In this study, 46 reservoirs in South Korea were characterized based on heavy metal concentration in sediments. We analyzed the relationship between heavy metal concentrations, physicochemical water quality and hydromorphological factors in each reservoir. Study reservoirs were classified into five groups of reservoirs, by hierarchical cluster analysis based on the similarities of heavy metal concentration. Group 1 had the most severe sediment heavy metal contamination among the groups, whereas Groups 2 and 3 showed low levels of heavy metal contamination. Group 4 displayed high value of Ni, and Group 5 showed high contamination of Pb, Cu, Cr, Ni, and Hg. Groups 1 and 5, which had high concentration of heavy metals in sediments, showed a high density of mines in the catchment of reservoirs. Heavy metal concentration was high in reservoirs with large capacity or the ones located at higher elevation, and also highly related with number of mines in the catchment of reservoir. This study can contribute to the systematic management of sediment heavy metals in reservoirs.

Understanding the characteristics of reservoir water quality is fundamental in reservoir ecosystem management. The water quality of reservoirs is affected by various factors including hydro-morphology of reservoirs, land use/cover, and human activities in their catchments. In this study, we classified 83 major reservoirs in South Korea based on nine physicochemical factors (pH, dissolved oxygen, chemical oxygen demand, total suspended solid, total nitrogen, total phosphorus, total organic carbon, electric conductivity, and chlorophyll-a) measured for five years (2015~2019). Study reservoirs were classified into five main clusters through hierarchical cluster analysis. Each cluster reflected differences in the water quality of reservoirs as well as hydromorphological variables such as elevation, catchment area, full water level, and full storage. In particular, water quality condition was low at a low elevation with large reservoirs representing cluster I. In the comparison of eutrophication status in major reservoirs in South Korea using the Korean trophic state index, in some reservoirs including cluster IV composed of lagoons, the eutrophication was improved compared to 2004~2008. However, eutrophication status has been more impaired in most agricultural reservoirs in clusters I, III, and V than past. Therefore, more attention is needed to improve the water quality of these reservoirs.

The present study investigated species richness and phytoplankton community structure in lakes in the Geum River Basin during autumn and spring seasons. Surveys were conducted between September and November 2019, and between April and May 2020, which corresponded to the autumn and spring seasons, respectively, to explore the distribution characteristics of the species. A total of 49 species of phytoplankton belonging to 31 genera and seven classes were identified in Cho Pyeong-ji, 51 species belonging to 29 genera and six classes were identified in Song Ak-ji, 49 species belonging to 32 genera and seven classes were identified in Cheong Cheon-ji, 82 species belonging to 45 genera and six classes were identified in Ye Dangji, and 70 species belonging to 40 genera and six classes were identified in Ganwol Lake. A total of 43 species belonging to 74 genera and seven classes were identified. The ranges of phytoplankton standing crop were as follows: 223~3533 cells mL-1 in Cho Pyeong-ji, 881~176018 cells mL-1 in Song Ak-ji, 402~6139 cells mL-1 in Cheong Cheon-ji, 262~10460 cells mL-1 in Ye Dang-ji, and 20413~330695 cells mL-1 in Ganwol Lake. Phytoplankton diversity in Cho Pyeong-ji, Song Ak-ji, Cheong Cheon-ji, Ye Dang-ji, and Ganwol Lake were 1.10~2.60, 0.56~2.03, 0.21~2.03, 0.65~2.57, and 0.44~1.12, respectively. Phytoplankton species richness in Cho Pyeong-ji, Song Ak-ji, Cheong Cheon-ji, Ye Dang-ji, and Ganwol Lake were 1.91~4.99, 1.82~3.26, 1.26~4.17, 2.07~5.37, and 1.90~2.43, respectively. Phytoplankton evenness indices in Cho Pyeong-ji, Song Ak-ji, Cheong Cheon-ji, Ye Dang-ji, and Ganwol Lake were 0.38~0.78, 0.18~0.69, 0.08~0.71, 0.22~0.72, and 0.14~0.38, respectively. Phytoplankton dominance indices in Cho Pyeong-ji, Song Ak-ji, Cheong Cheon-ji, Ye Dang-ji, and Ganwol Lake were 0.40~0.83, 0.55~0.96, 0.44~0.99, 0.42~0.93, and 0.89~0.97, respectively.

