Sixteen priority polycyclic aromatic hydrocarbons(PAHs) in surface water samples were analyzed by gas chromatograph-mass spectrometer(GC-MS) to study their distribution and characterizing sources.The water samples wer...Sixteen priority polycyclic aromatic hydrocarbons(PAHs) in surface water samples were analyzed by gas chromatograph-mass spectrometer(GC-MS) to study their distribution and characterizing sources.The water samples were collected from five sites(J1-J5) in the Jialing River of Chongqing downtown area from September 2009 to August 2010.The results demonstrate that the concentration of total PAHs in three samples upstream are relatively higher than those in other two sites downstream,with average concentration of total PAHs for each site ranging from 811.5 ng/L to 1585.8 ng/L.The 2,3 and 4-ring PAHs for sampling stations account for 13.0%,56.6% and 28.6%,respectively,in total PAHs.There are obvious tendencies of seasonal change for PAHs concentration in surface water.The PAHs concentration in April of wet season is 1 301.6 ng/L,which is 1.3 times the lowest amount of total PAHs in August of flood season.Ratios of specific PAH compounds were used to characterize the possible pollution sources.Experimental results indicate that the PAHs in surface water samples are primarily from pyrolytic PAHs because of factories along these sites,while the direct leakage of petroleum products may be significant for two sites,Jiahua Bridge(J4) and Huanghuayuan Bridge(J5),because of the wharf boat nearby.展开更多
Desorption of total saturated fractions(i.e. SAT, defined for this study as the summation of the concentrations of the saturated hydrocarbon from n-C10 to n-C26) and polycyclic aromatic fractions(i.e. PAH, defined as ...Desorption of total saturated fractions(i.e. SAT, defined for this study as the summation of the concentrations of the saturated hydrocarbon from n-C10 to n-C26) and polycyclic aromatic fractions(i.e. PAH, defined as the summation of the concentrations of all polycyclic aromatic fractions including the 16 EPA priority PAH) in two types of soils subjected to the changes of p H and salinity and different bio-surfactant concentrations were investigated. In general, compared with the experiments without bio-surfactant addition, adding rhamnolipid to crude oil-water systems at concentrations above its critical micelle concentration(CMC) values benefits SAT and PAH desorption. The results indicate that the change of p H could have distinct effects on rhamnolipid performance concerning its own micelle structure and soil properties. For loam soil, the adsorption of non-aqueous phase liquid(NAPL) and rhamnolipid would be the principle limiting factors during the NAPL removal procedure. For sand soil, less amount of rhamnolipid is adsorbed onto soil. Thus, with the increase of salinity, the solubilization and desorption of rhamnolipid solution are more significant. In summary, the p H and salt sensitivity of the bio-surfactant will vary according to the specific structure of the surfactant characteristics and soil properties.展开更多
Application of the linear regression between vehicle types/numbers and PAH contents (Particle + Vapor) within a radius of 60 and 300 miles can be employed to assess the impact of long range atmospheric transportation ...Application of the linear regression between vehicle types/numbers and PAH contents (Particle + Vapor) within a radius of 60 and 300 miles can be employed to assess the impact of long range atmospheric transportation (LRAT) to the level of PAHs in the rural atmosphere of Whitbourne,UK.In general,higher R-values coupled with lower P-values were found in those samples within a radius of 300 miles,whereas lower R-values were detected in those samples within a radius of 60 miles.R-values of PAH concentrations vs.all vehicle numbers within radius of 300 miles ranged from 0.51 to 0.92 with the arithmetic mean of 0.75 ± 0.12,whilst those R-values within a radius of 60 miles ranged from 0.05 to 0.61 with the arithmetic mean of 0.11 ± 0.28.This supports the hypothesis that PAHs in Whitbourne undergo LRAT.展开更多
