• Economic and Environmental Geology
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• v.37 no.1
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• pp.73-86
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• 2004

In order to estimate the post-ingestion bioavailability of heavy metals and to assess the risk of adverse health effects on human exposure to toxic heavy metals, environmental geochemical surveys were undertaken around the Dogok Au-Ag-Cu and the Hwacheon Au-Ag-Pb-Zn mine sites. Human risk assessment of toxic heavy metals was performed with the results of the SBET(simple bioavailability extraction test) analysis for soil and chemical analytical data for crop plant and water. Arsenic and other heavy metals were highly elevated in tailings from the Dogok(218 As mg/kg, 90.2 Cd mg/kg, 3,053 Cu mg/kg, 9,473 Pb mg/kg, 14,500 Zn mg/kg) and the Hwacheon(72 As mg/kg, 12.4 Cd mg/kg. 578 Pb mg/kg, 1,304 Zn mg/kg) mines. These significant concentrations can impact on soils and waters around the tailing dumps. The quantities of As, Cd and Zn extracted from paddy soils in the Hwacheon mine using the SBET analysis were 55.4%, 20.8% and 26.4% bioavailability, respectively, and for farmland soils in the Dogok mine, 40.8%, 37.6% and 33.0% bioavailability, respectively. From the results of human risk assessment, HI(Hazard Index) value exceeded 1.0 for As in the Hwacheon mine and for Cd in the Dogok mine. Thus, toxic risks for As and Cd exist via exposure(ingestion) of contaminated soil, water and rice grain in these mine sites. The cancer risk for As by the consumption of rice and groundwater in the Hwacheon mine area was 8E-4 and 1E-4, respectively. This risk level exceeds the acceptable risk(1 in 100,000) for regulatory purpose. Therefore, regular ingestion of locally grown rice and ground-water by the local population can pose a potential health threat due to long-term arsenic exposure.

• Journal of Korean Society of Forest Science
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• v.81 no.2
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• pp.156-163
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• 1992

Pinus koraiensis (Pk), P. rigida (Pr) and P. rigida ${\times}$ P. taeda (Pr. t) seedlings in a bare-rooted nursery were artificially inoculated with Pisolithus tinctorius (Pt) and Thelephora terrestris (Tt) to test long term effects of ectomycorrhizal inoculation on host growth. Mycelial inocula of Pt and Tt were mass-cultured in vermiculite-peatmoss mixture and introduced into fumigated nursery soil before seed sowing. Bare-rooted, inoculated seedlings at one to four years of age were outplanted to the field with $P_2O_5$ content of 25 ppm in soil. At the time of outplanting, Pk seedlings(4 years old), Pr seedlings(2 years old), and Pr.t seedlings(1 year old) all infected by Pt were significantly taller by 28%. 26%, and 77%, respectively, than controlled seedlings infected by natural population of mycorrhizal fungi in the non-fumigated plot. Ten years after inoculation or six to nine years after outplanting, Pk seedlings inoculated with Pt were significantly taller by 9% Pr.t seedlings significantly taller by 18%, and Pr slightly Caller by 2%(not significant) than controlled seedlings, suggesting that the stimulatory effect of Pt on host growth gradually declined or became minimal after outplanting. Tt failed to stimulate host growth either in the nursery or in the field, and the survival rate of outplanted seedlings was not different among fungal treatments. Considerable loss of the infected root system during lifting the seedlings for outplanting would be the primary cause of the reduced effect of Pt in the field. Pt infected more than 90% of the fine roots in the fumigated nursery during the first growing season, but Pt assumed to fail to compete successfully with natural population of ectomycorrhizal fungi in the field. It is necessary to select other mycorrhizal fungi which adapt well in both nursery and field.

• Journal of Life Science
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• v.24 no.10
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• pp.1110-1117
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• 2014

