現代の化学と応用

概要

Contribution of Statistical Analysis Methods to Assessment of the Physicochemical Quality of the Dam

Aissam Gaagai*, Hani Amir Aouissi, Salah Eddine Maalam, Mostefa Ababsa

We used statistical analysis to try to evaluate the temporal variations concerning surface water located in Baber watershed. So, we collected twenty-one samples, for each city, seven ones were collected. In these samples, we determined eleven physicochemical parameters concerning the eastern part (S1): The salinity of samples proves high TDs values, while low TDs levels were found in the west (S2). In the dam (S3) TDs values are considered as intermediate on average. Regarding the water type: It wasSO₄-Na in S1, HCO₃-Ca-Mg in S2 and finally SO₄-Ca- Mgin the dam (S3) which characterizes mixed water. In R-mode, Cluster analysis was used; we classified seven variables into two clusters which are controlled by SO₄. About Q-mode, 21 samples were grouped into three groups corresponding to our three stations: S1, S2 and S3. Factor analysis is indicating to us two factors: These factors explain 87% of the total variance related with data set about water quality. We have two factors (Salinization and sulfates) that explain respectively 73% and 14% of the total variance. We noticed by relying on time series analysis that Cl, Na, Mg, Ca and SO₄ have very similar trend with TDs, and we noticed similar pattern between K and NO₃. It suggests that five components are controlling the evolution of TDs. Negative correlations between K & NO₃ with TDs because of human activities, like domestic sewages (thrown into the tributaries of Wadi Arab) and fertilizers for example. We could notice, by establishing this study, the real benefit of the used technique (statistical analysis) to interpret complex data sets related to the analysis of spatio-temporal variations in the water surface’s quality.