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211.
Hyo-Taek Chon Kyoung-Woong Kim Ju-Yong Kim 《Environmental geochemistry and health》1995,17(3):139-146
To investigate the dispersion patterns and the characteristics of heavy metal contamination due to urbanisation and industrialisation, soils and dusts collected from the Seoul area were analysed for Cu, Pb, Zn and Cd. The metal concentrations in most soils and dusts are higher than the world averages. The pollution index (( Metal concentrations in soils/Permissible level for metal)÷(Number of metals)) of soils and dusts is > 1 in most of the Seoul area, a result that concurs with the industrialisation and urbanisation index of the Seoul area. The soils are contaminated with Cu, Zn, Cd and particularly Pb. This suggests that the contamination of the soils in the Seoul area are mainly caused by vehicular emissions. The pollution index of soil is the highest in the Kuro area where Cu and Zn contamination in soils are due to the indigenous brass and bronze factories. From the discriminant analysis, the Seoul area may be partitioned into control, traffic and industrialized areas by the metal concentrations in the order of Zn > Cu > Pb. 相似文献
212.
A Biosurfactant-Enhanced Soil Flushing for the Removal of Phenanthrene and Diesel in Sand 总被引:2,自引:0,他引:2
In order to examine the potential of biosurfactants in soil remediation, and to investigate the effects of several operating conditions, such as flow rate, biosurfactant concentration and surfactant type, biosurfactant-enhanced soil flushing was conducted. In the biosurfactant-enhanced soil flushing process, the removal efficiency increased as the flow rate decreased. Rhamnolipid showed no effect on the removal efficiency of phenanthrene and diesel from sand in the concentration range 0.3-0.5%. However, rhamnolipid showed higher efficiencies for the removal of phenanthrene and diesel from sand than Tween 80. Based on total recovery, following an equivalent pore volume flush, it was more difficult to remove diesel than phenanthrene. In order to obtain the specific removal efficiency, more pore volumes of surfactant solution may be required in field applications. Under optimum conditions, the biosurfactant removed as much as 70% of the phenanthrene and 60% of the diesel in the sand. These results indicate that the use of biosurfactants in the flushing process is favorable, not only with respect to the environment, but also on removal efficiencies. 相似文献
213.
Male capacity as related to sperm production,pregnancy initiation,and sperm competition in deer mice (Peromyscus maniculatus) 总被引:1,自引:0,他引:1
Summary Limitations on male capacity may be important to the evolution of mating strategies and behavior. Sperm counts in successive ejaculates of deer mice (Peromyscus maniculatus) decreased progressively through six ejaculations and remained depressed the following day. Males were as effective in inseminating females in cycling estrus with their second two ejaculates as with their first two and as effective in inseminating postpartum females with their fifth as with their first. In sperm competition situations males competed with rested males as effectively with their fourth, fifth, and sixth ejaculates as with their first. Thus, although sperm counts decrease in successive ejaculates, males suffer no apparent functional deficiency as long as they continue ejaculating. It is not clear whether or not deer mice are honest salesmen but they appear to be honest ejaculators and usually are honest intromitters. 相似文献
214.
Kijune Sung Jaisoo Kim C.L. Munster M. Yavuz Corapcioglu Soyoung Park M.C. Drew Y.Y. Chang 《Ecological modelling》2006,190(3-4):277-286
Microorganisms make an important contribution to the degradation of contaminants in bioremediation as well as in phytoremediation. An accurate estimation of microbial concentrations in the soil would be valuable in predicting contaminant dissipation during various bioremediation processes. A simple modeling approach to quantify the microbial biomass in the rhizosphere was developed in this study. Experiments were conducted using field column lysimeters planted with Eastern gamagrass. The microbial biomass concentrations from the rhizosphere soil, bulk soil, and unplanted soil were monitored for six months using an incubation–fumigation method. The proposed model was applied to the field microbial biomass data and good correlation between simulated and experimental data was achieved. The results indicate that plants increase microbial concentrations in the soil by providing root exudates as growth substrates for microorganisms. Since plant roots are initially small and do not produce large quantities of exudates when first seeded, the addition of exogenous substrates may be needed to increase initial microbial concentrations at the start of phytoremediation projects. 相似文献
215.
Enrichment of potentially toxic elements in areas underlain by black shales and slates in Korea 总被引:6,自引:0,他引:6
Jin-Soo Lee Hyo-Taek Chon Jong-Shin Kim Kyoung-Woong Kim Hi-Soo Moon 《Environmental geochemistry and health》1998,20(3):135-147
The Okchon black shale in Korea provides an important example of natural geological materials containing toxic elements; the Chung-Joo, Duk-Pyung, Geum-Kwan, I-Won and Chu-Bu areas are underlain by these black shales and slates of the Guryongsan Formation. This formation is part of the Okchon Group which is found in the central part of Korea. Geochemical surveys were undertaken in these five study areas in the Okchon Zone in order to examine the level of enrichment and dispersion patterns of potentially toxic elements in rocks and soils. After appropriate preparation, samples were analysed by instrumental neutron activation analysis and inductively coupled plasma atomic emission spectrometry for a range of elements. Arsenic, Cu, Mo, V, U and Zn are highly enriched in the Okchon black shales and their mean concentrations are significantly higher than those in black slates. These elements are closely associated with one another from a geochemical viewpoint and may be enriched simultaneously. Mean concentrations of As, Mo and U in soils derived from black shales occurring in the Duk-Pyung and Chu-Bu areas are higher than the permissible level suggested by Kloke (1979), and the enrichment index decreases in the order of Duk- Pyung > Chu-Bu > Chung-Joo > Geum-Kwan = I-Won areas. Uranium-bearing minerals such as uraninite and brannerite have been identified in black shales from the Chung-Joo area by electron probe micro-analysis. Uraninite grains are closely associated with monazite and pyrite with a grain size ranging from 2m to 10m whereas brannerite grains occur as a euhedral form 50m in diameter. 相似文献
216.