Tidal flats are continuously contaminated by human activities. This study assessed the bioremediation efficiency of tidal flat soil using microcosm reactors and microorganisms originating from the tidal area. We screened 135 bacterial strains that produce extracellular enzymes from the tidal area located in the North port of Incheon bay. Two bacterial strains (Pseudoalteromonas sp. and IC35 Halothiobacillus neapolitanus IC_S22) were selected and used in the microcosm reactors, which were specially designed to functionally mimic the ecological conditions of the tidal flats. Pseudoalteromonas sp. IC35 was selected based on its relatively high activity of the enzymes amylase, cellulose, lipase, and protease. Halothiobacillus neapolitanus IC_S22 was selected for oxidation of sulfur. The M1 and M2 microcosm reactors were operated by continuous feeding of seawater under the same conditions, but M2 was first inoculated with Pseudoalteromonas sp. IC35 before the seawater feeding. The initial COD in both the M1 and M2 microcosm reactors was 320 mg/l. The final COD was 21 mg/l (M1) and 7 mg/l (M2). The M3 and M4 microcosm reactors were operated by continuous feeding of seawater under the same conditions, but M4 was first inoculated with H. neapolitanus IC_S22. The initial sulfate concentration in both the M3 and M4 microcosm reactors was 660 mg/l, and the maximum sulfate concentration was 1,360 mg/l (M3) and 1,600 mg/l (M4).

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.3
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• pp.200-205
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• 1991

To evaluate cold tolerance of rice cultivars on the basis of a relationship between cold tolerance in the field test and a biochemical character, transition-temperature of respiratory activity of mitochondria(TRM) which were isolated from different parts and at different growth stages and from etiolated rice seedling was investigated, and its relationship with degree of cold tolerance(DCT) in the field experiment was studied. The results obtained were summarized as follows. 1. The transition-temperature of respiratory activity of mitochodria (TRM) isolated from etiolated seedling ($25^{\circ}C$, two week-grown in the dark) of cold tolerant cultivars tended to be low, while that of cold susceptible cultivars to be high. 2. The correlation between TRM of etiolated seedling and the degree of cold tolerance(DCT) was $r=0.8935^{**}$ in 1988 and $r=0.8236^{**}$ in 1989. The correlation coefficient between TRM of 4-leaf seedling and DCT was $0.6239^{**}$ 3. TRM of young panicle was correlated with DCT except a few varieties. 4. TRM of seedling increased with growth as $12.5^{\circ}C$, $14.5^{\circ}C$, $15.5^{\circ}C$ and $16.5^{\circ}C$ at 1, 2, 3~4 and 5weeks respectively. 5. The transition temperature of mitochondrial respiratory activity was not significantly influenced by growth stages as $15.0{\sim}16.0^{\circ}C$ in Pungsanbyeo and $17.0{\sim}18.0^{\circ}C$ in Satbyelbyeo, while it was significantly different depending upon the degree of cold tolerance(tolerant, medium, susceptible).

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.3
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• pp.285-294
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• 1999

Changes of chemico-physical properties and mturitiy during pig manure composting were analysed using three kinds of bulking agents with rice hull(T1), rice hull and extruding hull mixture (T2, 1:1, v/v), and extruding hull(T3). During composting process, temperature of T1, T2 and T3 were maintained over $50^{\circ}C$ for 31, 21, and 35 days respectively. Organic matter content of each treatment was decreased from 82.2%, 82.0%, and 82.8% to 70.5%, 68.9% and 69.7% and pH increased to 8.85, 9.91, and 8.80, respectively. Total nitrogen content of all treatments gradually decreased, but C/N ratio, phosphorous, and potassium content did not, show any changes during composting process. Both germination rate and early growth were tested using radish seeds for composting maturity. From those results, it was concluded that all treatments were stabilized after 45th day and extruding hull(T3) added compost was superior to others. The test of suppressive effect showed that all treatment have no effect against Fusarium oxysporum, Alternaria altemata, Botrytis cinerea. Compost supplemented with rice hull showed an inhibitory effect after 30th days, while compost supplemented with rice hull and extruding hull(T2) had an inhibitory effect during all period against Rhizoctonia solani. But treatment with extruding hull(T3) added compost did not have any inhibitory effect against Rhizoctonia solani. Only 63th samples in T1 and T2 treatment showed inhibitory effect against Colletoerichum gloeosporioides. However, T3 did not. Suppressive effect of extracts from 67 kinds of composts was investigated in vitro against plant pathogens, such as Fusauum oxysporum. Alternaria alternata, Colletotrichum gloeospoioides, Rhizoctonia solani, and Botrytis cinerea. Thirty two of them showed inhibitory effect against more than one phytopathogen, nine against one pathogen, four against two, six against three, six against four, and seven against five.

