• The Korean Journal of Pharmacology
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• v.30 no.1
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• pp.87-100
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• 1994

It has been known for some time that dopamine-containing cells are existed in sympathetic ganglia, i.e., small, intensely fluorescent cells. However, its role and mechanism of action as a peripheral neurotransmitter are poorly understood so far. In the present study, an attempt was made to examine the effect of apomorphine, which is known to be a selective agonist of dopaminergic $D_2$. receptor on secretion of catecholamines (CA) from the isolated perfused rat adrenal gland. The perfusion of a low concentration of 10uM apomorphine into an adrenal vein for 20 min produced significant reduction in CA secretion induced by 5.32 mM ACh, 56 mM KCl, 100 uM DMPP and 100 uM McN-A-343. Increasing apomorphine concentration to 30 uM led to more markedly decreased CA secretion as compared to the case of 10 uM apomorphine and also did inhibit clearly CA release by $10^{-5}M$ Bay-K-8644. Furthermore, in adrenal glands preloaded with a higher dose of 100 uM apomorphine, CA releases evoked by ACh, excess $K^+$, DMPP and McN-A-343 were almost abolished by the drug. The perfusion of $3.3{\pm}10^{-5}M$ metoclopramide, which is well-known as a selective dopaminergic $D_2$ antagonist, produced significantly inhibitory effect of CA release by ACh, DMPP and McN-A-343 but did not affect that by excess $K^+$. However, preloading of 30uM apomorphine in the presence of metoclopramide did not modify the CA secretory effect of excess $K+$ and DMPP. These experimental results demonstrate that apomorphine causes dose-dependent inhibition of CA secretion by cholinergic receptor stimulation and also by membrane depolarization from the isolated perfused rat adrenal gland, suggesting that these effects appear to be exerted by inhibiting influx of extracellular calcium into the rat adrenal medullary chromaffin cells through activation of inhibitory dopaminergic receptors.

• Applied Biological Chemistry
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• v.44 no.2
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• pp.97-102
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• 2001

Cheju island depends on a hydrogeologically vulnerable aquifer system as its principle source of drinking water. Most of golf courses are located in the area which is important for the ground water recharge, and pesticides are applied to golf courses often at relatively high rates. Therefore, turf pesticides in golf course should be applied without adversely impacting ground water. In this experiment, downward movement of pesticides was monitored in model greens of golf course, where different adsorbents were layered in 3-cm thickness at 35-cm depth, and effect of the adsorption layer on the leaching loss of pesticides was investigated. Major leachings were observed in the periods of heavy rain and very limited leaching was observed under artificial irrigation. Fenitrothion and triadimefon, which have relatively short persistence and high adsorption coefficient, were found in the leachate in low concentrations only at the first rainfall event, around 20 days after the pesticide application. However, diniconazole, which has a relatively long half-life (97 days), was detected in the leachate during the whole period of experiment and concentration was much higher than those of the other pesticides. Maximum leachate concentrations were 1.9, 10.3, and 84.5 ${\mu}l^{-1}$ for fenitrothion, triadimefon, and diniconazole, respectively. Therefore, in golf course green which allows rapid water percolation and has extremely low adsorption capacity, persistence in soil could be more important factor in determination of leaching potential of pesticides. Total quantity of pesticides leached from the model green was <0.2% for fenitrothion and triadimefon and 1.8% for diniconazole. Adsorption layers significantly reduced pesticide leaching, and active carbon and Orpar were more effective than zeolite. In the model green having adsorption layer of active carbon or Orpar, leaching loss of pesticides was reduced below 0.01% of the initial application.

• Journal of the Korean Society for Marine Environment & Energy
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• v.14 no.1
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• pp.40-50
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• 2011

We study the characteristic and total flux of non-point pollutants such as total suspended solids (TSS), chemical oxygen demand (COD), dissolved nutrients, total phosphorus (TP) and total nitrogen (TN) in the storm water runoff from urban streams and sewer outlets of Banweol Industrial Complex around Shihwa Lake. The concentrations of non-point pollutants were generally increased with increasing of the duration and intensity of rainfall. Mean TSS concentration of Ansan stream was higher than that of sewer outlets but mean concentrations of COD, TP and TN were approximately 2~5 times higher of sewer outlet than of urban stream. TSS showed statistically positive relationships with COD and TP but it had negative correlation with dissolved nutrients. There was a significant correlation between total flux of non-point pollutants in the storm water runoff and total basin area of each sewer outlet, showing that the highest runoff flux was observed at 3rd sewer outlet which represents the largest basin area from Banweol industrial complex. Total runoff fluxes for TSS, COD, TP and TN in this study were 187,536 kg, 17,118 kg, 922 kg, 13,519 kg, respectively. Given the basin area of sewer outlet in Banweol industrial complex which corresponds only 3% from total catchment area around Shihwa Lake, enormous amount of non-point pollutants will be entered into Shihwa Lake without any treatment. It is necessary to manage and reduce of various non-point sources and pollutants because the runoff of nonpoint pollutants during storm events should be deteriorating the water quality of Shihwa Lake. Our results provides useful informations on the development of best managements practices (BMPs) for effective implementation of total pollution loads management system of Shihwa Lake.

