• Journal of the Korean Society of Marine Environment & Safety
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• v.3 no.S1
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• pp.77-90
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• 1997

the observations in situ and the seawater analyses were conducted in July and August, 1996 for the purpose of evaluating the characteristics of seawater quality centered on eutrophication in Mokpo harbour. By applying the OECD standards of trophic classification to the parameters such as secchi depth, total inorganic nitrogen, phosphate phosphorus and chlorophyll-a, the trophic level of seawater in Mokpo harbour was evaluated to be in eutrophic state in summer. By the estimation of pollution index with relation to eutrophication, the seawater quality of Mokpo harbour was evaluated to be under the regular grades and this evaluation was found to be different from the results of evaluation obtained by the environmental index of single parameter, chemical oxygen demand. By the estimation of eutrophication index, the seawaters of Mokpo harbour were shown to have the high potentiality of red tide occurrence.

• Journal of the Korean Society for Marine Environment & Energy
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• v.4 no.3
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• pp.3-15
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• 2001

The in situ observations and the seawater analyses were conducted for 3 years from August 1996 to August 1999 in order to elucidate and evaluate seasonal variations of marine water quality and trophic state in Mokpo harbour of Korea. Compared the seasonal seawater qualities of Mokpo harbour with the OECD standards of trophic classification in parameters such as Secchi depth, dissolved inorganic nitrogen, phosphate phosphorus and chlorophyll-a, the trophic level of seawater in Mokpo harbour was evaluated to be in mesotrophic or eutrophic state through all 4 seasons and to be in eutrophic state, particularly In summer. The estimation of pollution index by eutrophication showed the seawater quality of Mokpo harbour to deteriorate and fall under the regular grades through all 4 seasons, although the seawater quality of Mokpo harbour was evaluated to be equivalent to the second or third class of the Korean seawater quality standards in view of COD values. The results of eutrophication index estimation showed the high potentiality of red tide occurrence In Mokpo harbour, particularly in summer or fall. In the light of the average atomic ratio of N/P in seawater, the limiting nutrient factor against the growth of phytoplankton was concluded to be phosphorus rather than nitrogen in Mokpo Harbour.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.1
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• pp.15-24
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• 2012

This study aims to investigate characteristics of water quality factors by using survey results of national marine environmental monitoring system from 2004 to 2010 at coastal area of the East Sea of Korea. In this study, we chose statistical methods to analyze the correlation among water quality parameters and principal component analysis for characteristics of each water environment. In addition to this, we evaluated each water's pollution level based on eutrophication standard of OECD, Eutrophication Index(EI), and Organic Pollution Index(OPI). Major factors were chlorophyll a and salt according to the analysis at coastal area of the East Sea. The sea was divided into the south and the central part by Jukbyeon. Also, Jukbyeon in the central part of the East Sea and Gampo in the southern sea coastal waters have been classified separately. The nutritional status of coastal area of East Sea presented Mesotrophic to Oligotrophic level and EI showed less than 1. OPI in all of the coastal area at the East Sea represented that the water quality condition was favorable.

• Journal of the Korean Society of Marine Environment & Safety
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• v.3 no.2
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• pp.51-61
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• 1997

The in situ observations and the seawater analyses were conducted in July and Auguse, 1996 for the purpose of evaluating the characteristics of seawater quality centered about eutrophication in Mokpo harbour. By applying the OECD standards of trophic classification to the parameters such as secchi depth, total inorganic nitrogen, phosphate phosphorus and chlorophyll-a, the trophic level of seawater in Mokpo harbour was evaluated to be in eutrophic state in summer. The estimation of pollution index by eutrophication showed the seawater quality of Mokpo harbour to deteriorate and fall under the regular grades. The results of eutrophic index estimation showed the high otentiality of red tide occurrence in Mokpo harbour.

