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

• The Korean Journal of Malacology
• /
• v.29 no.1
• /
• pp.51-63
• /
• 2013

To assess the effect of environmental factors on the sustainability of cultured production shellfish, we investigated the habitat characteristics of tidal flat (Namhae-po in Taean). We measured the physiochemical parameters (temperature, salanity, pH, dissolved oxygen and nutrients) and the geochemical characteristics (chemical oxygen demand, ignition loss, C/N ratio and C/S ratio). Surface sediments were collected from several site of tidal flat to examine the geochemical characteristics of both the benthic environment and heavy metal pollution. The grain size for research area of tidal flat were similar at the ratio of silt and clay in comparison with the other site of it. The C/N ratio was more than 5.0, reflecting the range arising from the mix of marine organism and organic matter. The C/S ratio (about 2.8) showed that survey area had anoxic or sub-anoxic bottom conditions. The enrichment factor (Ef) and index of accumulation rate (Igeo) of the metals showed that those research areas can be classified as heavily polluted, heavily to moderately polluted, or more or less unpolluted, respectively. Adult surf clam (Mactra veneriformis) density was highest at St. 2 (middle part of the Namhae-po), on the other hand, surf clam spat density was highest at St. 3 (lower part of the Namhae-po). Heavy rain, terrigenous suspended clay with fresh water from neighboring agricultural land, and severe high air temperature during summer could be thought as detrimental causes of spat and adult mortality in Namhae-po tidal flat. We suggested that the growth of shellfish in the tidal flat was effected by the various environmental conditions, so an improvement in the cultured method was needed.

• Korean Journal of Environment and Ecology
• /
• v.29 no.3
• /
• pp.333-343
• /
• 2015

This research aims at identifying the goshawk's possible and replaceable breeding ground by using the MaxEnt prediction model which has so far been insufficiently used in Korea, and providing evidence to expand possible protection areas for the goshawk's breeding for the future. The field research identified 10 goshawk's nests, and 23 appearance points confirmed during the 3rd round of environmental research were used for analysis. 4 geomorphic, 3 environmental, 7 distance, and 9 weather factors were used as model variables. The final environmental variables were selected through non-parametric verification between appearance and non-appearance coordinates identified by random sampling. The final predictive model (MaxEnt) was structured using 10 factors related to breeding ground and 7 factors related to appearance area selected by statistics verification. According to the results of the study, the factor that affected breeding point structure model the most was temperature seasonality, followed by distance from mixforest, density-class on the forest map and relief energy. The factor that affected appearance point structure model the most was temperature seasonality, followed by distance from rivers and ponds, distance from agricultural land and gradient. The nature of the goshawk's breeding environment and habit to breed inside forests were reflected in this modeling that targets breeding points. The northern central area which is about $189.5 km^2$(2.55 %) is expected to be suitable breeding ground. Large cities such as Cheongju and Chungju are located in the southern part of Chungcheongbuk-do whereas the northern part of Chungcheongbuk-do has evenly distributed forests and farmlands, which helps goshawks have a scope of influence and food source to breed. Appearance point modeling predicted an area of $3,071 km^2$(41.38 %) showing a wider ranging habitat than that of the breeding point modeling due to some limitations such as limited moving observation and non-consideration of seasonal changes. When targeting the breeding points, a specific predictive area can be deduced but it is difficult to check the points of nests and it is impossible to reflect the goshawk's behavioral area. On the other hand, when targeting appearance points, a wider ranging area can be covered but it is less accurate compared to predictive breeding point since simple movements and constant use status are not reflected. However, with these results, the goshawk's habitat can be predicted with reasonable accuracy. In particular, it is necessary to apply precise predictive breeding area data based on habitat modeling results when enforcing an environmental evaluation or establishing a development plan.

• Journal of agricultural medicine and community health
• /
• v.36 no.1
• /
• pp.36-46
• /
• 2011

Objectives: To investigate the experience and competence of physicians providing emergency medical services at public health sub-centers on remote Korean islands. Methods: This study enrolled 79 doctors who work at public health sub-centers on remote Korean islands. Data were collected in December 2009 via self-administered e-mail questionnaires. The response rate was 44.3%. Results: Emergent situations occurred at most (58.68%) of the public health sub-centers that were surveyed in December 2009. An average of 1.92 cases required treatment by public health physicians. Only 20.25% of the physicians were specialists in emergency medicine, while the remainder were general practitioners (GPs) without clinical experience as emergency doctors. We also found that the physicians we surveyed had insufficient knowledge of emergency medical care. At some health centers only one doctor was available, and there was no medical team in holiday, although most of the physicians indicated that the ideal number of doctors per center was two or three. In cases of emergency, patients were often sent to the mainland by ship without receiving first-aid treatment. The public health sub-centers lacked the necessary medical equipment to save lives in emergencies and lacked escort systems for emergency patients. Conclusions: The Korean government should address the importance of providing emergency care in remote areas. Health administrators should provide suitable manpower, medical equipment, guidelines for emergency medicine, and education for public health physicians on remote islands.

