• Journal of Ecology and Environment
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• 제48권1호
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• pp.110-119
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• 2024

Background: The Mae Kha Canal is one of Chiang Mai's most important waterways. It supports local agriculture, irrigation, and transportation as well as provides stormwater drainage to prevent floods. Due to the unregulated rapid urbanization of the city and lack of efficient waste and wastewater management systems over the past few decades, the canal has become heavily polluted. This study aimed to evaluate the water quality of Mae Kha canal through assessment of the physico-chemical water quality and coliform bacteria. Moreover, benthic macroinvertebrates were samples and assessed using the Biological Monitoring Working Party (BMWP^Thai) and Average Score Per Taxon (ASPT^Thai) as biological indices. Results: The physico-chemical showed low dissolved oxygen levels, high levels of ammonia and phosphates, and elevated levels of biochemical oxygen demand, indicating that the water quality had significantly deteriorated. The canal was found to be heavily polluted, with most sites falling into the polluted to very heavily polluted. Coliform bacteria analysis revealed alarmingly high levels of total coliform bacteria and fecal coliform bacteria in the canal. The BMWP^Thai and ASPT^Thai scores indicated poor to very poor water quality. Conclusions: The physico-chemical and coliform bacteria indicated that the water quality of the Mae Kha canal had significantly deteriorated. The biological indices also indicated the poor to very poor water quality. This study underscores the urgent need for comprehensive remediation efforts, emphasizing strategic planning, investment, and community engagement to revive the canal's ecological health and water quality.

• 한국물환경학회지
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• 제22권5호
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• pp.748-756
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• 2006

Accurate and timely information on status and trends in the environment is necessary to shape sound water quality management policy and to implement water quality improvement programs efficiently. One of the most effective ways to communicate information on water quality trends to policy-makers, scientists, and the general public is with comprehensive water quality indices. The derivation and structure of a water quality index (WQI) for the classification of surface water quality is discussed. The WQI generally developed through the selection, transformation and weighting of determinants with rating curves based on legal standards and quality directives or guidelines. The representative pollutants should be included in the index, and the relationship between the quantity of these pollutants in the water and the resulting quality of the water should be based on scientific results. The WQI be simply and meaningfully formulated that nonscientifically trained users can easily become familiar with the framework of the system and use the output data to evaluate their own pollution problems.

• 환경위생공학
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• 제18권2호
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• pp.16-26
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• 2003

Analysis of benthic macroinvertebrate community and biological estimation of water quality was conducted at the national park of Mt. Jiri and its nearby area in Gurye, Sancheong and Hadong-gun from June to November, 2002. Total taxa of benthic macroinvertebrates were 124 species, 45 families, 15 orders, 5 classes in 3 phyla. Aquatic insects were 33 species in ephemeroptera, 28 species in Trichoptera, 21 species in plecoptera, 13 species in Diptera, 8 species in odonata, 5 species in hemiptera and 5 species in coleoptera, respectively. Non-insects were 5 species in Mollusca, 2 species in Hirudinea, 1 species in oligochaeta and 1 species in crustacea, respectively. Ephemeroptera, trichoptera and plecoptera as indicators in clean water were very abundant. Occurrence species at each survey area was 68 species at Mt. 1025-goji, 59 species at Mt. Eungseok-bong, 57 species at Mt. Wangdeung-jae, 50 species at Mt. Cheonwang-bong and 39 species at Mt. 645-goji, respectively. Mean species diversity indices at Mt. Cheonwang-bong, Mt. 1025-goji, Mt. Wangdeung-jae, Mt. Eungseok-bong and Mt. 645-goji were 3.33, 3.03, 3.41, 3.02 and 2.91, respectively, According to the saprobic system based on the species diversity indices of benthic macroinvertebrates, most survey areas except some sites are determined as Limnosaprobic area.

