• Korean Journal of Weed Science
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• v.1 no.1
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• pp.5-14
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• 1981

Weed is one of the problems in the crop land as well as in uncultivated land, raising the farm management costs. Therefore, the weed control is essential for effective agricultural management. The cost for weed control in Korea occupies on the average 27.6% of the total labor cost required. Agricultural policies since 1960 were transferring from yield increase due to land productivities to increase of income due to labor productivities. Therefore, the weed control by hand is also changed to weed control by chemicals. The weed control by chemicals has also brought about some side-effects and needs better, improved weed control methods. The present weed control situation and related problems were studied to present new approaches for agricultural development in the future. There were 458 species of weeds in 82 families which were growing in the crop land. The weeds to control, however, are 12 in paddy field and 9 in upland. So far weeds in paddy field are well under control, while weeds in upland are poorly controlled due to change in chemical efficiency and chemical damage in the upland. The administration, research and extension work for the efficient use of agricultural chemicals have been done by various institutions, such as Office of Rural Development, Office of Forestry, and chemical companies. The courses for agricultural chemicals were offered in the agricultural colleges. However, the efficiency of chemicals could not be maximized due to the poor relationships among related institutes. The newly established Agricultural Chemical Research Center at the Office of Rural Development and the Korean Weed Science Association are expected to contribute toward improving weed control in Korea. The Korean agriculture in the future will eventually be mechanized and the varieties resistant to high nitrogen application and to high plant density will be required for high yields. The rice will be transplanted earlier and the whole growing period will be extended. The application of organic matter will be increased for increasing soil fertility, and the use of agricultural chemicals will be continued. Under such a condition, the studies on the weed occurrence and its integrated control measures will be needed. Also weed controls in the newly exclaimed land, crop varieties, horticultural varieties, forage crops, and forests are also needed to study. Basic and practical researches for the weed control to improve the labor productivity will be also needed. In order to meet the all requirements for efficient weed control, weed control systems including all the academics, research and extension workers, administratives, farmers and companies should be established. Also securing researchers and education of personnels are pre-required and research funds for the chemical studies should be provided efficiently and timely.

• Journal of Soil and Groundwater Environment
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• v.11 no.2
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• pp.1-12
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• 2006

A model describing the distributions of surfactants and HOCs (hydrophobic organic chemicals) in surfactant/HOC/activated carbon systems for surfactant reuse in soil washing process was developed. The model simulation was conducted for the evaluation of the effect of concentrations of surfactant, HOC, or activated carbons. Phenanthrene as a target HOC, Triton X-100 as surfactant and three granular activated carbons with different particle sizes (4-12, 12-20, and 20-40 mesh) were used in the model simulation. The distributions of HOC were significantly affected by surfactant dosages, especially at around the CMC(s). The results of selectivities for phenanthrene were much larger than 1 at various concentrations of surfactants, phenanthrene and activated carbons, which mean that the selective adsorption of phenanthrene by activated carbons is a proper separation method from surfactant solution. The model can be applied for the design of the surfactant reuse process using activated carbons without extra experimental efforts.

• Korean Journal of Environmental Agriculture
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• v.16 no.1
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• pp.72-79
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• 1997

Adsorption, leaching, and retention of the Flupyrazofos(KH-502), a new active ingredient for insecticide, in the soils under laborarory and field conditions were investigated to provide the basic data for the safety use and to assess a secondary impact of this insecticide on soil and water environments. A significant power function relation was found between the adsorbed KH-502 and time, representing that 45% of the added KH-502 was adsorbed within 30 min. but a quasiequilibrium was reached after 6 to 12 hr with a slower adsorption. Adsorption phenomena followed th first-order kinetics and time required for 50% adsorption was 5.8 hr. The equilibrium adsorption isotherm was explained by the Freundlich equation and was classified as S-type. The amounts of KH-502 leached through the soil column (C) as compared to initial conc. ($C_0$) were very low and these relative concentrations ($C/C_0$) were 0.073 and 0.017 in SL and CL soils, respectively. The residual conc. of KH-502 in the surface soil was comparatively low and decreased with time. Half-lives of KH-502 in the surface soil was comparatively low and decreased with time. Half-lives of KH-502 under the field conditions were estimated to be 20 and 18 days in the SL and CL soils, respectively. The KH-502 cone, transported to the subsurface soils was extremely low. These results demonstrate that KH-502 has a low pollution risk potential to the surrounding environment as far as it is used following the recommended guideline.

