Study of the influence of the physicochemical parameters on microbial abundance in various ambient conditions

Abstract

Nowadays, the problems of rejections constitute an increasingly important danger in the receiving mediums. Indeed, water is increasingly affected by minerals and organic matters and even by the micro-organisms of which some are pathogenic and thus dangerous for the ecosystem. In this context, the present study was conducted to investigate the microbiological pollution of water of the lake Mellah, located in the national park of El Kala, North-eastern Algerian. This lake is a depression which communicates with the sea and flowing the domestic effluents of the neighbouring localities. The physicochemical parameters (Temperature, pH; Eh; Electric conductivity; Salinity, Turbidity, and O₂) and bacteriological (coliformes total, coliformes thermo tolerant, streptococci) were followed during the year 2011 with a seasonal frequency (February, May, August, November). Seventeen (17) sites of three different habitats were investigated; the waste-water treatment plant (WWTP), Wadis and their upstream to the estuary and the lake. The follow-up of analysis of the physicochemical and biological parameters in the various points of observation was the object of a graphs data processing and statistics (ACP) to determine the bacteriological degree of pollution. Results showed a contamination by the fecal matter with a gradient decreasing from the upstream of the discharge system towards the downstream. Compared to rain waters, microbiological pollution in the lake was selective in time. The CT and the CTT decreased in dry season where the ambient conditions (salinity, pH and temperature) become unfavorable, putting the factor salinity concerned to degrade the water pollution.