• Journal of Preventive Medicine and Public Health
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• v.22 no.2 s.26
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• pp.290-301
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• 1989

This is preliminary report on anthrax epidemic occurred in an island with about 100 residents. Since 1982 there had been sudden deaths among all kinds of domestic animals including cattle, dogs, ducks, chicken and goat but only a few among cats in an isolated island about three hours distance away by ferry boat from Mokpo city. From 1986 through 1988 nine human deaths and four patients occurred, which made the government intervene for investigation on June 25 1988. The epidemiological investigation consisted of interview survey and medical examination, medical record analysis, laboratory work to isolate the pathogens under the direction of hypothesis derived from the study and further confirmation of the pathogens by international institute. The summarized results are as followings: 1. According to the interview survey there were many deaths among domestic animals usually in cold and dry season such as January through March and September through November; 36 heads of cattle leaving one head, more than 40 hogs(all), hundreds of chicken leaving few alive, goats that had taken home from mountain and two or three cats out of around 40 had sudden deaths from 1982 till 1985, when the residents stopped to purchase and take them into the island anymore. Also there were eleven persons who had experienced the similar syndrome complex to those of admitted and expired patients and four of them revealed typical chest X-ray findings; from one of these four patients(Rho) B. anthracis is isolated. 2. Medical record on patients who had been admitted, showed common characteristics of the disease course. On admission they had either gastrointestinal or upper respiratory infection symptoms which invariably progressed to septicemic nature with pulmonary interstitial infiltration and mediastinal widening/bulging, and then to deadly acute respiratory distress syndrome. At the end stage chest X-ray revealed multiple bullous emphysema. One of another characteristics was oral ulceration with bleeding occurred in about 50% of the patients. Laboratory test results in common were leukocytosis with left shift and abnormal liver and kidney functions, particularly at the later stage of the illness. 3. Epidemiological characteristics was striking in that both mortality and incidence rates were high: the mortality rate was 8.7% average, male being three times higher than females but there was no distictive clustering by age group. The incidence rate for both sexes was 28.2% and there was no sex difference although a tendency of higher incidence among older ages was noticed. The highest mortality and incidence were observed in Won village where the first death of animal occurred and with the highest frequency among three villages of the island. 4. Among twelve bacilli species isolated from various specimens, two strains, one from patient and the other from soil where the recently died cow is hurried, were confirmed as B. anthracis by Pasteur Institute and CDC of USA(strain from soil). CDC reported that the strain did not produce capsule in bicarbonate media but reacted with the bacteriophage and one of five sera taken from the patients. Mode of transmission as well as incubation period of the agent has not been established yet, which needs further investigation in relation to the antigenic structure of the variant when it is confirmed.

• Journal of Bio-Environment Control
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• v.11 no.3
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• pp.127-132
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• 2002

Enhanced supply of $Ca^{2＋}$ as well as NO$_3$$^{[-10]}$ is known to restrict the uptake of the Na$^{＋}$ and Cl$^{[-10]}$ ion and ameliorate growth under saline conditions. This test was conducted to investigate the ameliorating effects of Ca(NO$_3$)$_2$ or CaCl$_2$ on the growth and yield of NaCl-stressed tomato plants grown in plastic pot filled with soil. All treatments except for the control were supplied with 80 mM NaCl fur two weeks after transporting. The saline solutions with nutrient were supplemented with either 0, 10 or 20 mM Ca(NO$_3$)$_2$ and either 0, 10 or 20 mM CaCl$_2$ during harvesting time from two weeks after transporting. Ca(NO$_3$)$_2$ or CaCl$_2$ application enhanced the growth such as plant height, fresh weight, dry weight, fruit number, and fruit weight, and yield of NaCl-stressed tomato, and also their effects increased greater as concentration of supplemented Ca(NO$_3$)$_2$ or CaCl$_2$increased. Yield increased in 20 mM Ca(NO$_3$)$_2$ compared with the others except fur the control. Photosynthetic rate in Ca treatments was lower than that of the control, but higher than that of NaCl treatment. Leaf chlorophyll content was higher in Ca treatments compared with the others, especially in younger leaf, while that was not affected by concentration of supplemented Ca. Ca(NO$_3$)$_2$ or CaCl$_2$ supply increased the $K^{＋}$ and $C^{2＋}$ concentration of tomato plants, whereas the Na$^{＋}$ transport to the leaves was inhibited. There was a strong increase in the $K^{＋}$/Na$^{＋}$ ratio in plants treated Ca(NO$_3$)$_2$, or CaCl$_2$. Cl$^{[-10]}$ content of plants was decreased by supplemental Ca(NO$_3$)$_2$ but Cl$^{[-10]}$ was increased in plants with CaCl$_2$compared with Ca(NO$_3$)$_2$. N concentration in plants of tomato increased with enhanced Ca(NO$_3$)$_2$ or CaCl$_2$supply, In conclusion, our study confirms the potential of Ca(NO$_3$)$_2$ or CaCl$_2$to alleviate NaCl-induced growth reductions in tomato.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.3
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• pp.239-244
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• 1989

