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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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Related in: MedlinePlus

Heatmap of pairwise correlations and PCA between CAHs and environmental factors.Statistically significant correlations are indicated with a color surrounding the squares. Dark blue: p < 0.001; light blue: p < 0.01; green: p < 0.05.
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pone.0142241.g005: Heatmap of pairwise correlations and PCA between CAHs and environmental factors.Statistically significant correlations are indicated with a color surrounding the squares. Dark blue: p < 0.001; light blue: p < 0.01; green: p < 0.05.

Mentions: The PPC was calculated to indicate the relationships between CAHs and environmental variables (Fig 5A, S2 Table). The correlations between “DO” and other variables were not significant, but overall, were following an almost weak negative pattern. The oxidation-reduction state analysis indicated that the main part of the contamination plume was under Fe(III)-reducing conditions[27]. Due to the dechlorination of high-chlorinated substance such as 1,1,1-TCA, 1,1-DCA and 1,1-DCE in the Fe(III)-reducing condition, “%CA” and/or “%VC” should have been accumulated at a specific sampling well and positively correlated with “Fe2+” [28, 29]. Nevertheless, “Fe2+” was significantly positive correlated with most CAHs such as “1,1,1-TCA”, “1,1-DCA”, “1,1-DCE” and with “%TCA” (p<0.001), but without “%CA” and/or “%VC”. This may resulted from the higher concentration of 1,1,1-TCA, 1,1-DCA and 1,1-DCE in most sampling wells, which usually presented a magnitude higher than CA and VC. What confirmed this was that “Cl-” was significant positively correlated with “1,1-DCA” and “1,1-DCE” (p<0.001), Cl- is always the indicator for the dechlorination of CAHs [30].


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)

Heatmap of pairwise correlations and PCA between CAHs and environmental factors.Statistically significant correlations are indicated with a color surrounding the squares. Dark blue: p < 0.001; light blue: p < 0.01; green: p < 0.05.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0142241.g005: Heatmap of pairwise correlations and PCA between CAHs and environmental factors.Statistically significant correlations are indicated with a color surrounding the squares. Dark blue: p < 0.001; light blue: p < 0.01; green: p < 0.05.
Mentions: The PPC was calculated to indicate the relationships between CAHs and environmental variables (Fig 5A, S2 Table). The correlations between “DO” and other variables were not significant, but overall, were following an almost weak negative pattern. The oxidation-reduction state analysis indicated that the main part of the contamination plume was under Fe(III)-reducing conditions[27]. Due to the dechlorination of high-chlorinated substance such as 1,1,1-TCA, 1,1-DCA and 1,1-DCE in the Fe(III)-reducing condition, “%CA” and/or “%VC” should have been accumulated at a specific sampling well and positively correlated with “Fe2+” [28, 29]. Nevertheless, “Fe2+” was significantly positive correlated with most CAHs such as “1,1,1-TCA”, “1,1-DCA”, “1,1-DCE” and with “%TCA” (p<0.001), but without “%CA” and/or “%VC”. This may resulted from the higher concentration of 1,1,1-TCA, 1,1-DCA and 1,1-DCE in most sampling wells, which usually presented a magnitude higher than CA and VC. What confirmed this was that “Cl-” was significant positively correlated with “1,1-DCA” and “1,1-DCE” (p<0.001), Cl- is always the indicator for the dechlorination of CAHs [30].

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