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Zhang L.,Beijing Municipal Research Institute of Environmental Protection | Zhang L.,National Engineering Research Center for Urban Environmental Pollution Control | Zhang L.,Beijing Key Laboratory for Risk Modeling and Remediation of Contaminated Sites | Jiang L.,Beijing Municipal Research Institute of Environmental Protection | And 9 more authors.
Research of Environmental Sciences | Year: 2015

Exposure analysis and health risk assessment based on different scenarios (unrestricted land use (S1), multiple land use (S2) and multiple land use with underground space design (S3)) were carried out for a large-scale site contaminated by benzene in Beijing. The results showed that the primary exposure pathway was indoor vapor inhalation, with carcinogenic risks significantly higher than the acceptable level (1.0×10-6) based on the three scenarios. The results from S1 indicated that the indoor vapor inhalation was at a level of 9.2×10-5. The results from S2 based on multiple land use revealed that only the carcinogenic risk of region E exceeded the acceptable level (1.0×10-6), with the calculated carcinogenic risk at 4.3×10-4. However, if the inter-regional impacts were considered, region E caused the carcinogenic risks of all the neighboring regions to be higher than the acceptable level (1.0×10-6), with exposure concentrations of benzene about 3-5 orders of magnitude higher than those of the neighboring regions. The results from S3 revealed that the carcinogenic risks of region A, B and C were 1.2×10-7, 2.7×10-7, 2.5×10-7 respectively-lower than the acceptable risk. The risks of region E (2.7×10-5) were greatly mitigated due to contaminated soil excavation. The risk of region D was eliminated due to the excavation of all the contaminated soil, however, region D may still exceed the acceptable risk due to the impact from region E if region E is not cleaned up to meet the remediation goal. The present study concluded that land use plan and building design have great impacts on the results of risk analysis due to the impacts on calculation of exposure concentration and selection of site-specific parameters and exposure parameters and exposure pathways, and inter-regional impact analysis is also important if there is a highly elevated contamination region. ©, 2015, Editorial department of Molecular Catalysis. All right reserved. Source


Jiang L.,Beijing Municipal Research Institute of Environmental Protection | Jiang L.,Beijing Key Laboratory for Risk Modeling and Remediation of Contaminated Sites | Zhong M.-S.,Beijing Municipal Research Institute of Environmental Protection | Zhong M.-S.,Beijing Key Laboratory for Risk Modeling and Remediation of Contaminated Sites | And 10 more authors.
Huanjing Kexue/Environmental Science | Year: 2013

The procedures of implementing tiered health risk assessment approach were introduced in detail, and took a large-scale site polluted by benzene in Beijing as an example, the difference on the remediation target of benzene in soil, as well as the corresponding soil remediation volume and costs, were compared. The results indicate that the benzene concentration in soil within 1.5 m in depth and the one below should be remediated to 0.26 mg·kg-1 and 0.15 mg·kg-1, respectively, in order to keep the cumulative carcinogenic health risk below 1×10-6 based on tiered II assessment. However, according to tiered III assessment result, which is based on the benzene in soil gas within the contaminated areas in the investigated site, the soil in the corresponding depth should only be remediated to 2.6 mg·kg-1 and 1.5 mg·kg-1, respectively. That means the soil remediation volume delimited on tiered III assessment result is less than the one on tiered II by 139537 m3 and the corresponding remediation costs will be reduced by 57 million Yuan, meaning the enormous economic benefits compared to the costs (around 100 thousands Yuan) spent to carry out tiered III assessment in the site. Source


Zhong M.-S.,Beijing Municipal Research Institute of Environmental Protection | Zhong M.-S.,Beijing Key Laboratory for Risk Modeling and Remediation of Contaminated Sites | Jiang L.,Beijing Municipal Research Institute of Environmental Protection | Jiang L.,Beijing Key Laboratory for Risk Modeling and Remediation of Contaminated Sites | And 12 more authors.
Huanjing Kexue/Environmental Science | Year: 2013

