조류의 이상증식을 일으키는 새만금호 부영양화를 평가하기 위해 Carlson 지수를 적용하였다. 연구를 위해 2021년 월별로 새만 금호내 총 7개 정점에서 수질조사를 실시하였다. Chl.a의 농도는 동계에는 만경수계가 약간 높았고, 춘계와 하계에는 동진수계가 약간 높 게 나타났으나, 일부 시기를 제외하고는 전체적으로 호소 수질환경기준 3등급과 비슷하거나 낮은 농도를 나타내었다. COD는 만경수계와 동진수계 모두 하계와 추계에 호소 수질환경기준 4등급과 유사하거나 상회하는 수질을 나타내었다. TOC는 모든 지점에서 3등급 이내의 수질을 보였다. 총인 농도는 호수 수질환경기준 4등급을 초과하였고, 월별로는 1월과 강우 후 8월에 높게 나타났다. 수질인자간의 상관성 분석에서 염분 농도에 대한 유기물, 총인, 총질소의 상관성이 상대적으로 높게 나타나 배수갑문을 통한 해수유입과 상류 하천을 통한 담 수 유입에 의한 담수역, 기수역, 해수역의 수질 특징을 반영하고 있었다. 영양상태지수에 의한 새만금호의 부영양화 변동 특성을 보면, Chl.a와 SD, TN의 지수에서 부영양화 초기 단계의 수질을 보였으며, TP 지수의 경우 심각한 부영양화 상태를 나타내고 있었다. 수질인자 간 부영양화 지수의 크기는 모든 수계에서 TSI(TP) > TSI(TN) > TSI(SD) > TSI(CHL)의 순으로 나타났다. TSI(CHL)에 대한 TSI(TP) 및 TSI(SD)와의 편차를 2차원 평면으로 나타낸 사분면 분석 결과를 보면, 조류 성장에 대한 총인이 영향에서는 모든 수계에서 대부분의 총인 (TP)에 의한 제한적 영향은 나타나지 않았으며, 빛 감쇠에 영향을 미치는 인자는 외부로부터 유입되는 적은 입자상 물질에 의한 영향이 크게 나타나는 것으로 평가할 수 있다.

급격한 산업화와 도시화로 인해 해양 오염이 심각해지고 있으며, 이러한 해양 오염을 실효적으로 관리하기 위해 수질평가 지수(Water Quality Index, WQI)를 마련하여 활용하고 있다. 하지만 수질평가지수는 다소 복잡한 계산과정으로 인한 정보의 손실, 기준값 변동, 실무자의 계산오류, 통계적 오류 등의 불확실성(uncertainty)을 내포하고 있다. 이에 따라 국내ㆍ외에서 인공지능 기법을 활용하여 수질평가지수를 예측하기 위한 연구가 활발히 이루어지고 있다. 본 연구에서는 해양환경측정망 자료(2000 ~ 2020년)를 활용하여 우리나 라 전 해역 즉, 5개의 생태구에 대한 WQI를 추정할 수 있는 가장 적합한 인공지능기법을 도출하기 위해 총 6가지의 기법(RF, XGBoost, KNN, Ext, SVM, LR)을 실험하였다. 그 결과, Random Forest 기법이 다른 기법에 비해 가장 우수한 성능을 보였다. Random Forest 기법의 WQI 점수 예측값과 실제값의 잔차 분석 결과, 모든 생태구에서 시간적 및 공간적 예측 성능이 우수한 것으로 나타났다. 이를 통해 본 연구에서 개발한 Random Forest 기법은 높은 정확도를 바탕으로 우리나라 전해역에 대한 WQI를 예측 가능할 것으로 사료된다.

Benthic macroinvertebrates are important ecological and environmental indicators as primary or secondary consumers, and therefore are widely used in the evaluation of aquatic environments. However, there are no comprehensive river ecosystem monitoring surveys that link the major physicochemical water quality items with benthic macroinvertebrates in urban streams. Therefore, this study investigated the distribution characteristics of benthic macroinvertebrates and physicochemical water quality items (17 items) in Yangjaecheon and Yeouicheon from 2019 to 2020. At the same time, by applying Spearman’s rank correlation analysis and nonmetric multidimensional scaling (nMDS) analysis in the water quality data and biotic index, we tried to provide basic data for diagnosing the current status of river ecosystems in major urban rivers in Seoul. Based on the study results, a total of 39 species and 3,787 individuals were identified in Yangjaecheon, the water quality (based on BOD, TOC, and TP) of Yangjaecheon was higher than Grade Ib (good), and the BMI using benthic macroinvertebrates appeared as Grade C (normal) at all the sites. In Yeouicheon, a total of 51 species and 4,199 individuals were identified, the water quality (based on BOD, TOC, TP) was higher than Grade Ib (good) similar to Yangjaecheon, and the BMI of both Upstream and Saewon bridge was Grade B (good), while Yeoui bridge was Grade C (normal). Overall, analysis results for the distribution of benthic macroinvertebrates by a nonmetric multidimensional scaling method showed no significant difference between the two streams (p=0.1491). Also, significant environmental variables related to benthic macroinvertebrates distribution were determined as water temperature and DO. On the other hand, the results of the correlation analysis between biotic index and major water quality items confirmed that R1 and BMI could be used for on-site urban river water quality evaluation.

