Astel A, Biziuk M, Przyjazny A, Namieśnik J
Environmental Chemistry Research Unit, Biology and Environmental Protection Institute, Pomeranian Pedagogical Academy, 22a Arciszewskiego Str., 76-200 Słupsk, Poland.
Water Res. 2006 May;40(8):1706-16. doi: 10.1016/j.watres.2006.02.018. Epub 2006 Apr 17.
This case study reports multivariate techniques applied for the evaluation of temporal/spatial variations and interpretation of monitoring data obtained by the determination of chloro/bromo disinfection by-products in drinking water at 12 locations in the Gdańsk area (Poland), over the period 1993-2000. The complex data matrix (1756 observations) was treated with various multivariate techniques. Cluster analysis (CA) was successful, yielding two different groups of similarity reflecting different types of drinking water supplied (surface and groundwater). The locations supplied in general with groundwater could be further classified into two subgroups, depending on whether the groundwater was mixed with surface water or not. Analysis of variance (ANOVA) was used to classify and thus confirm the groups found by means of cluster analysis and proved the existence of statistically significant differences between the concentration levels of CHCl3, CHBrCl2+C2HCl3, CHBr2Cl, and CH2Cl2 in the samples collected. Of all the variables evaluated, only three were characterized by statistically significant correlations (CHCl3, CHBrCl2+C2HCl3, CHBr2Cl). The analysis of correlation coefficients revealed that chloroform formed as the main chlorinated disinfection by-product and, furthermore, the natural presence of bromide in water (both ground and surface) results in the formation of brominated disinfection by-products (DBPs). Temporal variations of volatile organic chlorinated compounds (VOCls) were also evaluated by multidimensional ANOVA. Observation of temporal changes in the concentration of VOCls at the location supplied with both surface and groundwater reveals a steady improvement in drinking water quality. In general, the study shows the importance of drinking water monitoring in connection with simple but powerful statistical tools to better understand spatial and temporal variations in water quality.
本案例研究报告了多元技术在评估时空变化以及解释监测数据方面的应用。这些监测数据是通过测定1993年至2000年期间波兰格但斯克地区12个地点饮用水中的氯/溴消毒副产物而获得的。对复杂的数据矩阵（1756次观测）采用了各种多元技术进行处理。聚类分析（CA）取得了成功，得出了两组不同的相似性结果，反映了不同类型的供水（地表水和地下水）。一般供应地下水的地点可进一步分为两个亚组，这取决于地下水是否与地表水混合。方差分析（ANOVA）用于分类，从而确认通过聚类分析找到的组，并证明所采集样本中三氯甲烷、二氯一溴甲烷+三氯乙烷、二溴一氯甲烷和二氯甲烷的浓度水平之间存在统计学上的显著差异。在所有评估的变量中，只有三个具有统计学上的显著相关性（三氯甲烷、二氯一溴甲烷+三氯乙烷、二溴一氯甲烷）。相关系数分析表明，氯仿是主要的氯化消毒副产物，此外，水中（包括地下水和地表水）天然存在的溴会导致溴化消毒副产物（DBPs）的形成。还通过多维方差分析评估了挥发性有机氯化物（VOCls）的时间变化。对同时供应地表水和地下水的地点VOCls浓度的时间变化观察表明，饮用水质量在稳步改善。总体而言，该研究表明了饮用水监测与简单但强大的统计工具相结合对于更好地理解水质时空变化的重要性。
