• Korean Journal of Soil Science and Fertilizer
• /
• v.27 no.3
• /
• pp.220-225
• /
• 1994

This study was conducted to investigate the influence of treatment of fly ash on heavy metal contents in the grain. Rice was cultivated on the two types of paddy field, clay loam and sandy loam soil, with 0, 4, 8, 12t/10a of anthracite fly ash and bituminous coal fly ash, respectively. And soybean was cultivated on the same types of upland field with those of 0, 3, 6, 9t/10a, respectively. Also. rice and soybean were cultivated the same types of paddy and upland field with those ashes of 0, 12ton/10a and 0, 9ton/10a, yearly for three years. At the harvest time, the heavy metal contents in rice and soybean were Investigated. The results were summarized as follows : 1. Amount of application. 1) The contents of Cd in brown rice increased in the clay loam soil. Cr and Ni increased sandy loam soil with the application of anthracite fly ash. 2) The contents of Zn in rice increased in the sandy loam soil with the application of bituminous coal fly ash. 3) The contents of Cu in soybean increased with the application of anthracite and bituminous coal fly ash, but Zn, Pb, Cr and Ni increased only with the bituminous. 2. Successive application. 1) The contents of Cd in brown rice increased in the clay and sandy loam soil, however Cu, Zn, Ni, Cr and Fe increased only in sandy loam soil with the anthracite fly ash. 2) The contents of Cr in soybean were increased in the clay and sandy loam soil, but Cu, Fe increased only sandy loam soil with anthracite fly ash. 3) The contents of Cd, Zn, and Cr in brown rice increased in the clay and sandy loam soil, but those of Cu, Mn increased only in the sandy loam soil with application of bituminous. 4) The contents of Cd, Pb, and Cr in soybean increased in the sandy loam soil with the application of bituminous coal fly ash.

• Economic and Environmental Geology
• /
• v.42 no.6
• /
• pp.575-589
• /
• 2009

Groundwater has been extracted for irrigation in Sacheon-Hadong area, which is close to the South Sea. We analyzed chemical components of groundwater to examine the effects of seawater intrusion and agricultural activities in the study area. Most groundwater samples displayed the Na/Cl concentration ratios similar to that of seawater (0.55) with an increasing tendency of electrical conductivity ($227-7,910\;{\mu}S/cm$) towards the coast. In addition, statistical interpretation of the cumulative frequency curves of Cl and $HCO_3$ showed that 30.1% of the groundwater samples were highly affected by seawater intrusion. Groundwaters in the study area mostly belonged to the Ca-Cl and Na-Cl type, demonstrating that they were highly influenced by seawater intrusion and cation exchange. The result of oxygen-hydrogen isotope analysis demonstrated slightly higher $\delta^{18}O$ ((-8.53)-(-6.13)‰) and ${\delta}D$ ((-58.7)-(-43.7)‰) comparing to mean oxygen-hydrogen isotope ratios in Korea. As a result of nitrogen isotope analysis, the $\delta^{15}N-NO_3$ values ((-0.5)-(19.1)‰) indicate two major sources of nitrate pollution (organic nitrogen in soil and animal and human wastes) and mixed source of the two. However, denitrification may partly contribute as a source of nitrogen. According to factor analysis, four factors were identified among which factor 1 with an eigenvalue of 6.21 reflected the influence of seawater intrusion. Cluster analysis indicated the classification of groundwater into fresh, saline, and mixed ones.

