• Journal of Environmental Science International
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• v.12 no.7
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• pp.689-695
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• 2003

The purpose of this study is to evaluate and to predict of eutrophication in lakes by using Vollenweider-OECD model and total phosphorus concentration and inflow rate which were measured in 1993∼2001. The results of study were as follows. The annual total phosphorus loading from the watershed was calculated to be 55∼195tP/yr at lake Soyang, 221∼466tP/yr at lake Taechong, 123∼278tP/yr at lake Andong, 57∼109tP/yr at lake Seomjin. These are discharged, far the most parts, from population and fishfarm facility. TP loading on the surface area at lake Soyang was 3.01gP/㎡/yr, 2.82gP/㎡/yr, 2.84gP/㎡/yr, 3.03gP/㎡/yr, 2.34gP/㎡/yr, 1.78gP/㎡/yr, 0.91gP/㎡/yr, 0.89gP/㎡/yr, 0.86gP/㎡/yr, lake Taechong was 6.71gP/㎡/yr, 7.25gP/㎡/yr, 7.24gP/㎡/yr, 6.53gP/㎡/yr, 6.50gP/㎡/yr, 7.06gP/㎡/yr, 7.04gP/㎡/yr, 4.05gP/㎡/yr, 3.44gP/㎡/yr and TP loading on the surface area of lake Andong, lake Soemjin were 5.39gP/㎡/yr, 4.47gP/㎡/yr, 4.56gP/㎡/yr, 4.45gP/㎡/yr, 3.33gP/㎡/yr, 2.38gP/㎡/yr, 2.53gP/㎡/yr, 2.46gP/㎡/yr, 2.54gP/㎡/yr, 4.09gP/㎡/yr, 4.10gP/㎡/yr, 3.98gP/㎡/yr, 3.73gP/㎡/yr, 2.80gP/㎡/yr, 3.46gP/㎡/yr, 3.22gP/㎡/yr, 2.19gP/㎡/yr, 2.13gP/㎡/yr respectively. The tropic states of four lakes can be assessed as eutrophy because phosphorus leading exceeds the critical phosphorus loading by Vollenweider-OECD model.

• Journal of Environmental Science International
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• v.7 no.4
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• pp.441-450
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• 1998

The purpose of this study is to evaluate and to predict of eutrophication in lakes by using VollenweiderGECD model and total phosphorus concentration and inflow rate which were measurded in 1993-1996. The results of study was as follows. The annual total phosphorus loading from the watershed was calculated to be 181-195tP /yr at lake Soyang, 591-680tP/yr at lake Chungju, 420-466tP/yr at lake Taechong, 229-278tP/yr at lake Andong, 103-106tP/yr at lake Hapchon, 57-59tP/yr at lake Imha, 194-244tP/yr at lake Namgang, 8386tP /yr at lake Chuam, 99-109tP /yr at lake Somjin. These are discharged, for the most parts, from population and ftshfarm facility. TP loading on the surface area at lake Soyang was 3.0lgP/$m^2$/yr, 2.82gP/$m^2$/yr, 2.84gP/$m^2$/yr, 3. 03gP/$m^2$/yr, at lake Chungju 7.91gP/$m^2$/yr, 6.87gP/$m^2$/yr, 7.38gP/$m^2$/yr, 7.l8gP/$m^2$/yr, at lake Taechong 6.7lgP/$m^2$/yr, 7.25gP/$m^2$/yr, 7.24gP/$m^2$/yr, 6.53gP/$m^2$/yr and TP loading on the surface area of Nakdong river basin, that is, lake Andong, Imha, Hapchon and Namgang were 5.39gP/$m^2$/yr, 4.47gP/$m^2$/yr, 4. 56gP/$m^2$/yr, 4.45gP/$m^2$/yr and 2.20gP/$m^2$/yr, 2.23gP/$m^2$/yr, 2.24gP/$m^2$/yr, 2.l7gP/$m^2$/yr and 4.50gP/$m^2$/ yr, 4.50gP/$m^2$/yr, 4.54gP/$m^2$/yr, 4.43gP/$m^2$/yr and 8.25gP/$m^2$/yr, 8.48gP/$m^2$/yr, 8.48gP/$m^2$/yr, 10. 39gP/$m^2$/yr respectively. Also those of lake Chuam was 2.51gP/$m^2$/yr, 2.61gP/$m^2$/yr, 2.52gP/$m^2$/yr, 2. 54gP/$m^2$/yr and TP loading on the surface area at lake Somjin was analysed 4.09gP/$m^2$/yr, 4.l0gP/$m^2$/yr, 3.98gP/$m^2$/yr,3.73gP/$m^2$/yr. The tropic states of nine lakes can be assessed as eutrophy because phosphorus loading exceeds the critical phosphorus loading by Vollenwelder-GECD model.

