Ecological health assessments using multiple parameters of fish blood tissues to community along with water chemistry in urban streams

안광국,강한일,최지웅,황석연 한국생태학회 2015 Journal of Ecology and Environment Vol.38 No.3

The objectives of this study were to identify multi-level stressors from blood biomarkers to community-level bioindica¬tors and diagnose the stream ecosystem health in polluted streams. Blood chemistry such as total protein (TPro), blood urea nitrogen (BUN), total cholesterol (TCho) and albumin (Alb) were analyzed from sentinel fish tissues; the functions of kidney, gill and liver were significantly decreased in the impacted zone (Iz), compared to the control zone (Cz). Histo¬pathological analysis showed that fish liver tissues were normal in the Cz. Fish liver tissues in the Iz, however, showed large cell necrosis and degeneration and also had moderate lobular inflammation and inflammatory cell infiltration of lymphocytic histocytes. Species biotic index (SBI) at species level and stream health assessment (SHA) at community level indicated that chemical impacts were evident in the Iz (ecological health; poor - very poor), and this was matched with the blood tissue analysis and histopathological analysis. The impairments of the streams were supported by water chemistry analysis (nitrogen, phosphorus). Tolerance guild analysis and trophic guild analysis of fish were showed sig¬nificant differences (P < 0.01) between Cz and Iz. Overall, multiple parameter analysis from biomarker level (blood tissues) to bioindicator level (community health) showed significantly greater impacts in the Iz than Cz. This approach may be effective as a monitoring tool in identifying the multilateral and forthcoming problems related to chemical pollution and habitat degradation of stream ecosystems.

대형 인공댐호이 효율적 수질 감시를 위한 적정 조사 빈도 설정 연구

안광국,홍욱희,최신석 ( Kwang Guk An,Wuk Hee Hong,Shin Suk Choi ) 한국하천호수학회 1995 생태와 환경 Vol.28 No.3

In water quality monitoring practices, frequent water sampling would promise data accuracy but may not be so cost effective. However, less frequent sampling would fail to provide accurate data which represents the exact quality of the water body. Hence, determining appropriate sampling frequencies will be enormously important in terms of data accuracy and cost saving, particularly when the sampled water bodies are of great importance as major water resources . In this study, such determination of sampling frequencies was carried out for the Lake Taechung. Total 13 water quality parameters sampled and analyzed every 2 to 3 days for a year were compared with the data sampled less frequently; once every 7 to 10 days, twice a month, and once a month. While general water quality parameters such as dissolved oxygen, pH, and turbidity were dynamically fluctuated throughout the year, the parameters related to the trophic state such as Secchi depths, total suspended solids, nutrients, and chlorophyll-a showed more distinctive fluctuations during the algal growth season. The effects of summer monsoon were remarkable in most water quality parameters. Based on these findings, it was suggested that during the algal growth season, June to September, at least weekly samplings should be carried out for VSS, total nitrogen, total phosphorus and chlorophyll-a. Nitrate- and ammonia-N, dissolved phosphorus, NVSS and other parameters may be measured twice a month during this season. During non-algal growth seasons, from October to May of the next year, bimonthly samplings were suggested for such parameters as total nitrogen, total phosphorus, and chlorophyll-a Monthly samplings would suffice for all other parameters.

준설 점토사면의 변형양상에 관한 원심모델링

안광국,김정열,정소전,이처근 한국지반환경공학회 2007 한국지반환경공학회논문집 Vol.8 No.2

본 연구에서는 준설에 따른 점토사면의 변형 및 변위양상과 파괴형태를 평가하기 위하여 준설사면의 기울기를 변화시키면서 원심모형실험을 실시하였다. 준설사면의 기울기는 1:2, 1:2.5, 1:3으로 변화시키면서 모형실험을 수행하였다. 실험 결과 기울기 1:3인 경우에는 4개월 경과시점까지 사면부내에서 변위는 발생되었지만, 초기단면과 유사하게 사면을 유지하고 있어 준설후 사면 안정성의 확보에는 문제가 없는 것으로 평가되었다. 준설사면 기울기가 1:2.5인 경우에는 4개월 경과시점에서 사면부내에서 국부적인 사면파괴가 발생하였으며, 기울기가 1:2인 사면의 경우 경과시간 2개월 후 원호파괴형태의 사면내 파괴가 발생되었다. 실험결과 지반의 최대 연직변위는 사면의 비탈머리에서 발생하였으며, 최대 수평변위는 비탈머리를 기준으로 0.5~1H(H : 초기 점토층의 높이) 떨어진 지점의 사면부 아래에서 발생하였으며, 최대 수평변위는 최대연직변위의 약 2배 정도인 것으로 나타났다. In this study, the centrifugal tests were performed with varying the angle of slope such as 1:3, 1:2.5, and 1:2 in order to analyze the deformation and failure type of dredged clay slope for a short term. The displacement mode, displacement vector and the variation of pore pressure with the different slope angle were measured. As a results, even though the displacement in the slope after 4 months were developed in the case of 1:3 for the dredged slope, there are little problems to obtain the stability of dredged slope because the original construction section maintains. Also, in the case of 1:2.5 after 4 months the local slope failure occurred and in the case of 1:2 after 2 months the circle failure starting from the point of the tensile crack occurred. After reviewing the results, the maximum vertical displacement occurred at the crest of slope and maximum horizontal displacement was about double of maximum vertical displacement.