This work was for the elucidation of heterogeneity in a natural population of Rhizobium japonicum existing in Seoul National University's Experiment Field and of sensitivities of R. japonicum isolates for several antibiotics by using a method based on intrinsic antibiotic resistance (IAR). In addition, the suitability of IAR method for the recognition of R. japonicum strain was elucidated. Twenty seven isolates from various soybean cultivars cultivated at SNU's Experiment Field were tested to 4 antibiotics (streptomycin sulphate, kanamycin sulphate, ampicillin, oxytetracycline);There were 21 different IAR patterns among 27 isolates. It demonstrated diverse distribution of R. japonicum strains in SNU's Experiment Field. Their growth was inhibited at from a low concentration of about $1{\mu}g/ml$ to a high concentration of $400{\mu}g/ml$ for streptomycin sulphate, ampicillin, and oxytetracyclin. For kanamycin sulphate, on the contrary, all 27 isolates showed their growth inhibitances at below the concentration of $12.5{\mu}g/ml$. Two isolates identified as different strains from each other by the previous seroimmunological tests showed the same sensitivities for 4 antibiotics, and it seemed that IAR method was not perfect for the exact recognition of R. japonicum strain.

• Weed & Turfgrass Science
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• v.7 no.3
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• pp.181-190
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• 2018

This study was conducted to investigate the occurrence of an acetolactate synthase (ALS) inhibiting herbicide resistant weed on paddy at 289 sites by soil sampling in Chungcheongbuk-Do of Republic of Korea from February to April in 2017. The most dominant weed was Monochoria vaginalis and Echinochloa oryzicola on each city and county. ALS inhibiting herbicide resistant ratio and occurrence area were 80.6% and 28,272 ha, respectively, in Chungcheongbuk-Do which was 3 times than in 5 years ago. The herbicide resistant ratio, Okcheon-Gun was the highest at 93.8%, Chungju-Si, Boeun-Gun, Yeongdong-Gun, Jincheon-Gun and Geosan-Gun were over 80%, Cheongju-Si, Eumseong-Gun and Jeungpyeong-Gun were over 70%. The herbicide resistant area, Cheongju-Si had the largest at 6,957 ha, Chungju-Si was 4,277 ha, Jincheon-Gun and Boeun-Gun was 3,536 ha and 3,282 ha, respectively. By weed, ALS inhibiting herbicide resistant ratio and occurrence area, Monochoria vaginalis was 49%, 17,646 ha, Echinochloa oryzicola 44%, 15,617 ha, Schoenoplectiella juncoides 29%, 10,377 ha, respectively. In all cities and counties of Chungcheongbuk-Do, Monochoria vaginalis and Echinochloa oryzicola are more than 40% resistant to ALS inhibiting herbicides, intensive management is required. The use of sulfonylurea herbicides is increasing, most farmers use herbicides 10 days after transplanting, so management after transplanting is necessary and the occurrence of herbicide resistant weeds should be reduced by alternating herbicide application every year.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.2
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• pp.271-277
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• 2011

To improve the quality of water from water supply source and to establish the management plan of dead plants in flood control reservoir around Juam Lake, the effect of water quality by dead plant in column with passing time was investigated. In column test, the amounts of release by Carex dimorpholepis were $7,893-7,917mg\;m^{-2}\;month^{-1}$ COD, $2,711-2,816mg\;m^{-2}\;month^{-1}$ T-N and $342-547mg\;m^{-2}\;month^{-1}$ T-P. The amounts of release by Miscanthus sacchariflorus were $6,487-6,507mg\;m^{-2}$ COD, $1,813-1,868mg\;m^{-2}$ T-N and $226-405mg\;m^{-2}\;month^{-1}$ T-P in column. Therefore, the release of COD, T-N and T-P by Carex dimorpholepis were more than those by Miscanthus sacchariflorus Benth in column.