• Korean Journal of Environmental Agriculture
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• v.6 no.1
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• pp.7-16
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• 1987

A study was undertaken to investigate the absorption, translocation and metabolism of carbofuran in rice paddies. Ring-3-$^{14}C-carbofuran$ applied onto the paddy soil surface was rapidly absorbed and translocated into rice plants. Within 2 days after treatment, it was observed that carbofuran reached shoot tips and accumulated. More than 15% of total radioactivity was recovered in rice plant from 3 to 20 days after treatment. In organic soluble fraction of rice plant extract, 3-hydroxycarbofuran was the major metabolite recording 43% and 4% of total organic soluble radioactivity in shoot and root at 20 days respectively. 3-Ketocarbofuran and phenolic metabolites including carbofuran phenol, 3-hydroxycarbofuran phenol and 3-ketocarbofuran phenol were also detected in the organic soluble fractions. Some glycosidic conjugates of carbofuran metabolites were found in water soluble fraction of rice plant extract and 3-hydroxycarbofuran was the most abundant aglycone. Radioactivity in paddy soil was rapidly decreased until 3 days after treatment and then maintained almost constant level. A significant portion (42∼56 %) of the total radioactivity remained in soil as nonextractable residue from 5 to 20 days after treatment. The nonextractable radioactivity was mainly located in soil organic matter distributing in humin, fulvic acid and humic acid fractions with the decreasing order. Evolution of $^{14}CO_2$ from ring cleavage of $3-^{14}C-carbofuran$ was negligible recording only 1.8% of total radioactivity during 20 days after treatment.

• Journal of Environmental Health Sciences
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• v.47 no.2
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• pp.155-165
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• 2021

Objectives: Acute exposure to high concentrations of chemicals can occur when a chemical accident takes place. As such exposure can cause ongoing environmental pollution, such as in the soil and groundwater, there is a need for a tool that can assess health effects in the long term. The purpose of this study was assessing the health risks of residents living near a chemical accident site due to long-term exposure while considering the temporal concentration changes of the toxic chemicals leaked during the accident until their extinction in the environment using a multimedia environmental dynamics model. Methods: A health risk assessment was conducted on three cases of formaldehyde chemical accidents. In this study, health risk assessment was performed using a multimedia environmental dynamics model that considers the behavior of the atmosphere, soil, and water. In addition, the extinction period of formaldehyde in the environment was regarded as extinction in the environment when the concentration in the air and soil fell below the background concentration prior to the accident. The subjects of health risk assessment were classified into four groups according to age: 0-9 years old, 10-18 years old, 19-64 years old, and over 65 years old. Carcinogenic risk assessment by respiratory exposure and non-carcinogenic risk assessment by soil intake were conducted as well. Results: In the assessment of carcinogenic risk due to respiratory exposure, the excess carcinogenic risk did not exceed 1.0×10-6 in all three chemical accidents, so there was no health effect due to the formaldehyde chemical accident. As a result of the evaluation of non-carcinogenic risk due to soil intake, none of the three chemical accidents had a risk index of 1, so there was no health effect. For all three chemical accidents, the excess cancer risk and hazard index were the highest in the age group 0-9. Next, 10-18 years old, 65 years old or older, and 19-64 years old showed the highest risk. Conclusion: This study considers environmental changes after a chemical accident occurs and until the substance disappears from the environment. It also conducts a health risk assessment by reflecting the characteristics of the long-term persistence and concentration change over time. It is thought that it is of significance as a health risk assessment study reflecting the exposure characteristics of the accident substance for an actual chemical accident.

• Environmental Analysis Health and Toxicology
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• v.17 no.4
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• pp.347-355
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• 2002

As concerns on the effects of soil contamination on human health have grown, more efforts have been made to quantify the effects. One of such efforts is the development of risk assessment methodology. The fundamental objectives of this approach is to investigate the alternative options that reduce the risk of hazardous chemicals results from environmental pollution, which will eventually lead to an accomplishment of removement of identified toxicants in polluted environment. The U.S. EPA Risk Assessment guidance for the superfund (RAGS) provides a methods for assessing the health risk of contaminated soils and determining the preliminary remediation goals (PRGs). Using this approach, we assessed the health risk and preliminary remediation goals of petroleum contaminated site in Kyounggi province.

• Journal of Korea Soil Environment Society
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• v.3 no.2
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• pp.127-145
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• 1998

Unlike water or air quality standards that have been established by legislation using potential human health impact as the primary criterion, soil quality depends on the soils primary function and its relevant environmental factors, which is much more site- and soil specific. A properly characterized soil quality assessment system should serve as an indicator of the soil capacity to produce safe and nutritious food, to enhance human and animal health, and to overcome degrative processes. For our proposed example, a high quality soil with regard to maintaining an adequate soil productivity as a food production resources must accommodate soil and water properties, food chain, sustainability and utilization, environment, and profitability, that (i) facilitate water transfer and absorption, (ii) sustain plant growth, (iii) resist physical degradation of soil, (iv) produce a safe food resources, (v) cost-effective agricultural management. Possible soil quality indicators are identified at several levels within the framework for each of these functions. Each indicator is assigned a priority or weight that reflects its relative importance using a multi-objective approach based on principles of systems to be considered. To do this, individual scoring system is differentiated by the several levels from low to very high category or point scoring ranging from 0 to 10, And then weights are multiplied and products are summed to provide an overall soil quality rating based on several physical and chemical indicators. Tlne framework and procedure in developing the soil quality assessment are determined by using information collected from an alternative and conventional farm practices in the regions. The use of an expanded framework for assessing effects of other processes, management practices, or policy issues on soil quality is also considered. To develop one possible form for a soil quality index, we should permit coupling the soil characteristics with assessment system based on soil properties and incoming and resident chemicals. The purpose of this paper is to discuss approaches to defining and assessing soil quality and to suggest the factors to be considered.