• Korean Journal of Ecology and Environment
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• v.37 no.4 s.109
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• pp.411-422
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• 2004

A limnological survey was conducted in a reservoir, Lake Hoengsung located in Kangwondo, Korea, from July 2000 to September 2001 on the monthly basis. Phosphorus loading from the watershed was estimated by measuring total phosphorus concentration in the main tributary. Secchi disc transparency, epilimnetic (0-5 m) turbidity, chlorophyll a (Chl-a), total phosphorus (TP), total nitrogen(TN) and silica concentration were in the range of 0.9-3.5 m, 0.1-8.5 NTU, 0.3-32.4 mgChl $m^{-3}$, 5-46 mgP $m^{-3}$, 0.83-3.55 mgN $L^{-1}$ and 0.5-9.6 mgSi $L^{-1}$, respectively. Green algae and cyanobacteria dominated phytoplankton community in warm seasons, from July through October, 2000. In July a green alga (Scenedesmus sp.) was dominant with a maximum cell density of 10,480 cells mL. Cyanobacteria (Microcystics sp.) dominated in August and September with cell density of 3,492 and 295 cells mL ,respectively. Species diversity of phytoplankton was highest (2.22) in July. The trophic state of the reservoir can be classified as eutrophic on the basis of TP, Chl-a, and Secchi disc transparency. Because TP concentration was high in flood period, most of phosphorus loading was concentrated in rainy season. TP loading was calculated by multiplying TP and flow rate. The dam managing company measured inflow rate of the reservoir daily, while TP was measured by weekly surveys. TP of unmeasured days was estimated from the empirical relationship of TP and the flow rate of the main tributary; $TP=5.59Q^{0.45}\;(R^2=0.47)$. Annual TP loading was calculated to be 4.45 tP $yr^{-1}$, and the areal P loading was 0.77 gP $m^{-2}\;yr^{-1}$ which is similar to the critical P loading for eutrophication by Vollenweider's phosphorus model, 0.72 gP $m^{-2}\;yr^{-1}$.

• Korean Journal of Ecology and Environment
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• v.34 no.1 s.93
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• pp.30-44
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• 2001

In this study limnological characteristics of Lake Juam was surveyed from June 1993 to May 1994 in order to provides important information regarding water resources. Secchi disc transparency, epilimnetic chlorophyll a (chi-a), total nitrogen (TN), total phosphorus (TP) concentration and primary productivity were in the range of $2.0{\sim}4.5\;m$, $0.9{\sim}13.6\;mgChl/m^3$, 0.78$\{sim}$2.32 mgN/l, $11{\sim}56\;mgP/m^3$, $270{\sim}2.160\;mgCm^{-2}\;day^{-1}$, respectively. On the basis of TP, Chl-a and Secchi disc depth, the trophic state of Lake Juam can be classied as mesotrophic lake. The phosphorus inputs from non-point sources are concentrated in heavy rain episodes during the monsoon season. As a result, phosphorus concentration are higher in summer than in winter. TP loading from the watershed were estimated to be $0.9\;gPm^{-2}yr^{-1}$, which correspond to a boundary of the critical loading ($1.0\;gPm^{-2}yr^{-1}$) for eutrophication. From the results of the algal assay, both phosphous and nitrogen act as limiting nutrients in algal growth. The seasonal succession of phytoplankton community structure in Lake Juam was similar to that observed in other temperate lakes. Diatoms (Asterionella formosa and Aulacoseira granulate var. angustissima)fujacofeira BraHuJafa uar. aHgusHrsiaia) weredominant in spring and winter, cyanobacteria) were dominant in warm season. The organic carbon, nitrogen and phosphorus content of lake sediment were $9.5{\sim}14.0\;mgC/g$, $1.01{\sim}1.82\;mgN/g$ and $0.51{\sim}0.65\;mgP/g$, respectively. The allochthonous organic carbon loading from the watershed and autochthonous organic carbon loading by primary production of phytoplankton were determined to be 1,122 tC/yr and 6,718 tC/yr, respectively. To prevent eutrophication of Lake Juam, nutrient management of watershed should be focus on reduction of fertilizer application, proper treatment of manure, and conservation of topsoil as well as point source.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.3
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• pp.423-431
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• 2001

Animals are one of the important memberships of the food chain. The low-efficiency rule of nutrient transfer from one member to the next in the food chain determines the low efficiency of animal agriculture for human food. On the average, about 20% feed proteins and 15% feed energy can be converted into edible nutrients for humans. The rest proportion of feed nutrients is exposed to the environment. Environmental pollution, therefore, is inevitable as animal agriculture grows intensively and extensively. The over-loading of the environment by nutrients such as nitrogen, phosphorus from animal manure results in soil and water spoilage. The emission of gases like $CH_2$, $CO_2$, $SO_2$, NO, $NO_2$ by animals are one of the contributors for the acidification of the environment and global warming. The inefficient utilization of natural resources and the probable unsafety of animal products to human health are also a critical environmental issue. Improving the conversion efficiency of nutrients in the food chain is the fundamental strategy for solving environmental issues. Specifically in animal agriculture, the strategy includes the improvements of animal genotypes, nutritional and feeding management, animal health, housing systems and waste disposal programs. Animal nutrition science plays a unique and irreplaceable role in the control of nutrient input and output in either products or wastes. Several nutritional methods are proved to be effective in alleviating environmental pollution. A lot of nutritional issues, however, remain to be further researched for the science of animal nutrition to be a strong helper for sustainability of animal agriculture.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.5
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• pp.17-27
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• 2018

The objective of this study is to identify the priority area where the nonpoint source pollution (NPS) management is required and to set up the load reduction goals for the identified priority area. In this study, the load duration curve (LDC) was first developed using the flow and water quality data observed at 286 monitoring stations. Based on the developed LDC, the priority area for the NPS pollution management was determined using a three-step method. The 24 watersheds were finally identified as the priority areas for the NPS pollution management. The water quality parameters of concern in the priority areas were the total phosphorus or chemical oxygen demand. The load reduction goals, which were calculated as the percent reduction from current loading levels needed to meet target water quality, ranged from 67.9% to 97.2% during high flows and from 40.3% to 69.5% during moist conditions, respectively. The results from this study will help to identify critical watersheds for NPS program planning purposes. In addition, the process used in this study can be effectively applied to identify the pollutant of concern as well as the load reduction target.