• Journal of Environmental Science International
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• v.31 no.6
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• pp.491-501
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• 2022

This study evaluated the contamination levels of inland pollution sources flowing into Taeanhaean National Park. The nutritional status of influents was assessed by analyzing water quality and trophic status index (TRIX) at 52 stations, and the contamination levels of sediments were evaluated by analyzing eutrophication cleanup index (CIET) and heavy metals at 36 stations. The results of the TRIX analysis showed that 26 of the 52 stations had influents with a TRIX value of 6-10 (poor water quality/very high trophic level), indicating atrocious water quality and high eutrophication levels. The results of the CIET analysis showed that 4 out of the 36 stations were highly contaminated with organic matter. Analysis of heavy metals showed that the copper (Cu) and zinc (Zn) levels exceeded the threshold effects level (TEL) and probable effects levels (PEL) at several stations. In addition, the arsenic (As) level exceeded the threshold effects level at one station, and the levels of the other heavy metals (Cd, Cr⁶⁺, Ni, Pb, and Hg) were lower. Most inland pollution sources have been identified as small-scale, but long-term and continuous exposure can negatively affect the marine ecosystem; therefore, it necessary to prepare inland pollution source management standards and measures suitable for the characteristics of the coastal area.

• Journal of Environmental Science International
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• v.19 no.11
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• pp.1445-1456
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• 2010

This study presented seasonal changes of the phytoplankton community in Junam reservoir by pollution and water quality of the lake. The water storage of the reservoir is 5.3 million ton, most of which are being utilized for agricultural, industrial and residential purposes. The annual precipitation during the investigation period was 1,868.9 mm, increasing by 20% from the average annual level of 1,506.7 mm in 2009. The annual average water storage was 57.3%. It decreased during agricultural season and then increased again after monsoon rainfall. The loads of BOD were $3,799kgday^{-1}$, and 81% of them came from livestock and household. The TN and TP loads were $1,164kgday^{-1}$ and $170kgday^{-1}$, respectively, and 76% of them came from livestock. We assessed water quality of the Junam reservoir using 17 variables. According to the result, the reservoir met the fourth grade, meaning slightly bad, because of high concentration of COD, SS and chlorophyll-a. Eutrophication assessment was conducted by revised Carlson's Index (TSIm, Aizaki), and it was found that the entire lake was eutrophicated with high chlorophyll-a concentration all through the year, except during February to April and in July. A total of 76 phytoplankton species were identified from the samples. Among them, the largest number of species were Chlorophyceae with 33 species(43.4%), followed by Bacilliophyceae with 27 species(35.5%), Cyanophyceae with 8 species(10.5%), and Cryptophyceae with species(10.5%). The total cell number of phytoplankton was the highest in October(7,884 cells $mL^{-1}$) among Cyanophyceae and Bacilliophyceae. The seasonal succession of Chlorophyceae (Chlamydomonas spp.), Cyanophyceae(Microcystis aeruginosa) and Cryptophyceae(Rhodomonas spp.) was observed during January to May, July to September and October to December respectively.

• Journal of Ocean Engineering and Technology
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• v.20 no.1 s.68
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• pp.55-62
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• 2006

Recently, pollution by development in coastal areas is going from bad to worse. The Korean government is attempting to make policies that prevent water pollution, but it is still difficult to say whether such measures are lowering pollution to an acceptable level. More specifically, the general investigation that has been done in KOREA does not accurately reflect the actual conditions of pollution in coastal areas. An investigation that quantitatively assesses water quality management using rational prediction technology must be attempted, and the ecosystem model, which incorporates both the 3-dimensional hydrodynamic and material cycle models, is the only one with a broad enough scope to obtain accurate results. The hydrodynamic model, which includes advection and diffusion, accounts for the ever-changing flow and (quality) of water in coastal areas, while the material cycle model accounts for pollutants and components of decomposition as sources of the carbon, phosphorus, and nitrogen cycles. In this paper, we simulated the rates of dissolved oxygen (DO), chemical oxygen demand (COD), total nitrogen(T-N) and total-phosphorous(T-P) in Korea's Ulsan Area. Using the ecosystem model, we did simulations using a specific set of parameters and did comparative analysis to determine those most appropriate for the actual environmental characteristics of Ulsan Area. The simulation was successful, making it now possible to predict the likelihood of coastal construction projects causing ecological damage, such as eutrophication and red tide. Our model can also be used in the environmental impact assessment (EIA) of future development projects in the ocean.