본 연구는 영산강·섬진강 수계에 위치한 16개 호소에 대해서 어류군집을 조사하고 호소별, 호소 규모별 어류군집 특성을 분석하였다. 조사 방법과 지점수는 환경부의 “생물측정망 조사 및 평가 지침”에 따라 이루어졌으며, 소형호, 중형호, 대형호로 구분하여 어류군집을 비교 분석하였다. 2018년 (7개 호소)에서 2019년 (9개 호소)에 이루어진 조사에서 총 13과 44종의 어류가 채집되었으며, 우점종은 치리 (Hemiculter eigenmanni, RA, 32.9%), 아우점종은 블루길 (Lepomis macrochirus RA, 31.4%)로 나타났다. 호소 규모에 따라 분석한 결과 소형호에서는 평균 (±표준편 차) 11±2.9종이 채집되었으며, 중형호는 14.3±2.1종, 대 형호는 22.7±0.6종으로 호소의 규모가 커질수록 출현 종수가 증가하는 양의 상관성을 나타냈다. 호소 규모별 어류 군집 요인은 총 6개 항목 (총 종수, 총 개체수, 풍부도, 초식 성종 개체수 비율, 육식성종 개체수 비율, 외래종 종수)에서 차이를 보였다 (P<0.05). 호소별 어류군집 유사도 분석 결과 16개 호소가 60%의 유사도에서 5개 그룹으로 구분 되었으며, 군집 유사도는 호소의 규모보다는 호소 간 거리, 수계, 호소의 발달 위치 및 환경유형이 영향을 미치는 것 으로 나타났다. 본 연구는 국내 호소의 어류군집 구조 이해에 도움이 될 수 있으며, 특히 영산강·섬진강 수계의 호소 관리 및 정책 마련에 기초자료로 활용될 수 있을 것이다.

인간 간섭에 영향을 크게 받는 인공호소가 대부분인 우리나라의 호소 특성과 보다 나은 생태계 관리 방안을 도출하고자 하는 목적에서 2005년 4개 호소의 이화학적 요인과 담수조류 정량분석에 의거한 기초자료를 바탕으로 통계학적 분석을 시도하였다. Canonical Correspondence Analysis(CCA)를 하구호인 남양호, 삽교호, 아산호 및 북한강 중하류 수계에 연쇄적으로 위치한 댐호 중 하나인 청평호에 적용하였다 그 결과, 청평호는 3개 하구호와 구분되는 특징을 보였으며, 청평호를 제외한 CCA결과, 아산호-삽교호-남양호 간에도 차이를 보여주었다. 담수조류 군집 구성은 제한된 자료량 때문인지 해석이 생태학적 해석에 어려움이 따랐다. 따라서, 보다 지속적이고 심화된 담수조류 연구 및 기타요인의 채집 및 분석이 수행될 필요가 있음이 나타났다. 그러나, 제한된 자료량에도 불구하고, 청평호 및 3개 호소의 큰 두 그룹으로 호소 그룹이 특징지워진 것은 CCA 적용이 유효함을 나타낸 것으로 보인다.

본 연구에서는 원심력을 이용한 하이드로싸이클론을 준설된 호소 퇴적물의 처리 공정에 적용하는 실험을 수행하였다. 준설된 퇴적물의 안정화 및 위생적 처리를 위해서는 경우에 따라 탈수 및 분급공정이 필요하다. 본 연구에서는 이러한 공정에 하이드로싸이클론을 적용하였으며, 실온에서 실제 호소 퇴적물과 폐 석탄회를 이용하여 분리효율을 실험하였다. 본 연구 결과 하부배출구의 크기는 한계분리입경(d(sub)50)에 큰 영향을 미치는 것을 알 수 있었고, 비중이 큰 입

The Dongbok lake water before and after alum coagulation and activated carbon adsorption were analyzed in terms of organic contents, molecular weight distributuin (MWD), and UV-absorbance. Dissolved organic compounds in the Dongbok lake were fractionated into three molecular size classes by gel permeation chromatography. The fractionation was reasonably successful in isolating compounds with MW>10,000 (Fraction Ⅰ) and those with 3,000MW (Fraction Ⅲ. The bulk of the dissolved carbon was present in compounds of molecular weight in the range of 3,000∼10,000. Alum coagulation preferentially treated molecules of high molecular weight, which has molecules larger than 10,000. The dissolved organic carbon (DOC) removal after activated carbon adsorption was high in the Fraction Ⅱ, Ⅲ. The A_260/DOC ratio after alum and activated carbon treatment was high in the Fraction Ⅰ, Ⅱ. This results suggest that the organics remaining after each treatment has a trihalomethane formation potential