Variability of pH in the Ogooué and M'passa rivers (Gabon)
Résumé
We consider here pH time series which recorded at high frequency and at fixed points during 2 hours on July 2013. These data from Ogooué and M'passa rivers located in Gabon. The M'passa River is one of tributary of Ogooué in France Ville. The Ogooué River rises in Congo and flows through Gabon and crosses France Ville town and the river flows into Atlantic in Port-gentil. These locations are subject to human activities (here kinds of waste generated by human activities, industrial effluents).The wastes coming from domestic consumption and industrial activities are discharged into rivers. In order to detect pollution degree caused by such waste, the sampling sites are selected according to pollutants along the courses. The first time, we consider the data from M'passa River in France Ville. Two sets data were recorded along the course. The second time, two sets data were also recorded along in the Ogooué River. The pH time series reveals high fluctuations and these fluctuations indicate the possible influence of natural factors (biological and chemical activity) and of pollution. We also considered the pH distribution using box whisker plot and we estimate also their probability density function (pdf). The pdfs reveal a variable repartition in pH dynamic. The comparison of sampling sites reveals large variability and the smaller pH values are found in polluted areas and according to degree of pollution. We find also that the pH values depend on sites thus pollutants