• Korean Journal of Ecology and Environment
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• v.37 no.4 s.109
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• pp.436-447
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• 2004

Wetland plants have evolved specialized adaptations to survive in the low-oxygen conditions associated with prolonged flooding. The development of internal gas space by means of aerenchyma is crucial for wetland plants to transport $O_2$ from the atmosphere into the roots and rhizome. The formation of tissue with high porosity depends on the species and environmental condition, which can control the depth of root penetration and the duration of root tolerance in the flooded sediments. The oxygen in the internal gas space of plants can be delivered from the atmosphere to the root and rhizome by both passive molecular diffusion and convective throughflow. The release of $O_2$ from the roots supplies oxygen demand for root respiration, microbial respiration, and chemical oxidation processes and stimulates aerobic decomposition of organic matter. Another essential mechanism of wetland plants is downward water movement across the root zone induced by water uptake. Natural and constructed wetlands sediments have low hydraulic conductivity due to the relatively fine particle sizes in the litter layer and, therefore, negligible water movement. Under such condition, the water uptake by wetland plants creates a water potential difference in the rhizosphere which acts as a driving force to draw water and dissolved solutes into the sediments. A large number of anatomical, morphological and physiological studies have been conducted to investigate the specialized adaptations of wetland plants that enable them to tolerate water saturated environment and to support their biochemical activities. Despite this, there is little knowledge regarding how the combined effects of wetland plants influence the biogeochemistry of wetland sediments. A further investigation of how the Presence of plants and their growth cycle affects the biogeochemistry of sediments will be of particular importance to understand the role of wetland in the ecological environment.

• Korean Journal of Ecology and Environment
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• v.45 no.1
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• pp.72-81
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• 2012

We investigated the effects of acid mine drainage (AMD) from abandoned coal mines on benthic macroinvertebrate communities in the upper reaches of the Nakdong River from May to October in 2009. Qualitative and quantitative sampling (Surber sampler: $50{\times}50$ cm; mesh size, 0.2 mm) was conducted at 7 study sites and 3 control sites in the study area. We thus sampled 117 species belonging to 53 families, 15 orders, 6 classes, and 5 phyla; the Ephemeroptera, Plecoptera, and Trichoptera group (EPT-group) represented the majority of the benthic macroinvertebrate community (71 species; 64.5%). In the quantitative sampling, a total of 11,575 individuals belonging to 58 species of benthic maroinvertebrates were sampled from the study sites (Sites 1-7), whereas 2,844 individuals belonging to 79 species were sampled from the control sites (Sites A-C). Tolerant species such as oligochaetes, $Epeorus$ $pellucidus$, $Baetis$ $fuscatus$, Hydropsychidae species, and Chironomidae species were predominant in the study sites. The community indices for the study sites, such as MacNaughton's dominance index (DI) (mean${\pm}$SD, $0.52{\pm}0.21$; range, 0.33-0.85) and the Shannon diversity index ($H^{\prime}$) ($2.06{\pm}0.60$; 1.06-2.57), were different from those for the control sites (DI: $0.29{\pm}0.07$, 0.22-0.35; $H^{\prime}$: $3.13{\pm}0.14$; 3.03-3.30). In the study sites, shredders and scrapers were scarce, whereas gathering-collectors (mainly Chironomidae species) were relatively abundant, as were clingers and burrowers. The detrended correspondence analysis (DCA) and similarity analyses showed that benthic macroinvertebrate communities in the study sites were clearly separated from those of the control sites, with the greatest dissimilarity being noted at the uppermost study site (Site 1), which is located close to an abandoned coal mine. The Korean saprobic index (KSI) and the ecological score using benthic macroinvertebrates (ESB) showed that the uppermost study site (Site 1) was ${\alpha}$-mesosaprobic or heavily polluted, whereas other study sites were in a fair or relatively good condition.