• Journal of agricultural medicine and community health
• /
• v.30 no.1
• /
• pp.75-88
• /
• 2005

Objectives: This survey was intended to provide basic data which can be available as a baseline in the set up of dietary guidelines for assuring community-based self-support of the rural elderly, through investigation of the relationship of the various dietary consumptions with their ADL and IADL. Methods: The study subjects, 439 rural residents(male: 196, female:243) aged over 65 in Kumsan Kun and Chongyang Kun, Chungchongnamdo Province were interviewed, in June of 2004, about their sociodemographic characteristics, daily life styles, the variety of dietary consumption, ADL and IADL with the following major findings: Results: In terms of the scores' distribution to show variety of food consumption among all subjects, 68.3% got 1~3 points, 23.2% 4~6 points, and 8.4% 7~10 points with a decreasing proportion of subjects in higher points. In terms of their functional status, normal-range groups showed 93.2% of ADL and 72.9% of IADL whereas, impaired ADL group 6.8% of ADL and 27.1% of IADL, respectively. Concerning the relation of ADL and IADL with the variety of their consumed food, the greater scores for food variety was associated with the significantly higher proportion of normal ADL group and the lower proportion of impaired ADL group. Multiple logistic regression analysis with ADL and IADL as dependent variables, and food variety scores as explanatory variables, the relative risk of impaired-ADL group was 0.84 in the food variety group of 4~6 points, 0.63 in 7~10 points with no statistical significance. The relative risk of impaired- IADL group was 0.52(p<0.01) in the food variety group of 4~6 points, 0.41(p<0.05) in 7~10 points with statistical significance. Conclusions: These study results suggest that the lower dietary variety, the lower functional capacity of daily living, and the variety of dietary is associated with the functional capacity of daily living in rural elderly.

• Journal of agricultural medicine and community health
• /
• v.25 no.1
• /
• pp.99-112
• /
• 2000

This survey was conducted to assess the utilization of health center including health sub-center and community health post and the health service demand of residents in a urban and rural unified community. Officials in Up·Myun·Dong offices visited randomly sampled 4,027 households(4.6% of total households in unified City) which included 3,337 households in urban area(4.9% of total households) and 690 households in rural area(3.7% of total households) and interviewed with heads or housewives of the households in September, 1995. There were significant differences in health-related demographic characteristics including age-sex distribution, educational level, period of residence in the community and medical insurance status of the interviewees between urban and rural areas. Of the respondents, 64.8% in urban area and 55.6% in rural replied that they had utilized the health center in the past. The most common purpose for visiting the health center was to get vaccination in urban area and to get outpatient care in rural area. The top priority health center activity that needs to be reinforced was communicable disease control and over 90% of the respondents preferred to have mobile clinic and home health care service in were also highly demanded. Eighty-six percent of the urban respondents replied that a health sub-center must be established in urban area. In the rural area, 90.3% of the respondents replied that they wanted to maintain the health sub-center and 88.3% wanted to maintain the community health post. Along with the improvement of facilities and equipments of the health center by Rural Health Service Improvement Project, new health service programs must be developed to meet the demand of the community.

• Journal of agricultural medicine and community health
• /
• v.29 no.2
• /
• pp.265-285
• /
• 2004

Objectives: The acute toxic effects of pesticide are well known. Concern has also been expressed that long-term exposure may result in damage to the central nervous system. This study was conducted to test the hypothesis that central nervous system symptoms might occur due to pesticide exposure. Methods: In a cross-sectional study, first, cumulative exposure index (CEI) was estimated. Neurologic symptoms (Q-16 questionnaire) for 541 farmers (exposed to pesticides) were compared with 119 non-exposed persons in spraying season nine rural areas in Korea. Results: The pesticides poisoning rates for last 3 months were 67.2% for orchard farmers, 55.3%for dry field farmers, and 20.5% for husbandry farmers, respectively, showing significant difference (p<0.001). Compared with non-exposure group, exposure groups (especially, orchard farmers) reported significantly more neurologic symptoms and had a higher overall neurological symptoms score (p<0.001). Factors related to the positive neurological symptoms (answers "yes" to six or more of Q-16 questionnaire) adjusted for age, sex, education level, smoking and alcohol drinking were type of farming (OR 3.08, 95% CI 1.50-6.30 in orchard farmers vs non-exposure group), CEI (OR 2.75, 95% CI 1.12-6.78 in Q3 vs Q1), past poisoning (OR 1.97, 95% CI 1.21-3.20 vs normal), current mild poisoning (OR 3.03, 9500 CI 1.47-6.22 vs normal) and current moderate poisoning (OR 6.34, 95% CI 3.03-13.25 vs normal), respectively. Conclusions: These results suggest that long-term exposure to pesticides appears to be associated with subtle changes in the central nervous system.

