• Resources Recycling
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• v.15 no.4 s.72
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• pp.3-12
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• 2006

The feasibility for the employment of manganese nodule as an adsorbent for $SO_{2}$ gas has been investigated. The specific surface area of manganese nodule particle, which used in the experiments, was ca. $221.5m^{2}/g$ and the content of sulfur in manganese nodule was observed to significantly increase after $SO_{2}$ was adsorbed on it. The EPMA for the distilled water-washed and methanol-washed manganese nodule particle after $SO_{2}$ adsorption showed that its sulfur content was slightly decreased to 14.7% and 13.1% respectively, from 15.4% before washing. The XRD analysis of manganese nodule showed that todorokite and birnessite, which are manganese oxides, and quartz and anorthite were the major mineralogical components and weak $MnSO_{4}$ peaks were detected after $SO_{2}$ was adsorbed on manganese nodule. For an comparative investigation, limestone was also tested as an adsorbent for $SO_{2}$, however, no peaks for $CaSO_{4}$ were found by XRD analysis after the adsorption of $SO_{2}$. As the size of adsorbent increased, time for breakthrough was decreased and the adsorbed amount of $SO_{2}$ was also diminished. The $SO_{2}$ adsorption was hindered when its flow rate became high and the adsorption capacity of manganese nodule was observed to be superior to that of limestone. In addition, the mixture of manganese nodule and limestone did not show an increase in the adsorption of $SO_{2}$. Finally, as the temperature was raised, the adsorbed amount of adsorbate on manganese nodule was found to be decreased.

• Journal of Wetlands Research
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• v.24 no.2
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• pp.83-92
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• 2022

The amount of the plastic waste has been increasing according to global demand for plastic. Microplastics are the most hazardous among all plastic pollutants due to their toxicity and unknown physicochemical properties. This study investigates the optimal methodology that can be applied to sewage samples for detecting microplastics before discussing reducing microplastics in MWTPs. In this study, the effect of different pretreatment methods while detecting microplastic analysis of MWTP influent samples was investigated; the samples were collected from the J sewage treatment plant. There are many pretreatment methods but two of them are widely used: Fenton digestion and hydrogen peroxide oxidation. Although there are many pretreatment methods that can be applied to investigate microplastics, the most widely used methods for sewage treatment plant samples are Fenton digestion and H₂O₂ oxidation. For each pretreatment method, there were factors that could cause an error in the measurement. To overcome this, in the case of the Fenton digestion pretreatment, it is recommended to proceed with the analysis by filtration instead of the density separation method. In the case of the H₂O₂ oxidation method, the process of washing with distilled water after the reaction is recommended. As a result of the analysis, the concentration of microplastics was measured to be 2.75ea/L for the sample using the H₂O₂ oxidation method and 3.2ea/L for the sample using the Fenton oxidation method, and most of them were present in the form of fibers. In addition, it is difficult to guarantee the reliability of measurement results from quantitative analysis performed via microscope with eyes. A calibration curve was created for prove the reliability. A total of three calibration curves were drawn, and as a result of analysis of the calibration curves, all R² values were more than 0.9. This ensures high reliability for quantitative analysis. The qualitative analysis could determine the series of microplastics flowing into the MWTP, but could not confirm the chemical composition of each microplastic. This study can be used to confirm the chemical composition of microplastics introduced into MWTP in the future research.

• Journal of Food Hygiene and Safety
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• v.37 no.4
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• pp.260-270
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• 2022

In this study, we tested for pesticide residues in 114 samples representing 20 different types of fruit circulating in Gyeonggido. A total of 341 pesticides were identified via a multi-residue method using GC-NPD, GC-ECD, GC-MSMS, and LC-MSMS. In whole fruit, pesticides were detected in 48 cases, with a concentration range of 0.0025-0.1663 mg/kg. In the peels, pesticides were detected in 85 cases, with a concentration range of 0.0026-4.7185 mg/kg and a higher average concentration than was found in whole fruit. In the pulp, pesticides were detected in 8 cases, with a concentration range of 0.0021-0.0993 mg/kg. In most of the peels, pesticides were detected below MRL. In the kiwi peel, deltamethrin (with an MRL of 0.05 mg/kg) was detected at 0.1020 mg/kg. Since MRLs are applied to whole fruit, these levels are not unsuitable for ingestion. However, washing is recommended before ingestion to promote healthier and safer inclusion of the peel in the diet. Continuous monitoring of the peel and pulp is indicated.