• Journal of Wetlands Research
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• v.20 no.4
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• pp.330-337
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• 2018

The Korean Eutrophication Index($TSI_{ko}$) was estimated using water quality monitoring data of eight main sites in the SoOoak River watershed. The environmental characteristics of rivers were classified and evaluated using the $TSI_{ko}$ for each factor calculated by COD, T-P, and Chl-a. There is a good condition for the algae to grow due to shallow water depth, inflow of non-point source pollution during rainfall, influx of sewage treatment effluent and increase of residence time. It shows trophic state more than mesotrophication year round. Especially, in case of Chuso point, which is the inflow point of Daecheong Lake, the water quality deteriorated due to hydraulic characteristics and showed the eutrophic state. Therefore, it is necessary to establish the measures to improve the water quality through the precise monitoring of SoOak River.

• Journal of Environmental Science International
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• v.21 no.11
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• pp.1349-1360
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• 2012

This study presented the phytoplankton communities of the three lakes (Sayeon, Daeam, Hoeya ) using for drinking water in the Ulsan reservoir. The water storage of the Lake Sayeon, Daeam and Hoeya were 25, 13, 21 million ton respectively and most of which were being utilized for industrial and residential purposes. The total precipitation of the Ulsan region in 2010 was 1,162 mm, decreasing 10 % from 1,275 mm of the annual. As for pollutant loads, BOD and TN discharge loads of Daeam was the highest with 3,277 kg/day, 1,931 kg/day and 90 % of them were came from non-point pollutant sources. TP discharge loads showed the highest in the lake Hoeya with 643 kg/day and 97 % of them were came from point sources as household, industry and livestock. We assessed water quality of the lake Sayeon, Daeam and Hoeya using 17 variables. The water quality assessment found that the lake Daeam met the fourth to fifth grade because of high concentration of COD, SS and chlorophyll-a. Eutrophication assessment was conducted by revised Carlson's Index (TSIm, Aizaki) and found that Lake Daeam was more eutrophicated than the other two lakes all the year through as for chlorophyll-a, transparency and the total phosphorus (TP). A total of 95~111 phytoplankton species were identified from the three lake samples. Among them, the largest number of species were Chlorophyceae with 35~51, followed by Bacillariophyceae with 36~45, Cyanophyceae with 9~11, and Cryptophyceae with 6~9 species. The total cell number of phytoplankton was the highest in February (15,254 cells/mL) with Bacillariophyceae in the lake Daeam and the seasonal succession shows that Bacillariophyceae (Stephanodiscus spp.) in the spring, Cyanophyceae (Anabaena spp.) in the summer and the autumn, Bacillariophyceae (Stephanodiscus spp.) in the winter.

• Journal of Environmental Science International
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• v.23 no.9
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• pp.1537-1549
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• 2014

The objectives of this study were to analyze reservoir trophic state, based on Trophic State Index (TSI), spatial variation patterns of three zones (riverine, transition, and lacustrine zone), and empirical models through 20-years long-term data analysis. Trophic variables of TP and CHL-a were highest during the summer monsoon, and decreased along the main axis from the riverine to lacustrine zone. In the mean time, TN did not show the trend. Ratios of N:P and Secchi disc transparency (SD) increased from the riverine to lacustrine zone. The analysis of trophic state index (TSI) showed that mean TSI (TP) and TSI (CHL-a) were 62 and 57, respectively, and these values were highest in the transition zone during the summer. This zone should be managed well due to highest lake water pollution. The analysis of Trophic State Index Deviation (TSID) showed that algal growth was primarily limited by light penetration, and this was most pronounced in the monsoon season. The analysis of empirical models showed that the value of $R^2$, based on CHL-SD model, was 0.30 (p < 0.0001) in the transition zone and the $R^2$, based on TP-SD model, was 0.41 (p < 0.0001) in the transition zone.