Bio-accumulation of Polycyclic Aromatic Hydrocarbons in the Grey Mangrove (Avicennia marina) along Arabian Gulf, Saudi Coast

The Arabian Gulf is considered as one of the most important sources for the crude oil all over the world. Due to the vast oil exploration and exploitation, huge amounts of organic pollutants infiltrate to the gulf. An important class of organic pollutants is polycyclic aromatic hydrocarbons (PAHs). One of the marine habitats in Arabian Gulf area is the mangrove stands, that are undoubtedly impacted by all anthropogenic factors like oil industries and sewage discharge. In the monitoring framework for mangrove ecosystem along Saudi coasts, nine mangrove stands were examined for the accumulation of PAHs in the Arabian Gulf coast. PAHs were measured using Gas Chromatography-Mass Spectrometry. The mean values detected for total PAHs in mangrove sediments, roots and leaf were 105.39, 680.0 and 282.4 ng/g, respectively. The trend of total PAHs concentrations in all sites showed the descending order: roots > leaf > sediments. Despite the sandy nature and low organic carbon contents of the mangrove sediments, moderate values of PAHs were detected in the major sites. PAH bio-accumulation factors for roots are higher than that in leaf. The diagnostic ratios revealed that the sources of PAHs are mainly pyrogenic, except for Damam and Damam Port that were found to be petrogenic

Fecal sterols and pahs in sewage polluted marine environment along the eastern Red Sea coast, South of Jeddah, Saudi Arabia

404-410Water and sediment samples were takes near the sewage discharge point on the eastern Red Sea Coast of Jeddah and analyzed for PAH and fecal sterols like coprostanol, cholesterol and cholestanol. PAH were estimated spectrofluorometrically and then further analyzed by GC-MS. Sterols were derivatized by BSTFA into their corresponding trimethyl silyl derivatives and then analyzed by gas chromatography and quantified with standard sterols. PAH ranged from 1.5 to 6.5 g 1-1 in eight stations. Concentration of coprostanol in water samples showed a maximum of 8.2 g 1-1 at station XVIII and minimum 0.1 g 1-1 at station 10C. The analysis of the sediment samples indicated much higher values for fecal sterols. It was found to be 785 g 1-1 in sediment and 6.5 g 1-1 in the water samples at station XVIII. PAH did not show any distinct increase in the sediment samples. According to Grimaldt equation the value of r* (5 / 5 + 5) was determined. Out of a total of sixteen samples, fourteen samples had a value of 0.7 or higher than 0.7. This indicate a definite and a positive sewage contamination infecting almost the whole area studied. The GC-MS of the PAH indicate the presence of phenanthrene, benzophenone and 2,4-diisoprophyl naphthalene, methylnaphthalene, and 9-H-methylene flourene. Present study infers that the sewage; either untreated or partially treated is dumped into the sea

Bio-concentration of Polycyclic Aromatic Hydrocarbons in the grey Mangrove (Avicennia marina) along eastern coast of the Red Sea

There are numerous sources of chemical pollutants which can impact the mangrove ecosystem through adjacent waters, industrial and sewage discharges and air depositions. Polycyclic aromatic hydrocarbons (PAHs) are semi volatile ubiquitous anthropogenic pollutants detected in all environmental compartments. In the monitoring framework for the mangrove ecosystem along the Red Sea coast of Saudi Arabia, nine mangrove stands were examined for the accumulation of PAHs. Polycyclic aromatic hydrocarbons were measured using Gas Chromatography-Mass Spectrometry (GC-MS). The mean values detected for total PAHs in sediments, roots and leaf were 2.98, 8.57 and 23.43 ng/g respectively. The trend of the total PAHs concentration in all sites showed the descending order: leaf > roots > sediments. Beside the sandy nature of the sediments, the presences of all stands in remote areas fare from the direct anthropogenic effects lead to these relative low values. PAH bio-concentration factors for leaf are two to three magnitudes higher than that in roots, suggesting atmosphere deposition /leaf uptake mechanism in addition to the sediment/root mechanism. The diagnostic ratios revealed that the sources of PAHs are mainly pyrogenic

Laboratory and Pilot-Plant Scale Photocatalytic Degradation of Polychlorinated Biphenyls in Seawater Using CM-n-TiO2 Nanoparticles

Photocatalytic degradation of polychlorinated biphenyls (PCBs) in seawater was successfully achieved at laboratory level with UV light and at pilot-plant scale under natural solar radiation using carbon-modified titanium oxide (CM-n-TiO2) nanoparticles. The photocatalytic performance of CM-n-TiO2 was comparatively evaluated with reference n-TiO2 under identical conditions. As a result of carbon incorporation, significant enhancement of photodegradation efficiency using CM-n-TiO2 was clearly observed. To optimize the operating parameters, the effects of catalyst loading and pH of the solution on the photodegradation rate of PCBs were investigated. The best degradation rate was obtained at pH 5 and CM-n-TiO2 loading of 0.5 g L−1. The photodegradation results fitted the Langmuir-Hinshelwood model and obeyed pseudo-first-order reaction kinetics