• Journal of Preventive Medicine and Public Health
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• v.31 no.1 s.60
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• pp.112-126
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• 1998

To investigate the effectiveness of the interventions in working environment and personal hygiene for the occupational exposure to the lead, the blood zinc protoporphyrin (ZPP) concentrations of 131 workers (100 exposed subjects and 31 controls) of a newly established battery factory were analyzed. They were measured in every 3 months up to 18 months. Ai. lead concentration (Pb-A) of the workplaces was also checked for 3 times in 6 months interval from August 1987. Environmental intervention included the local exhaust ventilation and vacuum cleaning of the floor. Intervention of the personal hygiene included the daily change of clothes, compulsory shower after work and hand washing before meal, prohibition of cigarette smoking and food consumption at the work site and wearing mask. Mean blood ZPP concentration of the controls was $16.45{\pm}4.83{\mu}g/d\ell$ at the preemployment examination and slightly increased to $17.77{\pm}5.59{\mu}g/d\ell$ after 6 months. Mean blood ZPP concentration of the exposed subjects who were employed before the factory was in operation (Group A) was $17.36{\pm}5.20{\mu}g/d\ell$ on employment and it was increased to $23.00{\pm}13.06{\mu}g/d\ell$ after 3 months. The blood ZPP concentration was increased to $27.25{\pm}6.40{\mu}g/d\ell$ on 6 months (p<0.01) after the employment which was 1 month after the initiation of intervention program. It did not increase thereafter and ranged between $25.48{\mu}g/d\ell$ and $26.61{\mu}g/d\ell$ in the subsequent 4 results. Mean blood ZPP concentration of the exposed subjects who were employed after the factory had been in operation but before the intervention program was initiated (Group B) was $14.34{\pm}6.10{\mu}g/d\ell$ on employment and it was increased to $28.97{\pm}7.14{\mu}g/d\ell$ (p<0.01) in 3 months later(1 month after the intervention). The values of subsequent 4 tests were maintained between $26.96{\mu}g/d\ell$and $27.96{\mu}g/d\ell$. Mean blood ZPP concentration of the exposed subjects who were employed after intervention program had been started (Group C) was$21.34{\pm}5.25{\mu}g/d\ell$ on employment and it was gradually increased to $23.37{\pm}3.86{\mu}g/d\ell$ (p<0.01) after 3 months, $23.93{\pm}3.64{\mu}g/d\ell$ after 6 months, $25.50{\pm}3.01{\mu}g/d\ell$ after 9 months, and $25.50{\pm}3.10{\mu}g/d\ell$ after 12 months. Workplaces were classified into 4 parts according to Pb-A. The Pb-A of part I, the highest areas, were $0.365mg/m^3$, and after the intervention the levels were decreased to $0.216mg/m^3$ and$0.208mg/m^3$ in follow-up test. The Pb-A of part II which was resulted in lowe. value than part I was decreased from $0.232mg/m^3$ to $0.148mg/m^3$, and $0.120mg/m^3$ after the intervention. The Pb-A of part III was tested after the intervention and resulted in $0.124mg/m^3$ in January 1988 and $0.181mg/m^3$ in August 1988. The Pb-A of part IV was also tested after the intervention and resulted in $0.110mg/m^3$ in August 1988. There was no consistent relationship between Pb-A and blood ZPP concentration. The blood ZPP concentration of the group A and B workers in the part of the highest Pb-A were lower than those of the workers in the parts of lower Pb-A. The blood ZPP concentration of the workers in the part of the lowest Pb-A increased more rapidly. The blood ZPP concentration of the group C workers was the highest in part III. These findings suggest that the intervention in personal hygiene is more effective than environmental intervention, and it should be carried out from the first day of employment and to both the exposed subjects, blue color workers and the controls, white color workers.

• Journal of the Korean Society of School Health
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• v.5 no.2
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• pp.74-90
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• 1992

