• Journal of the Korean Chemical Society
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• v.29 no.3
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• pp.247-251
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• 1985

Dichloro cobalt(III) complex of a flexible tetradentate ligand of ethylenediamine-N,N'-di-S-${\alpha}$-propionic acid (eddp) has been prepared via the air-oxidation technique. Only ${\Delta}$-cis isomer has been yielded showing high stereoselectivity of the eddp ligand. Elemental analysis, ir, nmr and electronic absorption spectra have been used to characterize the complex and the absolute configuration of the complex is assigned by means of the nmr spectroscopy.

• Journal of Environmental Science International
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• v.15 no.4
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• pp.293-304
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• 2006

Sea water samples collected in August, 1994 from 20 stations in the Kwangyang Bay were analyzed by gas chromatography/mass spectrometry-selected ion monitoring (GC/MS-SIM) to investigate persistence and distribution pattern of four organophosphorus pesticides (DDVP, Diazinon, IBP, EDDP). Except for IBP, the contamination by DDVP, Diazinon, and EDDP in marine aquatic environment in Korea has not been reported previously. In this study, however, all these four pesticides were detected in all stations (except DDVP) and their concentrations were in ng/L level. The concentrations ranged from detection limit to 15.3ng/L for DDVP, 1.8-27.7ng/L for Diazinon, 7.3-63.5ng/L for IBP, and 22.2-1100.1ng/L for EDDP. It is noteworthy that the measured concentrations of IBP and EDDP in this study would be much lower than usual, since the use of IBP and EDDP was less than 50% of average annual consumption due to unusually dry and hot weather condition in the summer of 1994. It was very surprising to find that the highest concentrations of organophosphorus pesticides were observed at stations near Daesa Streamlet instead of Seomjin River, which has more point source of the pesticides. This result suggests that the small river discharge during heavy ram period in summer can give harmful effect on marine biota (both wild and aqua-cultured) with its organophosphorus pesticide residue, despite of their short residence time in aquatic environment. In order to protect the marine life properly from acute toxicity of the organophosphorus pesticides, it needs to be emphasized that monitoring the level of agricultural pesticides in river run-off should be done during active consumption period rather at regular intervals.

• Journal of the Korean Society for Marine Environment & Energy
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• v.5 no.1
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• pp.38-50
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• 2002

To study the distribution of organophosphorus pesticides which are extensively used for agriculture in Korea. Surface sea water samples were taken from 2 coastal areas during July and :;eptember of 1999 and sediment samples were collected from Kyeonggi bay in July of 1999. These samples were analyzed using a Gas Chromatography/Nitrogen Phosphorus Detector(GC/NPD). In coastal waters of the study areas IBP was commonly found the most compound. Traces of Diazinon, DDVP, Ethoprouhos and Chlorpyrifos were also encountered. Concentration of the other major organophosphorus pesticides(Disulfoton, Parathion Methyl, Fenchlorfos, Prothiofos, EDDP) were generally be below the detection limit of the employed analytical method. Tn sediment of the study areas Chlorpyrifos w3s found the most compound. Temporal and geographical distribution of individual organophosphorus pesticides is likely to be affected by types of agricultural practices in the watershed.

• Fisheries and Aquatic Sciences
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• v.4 no.4
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• pp.201-207
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• 2001

To study the distribution of organophosphorus pesticides which are extensively used for agriculture in Korea. Sea water samples were taken from 4 coastal areas during May and August of 1997 and sediment samples were collected from two coastal areas in August of 1997. These samples were analyzed using a Gas Chromatography/Nitrogen Phosphorus Detector (GC/NPD). In August the most commonly found organophosphorus pesticides in the surface waters of Kunsan area were IBP < S-Benzyl O,O-di-isopropyl phosphorothioate > $(m=432.5ng\;L^{-1})$ and EDDP < O-ethyl S,S-diphenyl phosphorodithioate > $(m=37.4ng\;L^{-1}) $ which are largely used between June and September to prevent rice blast disease. In Danghang Bay, dry fields located near the mouth of the estuary seemed to affect the concentrations of certain organophosphorus pesticides in the surface waters. Since organophosphorus pesticides applied in the watershed are rapidly decomposed while being transported along freshwater streams, watershed size is not proportional to the concentrations of these pesticides in the coastal waters. Pesticides concentrations measured in August were compared with those in May. IBP concentrations in coastal waters were about an order of magnitude higher in August than in May. Temporal and geographical distribution of individual organophosphorus pesticides is likely to be affected by types of agricultural practices in the watershed. Chloropyrifos was the most important of the organophosphorus pesticides in the sediments of the study area because of its persistent nature and high affinity to particulates.