• Korean Journal of Soil Science and Fertilizer
• /
• v.25 no.3
• /
• pp.231-241
• /
• 1992

To study the relationships between major micrometeorological elements and their influences on evapotranspiration(ET) in the canopy of two rice cultivars, Daecheongbyo and Samgangbyo, synoptic meteorological factors, micrometeorological elements and ET from the canopy and biomass production were observed at various growth stages in the paddy field of Suwon Weather Forcast Office in 1989. ET from the rice community was highly correlated with the following factors in order of pan evaporation>air temperature>leaf temperature>solar radiation>sunshine duration>difference in vapor pressure depicit(VPD)>water temperature. ET observed showed higher correlation with the evaporation from small pan than that from Class A pan. Varietal difference would be noted in the relationships between ET in Samgangbyo canopy and the evaporations observed from the pans, with which closer a correlation was found in Samgangbyo than in Daecheongbyo. The ratio of canopy ET to the evaporation from Class A pan was maintained over 1.0 through the growth stages with the maximum of 1.9 at the late August. The evaporation observed from Class A pan was amounted to 71.9% of that from small pan. ET was better correlated with solar radiation than with net radiation which reached about 66% of solar radiation. Maximum temperature showed higher correlation with ET than mean air temperature, and also wind speed of 1m above ground revealed positive correlation. The relative humidity, however, had no correlation with the exception of ET in rainy days. A regression model developed to estimate ET as a function of meteorological elements being described with $R^2$ of 0.607 as : $ET=-5.3594+0.7005Pan\;A+0.1926T_{mean}+0.0878_{sol}+0.025RH$.

• Journal of Environmental Impact Assessment
• /
• v.26 no.6
• /
• pp.553-562
• /
• 2017

In these days, agricultural reservoirs are considered as a useful resource for recreational purposes, tour and cultural amenity for vicinity communities as well as irrigation water supply. However, many of the agricultural reservoirs are showing a eutrophic or hyper-eutrophic state and high level of organic contamination. In particular, about 44.7% of the aged agricultural reservoirs that constructed before 1945 exceed the water quality criteria for irrigational water use. In addition to external loading, internal nutrient loading from bottom sediment may play an important role in the nutrient budget of the aged reservoirs. The objectives of this study were to characterize variations of thermal structure of a shallow M reservoir (mean depth 1.7 m) and examine the potential of internal nutrient loading by continuous monitoring of vertical water temperature and dissolved oxygen (DO) concentration profiles in 2015 and 2016. The effect of internal loading on the total loading of the reservoir was evaluated by mass balance analysis. Results showed that a weak thermal stratification and a strong DO stratification were developed in the shallow M Reservoir. And, dynamic temporal variation in DO was observed at the bottom of the reservoir. Persistent hypoxic conditions (DO concentrations less than 2 mg/L) were established for 87 days and 98 days in 2015 and 2016, respectively, during the no-rainy summer periods. The DO concentrations intermittently increased during several events of atmospheric temperature drop and rainfall. According to the mass balance analysis, the amount of internal $PO_4-P$ loading from sediment to the overlying water were 37.9% and 39.7% of total loading during no-rainy season in 2015 and 2016, respectively on August when algae growth is enhanced with increasing water temperature. Consequently, supply of DO to the lower layer of the reservoir could be effective countermeasure to reduce nutrient release under the condition of persistent DO depletion in the bottom of the reservoir.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.40 no.2
• /
• pp.24-37
• /
• 2012

In this study, Community Garden of various national and international practices trends to an advanced research, the concept of community garden participated with a group operation out of initiative to produce safety food while securing space for the community, ensuring the area that has gone through a new form of active secure urban green space plan, urban renewal movement was defined as the mean. Furthermore, for the purpose of improving the poor welfare environment by attempting to experimentally make a community garden of a disabled welfare house rooftop and how to target its planning and construction process, partnership involvement, business processes have been investigated, such as cost sharing. The whole process including a budget for development of this case was conducted by the Busan Green Trust. Standard Chartered (SC) First Bank's 50% fund share by community chest, participation of volunteers, support of Busan City and Saba-gu, outside of that, sharing parts or trial to participate by diverse partnership of enterprise, public corporation and laboratory, these are the key in developing community garden's model. Established community garden places resulted food production to users of welfare center for the disabled, participating urban agricultural experience program, horticultural therapy, complex community chapter and cultural center. Furthermore, we could find the meaning of rooftop community garden in the point that it is a low cost garden by applying movable and unmovable planters. This study is profitable for improving urban environment, ensuring community chapter and urban green areas, regenerating a city to develop experimental community garden model by using a welfare house rooftop.

