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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 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 10 more authors.
Journal of Exposure Science and Environmental Epidemiology | Year: 2015

The cadmium (Cd) intake rates via diet of adults from different regions in China were between 0.160 and 0.557 μg/(kg BW·day), which were less than the provisional tolerable monthly intake (0.833 μg/(kg BW·day)) issued by Food and Agriculture Organization/World Health Organization in 2010, but higher than the one (0.365 μg/(kg BW·day)) issued by the European Food Safety Authority in 2011, to protect children, vegetarians and people living in heavily contaminated regions, and the intake rate of children (1.007 μg/(kg BW·day)) at the national scale was higher than the values recommended by the above institutes and those of adults. Vegetables were the critical contributors, followed by rice, flour, meats and aquatic products. Cd concentration in vegetable was the most sensitive factor in calculating the intake rate, followed by its contents in rice and aquatic products, and the intake rate of flour, indicating that more attention should be given to these parameters in future total diet surveys. When dietary exposure was incorporated, the derived national screening value of Cd under commercial scenario was reduced from 825 to 458 mg/kg, while the values of the north, south, Beijing and Shanghai were reduced to 627, 365, 693 and 489 mg/kg, respectively, indicating that the hazard would be underestimated if dietary exposure was not taken into account, especially for the south. The great variance between the screening values was due to the varied Cd intake rates, which indicated that deriving a screening value for each specific area based on its corresponding exposure characteristics was more appropriate. The national screening level for the residential scenario derived theoretically based on the dietary exposure characteristics of children was a negative value, meaning that the dietary intake rate was above the tolerable value. The method used in the United Kingdom to derive soil guideline values when non-soil exposure accounted for more than half of the maximum tolerable daily intake dose may be an appropriate estimate, but the exact ratio assigned to soil exposure should be assessed comprehensively based on a more sophisticated dietary exposure survey and the corresponding economic implications. © 2015 Nature America, Inc.


Jiang L.,Beijing Municipal Research Institute of Environmental Protection | Jiang L.,Beijing Key Laboratory for Risk Modeling and Remediation of Contaminated Sites | Peng C.,Beijing Municipal Research Institute of Environmental Protection | Peng C.,Beijing Key Laboratory for Risk Modeling and Remediation of Contaminated Sites | And 10 more authors.
Research of Environmental Sciences | Year: 2014

The health risk calculated based on site-specific bioaccessible fraction of heavy metals (HMs) is more realistic than the one based on the total concentration of HMs in soil. Bioaccessibility can be measured by simulating the digestive processes of HMs desorption in human gastrointestinal system. The test methods used currently were introduced with details during the simulation process and values of key parameters of the four wildly applied methods (PBET, SBET, RIVM and UBM). The problems were analyzed in the values of parameters (e. g., pH, extraction time, components of simulated gastrointestinal solution) and the simulated processes and environments (e. g., digestive process, environment, impact of food and microorganism in the digestive tract). Further, the acceptance of risk assessment incorporating HMs bioaccessibility to the environmental administrative staff and the public in the USA and EU were also discussed. Finally, based on the review of the research development in China, four research areas were suggested: (1) standardizing of bioaccessibility test of HMs in soil based on the digestive characteristic of Chinese people; (2) finding out the key influence factors that control HMs bioaccessibility in soil and development of an empirical model to predict HMs bioaccessibility based on them; (3) verifying the bioaccessibility test methods by in vivo test and developing a bioavailability test method by combining Caco-2 transportation model to the current in vitro methods; (4) developing a tiered risk assessment framework to incorporate HMs bioaccessibility and refine the guidelines currently in use.


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 10 more authors.
Huanjing Kexue/Environmental Science | Year: 2013

Site investigation was carried out on an area to be redeveloped as a subway station, which is right downstream of the groundwater of a former chemical plant. The results indicate the subsurface soil and groundwater in the area are both polluted heavily by 1, 2-dichloroethane, which was caused by the chemical plant upstream with the highest concentration was 104.08 mg·kg-1 for soil sample at 8.6 m below ground and the highest concentration was 18 500 μg·L-1 for groundwater. Further, a site-specific contamination conceptual model, giving consideration to the specific structure configuration of the station, was developed, and the corresponding risk calculation equation was derived. The carcinogenic risks calculated with models developed on the generic site conceptual model and derived herein on the site-specific conceptual model were compared. Both models indicate that the carcinogenic risk is significantly higher than the acceptable level which is 1×10-6. The comparison result reveals that the risk calculated with the former models for soil and groundwater are higher than the one calculated with the latter models by 2 times and 1.5 times, respectively. The finding in this paper indicates that the generic risk assessment model may underestimate the risk if specific site conditions and structure configuration are not considered.