• Journal of Korean Society on Water Environment
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• v.29 no.4
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• pp.489-496
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• 2013

Ground water underlying soil is vulnerable to pollution by organic chemicals through their percolation through the soil system. This study was conducted to provide information on the seepage behavior of organic chemical contaminants in clay, silty and sandy soils. Chloroform, 1,1,1-trichloroethane and trichloroethylene are readily transported through the soil; their percolated mass were 4.6-19.2 percent of the total mass applied. Tetrachloroethylene, 1,2-dichlorobenzene and 1,3-dichlorobenzene were retarded by soils due to sorption. Between 0.6 and 4.8 percent of the material applied to the surface percolated within the experimental period. Carbon tetrachloride was attenuated considerably by passage through soils. Only 0.1-0.4 percent of the mass reached the groundwater. Significant degradation of bromoform was observed. Apparent breakdown of intermediates of the brominated compounds were detected. Transformations of the brominated compounds appear to be the result of both biological and chemical processes. The effect of soil type on the mobility of organic chemical contaminants was considerable. The organic contaminants moved faster in sandy soil than in either clay or silty soils.

• Korean Journal of Environmental Agriculture
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• v.18 no.3
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• pp.250-258
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• 1999

The purpose of this study was to compare heavy metal concentrations in uncontaminated soil with those in soil influenced by industrial activities, and to investigate the relationship between change of heavy metal content and the kind of industry at the Iksan 2nd Industrial Complex that has started since 1995. Soils sampled in 0-3 cm and 3-6 cm soil depth, respectively were analized for content of Cd, Cu, Ni, Pb and Zn. The content of Cd in soil layer of 0 to 3 cm was 0.07-4.37ppm range, average concentration was 0.516ppm and 3-6 cm was 0.07-8.52ppm range, average concentration was 0.380ppm. Area of the chemicals, dyes and metal products manufacturing were higher than the other manufacturing area in Industrial Complex. The content of Cu in soil layer of 0 to 3 cm was 0.61-42.62ppm range, average concentration was 11.087ppm and 3-6 cm was 0.16-35.45ppm range, average concentration was 7.578ppm. Area of the metal products manufacturing were higher than the other manufacturing area in Industrial Complex. The content of Ni in soil layer of 0 to 3 cm was 0.19-15.93ppm range, average concentration was 5.525ppm and 3-6 cm was 0.39-15.59ppm range, average concentration was 5.310ppm. Area of the metal and chemical products manufacturing were higher than the other manufacturing area in Industrial Complex. The content of Pb in soil layer of 0 to 3 cm was 3.10-55.75ppm range, average concentration was 23.543ppm and 3-6 cm was 3.35-46.55ppm range, average concentration was 19.198ppm. Area of the chemicals and metal products manufacturing were higher than the other manufacturing area in Industrial Complex. The content of Zn in soil layer of 0 to 3 cm was 26.50-943.00ppm range, average concentration was 158.329ppm and 3-6 cm was 35.45-882.45ppm range, average concentration was 127.914ppm. Area of the chemicals and metal products manufacturing were higher than the other manufacturing area in Industrial Complex. As the result, this study was to compare Cd, Cu, Ni, Pb, Zn average concentration in uncontaminated soil of world with those in soil, that Cu, Ni were uncontaminated concentration level, Cd was somewhat higher compare with the concentration level of world, Pb and Zn were very higher. Soil contaminated degree of Iksan 2nd Industrial Complex was known a difference by type of industrial activities(chemical, dyes and metal of products)

• Journal of Soil and Groundwater Environment
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• v.18 no.1
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• pp.16-25
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• 2013

The Korean groundwater law regulates 20 groundwater contamination parameters, including 14 specific harmful substances. Expanding the number of groundwater quality standards are needed to cope with recent groundwater quality deterioration due to the use of various chemicals. Chemical ranking and scoring system (CRS) is a scientific tool to sort priority chemicals by considering exposure and toxicity potentials. In this study, we developed a CRS for scoring and ranking of possible groundwater pollutants and screened priority substances to be later considered in the Korean standard expansion. Chemical Ranking Of groundWater pollutaNts (CROWN) incorporates important parameters consisting of exposure potential, human and water ecotoxicity, interests, and certainty. Furthermore, CROWN additionally evaluated existence of other media standards to consider impacts by contamination of other media. The 197 substances that were common to 9 countries were selected first. CROWN evaluated and ranked each chemical, and finally suggested priority substances. Suggested priority substances were classified into two groups according to the groundwater use purposes: drinking and non-drinking. The priority substances were further classified into $1^{st}$ and $2^{nd}$ group priorities. The $1^{st}$ group consists of 75 substances, including the all the Korean groundwater standard parameters. CROWN will be used in selecting groundwater pollutants for possible inclusion in the Korean standard expansion.