하절기 장마동안 용존산소의 역동적 변화

안광국 한국육수학회 2000 생태와 환경 Vol.33 No.3

Seasonal oxygen content and deficit rates were evaluated from 17 sites of Taechung Reservoir during 1993∼1994. In 1993, river inflows peaked during the monsoon in July∼August and disrupted thermal stratification and anoxic layers in the headwaters, thereby confining the anoxia to the mid-lake and downlake reach. The volume of anoxic water with < 4 mg/ℓ DO comprised only < 10% of the total lake volume in this period. In contrast, during monsoon 1994, 85% of total lake volume was subject to hypoxic conditions with oxygen concentrations < 30% saturation, resulting in massive fishkills(Hypomesus olidus). Relative areal oxygen deficit (RAOD) was -0.024 mg O₂ cm^(-2) d^(-1) during monsoon 1993, whereas it rapidly decreased at the rate of 0.080 mg O₂cm^(-2) d^(-1) during monsoon 1994. Anoxic factor (AF) showed a same interannual pattern as the RAOD and was greater > 50 d in 1994 (76.5 d) than 1993 (21.3 d). Thus, the reservoir showed a river-characteristics (6∼11 mg/ℓ DO) in 1993 while lacustrine conditions ( < 4 mg/ℓ DO) dominated in 1994. Regression analysis showed that the variation of summer DO was mostly determined (R²=0.99, p < 0.0001) by inflow. These findings suggest that the primary factor regulating the oxygen content in this system during summer is an intensity of the monsoon rain.

호수내 인의 주요원으로 몬순 유입수

안광국 한국육수학회 2000 생태와 환경 Vol.33 No.3

Spatial and temporal variation of phosphorus in response to intensity of summer monsoon was evaluated in Taechung Reservoir during 1993∼1994. Total phosphorus (TP) averaged 31 ㎍/ℓ during the study and varied from 6 to 197 ㎍/ℓ. Concentrations of TP were highest in the headwaters during the monsoon of July∼August 1993, and these values were mainly made of particulate P and were closely associated (R²=0.74, p < 0.001) with high inorganic suspended solids (NVSS). In-lake TP in the headwaters was mainly influenced by the watershed runoff and declined toward the dam. Values of TP downlake was only one-fifth of the peak in the headwaters and had no correlation with NVSS. In 1994, inlake TP was markedly lower relative to 1993 and showed low spatial and temporal variation. Maximum TP during monsoon 1994 in the headwaters and mid-lake was 72% and 52% lower, respectively, than in those two zones in 1993 whereas TP downlake was similar between the two years. These results suggest that temporal variation downlake is much less influenced by seasonal inflow compared to the headwaters. In 1993, mean TP before fall overturn, based on average value for all sites, was significantly (t = 5.99, p < 0.001) greater than the mean after fall overturn, whereas in 1994 mean TP after fall overturn (32 ㎍/ℓ) was greater. This outcome indicates that in 1993 major P-input originated from the external source from the watershed during the intense monsoon, whereas in 1994 internal processes dominated during the weak monsoon. Overall data suggest that annual budget of inlake P is regulated by intensity of the summer monsoon, and phosphorus data measured at single site near the dam or headwater zone may not be represent seasonal trends of the system due to large spatial variation of Taechung Reservoir.

