• Korean Journal of Ecology and Environment
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• v.41 no.3
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• pp.275-282
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• 2008

Water hardness is a significant parameter as related to aquatic toxicity of some heavy metals. Hardness dependent metals include cadmium, copper, chromium (III), nickel, lead, zinc and silver. Developed countries have applied the hardness correction procedure to derive the water quality criteria for protecting the aquatic organisms. In the present study, we investigated the hardness correction algorithms used in United States of America, European Union, Australia/New Zealand, and Canada, and analyzed the details associated with those algorithms. Toxicity values of heavy metals were definitely different after hardness correction for all of algorithms analyzed. We found that the hardness corrected toxicity values followed by the algorithms of USA and Australia/New Zealand were very similar or same, however they were slightly different for cadmium at the hardness less than 30 mg $CaCO_3\;L^{-1}$. Among the hardness correction algorithms studied, the algorithm used in Australia/New Zealand appears to be a good choice to apply in Korean situation due to its simplicity compared to the algorithm of USA.

• Korean Journal of Environmental Agriculture
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• v.21 no.2
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• pp.96-101
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• 2002

This study was conducted to survey and identify kinds and population of the freshwater invertebrate fauna according to the managements of paddy rice fields at Ok-Chun and Yang-Pyung. The experiment was conducted in 4 paddy plots; conventional fertilization plot (CF), fertilization by prescription with soil testing with (ST+A) or without soil amendment (ST), and no fertilization as the control. In addition, the freshwater invertebrate fauna was also surveyed at 3 sections of as upper, intermediate and down, in both Jitan and Bungsan stream. The total number of the freshwater invertebrates was higher in the order of ST>CF>ST+A>C and ST>ST+A>CF>C at Ok-Chun and Yang-Pyung, respectively. The population density of aquatic insects was higher in plots fertilized by prescription with soil testing than in the other plots at both demonstration villages. The freshwater invertebrates collected in Jitan and Bungsan stream were identified and classified into 59 families and 90 species, and their population density was highest in the downstream among.

• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.1
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• pp.99-118
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• 2012

The aim of this study is to define a correlation between spatial distribution characteristics of FFG(Functional Feeding Groups) of aquatic insects and related environmental factors in the Geum River based on the theory of RCC(River Continuum Concept). For that objective we had used SMRA(Stepwise Multiple Regression Analysis) method to analyze close relationship between the distribution of aquatic insects and the physical and chemical factors that may affect their inhabiting environment in the study area. And then, a probabilistic method named Frequency Ratio Model(FRM) and spatial analysis function of GIS were applied to produce a predictive distribution map of biota community considering their distribution characteristics according to the environmental factors as related variables. As a result of SMRA, the values of decision coefficient for factors of elevation, stream width, flow velocity, conductivity, temperature and percentage of sand showed higher than 0.5. Therefore these 6 environmental factors were considered as major factors that might affect the distribution characteristics of aquatic insects. Finally, we had calculated RMSE(Root Mean Square Error) between the predicted distribution map and prior survey database from other researches to verify the result of this study. The values of RMSE were calculated from 0.1892 to 0.4242 according to each FFG so we could find out a high reliability of this study. The results of this study might be used to develop a new estimation method for aquatic ecosystem with macro invertebrate community and also be used as preliminary data for conservation and restoration of stream habitats.

• The Korean Journal of Pesticide Science
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• v.15 no.1
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• pp.48-54
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• 2011

Risk assessments of pesticides detected in six major rivers during peak season were estimated for algae, Daphnia, and fish using hazard quotient (HQ) indexes. The eight pesticides (isoprothiolane, hexaconazole, diazinon, chlorpyrifos, prothiofos, alachlor, butachlor, molinate) were detected within the range of 0.027~12.871 ${\mu}g/L$. Detection frequency of isoprothiolate was estimated to be high at 67.5%, and those of the others varied from 15.0 to 37.5%, Hazard Quotients (HQ) indexes varied by freshwater organisms (algae, Daphnia, and fish). Overall, the ecological risk probability due to exposure of pesticides detected in major rivers did not reveal based on HQ indexes below 1.0. Particularly, butachlor and molinate for algae, chlorpyrifos, diazinon, prothiofos for Daphnia, and chlorpyrifos for fish acted as dominant contributors in increasing the ecological risk in six major rivers. This implied that integrated ecological risk assessment is required using various biological species, reflecting toxicity sensitivity. This study may provide the essential data in establishing the priority for pesticides management in major rivers, Korea.

• KLA journal
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• v.24 no.6
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• pp.12-18
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• 1983

• KLA journal
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• v.23 no.5
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• pp.4-12
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• 1982

• Bulletin of Korea Environmental Preservation Association
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• v.12 no.8
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• pp.2-3
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• 1990

• Hwankyungkyoyuk
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• v.10 no.1
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• pp.35-38
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• 1997

• Korean Architects
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• no.1 s.405
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• pp.58-63
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• 2003

• Korean Journal of Environment and Ecology
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• v.22 no.5
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• pp.544-550
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• 2008

This study conducted a survey on the ecosystem of Wonju stream from May until November in 2004 and made an health assessment of Wonju stream using family biotic indices(FBI) and physical habitat assessment(PHA) of the aquatic insects. Through this survey, aquatic insects covering 8 orders, 37 families, 62 genuses, and 92 species were observed at 9 stations along Wonju stream. In terms of family biotic indices, it was confirmed that station 1,2 and 3 were maintaining the healthiest stream ecosystem with the value ranging from 4.55 to 4.82. In addition, station 2 was found to have the best habitat environment in the correlation between physical habitat assessment and family biotic indices with its value of 100 and 4.82, respectively. However, station 7 and 9 showed the lowest habitat environment with the value of 45, 6.17 and 45, 6.97, respectively. posing the need for improvement in PHA; further, station 7 and 9 showed inverted correlationship between PHA and FBI.