Polluted and non-biologically treated water causes serious health effects as microbes pass through non-treated wastewater drainage networks to surface and groundwater sources, leading to contamination. In this study, the Coliform Bacteria and Escherichia Coli Pollution Index was detected on coastal water from the Souq Al Jumaa area to the Tajoura region, which is about 15 km long, by the beginning of the summer. The area was divided into 10 stations, Each plant was divided into 3 levels. Microbiological analyzes and detection of Escherichia coli were carried out using the compact dry method. It is a modern, easy, fast and accurate method of testing. It produces faster results compared to traditional methods used by ISO 16140, On alternative methods of jurisprudence Microval official Association for chemical and microbiological analyzes AOAC. The results of the bacteriological analysis showed that 90% of the samples of the studied sites were contaminated with the Escherichia coliform group where the numbers ranged between (zero unit, 4350 units),The results showed that 100% of the samples were contaminated with E. coli, where the number ranged between 833 and 11316 units compared to the Tunisian standards for coastal water quality.
The results showed that the BOD5 values increased in the stations (4,6,7,8,9) from 6.4 to 6.6 mg / L, which recorded higher pollution rates than the rest of the stations, which led to an increase in bio-demand for oxygen in seawater, Confirms that the increase in the values of oxygen consumed in these plants may be due to the abundance of nutrients in wastewater and the increase of microorganisms in this water, including increased demand for DO in this water. Thus, it can be said that the discharge of water through untreated sewage networks to shore waters and with the increase in the prevalence of random surges for the holidaymakers and others and their exploitation by beneficiaries and the absence of environmental and regulatory legislation can have contributed significantly to the occurrence of this bacteriological pollution.