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Characterization of Chlorinated Aliphatic Hydrocarbons and Environmental Variables in a Shallow Groundwater in Shanghai Using Kriging Interpolation and Multifactorial Analysis.

Lu Q, Luo QS, Li H, Liu YD, Gu JD, Lin KF, Fei Lin K - PLoS ONE (2015)

Bottom Line: The results showed that the overall CAHs plume area (above DIV) was approximately 9,000 m(2) and located in the 2-4 m underground, DNAPL was accumulated at an area of approximately 1,400 m(2) and located in the 6-8m sandy silt layer on the top of the muddy silty clay.Heatmap of PPC for CAHs and environmental variables showed that the correlation between "Fe(2+)" and most CAHs such as "1,1,1-TCA", "1,1-DCA", "1,1-DCE" and "%TCA" were significantly positive (p<0.001), but "%CA" and/or "%VC" was not, and "Cl-" was significantly positive correlated with "1,1-DCA" and "1,1-DCE" (p<0.001).The PCA demonstrated that the relative proportions of CAHs in groundwater were mostly controlled by the sources and the natural attenuation.

View Article: PubMed Central - PubMed

Affiliation: State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resource and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, P.R. China.

ABSTRACT
CAHs, as a cleaning solvent, widely contaminated shallow groundwater with the development of manufacturing in China's Yangtze River Delta. This study focused on the distribution of CAHs, and correlations between CAHs and environmental variables in a shallow groundwater in Shanghai, using kriging interpolation and multifactorial analysis. The results showed that the overall CAHs plume area (above DIV) was approximately 9,000 m(2) and located in the 2-4 m underground, DNAPL was accumulated at an area of approximately 1,400 m(2) and located in the 6-8m sandy silt layer on the top of the muddy silty clay. Heatmap of PPC for CAHs and environmental variables showed that the correlation between "Fe(2+)" and most CAHs such as "1,1,1-TCA", "1,1-DCA", "1,1-DCE" and "%TCA" were significantly positive (p<0.001), but "%CA" and/or "%VC" was not, and "Cl-" was significantly positive correlated with "1,1-DCA" and "1,1-DCE" (p<0.001). The PCA demonstrated that the relative proportions of CAHs in groundwater were mostly controlled by the sources and the natural attenuation. In conclusion, the combination of geographical and chemometrics was helpful to establishing an aerial perspective of CAHs and identifying reasons for the accumulation of toxic dechlorination intermediates, and could become a useful tool for characterizing contaminated sites in general.

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The Geology of the investigated site.
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pone.0142241.g002: The Geology of the investigated site.

Mentions: The stratum of the study area consisted of fill materials, clayey silt, sandy silt, muddy silty clay, muddy clay, silty clay and sandy silt (Fig 2). Fill materials occurred from the surface to depths ranging between 0.7–2.6 m and consisted of brown silty clay with occasional gravel, brick fragment. Clayey silt, ranged 1.1 m and 4.4 m in the thickness, was mainly brown, moist to saturated, and medium to low plasticity. Sandy silt, was grey, saturated, soft and low plasticity, ranging between 0.8 m and 4.0 m in thickness, and this layer was not continuous across the whole site as both conducting cone penetration test (CPT) and field observation indicated the lack of sandy silt layers in some locations. Muddy silty clay, ranged 2.5 m and 4.0 m in thickness, was mainly grey, saturated soft and low plasticity. Muddy clay was mainly grey, saturated, soft and low plasticity with very thin sand layer at some locations, and the top surface of muddy clay was encountered between 9.0 m and 10.2 m, while the bottom surface was between 18.4 m and 19.5 m. Silty clay was encountered at depth between 18.4 m and 19.5 m, while the bottom surface between 44.7 m and 46.8 m. Sandy silt was encountered at 44.7 m to 46.8 m extending to the CPT termination depth of 60.0 m.