• Journal of Wetlands Research
• /
• v.25 no.4
• /
• pp.297-305
• /
• 2023

The recycled irrigation is a type of irrigation that uses downstream water to fulfill irrigation demand in the upstream agricultural areas; the used irrigation water returns back to the downstream. The recycled irrigation is advantageous for securing irrigation water for plant growth, but the returned water typically contains high levels of nutrients due to excess nutrients inputs during the agricultural activities, potentially deteriorating stream water quality. Therefore, quantitative assessment on the effect of the recycled irrigation on the stream water quality is required to establish strategies for effective irrigation water supply and water quality management. For this purpose, a watershed model is generally used; however no functions to simulate the effects of the recycled irrigation are provided in the existing watershed models. In this study, we used multi-reservoir model coupled with the Hydrological Simulation Program-Fortran (HSPF) to estimate the effect of the recycled irrigation on the stream water quality. The study area was the Gwangok stream watershed, a subwatershed of Gyeseong stream watershed in Changnyeong county, Gyeongsangnam-do. The HSPF model was built, calibrated, and used to produce time series data of flow and water quality, which were used as hypothetical observation data to calibrate the multi-reservoir model. The calibrated multi-reservoir model was used for simulating the recycled irrigation. In the multi-reservoir model, the Gwangok watershed consisted of two subsystems, irrigation and the Gwangok stream, and the reactions (plant uptake, adsorption, desorption, and decay) within each subsystem, and fluxes of water and materials between the subsystems, were modeled. Using the developed model, three scenarios with different combinations of the operating conditions of the recycled irrigation were evaluated for their effects on the stream water quality.

• Korean Journal of Soil Science and Fertilizer
• /
• v.44 no.5
• /
• pp.734-744
• /
• 2011

A soil stabilization method is an effective and practical remediation alternative for arsenic (As) and heavy metal contaminated farmland soils nearby abandoned metal mine in Korea. This method is a technique whereby amendments are incorporated and mixed with a contaminated soil. Toxic metal bind to the amendments, which reduce their mobility in soil, so the successful stabilization of multi-element contaminated soil depends on the combination of critical elements in the soil and the type of amendments. The objective of this study is to investigate the treatment effects and applicability of limestone (LS) and steel refining slag (SRS) as the amendment for farmland soil contaminated with As and heavy metals, and a lab-column test was conducted for achieving this purpose. The result showed that soil treated with LS and SRS maintained pH buffer capacity and, as a result, the heavy metal leaching concentration was quite low below the water quality standard compared to untreated soil which leachate exceeding the water quality standard was observed, however, the arsenic concentration rather increased with increasing mixture ratio of SRS. This was believed to be related to phosphorus (P) contained in SRS, and dominancy in the competitive adsorption relation between As and P binding strongly to iron might be different according to soil characteristic. We suggested that LS is a effective amendment for reducing heavy metals in soil, and SRS should be used after investigating its applicability based on the adsorption selectivity of arsenic and phosphorus in selected soil.

• Journal of Korea Water Resources Association
• /
• v.56 no.11
• /
• pp.775-784
• /
• 2023

