Re-Evaluation of the Impact of Sewage Disposal on Coastal Sediments of the Southern Corniche, Jeddah, Saudi Arabia

Abstract

The southern corniche area of Jeddah receives through Al-Kumra effluent the equivalent of 300,000 m 3 of semi-treated sewage. Before 2001, the sewage was directly dumped from an outlet situated at about 1 m above the sea surface. Since 2001, the same volume of municipal wastewater is disposed from underwater diffuser situated at about 3 km south of the old effluent. In order to study the environmental consequences of the dumping site transfer from a sheltered to an open sea area, the region was revisited and sediment samples were collected from the same stations sampled prior to the transfer of the effluent. Samples were analysed for their grain size distribution and their content of organic carbon, Al, Fe, Mn, Cu, Zn, Cr, Cd and Pb. Results were compared to those obtained in a previous study carried out in 1999. The study showed that despite the very pronounced dilution effect, the impact of the effluent is measurable and extends, in situ, north and south directions along the entire study area. The impact is very pronounced in the coastal area as shown by the excessive development of algal production which extends further southward and by the destruction of the mangrove stand. Sediments are becoming enriched in heavy metals where concentrations of Al, Fe, Mn, Cu, Zn and Cr are almost doubled. The present study is the first of its kind to be carried out after the effluent transfer. The authors therefore believe that the system did not yet reach a steady state and will continue to change and develop for several years.

Coral bacterial community structure responds to environmental change in a host-specific manner

“…In addition, site E was less than five km from the three main discharge points of Jeddah’s sewage treatment facilities, which regularly discharge extensive amounts (35,000, 68,000, and 300,000 m 3 d −1 , respectively) of untreated or only partially treated sewage that lead to intermittent increases in nitrate levels (Supplementary Fig. 11, Source Data) 66,67 . Hence, this site is subjected to elevated turbidity and highest sedimentation loads (Supplementary Fig.…”

Comprehensive Genomic Analyses of the OM43 Clade, Including a Novel Species from the Red Sea, Indicate Ecotype Differentiation among Marine Methylotrophs

“…A "resistance" island with high similarity to a plasmid in Shewanella sp. may be the result of horizontal gene transfer as an adaptation to high concentrations of metals, such as Cu, Zn, and Cd, among others, that have been associated with the anthropogenic impact in the coastal areas of the Red Sea (77,78) and may also affect the near offshore areas from which the strains were isolated. These potential niche adaptations described through the comparative genomics of a few OM43 isolates were also reflected in the distribution and abundance of this bacterial clade along different marine provinces.…”

Input and dispersion of nutrients from the Jeddah Metropolitan Area, Red Sea

“…The arid climate is characterised by high air temperatures, with a multi-annual mean of 28.5°C, winds from the N to NNW directions (Basaham et al, 2009), and very little precipitation (54 mm y À1 ) (Ewea, 2010). Apart from a low number of rarely flooded wadis, no riverine freshwater runoff from the hinterland http://dx.doi.org/10.1016/j.marpolbul.2014.01.052 0025-326X/Ó 2014 Elsevier Ltd. All rights reserved.…”