A multivariate statistical analysis of surface water chemistry data--the Ankobra Basin, Ghana.
A multivariate statistical analysis of surface water chemistry data--the Ankobra Basin, Ghana.
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DOI：
10.1016/j.jenvman.2006.11.023
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发表时间：
2008
影响因子：
8.7
通讯作者：
S. Yidana;D. Ophori;B. Banoeng-Yakubo
中科院分区：
文献类型：
--
作者：
S. Yidana;D. Ophori;B. Banoeng-Yakubo
同时对加纳安科布拉盆地三个不同地点的地表水水化学数据进行了R型层次聚类和主成分分析，以提取与不同的水化学变异来源相对应的主要因素，目的是确定盆地尺度上的水化学的主要控制因素。使用Kaiser准则，从数据中提取主成分(PC)，并使用VARIMAX归一化对每个位置进行旋转。VARIMAX旋转确保了数据的变异最大化，以便更容易地解释结果。分析分别将安克瓦索、多米尼斯和普雷斯特亚的30个、33个和33个数据点减少到4个、3个和4个pC，代表了三个不同地点的水化学变化来源。尽管PC分析在揭示水化学变化来源方面比R型层次聚类分析(HCA)更可靠，但两种技术的结合使用导致了对水化学的更可靠的解释。在这些分析的基础上，盆地的水化学在很大程度上受控于来自双陆系和塔尔克瓦系下伏变质沉积物的矿物(硅酸盐、碳酸盐、石膏和磷灰石)的风化，以及来自森林茂密地区的有机质的衰变。主要化学参数的浓度在自然可接受的范围内，不会对当地生态和人类构成威胁。没有强有力的证据表明，这项研究中使用的主要阴离子和阳离子受到了很大的人为影响，尽管研究的不同地点存在差异。安克瓦索的水化学主要受硅酸盐矿物风化的控制，而Dominase和Prestea的水化学分别受降水和生活污水以及有机质腐烂的影响。
R-mode hierarchical cluster and principal component analysis (PCA) were simultaneously applied to surface water hydrochemical data from three different locations, Ankwaso, Dominase and Prestea, along the Ankobra Basin, Ghana, to extract principal factors corresponding to the different sources of variation in the hydrochemistry, with the objective of defining the main controls on the hydrochemistry at the basin scale. Using the Kaiser criterion, principal components (PC) were extracted from the data and rotated using varimax normalization, for each location. The varimax rotation ensured that variation in the data was maximized for easy interpretation of the results. The analysis reduced 30, 33 and 33 data points, respectively, for Ankwaso, Dominase and Prestea to four, three and four PC representing the sources of variation in the hydrochemistry at the three different locations. Though the PC analysis proved to be more robust at unveiling the sources of variation in the hydrochemistry than the R-mode hierarchical cluster analysis (HCA), the combined use of both techniques resulted in more reliable interpretations of the hydrochemistry. On the basis of these analyses, the hydrochemistry of the basin is controlled largely by the weathering of minerals (silicates, carbonates, gypsum and apatite) from the underlying meta-sediments of the Birimian and Tarkwaian Systems, and the decay of organic matter from the heavily forested regions. Concentrations of the major chemical parameters are within naturally acceptable limits and do not pose threats to the local ecology and humans. There is no strong evidence of high anthropogenic impacts on the major anions and cations used for this research, though there are variations at the different locations studied. The hydrochemistry at Ankwaso is principally controlled by the weathering of silicate minerals, whereas those of Dominase and Prestea are, respectively, influenced by precipitation and domestic wastewaters, and the decay of organic matter.