저서동물은 저서환경특성을 나타내는 중요한 지시자로 알려져 있다. 본 연구에서는 무안만 조 하대의 환경 및 저서동물의 분포특성을 조사하였으며, 수질평가지수(WQI)와 저서생물지수 (AMBI)를 이용하여 저서생태계 건강성을 평가하였다. 현장채집은 2019년 하계 무안만 조하대 의 10개 정점에서 이루어졌다. 무안만 조하대는 상부지역이 하부지역에 비해 세립한 입도특성 을 나타내고 있었으며, 높은 유기물 함량을 보였다. 일부 정점에서 오염지표종인 Musculista senhousia, Theora fragilis and Lumbrineris longifolia과 같은 종들도 우점을 나타내고 있었다. 군집분석결과 무안만 조하대는 상부, 중부, 하부 그룹으로 구분되었으며, 유기물 함량과 저서 건강성 평가지수(WQI 및 AMBI)와의 상관결과와 일치하였다. 본 연구결과, 무안만 조하대의 저서생태계는 양호한 것으로 평가되었다. 하지만 저서동물이 균등하게 분포하지 않고, 기회 종이 출현하고 있어 조하대의 유기물 부하량이 증가하고 있는 것으로 보인다.

Applicability of corrosion inhibitor was evaluated using pilot scale water distribution pipe simulator. Calcium hydroxide was used as corrosion inhibitor and the corrosion indices of the water were investigated. Corrosion indices, Langelier saturation index (LI) increased by 0.8 and calcium carbonate precipitation potential (CCPP) increased by 9.8 mg/L. This indicated that corrosivity of water decreased by corrosion inhibitor and the effects lasted for 18 days. Optimum calcium hydroxide dose was found to be 3~5 mg/L for corrosion inhibition. We suggest that monitoring of CCPP as well as LI need to be conducted to control corrosivity of water.

본 연구는 한강하류역에서 2개 정점을 선정하여 2004년 2월부터 2005년 2월까지 갈수기에 격주 간격으로 인공기질을 이용하여 부착돌말류에 의한 수질평가를 수행하였다. 조사기간 중 출현한 부착돌말류는 총 60분류군으로 2목 3아목 8과 18속 51종 7변종 2품종으로 구성되어 있었다. 정점별 우점종은 정점 1에서 광적응성 종인 A. granulata (22.76~30.30%), M. varians (17.44~34.78%)와 호오염성

Concern about water quality and pollution was heightened as contaminants flowed into the Namhan River downstream of the Chungju Dam. Thus, this study calculated the Real-Time Water Quality Index (RTWQI) using monthly average water quality monitoring data for major tributaries that require water quality control, which were obtained between 2010 and 2019. To review the applicability of the RTWQI for water quality assessment in the major tributaries of the Namhan River, it was compared with the living environment standard river. The calculated RTWQI result indicated that Bokhacheon, with 59 points, was in the “fair” grade, and this stream was identified as a tributary that preferentially requires water quality improvement as it showed a decreasing (-) tendency of RTWQI. A comparison between RTWQI and the living environment standard of T-P showed that the categories of “completely coincident” and “different by one grade” accounted for 45% of the total, and the water quality of major tributaries was assessed as low. Therefore, the RTWQI, which applies comprehensive water quality parameters and has higher reliability than assessing a single water quality parameter, was determined to be efficient for water quality assessment of the major tributaries of the Namhan River.

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.

The key objective of this study was to evaluate trophic state and empirical water quality models along with analysis of fish trophic guilds in relation to water chemistry (N, P). Trophic state index (TSI), based on total phosphorus (TP) and chlorophyll-a (CHL), ranged between oligotrophic and hypereutrophic state, by the criteria of Nürnberg(1996), and was lower than the trophic state of total nitrogen (TN). Trophic relations of Secchi depth (SD), TN, TP, and CHL were compared using an empirical models of premonsoon (Pr), monsoon (Mo), and postmonsoon (Po). The model analysis indicated that the variation in water transparency of Secchi depth (SD) was largely accounted (p < 0.001, range of R2 : 0.76–0.80) by TP during the seasons of Mo and Po and that the variation of CHL was accounted (p < 0.001, R2 = 0.70) up to 70% by TP during the Po season. The eutrophication tendency, based on the TSITP vs. TSIN:P were predictable (R2 ranged 0.85–0.90, p < 0.001), slope and y intercept indicated low seasonal variability. In the mean time, TSIN:P vs. TSICHL had a monsoon seasonality in relation to values of TSIN:P during the monsoon season due to a dilution of reservoir waters by strong monsoon rainfall. Trophic compositions of reservoir fish reflected ambient contents of TN, TP, and CHL in the reservoir waters. Thus, the proportions of omnivore fish increased with greater trophic conditions of TP, TN and CHL and the proportions of insectivore fish decreased with greater trophic conditions.