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.


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.


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 8 more authors.
Research of Environmental Sciences | Year: 2014

Effects of biodegradation on the attenuation factor (ai-s) and screening level of benzene in the soil vapor were studied by using the one dimensional model, Bio-vapor for sandy soil, in particular on critical influential factors of biodegradation were simulated and discussed, including source intensity (cs), vertical separation distance between building foundation and source (LT), depth of aerobic zone in soil (La), biodegradation rate (kw). The results indicated that contribution from biodegradation of benzene to ai-s was negligible, when cs was higher than 5×105 mg/m3. When cs was less than 1×104 mg/m3, ai-s was 1-2 orders of magnitude reduction when the aerobic biodegradation process was included compared to the non-biodegradation case, but the reduction is insensitive to the change of cs and LT. When cs falls in between, ai-s decreases by 2 orders of magnitude as LT increases by 1 order of magnitude, and LT is a sensitive parameter. La is a critical factor in determining the biodegradation effect, and bio-attenuation decreases by 2 orders of magnitude as La just increases from 0.50 to 1.50 m. Compared with the field measured results for La, which were always deeper than 1.50 m, the modeled results for the sandy soil was 0.63 m, indicating that Bio-vapor is conservative in predicting the depth of aerobic zone. Therefore determination of La through measuring the soil vapor profile in practical project is recommended. Bioattenuation was more sensitive to kw for light contaminated sites, and ai-s decreases by 2 orders of magnitude as kw increases from 0.033 to 2.000 h-1 when cs is no more than 5×104 mg/m3. The vapor screening value for benzene is 1-2 orders of magnitude lower when biodegradation is considered for the same conceptual model scenario with no biodegradation.


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.


Jiang L.,Beijing Municipal Research Institute of Environmental Protection | Jiang L.,National Engineering Research Center for Urban Environmental Pollution Control | Jiang L.,Beijing Key Laboratory for Risk Modeling and Remediation of Contaminated Sites | Zhong M.-S.,Beijing Municipal Research Institute of Environmental Protection | And 14 more authors.
Huanjing Kexue/Environmental Science | Year: 2013

A multiple lines of evidence analysis technology was applied to assess whether sites were contaminated by heavy metals (HMs). Firstly, the baseline upper limit concentration for As and Cr6+ were derived for the two investigated sites based on the analysis of the relative cumulative probability plots of the two metals and their spatial distribution in the soil. The results indicated that the baseline upper limit concentrations for As and Cr6+ at site 1 were 29.8 mg · kg-1 and 76.1 mg · kg-1, respectively, which were much higher than those reported for the local area by others. But at site 2, the baseline upper limit concentrations for As and Cr6+ were 10.6 mg · kg-1 and 33 mg · kg-1, respectively, which were only a little higher than the reported values. Taken the derived baseline concentrations as the assessment criteria, both sites were contaminated by the heavy metals to some degree, which is consistent with the site historical activities review results and element correlation analysis results. At site 1, the As concentration in 3.8% samples exceeded the derived baseline concentration, while the Cr6+ concentration in 6.0% samples exceeded the baseline concentration. At site 2, only the concentration of As in 5.2% samples exceeded the derived baseline value. All the above exceeding rates were much lower than those based on the reported baseline values, which were 77.7% and 96.7% for As and Cr6+ at site 1, respectively and 41.9% for As at site 2. The difference indicates that for a specific site, the baseline concentrations for heavy metals reported in literatures should not be directly applied as the criteria to assess whether the site is contaminated or not, which may cause the results to lose the objectivity and leading to the misallocation of lots of rare resource to remediate soil that maybe not contaminated.


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.


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.

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