• Korean Journal of Ecology and Environment
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• v.47 no.2
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• pp.116-126
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• 2014

To evaluate the relationship between dynamics of Cyanobacterial bloom and rainfalls, a monthly monitoring of water quality and phytoplankton from the three serial lakes (Lake Ui-am, Lake Chung-pyeong and Lake Pal-dang) in the North Han River System were examined 12 times from May 2012 to March 2013. A dense bloom of cyanobacterium Anabaena spp., was occurred over three lakes in the summer season of 2012. In Lake Ui-am, the Anabaena population appeared in June, showed a peak in July (43,850 cells $mL^{-1}$) and disappeared in November 2012. In Lake Chung-pyeong and Lake Pal-dang, Anabaena population commonly appeared in July, showed the peaks (31,648 cells $mL^{-1}$ and 7,136 cells $mL^{-1}$, respectively) in August, and entirely disappeared in September 2012. Over the three lakes, the phytoplankton community was commonly dominated by diatoms before Monsoon, cyanobacteria during Monsoon, and diatoms after Monsoon, respectively, indicating a Monsoon-dependent succession. A correlation analysis revealed that dynamics of Anabaena population was strongly related with rainfall (r=0.72, r=0.83, r=0.88, P<0.01 for three lakes), and partly with nutrients, inflow and outflow of lakes. Therefore, this study indicates that the outbreak and destruction of Anabaena bloom in North Han River System between 2012 and 2013 was impacted by rainfalls. However, a high density of cyanobacteria in Lake Ui-am remained after Monsoon, and thus, may paroduce bad-order and toxins from phytoplankton.

• Journal of Soil and Groundwater Environment
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• v.7 no.3
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• pp.115-132
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• 2002

To distinguish the anthropogenic inputs from the chemical weathering with water-rock interaction on the chemical compositons of groundwater in Kwangju city, four different water groups were established based on the landuse type, lithology and topology. The sample from greenbelt area belongs to Group Ⅰ, whereas those from green buffer zone, urban area and industrial area belong to Group II, Group Ⅲ and Group Ⅳ, respectively. The geology of this city mainly consists of biotite granite and granitic gneiss. The concentration of main cations is subject to the behavior of feldspars, micas and carbonate minerals. Cl$\^$-/ and NO$_3$$\^$-/ are supplied by anthropogenic inputs such as domestic sewage whose concentration of these anions is highest in the Group Ⅲ samples. With the Piper diagram, the groundwaters of Group Ⅲ are mainly plotted in CaSO$_4$-CaCl$_2$ type, whereas those of other groups are plotted in Ca(HCO$_3$)$_2$ type, The calculation for the activities of ions and saturation indices of some minerals shows that most of the minerals are undersaturated and plotted in the area of equlibrium with kaolinite. Three factors were extracted from the factor analysis for chemical data. Factor 1 controlled by HCO$_3$$\^$-/, Ca$\^$2-/, SO$_4$$\^$2-/, Mg$\^$2+/ and Na$\^$+/, explains the dissolution of carbonate minerals. mica and plagioclase. Factor 2, controlled by Cl$\^$-/ and NO$_3$$\^$-/, explains the influence of artificial pollution. Factor 3, controlled by Mn, Fe and Zn is subject to the industrial waste water, but the evidence is not clear. Factor 1 is dominant in the Group I and II, indicating that those samples are subjected to natural chemical weathering, The higher scores of factor 2 in the Group Ⅲ samples indicate the potential artificial pollution.

• Journal of the Korean Society of Groundwater Environment
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• v.4 no.2
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• pp.85-94
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• 1997

The study is aimed to find out the causes of rapidly increasing chloride (Cl$^{－}$) concentration of the Samyang 3rd pumping station originated from coastal springs of Cheju since January 1996. The study results show that it was caused by following complicated natural and anthropogenic effects. Due to severe draught in 1996 with total rainfall of only 41.7% of annual mean of the last 36 years (1991 to 1995), it creates firstly), significant decrease of the spring discharges as well decline of the groundwater level at the site . Sea water level was in general 4.4 cm to 12.4 cm higher than the groundwater level of the site during 2 to 3.8 hours at each high tide. Those higher potential head of sea water motivates the sea water intrusion into the fresh water lens through the permeable clinkers and fracture zones situated beneath the existing grouted zone which was installed to a maximum 10 m below the ground water surface, The repeated expansion and contraction of the fresh water lens occurred by periodic changes of the sea water level at high and low tide accelerates secondly the enlargement of the transition zone between the fresh and sea water at the site. The decrease of recharge amount by rainfall shortage creates thirdly the reverse flow at the interface of sea water and groundwater. The repeated groundwater extraction of 2790${\pm}$450 $m^3$d$^{－1}$ at the time of low tide, when the fresh water lens of the sire is under the contraction stare, makes additional drawdown of the ground water level and induces the upconing of salt water into the fresh water lens. The duration of spring discharge whose Cl concentration is less than 150 mg/1 at the low tide measured at the nearby springs was about two hours with discharge rate of 532 $m^3$d$^{－1}$ and after that Cl$^{－}$ concentration is increased up to more than 1900 mg/ι.eased up to more than 1900 mg/L.

