2007, Vol.16, No.1

Journal of Environmental Impact Assessment 2023 KCI Impact Factor : 0.51

pISSN : 1225-7184
https://journal.kci.go.kr/kseia

This study was carried out to estimate the emission reduction rates for the regional allowableemissions by special measures to achieve the target air quality in Seoul Metropolitan Area(SMA).A modeling system was designed to validate the details in enforcement regulations set up bylocal governments based on the current status and plans for air quality improvement.Modeling system was composed of meteorological model (MM5), emission model (SMOKE),and air quality model (CMAQ). Predicted results by this system show quiet well not only dailyair pollutants concentration but also the tendencies of wind direction, wind speed andtemperature.To achieve the target air quality in Seoul Metropolitan Area (SMA), emission allowances areestimated by seasons and regions. Referring to the base year 2002, it was estimated thatemission reduction rates to achieve the intermediate goal in 2007 were 14.2% and 16.6% forNOx and PM10, respectively. It was also estimated that 52% of NOx and 48% of PM10reductions from the base year 2002 would be required to accomplish the air qualityimprovement goal of 22 ppb for NO2, and 40 mg/m3for PM10 in year 2014.To improve NO 2 and PM 10 concentration through emissions reduction policies, it was foundthat emissions reduction for the on-road mobile sources would be the most effective in SMA.

Surface water is the main drinking water source in Korea. Algal bloom caused byphytoplankton in reservoir is common event in every summer season. To prevent or control thealgal blooms, artificial circulation system has been adopted in many reservoirs, includingHoengseung reservoir. Total 7 hydraulic-gun-aerators were installed around the intake tower inHoengseung reservoir since 2000. This study is to elucidate the effects of hydraulic-gun-aeratorson phytoplankton bloom, pH, DO, temperature and evaluate the selective withdrawal andvertical distribution of phytoplankton by means of submersible fluorescence probe, whichfeatures high correlation with a standard ISO method (r=0.90, P<0.0001) for chlorophyll-aquantification.

Hexavalent chromium-contaminated soils are encounted at many unregulated discharge andimproper handling of wastes from electroplating, leather tanning, steelmaking, corrosioncontrol, and wood preservation industries. Contamination of hexavalent chromium in the soil isa major concern because of its toxicity and threat to human life and environment.Current technologies for hexavalent chromium-contaminated soil remediation are usuallycostly and/or cannot permanently prohibit the toxic element from entering into the biosphere.Thus, as an alternative technique, immobilization is seen as a cost-effective and promisingremediation technology that may reduce the leachable potential of hexavalent chromium.The purpose of this paper is to develope an immobilization technique for the formation of thegeochemically stabilized hexavalent chromium-contaminated soil from the reactions of labilesoil hexavalent chromium forms with the added soluble phosphate and chromium reducingagent. From the liquid phase experiment, reaction order of chromium reducing agent, solublephosphate, alkali solution shows the best removal efficiency of 95%. In addition, actual soilphase experiment demonstrates up to 97.9% removal efficiency with 1:1 molar ratio ofchromium reducing agent and soluble phosphate.These results provide evidence for the potential use of soluble phosphate and chromiumreducing agent for the hexavalent chromium-contaminated soil remediation.