Microbial pollution indicators along the Egyptian coastal waters of Suez and Aqaba Gulfs and Red Sea

Abstract

Nowadays, the Egyptian coasts of the Aqaba and Suez Gulfs, and the Red Sea proper, are under the direct effects of many recreational resorts, urban agglomeration, marine shipping, activity of the phosphate industry, fishing ports, and limited freshwater and sewage surfaces. Therefore, the water, especially those used for recreational activities, must be of a very good quality to be able to increase the national income. To investigate the conventional water-quality bacteria, total coliforms (TC), Escherichia coli (EC), and fecal streptococci (FS), in the Egyptian coastal waters of Suez and Aqaba Gulfs and the Red Sea. A total of 2372 surface water samples were collected from 42 sampling sites during 12 years (1998-2009) to detect and estimate TC, EC, and FS using the membrane filtration method. On the basis of the national and international bacterial standards, 540 samples (22.8%) out of 2372 were found to exceed the guide values (positive samples) and were not accepted for marine recreational purposes. During the course of the study, Suez Gulf showed the highest positive records of 54 and 96 for TC and EC, respectively, whereas FS recorded 94 and 88 positive samples in the Red Sea and Suez Gulf, respectively. The lowest positive records were found in 1998 and 2009, whereas the highest were in 2000 and 2002-2004. The highest polluted sampling sites were recorded in Su7 (Suez Gulf), Aq2 (Aqaba Gulf), and Re15 (Red Sea), and were generally affected by sewage disposal and/or anthropogenic influences. The most polluted sites were in the Suez Gulf, reaching 238 sites, followed by 194 sites in the Red Sea, whereas the Aqaba Gulf had only 108 polluted sites. Moreover, the most polluted sample locations throughout the study were Su7, Aq2, and Re15, without implementation of corrective actions from authorized organizations. The data of the current study must be taken into consideration by the government for a safer and cleaner seawater in the eastern Egyptian coasts, especially those in which critical limitations in terms of microbial pollution are found.