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Applying factor analysis combined with kriging and information entropy theory for mapping and evaluating the stability of groundwater quality variation in Taiwan.

Shyu GS, Cheng BY, Chiang CT, Yao PH, Chang TK - Int J Environ Res Public Health (2011)

Bottom Line: Groundwater quality demonstrated apparent differences between the northern and southern areas of Taiwan when divided by the Wu River.Approximately 52% of the monitoring wells in southern Taiwan suffered from progressing seawater intrusion, causing unstable groundwater quality.The method proposed in this study for analyzing groundwater quality inspects common stability factors, identifies potential areas influenced by common factors, and assists in elevating and reinforcing information in support of an overall groundwater management strategy.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Management, Tungnan University, Taipei County 222, Taiwan. gsshyu@mail.tnu.edu.tw

ABSTRACT
In Taiwan many factors, whether geological parent materials, human activities, and climate change, can affect the groundwater quality and its stability. This work combines factor analysis and kriging with information entropy theory to interpret the stability of groundwater quality variation in Taiwan between 2005 and 2007. Groundwater quality demonstrated apparent differences between the northern and southern areas of Taiwan when divided by the Wu River. Approximately 52% of the monitoring wells in southern Taiwan suffered from progressing seawater intrusion, causing unstable groundwater quality. Industrial and livestock wastewaters also polluted 59.6% of the monitoring wells, resulting in elevated EC and TOC concentrations in the groundwater. In northern Taiwan, domestic wastewaters polluted city groundwater, resulting in higher NH(3)-N concentration and groundwater quality instability was apparent among 10.3% of the monitoring wells. The method proposed in this study for analyzing groundwater quality inspects common stability factors, identifies potential areas influenced by common factors, and assists in elevating and reinforcing information in support of an overall groundwater management strategy.

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Relations between the factor score and information entropy value (a) South-EC, (b) South-Ca2+, (c) South-TOC, (d) South-Alk, (e) North-Alk, (f) South-Fe2+, (g) South-Temp., (h) North-Fe2+, (i) North-NH3-N, (j) North-TOC.
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f6-ijerph-08-01084: Relations between the factor score and information entropy value (a) South-EC, (b) South-Ca2+, (c) South-TOC, (d) South-Alk, (e) North-Alk, (f) South-Fe2+, (g) South-Temp., (h) North-Fe2+, (i) North-NH3-N, (j) North-TOC.

Mentions: Figure 6 shows the relationship between factor scores and calculated information entropy values of the various hydrochemical parameters for each monitoring well in the northern area and the southern area. In the southern area, the relationship between Factor 1 scores and information entropy values are similar for Factor 1-contained hydrochemical parameters, except for Ca2+. Only the results for EC and Ca2+ are displayed in Figure 6(a) and Figure 6(b). The comparison of EC and Ca2+ reveals a specific relation between EC factor scores and information entropy values. In terms of Factor 1, the relations are similar for the northern and southern areas. The only difference is that in the southern area, there is no similar relation for the parameter Ca2+. Therefore, including Ca2+ in Factor 1 is not appropriate for the southern area. Figure 6(c) and Figure 6(d) show the results of TOC and Alk, which are parameters for Factor 2 in the southern area. The information entropy values of parameters TOC and Alk have no relationship with Factor 2 scores, indicating extensive groundwater pollution by organic matter. The regions where groundwater quality is unstable assist in finding the location of potential pollution areas. In the northern region, the Alk parameter in Factor 2 is similar to that in the southern area, and the Factor 2 score does not relate to the information entropy value shown in Figure 6(e). Both parameters Ca2+ and pH are also in Factor 2 in the northern area due to different sources. Hence, natural effects caused the instability of Alk in groundwater of the northern area.


Applying factor analysis combined with kriging and information entropy theory for mapping and evaluating the stability of groundwater quality variation in Taiwan.

Shyu GS, Cheng BY, Chiang CT, Yao PH, Chang TK - Int J Environ Res Public Health (2011)

Relations between the factor score and information entropy value (a) South-EC, (b) South-Ca2+, (c) South-TOC, (d) South-Alk, (e) North-Alk, (f) South-Fe2+, (g) South-Temp., (h) North-Fe2+, (i) North-NH3-N, (j) North-TOC.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3118879&req=5

f6-ijerph-08-01084: Relations between the factor score and information entropy value (a) South-EC, (b) South-Ca2+, (c) South-TOC, (d) South-Alk, (e) North-Alk, (f) South-Fe2+, (g) South-Temp., (h) North-Fe2+, (i) North-NH3-N, (j) North-TOC.
Mentions: Figure 6 shows the relationship between factor scores and calculated information entropy values of the various hydrochemical parameters for each monitoring well in the northern area and the southern area. In the southern area, the relationship between Factor 1 scores and information entropy values are similar for Factor 1-contained hydrochemical parameters, except for Ca2+. Only the results for EC and Ca2+ are displayed in Figure 6(a) and Figure 6(b). The comparison of EC and Ca2+ reveals a specific relation between EC factor scores and information entropy values. In terms of Factor 1, the relations are similar for the northern and southern areas. The only difference is that in the southern area, there is no similar relation for the parameter Ca2+. Therefore, including Ca2+ in Factor 1 is not appropriate for the southern area. Figure 6(c) and Figure 6(d) show the results of TOC and Alk, which are parameters for Factor 2 in the southern area. The information entropy values of parameters TOC and Alk have no relationship with Factor 2 scores, indicating extensive groundwater pollution by organic matter. The regions where groundwater quality is unstable assist in finding the location of potential pollution areas. In the northern region, the Alk parameter in Factor 2 is similar to that in the southern area, and the Factor 2 score does not relate to the information entropy value shown in Figure 6(e). Both parameters Ca2+ and pH are also in Factor 2 in the northern area due to different sources. Hence, natural effects caused the instability of Alk in groundwater of the northern area.

Bottom Line: Groundwater quality demonstrated apparent differences between the northern and southern areas of Taiwan when divided by the Wu River.Approximately 52% of the monitoring wells in southern Taiwan suffered from progressing seawater intrusion, causing unstable groundwater quality.The method proposed in this study for analyzing groundwater quality inspects common stability factors, identifies potential areas influenced by common factors, and assists in elevating and reinforcing information in support of an overall groundwater management strategy.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Management, Tungnan University, Taipei County 222, Taiwan. gsshyu@mail.tnu.edu.tw

ABSTRACT
In Taiwan many factors, whether geological parent materials, human activities, and climate change, can affect the groundwater quality and its stability. This work combines factor analysis and kriging with information entropy theory to interpret the stability of groundwater quality variation in Taiwan between 2005 and 2007. Groundwater quality demonstrated apparent differences between the northern and southern areas of Taiwan when divided by the Wu River. Approximately 52% of the monitoring wells in southern Taiwan suffered from progressing seawater intrusion, causing unstable groundwater quality. Industrial and livestock wastewaters also polluted 59.6% of the monitoring wells, resulting in elevated EC and TOC concentrations in the groundwater. In northern Taiwan, domestic wastewaters polluted city groundwater, resulting in higher NH(3)-N concentration and groundwater quality instability was apparent among 10.3% of the monitoring wells. The method proposed in this study for analyzing groundwater quality inspects common stability factors, identifies potential areas influenced by common factors, and assists in elevating and reinforcing information in support of an overall groundwater management strategy.

Show MeSH