호수 지형 및 수리수문학적 변화에 대한 몬순 영향

안광국 한국육수학회 2000 생태와 환경 Vol.33 No.4

This paper demonstrates the influence of intensity of the monsoon on morpho-hydrological fluctuations in Taechung Reservoir during 1993∼1994. During the study, hydrological variables including rainfall, inflow, and discharge volume showed distinct contrast between 1993 and 1994. Interannaul differences in rainfall occurred during the monsoon in July∼August monsoon and influenced inflow, discharge, and water residence time (WRT). Total inflow in 1993 was four times greater than that of 1994, and summer inflow in 1993 was 8 times greater than summer 1994. Annual Mean WRT was 93.2 d in 1993 vs. 158.6 d in 1994 and the largest differences occurred between monsoons of 1993 and 1994. Morphometric variables reflected the interannual contrasts of hydrology, so that in 1993 surface area, total volume, shoreline development, and mean depth increased consistently from premonsoon to postmonsoon and over this same period in 1994 they decreased. This outcome indicates that the area of shallow littoral zones in 1993 was greater than in 1994. Also, the drainage area to surface area (D/L) at 80 m MSL was 60.7 which was much greater than values in Soyang and Andong reservoirs and natural lakes world-wide. The morpho-hydrodynamic conditions seemed to influence in-reservoir nutrient concentration which is one of the most important factors regulating the eutrophication processes. I believe, under the maximum hydrodynamic fluctuations in Korean waterbodies during the monsoon, applications of mass balance models to man-made lakes for assessments of external loading should be considered because the models can be used under the seasonally stable inflow and water residence time.

Variations of Calcium, Bicarbonate, and Cation in the Lacustrine Zone by Interannual Differences in Up-River Discharge

안광국,이재훈,한정호 한국하천호수학회 2010 생태와 환경 Vol.43 No.4

Monthly up-river discharge in the riverine zone analysis resulted in large interannual variations and differences in calcium (Ca2+), bicarbonate (HCO3 -), and cations in the lacustrine zone (Lz) of Daecheong Reservoir during the wet year (Wy, 1993) vs. dry year (Dy, 1994). Total up-river discharge in the Wy was four times that of the Dy, and the up-river discharge in July~August of the Wy was eight times greater than that of same period of Dy. Annual water retention time in the Lz showed large difference between the two years. Water residence time (WRT) was minimum when the up-river discharge peaked, whereas the WRT was maximum when the up-river discharge was at minimal condition. This peak discharge from the up-river on early July reduced residence time in the Lz on mid-July~late July. Monthly pattern, based on data of May~November, was similar between the two years, but, but mean retention time in the Wy was 50 days shorter than in the Dy. Such hydrology, up-river discharge, and WRT reduced Ca2+, HCO3 -, and cations in the Lz. At low up-river discharge in Wy during April~May, the cation content of Ca+Mg+Na+K averaged 1.17 meq L-1 (range= 1.09- 1.26 meq L-1), but as the up-river discharge increased suddenly, the values decreased. Seasonal fluctuations of Ca2+ showed exactly same pattern with bicarbonate ion of HCO3 -. The minimum Ca2+ (0.03 meq L-1) was occurred in the early August of wet year and coincided with the minimum HCO3 -. These results suggest that the magnitude of variation in Ca2+, bicarbonate, and cations in the lacustrine zone is directly determined by the peak magnitude of up-river discharge. The magnitude of up-river discharge determined water retention time and the magnitude of ionic dilution in the lacustrine zone, resulting in functional changes of the ecosystem.

대형 인공호에서 무기 질소원에 대한 점오염원 및 유입수의 영향

안광국 한국육수학회 2000 생태와 환경 Vol.33 No.4

This paper evaluated the influence of point source and flow events on inorganic nitrogen fractions at 17 sites of Taechung Reservoir during 1993∼1994. Total nitrogen (TN) averaged 1.53 mg/L during the study and ranged between 0.70 and 2.56 mg/L. Dissolved inorganic nitrogen (DIN) accounted for > 90% of TN regardless of season and location, indicating a nitrogen-rich system showing eutrophic∼hypereutrophic conditions. Some 67∼94% of DIN was NO₃-N, whereas mean level of NH₄-N was less than 5% of DIN. During monsoon 1993, dilution of NO₃-N was evident in the headwaters as a result of mixing of lake water with rain water, while NH₄-N increased> 100% compared to the premonsoon. Values of NH₄-N had a positive correlation with rainfall (r = 0.85; p < 0.001) and negative correlations with theoretical water residence time (r = 0.90; p < 0.001) and conductivity (r = -0.78, p < 0.001), respectively. These outcomes suggest that NH₄-N came from external input from the watershed during the monsoon. In both years, mean TN was greater in the mid-lake sites than any other sites. A great amount of TN in the midlake was most pronounced in monsoon 1994 because of an accumulated influence of the point sources during low inflow. Overall data suggest that concentrations of TN in this system did not show large differences along the longitudinal gradients and its distributions is likely determined by point-sources rather than inflow regime.

금강 (錦江) 담수어의 (淡水魚) 대상분포와 (帶狀分布) 군집분석에 (群集分析) 관한 연구

안광국,홍영표,김재구,최신석 한국수생태학회(구 한국하천호수학회) 1992 생태와 환경 Vol.25 No.2

대청호의 취수탑 주변의 이화학적 , 생물학적 상태에 대한 계절경강우의 영향

안광국,서진원,박석순 한국수생태학회(구 한국하천호수학회) 2001 생태와 환경 Vol.34 No.4