decreased linearly with increasing metal loading rates, with a decrement of up to 1.3 units at 400 mg Cu/kg addition. Influences of Cu on each of these soil quality parameters were consistently greater than those of Cd. These effects were of a detrimental nature and large enough in most cases to significantly impact soil productivity. It is clear that new protocols are needed for evaluating potential effects of heavy metal loading of soils.