The purpose of this study is to know the effects on school lunch service programme of elementary school in rural area, by using the group consisting of the sixth year students in the schools that have provided them with the lunch for six years or longer(male student:312, & female student:324), while using the comparing group consisting of the sixth year students in the schools that have not provided them with the school lunch under their similar living condition(male student: 306 & female student:322). In addition, this study was carried out by examining all continued information about their height and weight shown in the developmetal record for six years from the 1st to 6th year, and by checking their eating habits on the basis of questionnaires. The result of this study is summarized as follows. As the result of comparing the values of their height and weight grown for 6 years, it was shown that the height of the male group provided with school lunch is 27.8 cm while the male group without lunch is 27.1 cm. And the female group provided with school lunch indicated the growing value of 29.9 cm while the group without lunch did 28.4 cm. Then, it appeared that both male and female groups provided with school lunch show higher growing values of 0.7 cm, respectively, and 1.5 cm than these groups without lunch. Also, the weight of the group without lunch was 14.8 kg. Moreover, the weight of the female group provided with school lunch was 16.9 kg while the group without lunch was 17.2 kg. Then, it was shown that the male group provided with school lunch indicates heavier growing value of 0.9 kg than the group without lunch while the female group without lunch does heavier value of 0.3 kg than the group provided with school lunch. It's figure showed that although this distribution according to percentile in the 1st year is similar to the standard regular curve it is positioned in the upper group(more thatn 70%) divided centering around 50% in the 6th year, of which distribution of children provided with school lunch was higher. When comparing the values of physical status in the 6th year, it was also shown that male children with school lunch are better than these children without lunch in jumping, throwing, chinning and lifting while female children are better than these children without lunch only in jumping, which were a significant difference. In addition, the group provided with lunch showed distribution of the higher physical grade. The result of analysis on their breakfast indicated that the children with every morning breakfast account for 67.6% of the group provided with school lunch while the group without lunch for 57.8%. Regarding the reason that they do not have the breakfast, the group with school lunch answered "Because of habits"(50.7%) while the group without lunch did "Because they have no appetite"(58.9%). When comparing the degree of preference for hot or salty food, it was apparent that these children with school lunch generally tend to prefer less hot or sailty food. With respect to the frequency and place of their eating between meals, it was shown that about 70.0% of both groups has the eating between meals, more than one time a day. Then, the group with school lunch had the eating between meals at home(45.2%) while the group without lunch did it in the process of returning to home(48.4%). Regarding the degree of their preference for a certain food, it was shown that more children of the group with school lunch do not prefer a food to others. Also, their eating attitude indicated that such children as eating the food with chat after completely swallowing food and with T.V watching are larger and lower among the group with school lunch, which showed a remarkable defference from the group without lunch. With respect to their sanitary habits such as hand washing and toothing, these children who always wash their hand before eating, accounted for 84.4 % of the group provided with school lunch while the group without lunch did for 63.6%, of which the female group with school lunch indicated a remarkable difference. The actual condition of their nutrition education showed that these children who answered "Received this education" accounted for 78.0% of the group with school lunch while the group without lunch accounted for 57.5%.

• Journal of Food Hygiene and Safety
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• v.34 no.1
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• pp.40-51
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• 2019

Ginseng has a unique production system that is different from those used for other crops. It is subject to the Ginseng Industry Act., requires a long-term cultivation period of 4-6 years, involves complicated cultivation characteristics whereby ginseng is not produced in a single location, and many ginseng farmers engage in mixed-farming. Therefore, to bring the production of Ginseng in line with GAP standards, it is necessary to better understand the on-site practices of Ginseng farmers according to established control points, and to provide a proper action plan for improving efficiency. Among ginseng farmers in Korea who applied for GAP certification, 77.6% obtained it, which is lower than the 94.1% of farmers who obtained certification for other products. 13.7% of the applicants were judged to be unsuitable during document review due to their use of unregistered pesticides and soil heavy metals. Another 8.7% of applicants failed to obtain certification due to inadequate management results. This is a considerably higher rate of failure than the 5.3% incompatibility of document inspection and 0.6% incompatibility of on-site inspection, which suggests that it is relatively more difficult to obtain GAP certification for ginseng farming than for other crops. Ginseng farmers were given an average of 2.65 points out of 10 essential control points and a total 72 control points, which was slightly lower than the 2.81 points obtained for other crops. In particular, ginseng farmers were given an average of 1.96 points in the evaluation of compliance with the safe use standards for pesticides, which was much lower than the average of 2.95 points for other crops. Therefore, it is necessary to train ginseng farmers to comply with the safe use of pesticides. In the other essential control points, the ginseng farmers were rated at an average of 2.33 points, lower than the 2.58 points given for other crops. Several other areas of compliance in which the ginseng farmers also rated low in comparison to other crops were found. These inclued record keeping over 1 year, record of pesticide use, pesticide storages, posts harvest storage management, hand washing before and after work, hygiene related to work clothing, training of workers safety and hygiene, and written plan of hazard management. Also, among the total 72 control points, there are 12 control points (10 required, 2 recommended) that do not apply to ginseng. Therefore, it is considered inappropriate to conduct an effective evaluation of the ginseng production process based on the existing certification standards. In conclusion, differentiated certification standards are needed to expand GAP certification for ginseng farmers, and it is also necessary to develop programs that can be implemented in a more systematic and field-oriented manner to provide the farmers with proper GAP management education.