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Zhong M.-S.,Beijing Municipal Research Institute of Environmental Protection | Zhong M.-S.,Beijing Key Laboratory for Risk Modeling and Remediation for Contaminated Sites | Jiang L.,Beijing Municipal Research Institute of Environmental Protection | Jiang L.,Beijing Key Laboratory for Risk Modeling and Remediation for Contaminated Sites | And 11 more authors.
Research of Environmental Sciences | Year: 2014

Generic soil screening values for 27 kinds of VOCs (volatile organic compounds), 31 kinds of SVOCs (semi-volatile organic compounds), 11 kinds of pesticides, PCBs and dioxin were derived for groundwater protection according to different hydro-geological conditions in Beijing using two methods: three-phase equilibrium equation combined with groundwater dilution model (method 1) and SESOIL model combined with groundwater dilution model (method 2). The results revealed that the screening values for the downstream areas of the Yongding River alluvial-proluvial fan were the most conservative, followed by the values for the upstream and middle areas. The screening values derived with method 1 for the middle areas were 1.1-1.4 times and 9.9-34.9 times those for the upstream and downstream areas, respectively, while the values for the upstream areas were 10.7-24.9 times those for the downstream areas. For method 2, the values for the middle areas were 9.8-49.9 times those for the downstream areas. In addition, for the areas in the middle and downstream where continuous aquitard existed, the screening values derived by method 2 were more conservative than those derived by method 1. For PAHs, PCBs, dioxin, most pesticides and esters, whose Koc (organ-water partition coefficients) were high, the results derived by method 2 indicated they would hardly penetrate the clean soil in the vadose zone, meaning less risk of groundwater contamination. For VOCs and phenols, whose Koc were low, the values derived with method 2 were 4.3-18.4 times those derived by method 1 for the middle areas, and 3.0-24.6 times those for the downstream areas. Given the conservative nature of the generic screening levels and its risk screening function, the conservative values among screening levels derived for the upstream areas with method 1 and for the middle and downstream areas with method 2 were recommended as the generic screening values of Beijing to prevent groundwater contamination from soil pollution. Source


Li T.-T.,Beijing Municipal Research Institute of Environmental Protection | Li T.-T.,Beijing Key Laboratory for Risk Modeling and Remediation for Contaminated Sites | Li T.-T.,Capital Normal University | Zhong M.-S.,Beijing Municipal Research Institute of Environmental Protection | And 11 more authors.
Research of Environmental Sciences | Year: 2013

Two assessment methods, three-phase equilibrium in combination with groundwater dilution model recommended by US EPA and Sesoil in combination with groundwater dilution model recommended by New Jersey, were compared for evaluating impacts on groundwater through backfilling soil contaminated by 1, 2-dichloroethane and other 9 organic pollutants. The results showed that the concentrations of the 10 contaminants in groundwater predicted by the US EPA method were 3-10 times of those predicted by the New Jersey method. The difference was much more obvious by an order of magnitude, when the Henry's law constants and the carbon-water adsorption factors of the contaminants were high. However, the difference was not significant regarding to strong hydrophobic contaminants such as PAHs. Generally, the method recommended by US EPA was conservative and needs less parameter inputs, which would be a cost saving tool. Moreover, this method could be applied to drive general soil screening levels at the national level or regional scale to protect groundwater. In a case that concentrations of contaminants in soil were higher than the corresponding general screening values, further intensive hydro-geological investigation and sophisticated Sesoil with groundwater dilution model is recommended for further evaluation or calculation of the site-specific screening to save the remediation costs. Source

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