With the increasing trend of extreme rainfall that exceeds the design frequency of man-made structures due to extreme weather, it is necessary to review the safety of agricultural reservoirs designed in the past. However, there are no local government-managed reservoirs (13,685) that can be discharged in an emergency, except for reservoirs over a certain size under the jurisdiction of the Korea Rural Affairs Corporation. In this case, it is important to quickly deploy a mobile siphon to the site for preliminary discharge, and this study evaluated the applicability of a mobile siphon with a diameter of 200 mm, a minimum water level difference of 6 m, 420 (m²/h), and 10,000 (m²/day), which can perform both preliminary and emergency discharge functions, to the Yugum Reservoir in Gyeongju City. The test bed, Yugum Reservoir, is a facility that was completed in 1945 and has been in use for about 78 years. According to the hydrological stability analysis, the lowest height of the current dam crest section is 27.15 (EL.m), which is 0.29m lower than the reviewed flood level of 27.44 (EL.m), indicating that there is a possibility of lunar flow through the embankment, and the headroom is insufficient by 1.72 m, so it was reviewed as not securing hydrological safety. The water level-volume curve was arbitrarily derived because it was difficult to clearly establish the water level-flow relationship curve of the reservoir since the water level-flow measurement was not carried out regularly, and based on the derived curve, the algorithm for operating small and medium-sized old reservoirs was developed to consider the pre-discharge time, the amount of spillway discharge, and to predict the reservoir lunar flow time according to the flood volume by frequency, thereby securing evacuation time in advance and reducing the risk of collapse. Based on one row of 200 mm diameter mobile siphons, the optimal pre-discharge time to secure evacuation time (about 1 hour) while maintaining 80% of the upper limit water level (about 30,000 m²) during a 30-year flood was analyzed to be 12 hours earlier. If the pre-discharge technology utilizing siphons for small and medium-sized old reservoirs and the algorithm for reservoir operation are implemented in advance in case of abnormal weather and the decision-making of managers is supported, it is possible to secure the safety of residents in the risk area of reservoir collapse, resolve the anxiety of residents through the establishment of a support system for evacuating residents, and reduce risk factors by providing risk avoidance measures in the event of a reservoir risk situation.

• Korean Journal of Soil Science and Fertilizer
• /
• v.26 no.2
• /
• pp.78-84
• /
• 1993

In order to know the effect of sludge from water treatment plants un agricultural environment, an experiment of water treatment sludge application for Altari radish (Raphanus sativus L.) was carried out. And the results were as follows ; 1. The pH of water treatment sludge was 7.2, which was higher than that of the experimental soil. The exchangeable Ca content in the sludge was very high being 29me/100g sludge. So when the sludge was applied to the soil, amending effect for soil acidity was supposed. 2. With the application of the water treatment sludge to the soil, soil pH and organic matter content were increased. With the increase of the level of sludge application, contents of crude fiber and Ca in Altari radish were increased, white those of P and Mg tended to decrease. 3. The length of the root and the amount of fresh yield of the whole plant of radish tended to increase with the increase of sludge application, and this tendency was more evident on the infertile soil. From the above results, it was concluded that the fresh yield of Altari radish increased up to 75ton/ha sludge application on the fertile soil, but the yield decreased when higher levels of sludge was applied. While on the infertile soil, the yield increased up to the application of 300ton/ha, and the heavier application level did not adversely affect the yield of Altari radish.

• Journal of Soil and Groundwater Environment
• /
• v.12 no.4
• /
• pp.35-53
• /
• 2007

Geochemical and isotope studies on the groundwater system of the Youngcheon area were carried out. Most groundwaters belong to Ca-$HCO_3$ and Ca-$SO_4$ types and some groundwaters belong to Na-$HCO_3$ type. Geochemical characteristics of these groundwaters were mainly affected by their basement rocks around the boreholes. High $SO_4$ content of groundwater is the result of reaction with sulfate or sulfide minerals in the host rock. Ca was originated from the carbonate minerals in the sedimentary rock. After the groundwater was saturated with calcite, the Na-$HCO_3$ type groundwaters were evolved by the reaction with plagioclase for a relatively long residence time. This explanation was supported by low tritium contents of Na-$HCO_3$ type groundwaters. ${\delt}a^{18}O$ and ${\delta}D$ data indicate that the groundwaters are of meteoric water origin and there was no difference between the various types of waters. Grondwaters from the boreholes BH-1, BH-9 and BH-12 showed the geochemical and isotopic characteristics of deep groundwater. Most borehole groundwaters except them did not show the systematic geochemical variations with sampling depth indicating that the shallow and deep groundwaters were mixed with each other throughout the study area. The results of water quality analysis indicate that the study area is highly contaminated by the introduction of agricultural sewage.