• 대한원격탐사학회지
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• 제22권3호
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• pp.183-197
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• 2006

Combinations of visible and near-infrared (NIR) bands in an image are widely used for estimating vegetation vigor and productivity. Using this approach to understand within-field grain crop variability could allow pre-harvest estimates of yield, and might enable mapping of yield variations without use of a combine yield monitor. The objective of this study was to estimate within-field variations in crop yield using vegetation indices derived from hyperspectral images. Hyperspectral images were acquired using an aerial sensor on multiple dates during the 2003 and 2004 cropping seasons for corn and soybean fields in central Missouri. Vegetation indices, including intensity normalized red (NR), intensity normalized green (NG), normalized difference vegetation index (NDVI), green NDVI (gNDVI), and soil-adjusted vegetation index (SAVI), were derived from the images using wavelengths from 440 nm to 850 nm, with bands selected using an iterative procedure. Accuracy of yield estimation models based on these vegetation indices was assessed by comparison with combine yield monitor data. In 2003, late-season NG provided the best estimation of both corn $(r^2\;=\;0.632)$ and soybean $(r^2\;=\;0.467)$ yields. Stepwise multiple linear regression using multiple hyperspectral bands was also used to estimate yield, and explained similar amounts of yield variation. Corn yield variability was better modeled than was soybean yield variability. Remote sensing was better able to estimate yields in the 2003 season when crop growth was limited by water availability, especially on drought-prone portions of the fields. In 2004, when timely rains during the growing season provided adequate moisture across entire fields and yield variability was less, remote sensing estimates of yield were much poorer $(r^2<0.3)$.

• 한국환경보건학회지
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• 제28권2호
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• pp.149-160
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• 2002

Analysis of benthic macroinvertebrate community structure and biological estimation of water quality by the benthic macroinvertebrates from the Mt. Myungji(1267m), Mt. Kalbong(840m), Mt. Daegeum(704m) and Mt. Jubal(489m) region of Gapyung-gun, Kyunggi-do were investigated from April to November, 2001. Total taxa of benthic macroinvertebrates were 105 species, 38 families, 13 orders, 5 classes in 4 phyla. Aquatic insects were 33 species in ephemeroptera, 5 species in odonata, 13 species in plecoptera, 2 species in hemiptera, 1 species in megaloptera, 27 species in trichoptera, 3 species in coleoptera and 13 species in diptera, respectively. Non-insects were 1 species in platyhelminthes, 5 species in gastropoda, 1 species in oligochaeta, 1 species in crustacea, respectively. Ephemeroptera, trichoptera and plecoptera as indicators in clean water were very abundantly. Occurrence species at each survey area was 67 species at Mt. Myungji and 69 species at Mt. Kalbong, 48 species at Mt. Daege.um and 47 species at Mt. Jubal, respectively. Mean species diversity indices at Mt. Myungji, Mt. Kalbong, Mt. Daegeum and Mt. Jubal were 3.30, 3.33, 2.59 and 3.43, respectively. According to the saprobic system based on the species diversity indices of benthic macroinvertebrates, Mt. Myungji, Mt. Kalbong and Mt. Jubal are determined as Limnosaprobic area, respectively, but Mt. Daegeum is determined as $\beta$-mesosaprobic area.

• 환경영향평가
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• 제30권2호
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• pp.61-74
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• 2021

본 연구에서는 해양에서 진행되는 개발사업으로 인하여 해양환경에 미치는 영향을 효율적으로 판단할 수 있는 평가지수들을 비교·검토하였다. 해양수질 분야에는 수질평가지수(WQI), 해양저질 분야에는 유해화학물질 정화지수(CIHC), 부영양화 정화지수(CIET), 농축계수(EF), 해양저서생물 분야에는 저서건강도지수(BHI), 저서오염지수(BPI)를 선정하였다. 개발사업에서 관측된 자료를 각각의 평가지수에 적용하여 평가지수의 특성 및 효용성을 파악하였다. 수질평가지수, 유해화학물질 정화지수, 저서건강도지수가 평가방법 및 평가기준이 명확히 정의되어 있으며, 통합적인 환경영향 분석이 가능하였다. 동 연구에서 제시된 지수이외에도 해양환경을 평가하는 다양한 지수가 있으며, 사업별 특성에 따라 적합한 지수를 활용하는 것도 중요하다.