Characterization of Chlorinated Aliphatic Hydrocarbons and Environmental Variables in a Shallow Groundwater in Shanghai Using Kriging Interpolation and Multifactorial Analysis.

Lu Q, Luo QS, Li H, Liu YD, Gu JD, Lin KF, Fei Lin K - PLoS ONE (2015)

The Geology of the investigated site.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4643907&req=5

pone.0142241.g002: The Geology of the investigated site.
Mentions: The stratum of the study area consisted of fill materials, clayey silt, sandy silt, muddy silty clay, muddy clay, silty clay and sandy silt (Fig 2). Fill materials occurred from the surface to depths ranging between 0.7–2.6 m and consisted of brown silty clay with occasional gravel, brick fragment. Clayey silt, ranged 1.1 m and 4.4 m in the thickness, was mainly brown, moist to saturated, and medium to low plasticity. Sandy silt, was grey, saturated, soft and low plasticity, ranging between 0.8 m and 4.0 m in thickness, and this layer was not continuous across the whole site as both conducting cone penetration test (CPT) and field observation indicated the lack of sandy silt layers in some locations. Muddy silty clay, ranged 2.5 m and 4.0 m in thickness, was mainly grey, saturated soft and low plasticity. Muddy clay was mainly grey, saturated, soft and low plasticity with very thin sand layer at some locations, and the top surface of muddy clay was encountered between 9.0 m and 10.2 m, while the bottom surface was between 18.4 m and 19.5 m. Silty clay was encountered at depth between 18.4 m and 19.5 m, while the bottom surface between 44.7 m and 46.8 m. Sandy silt was encountered at 44.7 m to 46.8 m extending to the CPT termination depth of 60.0 m.

Bottom Line: The results showed that the overall CAHs plume area (above DIV) was approximately 9,000 m(2) and located in the 2-4 m underground, DNAPL was accumulated at an area of approximately 1,400 m(2) and located in the 6-8m sandy silt layer on the top of the muddy silty clay.Heatmap of PPC for CAHs and environmental variables showed that the correlation between "Fe(2+)" and most CAHs such as "1,1,1-TCA", "1,1-DCA", "1,1-DCE" and "%TCA" were significantly positive (p<0.001), but "%CA" and/or "%VC" was not, and "Cl-" was significantly positive correlated with "1,1-DCA" and "1,1-DCE" (p<0.001).The PCA demonstrated that the relative proportions of CAHs in groundwater were mostly controlled by the sources and the natural attenuation.

View Article: PubMed Central - PubMed

Affiliation: State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resource and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, P.R. China.

ABSTRACT
CAHs, as a cleaning solvent, widely contaminated shallow groundwater with the development of manufacturing in China's Yangtze River Delta. This study focused on the distribution of CAHs, and correlations between CAHs and environmental variables in a shallow groundwater in Shanghai, using kriging interpolation and multifactorial analysis. The results showed that the overall CAHs plume area (above DIV) was approximately 9,000 m(2) and located in the 2-4 m underground, DNAPL was accumulated at an area of approximately 1,400 m(2) and located in the 6-8m sandy silt layer on the top of the muddy silty clay. Heatmap of PPC for CAHs and environmental variables showed that the correlation between "Fe(2+)" and most CAHs such as "1,1,1-TCA", "1,1-DCA", "1,1-DCE" and "%TCA" were significantly positive (p<0.001), but "%CA" and/or "%VC" was not, and "Cl-" was significantly positive correlated with "1,1-DCA" and "1,1-DCE" (p<0.001). The PCA demonstrated that the relative proportions of CAHs in groundwater were mostly controlled by the sources and the natural attenuation. In conclusion, the combination of geographical and chemometrics was helpful to establishing an aerial perspective of CAHs and identifying reasons for the accumulation of toxic dechlorination intermediates, and could become a useful tool for characterizing contaminated sites in general.

Show MeSH
Related in: MedlinePlus