• Journal of agricultural medicine and community health
• /
• v.36 no.4
• /
• pp.227-237
• /
• 2011

Objectives: This study was conducted to investigate the utilization and its determinants of rehabilitation services of people with disabilities in a rural area. Methods: From March 2 to April 1, 2011, we interviewed 101 disabled people with either physical disabilities or brain lesions. The subjects completed questionnaires about the utilization of rehabilitation services, general characteristics (age, sex, marital status, education level, economic status, health insurance, housing, and employment) and disability characteristics (type, level, comorbidity, reason for the occurrence of the disability, self-rated degree of disability, and daily life care giver). Frequency, Pearson's chi-square test, and a multiple logistic regression were used for statistical analysis. Results: This study showed that 70.3% of the people in this rural area with disabilities were using rehabilitation services. The two most common reasons for not using the services were "doubt about the effectiveness of the service" and "no facilities nearby." The facilities that the disabled people were currently using, in the order of most used to least, were general hospitals or clinics, rehabilitation centers, oriental medicine clinics, and public health centers. Only 19.7% of those who received rehabilitation responded that they were satisfied with the service. Significant factors in the utilization of rehabilitation services were sex, employment, self-rated economic status, and the reason for the occurrence of the disability. Women, people who were currently working, people who were of middle or higher economic status, or people who had acquired a disability were significantly more likely to use the services. Conclusions: A large number of people with disabilities in a rural area use rehabilitation services at present, but accessibility and satisfaction were low. Quantitatively and qualitatively, rehabilitation services for disabled people in a rural area should be centered around Community-based Rehabilitation (CBR). Effective strategies, for example reaching those who have not used the rehabilitation services, will be needed to improve services in rural areas.

• Journal of agricultural medicine and community health
• /
• v.34 no.2
• /
• pp.175-187
• /
• 2009

Objectives: This study was conducted to investigate whether joint effects between family allergy history and environmental tobacco smoke(ETS) by parents were associated with pediatric asthma and wheezing. Methods: The study objects of this study were 2301 element school students and their parents in an urban-rural areas of Gyeonggi-do. Pediatric asthma and wheezing were identified by measures of International Study of Asthma and Allergies in Childhood (ISAAC) questionnaires. We investigated history of parental allergy, ETS, and other socioeconomic status of both parent. Data were analyzed using logistic regression methods. Results: After adjusting other variables, children with maternal asthma history were more likely to be reported life time wheezing (OR: 3.79 95%CI:2.43-5.90), recent wheezing (OR:4.09 95%CI:2.28-7.38), and diagnostic asthma (OR:2.61 95%CI: 1.44-4.75). Paternal asthma history increasing risk of life time wheezing (OR 2.01 95%CI:1.19-3.38) and recent wheezing (OR:2.38 95%CI:1.24-4.56). Joint effect between parental allergy history and ETS significantly effected on child's life time wheezing and recent wheezing. The risks of life time wheezing (OR:2.47 95%CI:1.64-3.717) and recent wheezing (OR: 2.51 95%CI:1.34-4.69) were significantly higher than others without both factors. The risk of recent wheezing of children with maternal recent smoking and parental allergy history (OR:4.83 95%CI:1.89-12.33) was higher than their counterpart. Conclusions: The result of this study implies that children with family allergy history and passive smoking are more likely to be get asthma and wheezing than children with family allergy history and non-passive smoking. This study provide the object information to increase the efficiency of non-smoking campaign and education for decreasing pediatric asthma risk.

• Journal of agricultural medicine and community health
• /
• v.38 no.1
• /
• pp.14-24
• /
• 2013

Objectives: Pregnant women in rural areas do not have access to sufficient obstetric services in their own communities due to the shortage of obstetricians. Therefore, most of these women must seek obstetrician outside of their communities. The purpose of this study was to investigate the relationship between obstetric complications and accessibility to local obstetric care in Korea. Methods: This study was an ecological study in which the unit of analysis was an administrative district. Using Korea National Health Insurance Corporation data, the total number of deliveries and the delivery proportion within and outside of the community from 2001 to 2008 were calculated for 232 administrative districts nationwide. Three outflow levels were categorized based on each district's out-of-community delivery proportion: high outflow (upper one third), moderate outflow (middle one third), and low outflow (lower one third). In addition, three obstetric complication rates (the rate of complications following abortion, ectopic and molar pregnancy, the abortion rate, and the eclampsia rate) were calculated for the 232 districts. One-way ANOVA and multivariate linear regression were used to evaluate obstetric complications among the three outflow levels. Results: The high outflow districts had higher rates of eclampsia and complications following abortion, ectopic, and molar pregnancy compared to the other districts (ANOVA, p<0.05). However, there was no significant difference in the abortion rate among the three groups. Multiple linear regression analysis showed that high outflow districts were statistically significant in the rate of complications following abortion, ectopic and molar pregnancy and eclampsia rate after adjusting for local tax per capita (p<0.01). Conclusion: These results indicate that poor access to local obstetric care correlate with poor obstetric outcomes (delayed or excessive bleeding, embolism, genital tract or pelvic infection, shock or other complications following abortion and ectopic or molar pregnancy, or eclampsia).