Atmospheric lifetimes and traveling distances of 15 PAHs(Ac:acenaphthylene,Ace:acenaphthene,Ph:phenanthrene,MePh3:3-methyl-phenanthrene,MePh9:9-methyl-phenanthrene,MePh1:1-methyl-phenanthrene,MePh2:2-methyl-phenanthre...Atmospheric lifetimes and traveling distances of 15 PAHs(Ac:acenaphthylene,Ace:acenaphthene,Ph:phenanthrene,MePh3:3-methyl-phenanthrene,MePh9:9-methyl-phenanthrene,MePh1:1-methyl-phenanthrene,MePh2:2-methyl-phenanthrene,Ret:retene,B[a]A:benzo[a]anthracene,Chry:chrysene,B[b,j,k]F:benzo[b,j,k]fluoranthene,B[e]P:benzo[e]pyrene,B[a]P:benzo[a]pyrene,Ind:indeno[1,2,3-cd]pyrene,B[g,h,i]P:benzo[g,h,i]perylene)at Whitbourne,UK,were estimated by using the rate constants for reaction with OH,O3,and the first order rate constants of eight species of high molecular weight PAHs(i.e.B[a]A,Chry,B[b]F,B[k]F,B[a]P,Ind,B[g,h,i]P and Ret)as a function of humidity,solar intensity and temperature by using Multiple Regression Analysis.The predicted atmospheric lifetime of Ac,Ace,Ph,MePh3,MePh9,MePh2 and MePh1 ranged between 11.42 h-79.12 h in cold period and 1/31 h-14.33 h in warm period respectively.The binary ratios of atmospheric lifetime of B[k]F/B[g,h,i]P,B[k]F/B[g,h,i]P,B[g,h,i]P/Ind and B[k]F/Ind displayed non-significant differences between cold and warm period,indicating that high molecular weight PAHs are difficult to be decomposed by UV light and thus may be conveyed to the rural regions via long range atmospheric transportation(LRAT).The decreased level of the atmospheric lifetime of low molecular weight PAHs in summer can be attributed to an increased level of OH radical content and solar radiation.展开更多
基金Project(41101457) supported by the National Natural Science Foundation of ChinaProject(2009-122) supported by the Fund of Chongqing Municipal Construction Commission, China
文摘Sixteen priority polycyclic aromatic hydrocarbons(PAHs) in surface water samples were analyzed by gas chromatograph-mass spectrometer(GC-MS) to study their distribution and characterizing sources.The water samples were collected from five sites(J1-J5) in the Jialing River of Chongqing downtown area from September 2009 to August 2010.The results demonstrate that the concentration of total PAHs in three samples upstream are relatively higher than those in other two sites downstream,with average concentration of total PAHs for each site ranging from 811.5 ng/L to 1585.8 ng/L.The 2,3 and 4-ring PAHs for sampling stations account for 13.0%,56.6% and 28.6%,respectively,in total PAHs.There are obvious tendencies of seasonal change for PAHs concentration in surface water.The PAHs concentration in April of wet season is 1 301.6 ng/L,which is 1.3 times the lowest amount of total PAHs in August of flood season.Ratios of specific PAH compounds were used to characterize the possible pollution sources.Experimental results indicate that the PAHs in surface water samples are primarily from pyrolytic PAHs because of factories along these sites,while the direct leakage of petroleum products may be significant for two sites,Jiahua Bridge(J4) and Huanghuayuan Bridge(J5),because of the wharf boat nearby.
基金Project(8102032) supported by Beijing Natural Science Foundation of China
文摘Desorption of total saturated fractions(i.e. SAT, defined for this study as the summation of the concentrations of the saturated hydrocarbon from n-C10 to n-C26) and polycyclic aromatic fractions(i.e. PAH, defined as the summation of the concentrations of all polycyclic aromatic fractions including the 16 EPA priority PAH) in two types of soils subjected to the changes of p H and salinity and different bio-surfactant concentrations were investigated. In general, compared with the experiments without bio-surfactant addition, adding rhamnolipid to crude oil-water systems at concentrations above its critical micelle concentration(CMC) values benefits SAT and PAH desorption. The results indicate that the change of p H could have distinct effects on rhamnolipid performance concerning its own micelle structure and soil properties. For loam soil, the adsorption of non-aqueous phase liquid(NAPL) and rhamnolipid would be the principle limiting factors during the NAPL removal procedure. For sand soil, less amount of rhamnolipid is adsorbed onto soil. Thus, with the increase of salinity, the solubilization and desorption of rhamnolipid solution are more significant. In summary, the p H and salt sensitivity of the bio-surfactant will vary according to the specific structure of the surfactant characteristics and soil properties.