• 한국물환경학회지
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• 제34권5호
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• pp.514-536
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• 2018

GPI (Group Pollution Index) using 29 indicator groups of Korean benthic macroinvertebrates was proposed in 1992, a higher category taxa-level index developed for rapid field assessment of organic water pollution. This study was performed to revise the assessment scheme of GPI based on taxonomic performance and ecological information accumulated since 1992. The original GPI was renamed SBMI (Simple Benthic Macroinvertebrates Index), and SBMI was based on saprobic valency of 26 indicator groups composed of higher category taxa (mainly family ~ phylum) excluding some genus or species-level taxa. SBMI revealed highly significant correlation with concentration of 5-day biochemical oxygen demand ($BOD_5$) (correlation coefficient r = 0.78, n = 569 sites), total suspended solids (r = 0.69), and total phosphorus (r = 0.77). Also, SBMI revealed strong correlation with Shannon-Weaver's species diversity (r = -0.85), Margalef's species richness (r = -0.85), and McNaughton's dominance (r = 0.83). Determination coefficient of SBMI to concentration of water quality items and values of community indices such as species diversity was 3 ~ 8 % and approximately 11 ~ 14 % higher than that of GPI, respectively. Correlation between SBMI and water quality factors or community indices such as species diversity did not reveal much difference compared to that of species-level indices, such as BMI (Benthic Macroinvertebrates Index) and ESB (Ecological Score of Benthic Macroinvertebrates). SMBI is a simple-qualitative index with higher category taxa easily identified, and is applicable for rapid field assessment of water environment impairment.

• 한국물환경학회지
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• 제35권6호
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• pp.539-549
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• 2019

In 2016, Benthic Macroinvertebrates Streambed Index (BMSI) was proposed as an index to evaluate streams as benthic macroinvertebrate depending on the substrate type of streambed. However, orignal BMSI were selected without consideration of water quality. Analyzes without water quality do not constitute biological indices based solely on the substrate type of streambed. Therefore, in this study, the indicator value was improvement in consideration of water quality, and the distribution characteristics of benthic macroinvertebrates according to the substrate type of streambed were analyzed under relatively equal water quality conditions. We surveyed 20,155 sampling units in Korea from 2008 to 2018, and we re-estimated each lithophility of 191 taxa. As a result of estimating the streambed of each newly lithophilic value classification group considering the water quality, it was different from the original lithophilic value. Representative integer lithophilic values were newly calculated from 126 taxa among the 191 index taxa used in the analysis. The correlation between new constructed BMSI and community structure was compared and analyzed. It showed extreamely significance (p<0.001) in the dominance index, diversity index, abundance index, and evenness index of the community structure. Diversity index, abundance index, and evenness index showed positive correlation, and dominance index showed negative correlation. The correlation coefficient (r) was the highest in the richness index of about 0.664.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 총회 및 춘계학술발표회
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• pp.459-462
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• 2004

This study assesses groundwater vulnerability to contaminants in 12 administrative districts of the city of Changwon, using DRASTIC technique. DRASTIC was originally applied to situations in which the contamination sources are at the ground surface, and the contaminants flow into the groundwater with infiltration of rainfall. However, groundwater contamination in urban areas can also be related to excessive pumping resulting in a lowering of the water level. The correlation coefficient between minimum DRASTIC indices and the degree of poor water quality for 10 districts is low as 0.40. The correlation coefficients between minimum DRASTIC indices and the groundwater discharge rate, and between minimum DRASTIC indices and well density per unit area are 0.70 and 0.87, respectively. Thus, to evaluate the potential of groundwater contamination in urban areas, it is necessary to consider other factors such as groundwater withdrawal rate and well density per unit area with ratings and weights as well as the existing six DRASTIC factors.

• 한국환경과학회지
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• 제28권12호
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• pp.1071-1083
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• 2019

In this study, water quality levels were classified and water quality indices were calculated and analysed by using the water quality components of living environmental standards monitored 10 years (2008 ~ 2017) at four stations in the West Nakdong River. As a result of analyzing the monthly variation of the water quality components of the living environmental standards, the water quality in the West Nakdong River was worse downstream than upstream, and pollution at the WNR3 located in the downstream of the Jomangang was the most serious. As a result of classification of water quality levels, BOD and COD levels were the lowest, so water quality pollution in the West Nakdong River was found to be highly influenced by organic matters. The water quality index was the lowest in July and August at four stations, so water quality is showing the worst in summer. As a result of analyzing the correlation between the water quality components and the water quality index, the correlation between the TOC and the water quality index was high in the four stations, and the water quality index in the West Nakdong River was dominated by organic matters and nutrients.