تأثير تصريف مياه الصرف الصحي غير المعالجة على الخواص الميكروبيولوجية لمياه البحر

الملخص EN

This investigation was carried out to locate the position of the outlets through which untreated wastewater has been disposed to the shores of Tripoli and Tajura, and to study the effect of this act upon the microbiological characteristics of seawater in this region.

Thirty two outlets were identified and 242 surface seawater samples were collected and analyzed seasonally during the period from April, 2004 to March, 2005 from 4 stations at each outlet.

The position of the first stations is 10 m northern of each outlet, whereas the positions of the second, third and fourth stations are 100, 300 and 500 m respectively northern of each outlet.

The highest levels of microbial contamination were recorded in seawater samples collected from the stations at Souk-El-Jouma, Borj-Abolila and Kaiet-El-Shaab outlets at the shores of Tripoli city respectively.

The MPN index for total coliforms and faecal coliforms ranged between 4.6 x 104 to >1.1 x 105 and between 1.6 x 102 to > 1.1 x 105 /100 ml respectively; and Total Viable Count ranged between 4.4 x 102 to >2.5 x 105 C.F.U.

/ml for Souk-El-Jouma outlet.

For Borj-Abolila and Kaiet-El-Shaab, the MPN index for Total Coliforms ranged between 26.1 to > 1.1 x 105 / 100 ml and between 97 to > 1.1 105 / 100 ml; and ranged for Faecal Coliforms between 3.3 to > l.lxlO5 / 100 ml and 5.5 to > l.lxlO5 / 100 ml respectively; whereas, the Total Viable Count ranged between < 10 to > 2.5 x 105 and between 2.2 x 102 to > 2.5 x 105 C.F.U.

/ml respectively.

However, all control samples were free from Coliforms, which indicate that untreated wastewater is the source of these bacteria and possible presence of intestinal pathogens.

The high microbial levels were not only limited to the first and second stations, but extended also to the third and fourth stations.

Thus, the suitability of seawater in the area near these outlets for swimming, production of drinking water by desalination or for fishing purposes is questionable.