Uranium Accumulation of Crop Plants Enhanced by Citric Acid 总被引:6,自引:0,他引:6
Citric acid was applied to soil to enhance U accumulation in four crop plants. While the highest enhanced U accumulation of
aboveground tissues (a.c. 2000 mg kg−1 dry weight) occurred in the leaves of Indian mustard (Brassica juncea), the highest enhanced U accumulation of roots (a.c. 3500 mg kg−1 dry weight) occurred in canola (Brassica napus var. napus). Uranium translocation among tissues of test plants is in the relation of roots>shoots ≅ leaves. The flowers of sunflower
(Helianthus annuus) contained similar or higher U concentrations than those found in shoots, but concentrations in seeds are close to zero.
In conclusion, Indian mustard is recommended as a potential species for phytoextraction for U-contaminated soil due to its
high U accumulation of aboveground biomass (a.c. 2200 μg per plant). There is no evidence that two types of soils cause a
significant difference of the enhanced U accumulation (p<0.05). Results, however, indicate that additional citric acid may result in downward U migration that may contaminate groundwater.
Speciation of U that is taken up by plants is also discussed in the end. 相似文献
217.
In order to investigate the optimum conditions for the application of soil flushing of arsenic, a batch test was carried out using EDTA at various concentration and pH levels. Based on the optimum condition derived from the batch test, a column test was conducted to examine the feasibility of the soil-flushing technology under field-equivalent conditions. In this column test, a low flushing solution flow rate showed a significantly higher As removal efficiency (71.6%) than a high flow rate (56.3%). TCLP (toxicity characteristic leaching procedure) and a seed germination test were carried out to monitor the toxicity both during and after the treatment. The finally treated tailings were shown to be significantly remediated, having a reduced toxicity by both the TCLP and seed germination tests. 相似文献
218.
Cysts of the planktonic oligotrich ciliate Strombidium conicum were isolated from sediment samples, collected monthly in Onagawa Bay on the northeastern Pacific coast of Japan, and incubated
under laboratory conditions of 20 °C in light. The excystment ability changed seasonally in a regular manner, which was demonstrated
by alternation of three characteristic seasonal patterns of the cumulative excystment curve, i.e., rapid, delayed and transitional
patterns. While the transitional excystment pattern was characteristic during the period from spring to midsummer, the rapid
pattern occurred during late summer to early winter. The pattern changed again to transitional in midwinter and finally returned
to the delayed pattern in late winter or early spring. We suggest that mud temperature was the most determinative factor of
this seasonality in excystment ability. Such synchronization of annual excystment helps this species to proliferate rapidly
and maintain the vegetative part of the population in the upper water column for a longer period of time where it is subjected
to the dispersion process due to water movement.
Received: 17 September 1996 / Accepted: 18 November 1996 相似文献
219.
We present an in-depth decompositionanalysis using physical indicators oftrends in Carbon dioxide (CO2) emissions in the cementindustry in Brazil, China, South Korea andthe United States. Physical indicatorsallow a detailed analysis of intra-sectoraltrends, in contrast to the often usedmonetary indicators. We assess thecontribution of different factors affectingCO2 emissions in the cement industry,including change in product mix, efficiencyof power generation, changes in fuel mixand changes in energy efficiency. Thedecomposition results show that in allexamined countries, increased productionwas the main contributor to the increase intotal CO2 emissions. Energy-efficiencyimprovement is the most important factorthat led to the reduction of emissionintensities for all countries except Korea.For Korea, structural change in the productmix is the most important factorcontributing to the emission intensityreduction. 相似文献
220.
Cadmium accumulation and elimination in tissues of juvenile olive flounder, Paralichthys olivaceus after sub-chronic cadmium exposure 总被引:1,自引:0,他引:1
Experiments were carried out to investigate the accumulation and elimination of cadmium (Cd) in tissues (gill, intestine, kidney, liver and muscle) of juvenile olive flounder, Paralichthys olivaceus, exposed to sub-chronic concentrations (0, 10, 50, 100 microg l(-1)) of Cd. Cd exposure resulted in an increased Cd accumulation in tissues of flounder with exposure periods and concentration, and Cd accumulation in gill and liver increased linearly with the exposure time. At 20 days of Cd exposure, the order of Cd accumulation in organs was gill > intestine > liver > kidney > muscle and after 30 days of exposure, those were intestine > gill > liver > kidney > muscle. An inverse relationship was observed between the accumulation factor (AF) and the exposure level, but AF showed an increase with exposure time. During the depuration periods, Cd concentration in the gill, intestine and liver decreased immediately following the end of the exposure periods. No significant difference was found Cd in concentration in the kidney and muscle during depuration periods. The order of Cd elimination rate in organs were decreased intestine > liver > gill during depuration periods. 相似文献