• 한국작물학회:학술대회논문집
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• 한국작물학회 2020년도 추계학술대회
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• pp.62-62
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• 2020

• 한국작물학회:학술대회논문집
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• 한국작물학회 2018년도 추계학술대회
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• pp.263-263
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• 2018

• 한국작물학회:학술대회논문집
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• 한국작물학회 2021년도 추계학술대회
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• pp.259-259
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• 2021

• 한국물환경학회지
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• 제27권4호
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• pp.491-498
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• 2011

We investigated the ranges of total cellular microcystins content of cyanobacterial blooms collected in Korean lakes and rivers from 2005 to 2009. The amount and composition of microcystins of Korean cyanobacteria varied depending on the sampling water bodies and dominant cyanobacterial genera. Toxic cyanobacterial cell numbers equivalent to $1{\mu}g$ MCYSTs/L using total cellular microcystin content of Korean cyanobacteria were in the range of 2,348 to 66,980,638 cells/mL. Only four samples among forty nine samples showed less cell numbers than current criterion of Harmful Algae Alert System, 5,000 cells/mL indicating current criterion do not reflect properly the microcystins content of Korean cyanobacteria. Anabaena and Aphanizomenon spp. showed three to six times higher cell numbers equivalent to $1{\mu}g$ MCYSTs/L than Microcystis spp. To propose criteria of Harmful Algae Alert System for Korean toxic cyanobacteria, we calculated about 50% selective geometrical means of cyanobacterial cell numbers equivalent to $1{\mu}g$ MCYSTs/L in order of toxic content. The proposed criteria for Microcystis, Oscillatoria, Anabaena, and Aphanizomenon spp., are 10,000, 20,000, 40,000, and 80,000 cells/mL, respectively.

• 생태와환경
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• 제51권4호
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• pp.354-364
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• 2018

본 연구는 2008년부터 2016년까지 한강 지류 중랑천을 대상으로 수환경 변화에 따른 어류 군집 양상을 파악하고자 실시하였다. 조사결과, 중랑천에서 서식하는 어류는 총 9과 37종 8,421개체로 나타났으며 과별 출현 종수는 잉어과에서 23종(62.2%)으로 가장 많은 종이 출현하였고, 생태계교란종 및 외래종은 모두 강우기 후 출현하는 특성을 보였다. 수질변화에 따르면, BOD, EC, TN, TP의 변화는 강우량의 증가에 따라 감소하는 양상을 보이는 반면, SS 변화는 증가하는 양상을 보였다. 지점간 CA결과 한강 본류와 인접한 St. 7과 St. 1, 3, 5가 어류의 출현양상 차이를 보였으며, PCA 분석결과 상류에서 하류, 강우기 전과 후의 어류출현양상과 유기오염지표의 변화 양상을 보였다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2019년도 추계학술대회
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• pp.217-217
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• 2019

• 한국작물학회:학술대회논문집
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• 한국작물학회 2023년도 춘계학술대회
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• pp.94-94
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• 2023

• 한국물환경학회지
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• 제35권1호
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• pp.19-27
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• 2019

The purpose of this study is to evaluate the water quality and phytoplankton community in Bukhan River which account for 44.4 % of the total inflow into Lake Paldang, using multivariate statistical techniques (i.e., correlation analysis, principal component analysis (PCA)/factor analysis (FA)). Water samples were collected from March to November 2015 and the following parameters measured; water temperature, pH, DO, EC, SS, BOD, Chl-a, COD, TN, $NO_3-N$, $NH_3-N$, TP, DTP, $PO_4-P$, and phytoplankton community. The water quality of the main stream and the tributaries were not significantly different apart from the relatively high concentration of BOD, COD and nutrients recorded in MH. The highest cell density of Stephanodiscus hantzschii and Merismopedia glauca dominated phytoplankton was observed in PD. Based on the correlation analysis, total phytoplankton and cyanophyceae were highly correlated with BOD, COD and nutrients. PCA/FA resulted in four main factors accounting for 82.240 % of the total variance in the water quality dataset. The group of component 1 (TN, DTN, DO, $NO_3-N$, water temperature) and component 2 ($PO_4-P$, T-P, DTP, SS) were classified as nutrient element factor whereas component 3 (Chl-a, COD, BOD, $NH_3-N$, pH) was related to organic substances. Hence, the identification of the main potential environmental pollution factors in Bukhan River will help policy makers make better and more informed decisions on how to improve the water quality.

• 한국물환경학회지
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• 제39권1호
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• pp.46-60
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• 2023

Climate change causes fluctuations in water quality in the aquatic environment, which can cause changes in water circulation patterns and severe adverse effects on aquatic ecosystems in the future. Therefore, research is needed to predict and respond to water quality changes caused by climate change in advance. In this study, we tried to predict the dissolved oxygen (DO), chlorophyll-a, and turbidity of the Paldang reservoir for about two weeks using long short-term memory (LSTM) and gated recurrent units (GRU), which are deep learning algorithms based on recurrent neural networks. The model was built based on real-time water quality data and meteorological data. The observation period was set from July to September in the summer of 2021 (Period 1) and from March to May in the spring of 2022 (Period 2). We tried to select an algorithm with optimal predictive power for each water quality parameter. In addition, to improve the predictive power of the model, an important variable extraction technique using random forest was used to select only the important variables as input variables. In both Periods 1 and 2, the predictive power after extracting important variables was further improved. Except for DO in Period 2, GRU was selected as the best model in all water quality parameters. This methodology can be useful for preventive water quality management by identifying the variability of water quality in advance and predicting water quality in a short period.

• 한국물환경학회지
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• 제37권2호
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• pp.75-91
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• 2021

Ocean dumping manure was prohibited in Korea until the end of 2012. Undumped manure was treated by resourcification, purification, and public process in a facility. But poor storage of untreated manure and overproduced compost can pollute river water. In this study, linear regression, Mann-Kendall, Seasonal Mann-Kendall, LOWESS trend, and Spearman's correlation analysis were conducted for investigating the changes in the water quality of Bukhan and Imjin river before and after the prohibition of ocean dumping. In 2017, the Imjin Riv er basin had more than 5.7 times liv estock breeding heads than the Bukhan Riv er basin and more than 3.5 times livestock manure. The areas of land, farmland, and nutrient balance were also higher in the Imjin River basin. Since the two basins have different environments, it is expected that the characteristics of changes in water quality due to the increase in livestock manure generation and treatment methods will be different when comparing the water quality trends before and after the ban. The result of the trend analysis revealed a decrease in EC before the ban but an increase afterward. T-N and BOD of Imjin river increased slightly before the ban but demonstrated great enhancement thereafter. Other sites and T-P exhibited no trend. The correlation analysis result showed that the increase in the number of livestock rearing was correlated with the increase in T-P of Bukhan River and BOD of Imjin River. The increase in livestock manure production was not correlated with the Imjin River basin, while a correlation was observed with the Bukhan River with an increase in T-N and EC and the decrease in T-P.