The tiered approach for assessing the impact of backfilling treated contaminated soil on groundwater was presented in details with a case study. The soil was contaminated by 1, 2-dicholorenthane and 9 other organic pollutants and had been remediated before backfilling to meet the pre-set remediation goals based on health risk assessment. The results from tiered I assessment indicate that the concentrations of 8 contaminants in the leachate of the backfilling soil layer would exceed the assessment standards probably leading to groundwater contamination. However, the results from tiered II assessment, in which the adsorption and retardation of vadose zone soil was taken into account and the concentrations of pollutants reaching the groundwater table were predicated, reveal that only the concentrations of 6 contaminants would exceed the assessment standards. Further, taking the dilution and mixing of the groundwater into consideration, tiered III assessment was adopted and the results reveal that only 4 contaminants were beyond the standards. Finally, tiered IV assessment, aiming at predicting the concentration at the target well downstream, was carried out by considering the retardation of contaminants in saturated layer, and the results indicate only 1 pollutant was above the assessment standard. Therefore, it can be seen that the predicted concentrations of the target pollutants at advanced assessment levels will be closer to those at the target drinking water well and the amount of contaminants whose initially-set remediation goals need to be modified will decrease correspondingly, indicating the reduction in pollution prevention cost, although more efforts should be made and more field data should be collected to implement the advance assessment level. Source


Xia T.,Beijing Municipal Research Institute of Environmental Protection | Xia T.,Beijing Key Laboratory for Risk Modeling and Remediation of Contaminated Sites | Jiang L.,Beijing Municipal Research Institute of Environmental Protection | Jiang L.,Beijing Key Laboratory for Risk Modeling and Remediation of Contaminated Sites | And 6 more authors.
Frontiers of Environmental Science and Engineering | Year: 2014

Application of Probabilistic Risk Assessment (PRA) and Deterministic Risk Assessment (DRA) at a coking plant site was compared. By DRA, Hazard Quotient (HQ) following exposure to Naphthalene (Nap) and Incremental Life Cancer Risk (ILCR) following exposure to Benzo(a)pyrene (Bap) were 1.87 and 2.12 × 10-4. PRA revealed valuable information regarding the possible distribution of risk, and risk estimates of DRA located at the 99.59th and 99.76th percentiles in the risk outputs of PRA, which indicated that DRA overestimated the risk. Cleanup levels corresponding acceptable HQ level of 1 and ILCR level of 10-6 were also calculated for both DRA and PRA. Nap and Bap cleanup levels were 192.85 and 0.14 mg·kg-1 by DRA, which would result in only 0.25% and 0.06% of the exposed population to have a risk higher than the acceptable risk, according to the outputs of PRA. The application of PRA on cleanup levels derivation would lift the cleanup levels 1.9 times for Nap and 2.4 times for Bap than which derived by DRA. For this coking plant site, the remediation scale and cost will be reduced in a large portion once the method of PRA is used. Sensitivity analysis was done by calculating the contribution to variance for each exposure parameter and it was found that contaminant concentration in the soil (C s), exposure duration (ED), total hours spent outdoor per day (ET out), soil ingestion rate (IR s), the air breathing rate (IR a) and bodyweight (BW) were the most important parameters for risk and cleanup levels calculations. © 2013 Higher Education Press and Springer-Verlag Berlin Heidelberg. Source


Jiang L.,Beijing Municipal Research Institute of Environmental Protection | Jiang L.,National Urban Environment Pollution Control Engineering Techniques Research Center | Jiang L.,Beijing Key Laboratory for Risk Modeling and Remediation of Contaminated Sites | Jia X.-Y.,Beijing Municipal Research Institute of Environmental Protection | And 14 more authors.
Research of Environmental Sciences | Year: 2013

Based on the previous results of contamination survey on a coking plant in Beijing, the effects of uncertainty of 15 exposure parameters and soil pollutant concentrations on human health risk assessment of benzene and benzo[a]pyrene were investigated with the methods of probabilistic risk assessment (PRA). Results showed that the risk values of PRA, which was located at the 95th centile in the probabilistic range of risk values, were lower than that of deterministic risk assessment (DRA) of benzene and benzo[a]pyrene in both surface and subsurface soil through single and total exposure pathways. The total risk calculated by PRA ranged from 1.5×10-8 to 6.9×10-3 for benzene and 2.3×10-9 to 2.2×10-3 for benzo[a]pyrene, and the values were located at the 95th centile in the probabilistic range of risk were 3.8×10-4 and 1.1×10-4, respectively. The total risks conducted by DRA were located at the 96.8th and 99.1th centiles in the probabilistic range of risk, which were 1.5 and 3.2 times of the values by PRA. This indicated that the methods of DRA overestimated the real risk. The results of parameter sensitivity analysis revealed that the concentration of benzene in the subsurface soil (94.63%) and the adult exposure duration (4.12%) contributed the most to the uncertainty in benzene risk assessment, and the concentration of benzo[a]pyrene in the surface soil (92.3%), adult exposure duration (2.40%), soil ingestion rate (2.12%) and child exposure duration (1.21%) contributed the most to the uncertainty in benzo[a]pyrene risk assessment. Source

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