文摘Application of the linear regression between vehicle types/numbers and PAH contents (Particle + Vapor) within a radius of 60 and 300 miles can be employed to assess the impact of long range atmospheric transportation (LRAT) to the level of PAHs in the rural atmosphere of Whitbourne,UK.In general,higher R-values coupled with lower P-values were found in those samples within a radius of 300 miles,whereas lower R-values were detected in those samples within a radius of 60 miles.R-values of PAH concentrations vs.all vehicle numbers within radius of 300 miles ranged from 0.51 to 0.92 with the arithmetic mean of 0.75 ± 0.12,whilst those R-values within a radius of 60 miles ranged from 0.05 to 0.61 with the arithmetic mean of 0.11 ± 0.28.This supports the hypothesis that PAHs in Whitbourne undergo LRAT.
文摘Atmospheric lifetimes and traveling distances of 15 PAHs(Ac:acenaphthylene,Ace:acenaphthene,Ph:phenanthrene,MePh3:3-methyl-phenanthrene,MePh9:9-methyl-phenanthrene,MePh1:1-methyl-phenanthrene,MePh2:2-methyl-phenanthrene,Ret:retene,B[a]A:benzo[a]anthracene,Chry:chrysene,B[b,j,k]F:benzo[b,j,k]fluoranthene,B[e]P:benzo[e]pyrene,B[a]P:benzo[a]pyrene,Ind:indeno[1,2,3-cd]pyrene,B[g,h,i]P:benzo[g,h,i]perylene)at Whitbourne,UK,were estimated by using the rate constants for reaction with OH,O3,and the first order rate constants of eight species of high molecular weight PAHs(i.e.B[a]A,Chry,B[b]F,B[k]F,B[a]P,Ind,B[g,h,i]P and Ret)as a function of humidity,solar intensity and temperature by using Multiple Regression Analysis.The predicted atmospheric lifetime of Ac,Ace,Ph,MePh3,MePh9,MePh2 and MePh1 ranged between 11.42 h-79.12 h in cold period and 1/31 h-14.33 h in warm period respectively.The binary ratios of atmospheric lifetime of B[k]F/B[g,h,i]P,B[k]F/B[g,h,i]P,B[g,h,i]P/Ind and B[k]F/Ind displayed non-significant differences between cold and warm period,indicating that high molecular weight PAHs are difficult to be decomposed by UV light and thus may be conveyed to the rural regions via long range atmospheric transportation(LRAT).The decreased level of the atmospheric lifetime of low molecular weight PAHs in summer can be attributed to an increased level of OH radical content and solar radiation.
文摘多环芳烃(polycyclic aromatic hydrocarbons,PAHs)是地下水中的主要有机污染物之一,地下水中多环芳烃运移数值模拟在开展地下水污染高效修复中起重要作用。在实际地下水污染条件下,由于难以准确刻画含水介质中的胶体类型及其分布,通常忽略污染物-胶体共运移机制,建立的模型存在结构误差,导致模型预测具有显著偏差。本研究以荧蒽和菲为研究对象,针对忽略的PAHs-胶体的共运移机制,使用高斯过程回归(Gaussian process regression,GPR)修正模型结构误差,建立耦合数据驱动和物理机制的多环芳烃运移模型。通过饱和砂柱PAHs运移室内试验,对比分析了未耦合和耦合数据驱动方法的模型预测结果。结果表明,忽略PAHs-胶体的共运移机制的地下水多环芳烃运移模型具有显著的模型结构误差,直接进行参数识别不能弥补忽略的共运移机制,预测结果存在显著偏差。使用GPR模型可以有效补偿PAHs-胶体的共运移机制,修正地下水模型的结构误差。验证期荧蒽、菲预测结果的95%置信区间对观测数据的覆盖率分别提升了56.84%和19.04%,纳什系数分别提升了40.09%和21.73%,均方根误差分别降低了33.10%和55.38%,平均绝对误差分别降低了32.00%和46.34%,地下水多环芳烃运移模型的预测性能显著提高。本研究提出的耦合数据驱动和物理机制方法为场地地下水多环芳烃运移精准模拟提供了可行思路,有助于实现地下水污染的精准高效修复。