• Korean Journal of Ecology and Environment
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• v.50 no.4
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• pp.459-469
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• 2017

Nitrogen (N) loading from domestic, agricultural and industrial sources can lead to excessive growth of macrophytes or phytoplankton in aquatic environment. Many studies have used stable isotope ratios to identify anthropogenic nitrogen in aquatic systems as a useful method for studying nitrogen cycle. In this study to evaluate the precision and accuracy of denitrification bacteria method (Pseudomonas chlororaphis ssp. Aureofaciens ($ATCC^{(R)}$ 13985)), three reference (IAEA-NO-3 (Potassium nitrate $KNO_3$), USGS34 (Potassium nitrate $KNO_3$), USGS35 (Sodium nitrate $KNO_3$)) were analyzed 5 times repeatedly. Measured the ${\delta}^{15}N-NO_3$ and ${\delta}^{18}O-NO_3$ values of IAEA-NO-3, USGS 34 and USGS35 were ${\delta}^{15}N:4.7{\pm}0.1$‰ ${\delta}^{18}O:25.6{\pm}0.5$‰, ${\delta}^{15}N:-1.8{\pm}0.1$‰ ${\delta}^{18}O:-27.8{\pm}0.4$‰, and ${\delta}^{15}N:2.7{\pm}0.2$‰ ${\delta}^{18}O:57.5{\pm}0.7$‰, respectively, which are within recommended values of analytical uncertainties. Also, we investigated isotope values of potential nitrogen source (soil, synthetic fertilizer and organic-animal manures) and temporal patterns of ${\delta}^{15}N-NO_3$ and ${\delta}^{18}O-NO_3$ values in river samples during from May to December. ${\delta}^{15}N-NO_3$ and ${\delta}^{18}O-NO_3$ values are enriched in December suggesting that organic-animal manures should be one of the main N sources in those areas. The current study clarifies the reliability of denitrification bacteria method and the usefulness of stable isotopic techniques to trace the anthropogenic nitrogen source in freshwater ecosystem.

• Journal of Wetlands Research
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• v.16 no.4
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• pp.379-388
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• 2014

A sewage was treated using a serially combined vertical(VFCW) and horizontal flow double media (sand and zeolite for VFCW and sand and waste oyster-shell for HFCW) reed constructed wetland(HFCW) with intermittent feeding (see Fig. 1). The sewage was fed into the reed constructed wetland for 10 minutes every 6 hours at the hydraulic load of $314L/m^2{\cdot}day$. The summarized results were as follows: pH values in the effluent depended very heavily on oyster-shell height filled in the HFCW. They were maintained at less than pH 6.24 when the height of the oyster-shell layer was 200 mm. Influent DO(oxygen demand) values(average 0.19 mg/L) were increased in the VFCW(average 7.65 mg/L) and decreased again in the HFCW(average 6.49 mg/L). They were higher in the winter than in the summer. The OTR(oxygen transfer rate) was $57.15g\;O_2/m^2{\cdot}day$ in the VFCW and $5.65g\;O_2/m^2{\cdot}day$ in the HFCW. The removal efficiency of $NH_4{^+}$-N was 80.17%(6.01 $NH_4{^+}$-N mg/L in the effluent). It was lower than that in the case where only zeolite was filled in the reed constructed wetland. But it was expected that treated sewage effluent using a double media reed constructed wetland with 300 mm zeolite layer could stably meet the Korean treated sewage effluent standard(20 mg T-N/L). Average removal efficiencies were SS 88.09%, BOD 88.12%, $COD_{Cr}$ 83.11%, $COD_{Mn}$ 85.58%, T-N 57.21%, $NH_4{^+}$-N 80.17%, T-P 86.73%. Nearly, The concentration of $NO_3{^-}$-N in the effluent of the VFCW was decreased in that of the HFCW. More than half of T-N in the effluent was $NO_3{^-}$-N(7.92 mg/L) but the concentration of $NO_2{^-}$-N in the effluent was average 0.90 mg/L. The removal efficiencies of T-P were 93.24%, 86.30% and 55.44% at the height of the oyster-shell-filled constructed wetland of 800 mm, 500 mm and 200 mm, respectively and therefore, they were proportional to oyster-shell height filled in the HFCW.