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Due to the scarcity of drinking water, the city of Tobruk depends mainly on desalination of sea water for drinking. The water quality of 16 sites along Tobruk bay was investigated during two seasons (winter and summer). Varying analytical techniques have been utilized to analyze group of environment-sensitive elements, including Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn. These tests were performed using the Inductively Coupled Plasma/Atomic Emission Spectroscopy ICP/AES. To evaluate the suitability of water for aquatic life and drinking purposes the contamination index (Cd) was computed. The results of the present study indicated the bay is affected by intensive load of urban, agricultural and industrial wastewater showed serious deterioration of water quality compared with other sites along the Mediterranean Sea. The studied sites of Tobruk bay showed high Cd values which associated with high risks, where, most of the studied metals often exceeded the drinking water and aquatic life permissible limits as compared with WHO specifications, as well as Libyan specifications.

The Arab Petroleum Pipelines Company “SUMED” is a joint stock company that owns and operates two parallel pipelines Ain Sukhna on the Red Sea to Sidi Kreir on the Mediterranean. A huge tanks farm at each oil terminal, which serves operation. Daily routine operations may cause some environmental risks. Although relatively rare, major accidental oil spills do happen and can potentially cause a major impact on marine environment.

In this work five surface sediments samples and seven surface water samples were collected from specifically chosen locations in the vicinity of Sidi Kreir area which is considered a hot spot area in the Mediterranean Sea due to presence of power station, The Arab Petroleum Pipelines Company “SUMED” as well as increasing the movement of ships that are transferring oil and its derivatives. A total of thirteen Polycyclic Aromatic hydrocarbons (PAHs) were determined in sediment and water samples in order to study the adverse environmental and health effects. The concentration of total PAH ranged from 249.62 ng.l−1 to 556.56 ng.l−1 dry wt. and from 41.96 ng.l−1 to 292 ng.l−1 in sediment and water respectively.

The Tobruk Bay represents great commercial and economic importance as a result of population growth, urban development, economic and industrial activity. Large quantities of municipal and industrial waste are disposed directly in seawater. Heavy metals are the most important and most serious problems in aquatic environments. This study was conducted to evaluate the concentrations of heavy metals contamination and their distribution in the sediments. Sixteen sites were selected and identified accurately representing the study area. Samples placed in self-closing polyethylene bags and stored in ice boxes then transfer to the laboratory, they stored in the refrigerator at −20 ℃ in the dark until analysis. The ICP-OES instrument was used to detect the desired heavy metals (Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in the surface sediment samples. The ranges of TOC and the fine fraction (clay and silt) contents of analyzed sediments are 2.2%–4.7% and 0.2%–1.7%, respectively. Their average values are 3.3% and 0.8%, respectively. The comparison of heavy metal concentrations in this study with that of previous studies in other regions shows that the concentration of heavy metals in surface sediments of Tobruk bay is lower than concentrations of heavy metals in Western Xiamen Bay, China, New York Harbor, Bremenn Harbor Germany, Izmir Harbor, Turkey regions. The calculated results of Igeo values indicated that all the sampling stations were extremely polluted with As, also enrichment factor revealed the same results.

Air pollution is reported as one of the most severe environmental problems in the Middle East and North Africa (MENA) region. Remotely sensed data from newly available TROPOMI - TROPOspheric Monitoring Instrument on board Sentinel-5 Precursor, shows an annual mean of high-resolution maps of selected air quality indicators (NO2, CO, O3, and UVAI) of the MENA countries for the first time. The correlation analysis among the aforementioned indicators show the coherency of the air pollutants in urban areas. Multi-year data from the Aerosol Robotic Network (AERONET) stations from nine MENA countries are utilized here to study the aerosol optical depth (AOD) and &Aring, ngstr&ouml, m exponent (AE) with other available observations. Additionally, a total of 65 different machine learning models of four categories, namely: linear regression, ensemble, decision tree, and deep neural network (DNN), were built from multiple data sources (MODIS, MISR, OMI, and MERRA-2) to predict the best usable AOD product as compared to AERONET data. DNN validates well against AERONET data and proves to be the best model to generate optimized aerosol products when the ground observations are insufficient. This approach can improve the knowledge of air pollutant variability and intensity in the MENA region for decision makers to operate proper mitigation strategies.

Atmospheric aerosol particles affect the formation of precipitation through influencing on microphysical properties of water and ice clouds. In early May of 2018, we observed the coincident of strong dust and rain events in the Nile Delta area. We also used Hybrid-Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model, NMMB/BSC-dust model and NOAA-18 Cloud Height product to validate this same movement of dust and clouds that induced precipitation. In addition, Nino 3.4 index with historical rain and dust anomalous events during 1980–2017 were analyzed to reveal the relationship between these events and global climate system. The results revealed an obvious matching in both intensity and movement for both dust and precipitation events in early May 2018. Extreme precipitation anomalies during 1990–1999 occurred in company with positive Nino indices and less dust events.

Organochlorine contamination in the Mediterranean coastal environment of Egypt was assessed based on 26 surface sediments samples collected from several locations on the Egyptian coast, including harbors, coastal lakes, bays, and estuaries. The distribution and potential ecological risk of contaminants is described. Organochlorine compounds (OCs) were widely distributed in the coastal environment of Egypt. Concentrations of PCBs, DDTs, and chloropyrifos ranged from 0.29 to 377 ng g −1 dw, 0.07 to 81.5 ng g −1 dw, and below the detection limit (DL) to 288 ng g −1 dw, respectively. Other organochlorinated pesticides (OCP) studied were 1–2 orders of magnitude lower. OCP and PCBs had higher concentrations at Burullus Lake, Abu Qir Bay, Alexandria Eastern Harbor, and El Max Bay compared to other sites. OCP and PCB contamination is higher in the vicinity of possible input sources such as shipping, industrial activities and urban areas. PCB congener profiles indicated they were derived from more than one commercially available mixture. The ratios of commercial chlordane and heptachlor metabolites indicate historical usage; however, DDT and HCHs inputs at several locations appear to be from recent usage. The concentrations of PCBs and DDTs are similar to those observed in sediments from coastal areas of the Mediterranean Sea. Ecotoxicological risk from DDTs and PCBs is greatest in Abu Qir Bay, Alexandria Harbor, and El-Max Bay.

This investigation represents the first extensive study of the spatial distribution, sources, and potential effects of polycyclic aromatic hydrocarbons (PAHs) in sediments from Lake Manzala, the largest of Egypt's Mediterranean coastal lakes. The concentrations of PAHs (Σ39 components) ranged from 246 to 9910 ng g−1 dry wt., the highest values corresponding to urban hotspots with high anthropogenic input coming from wastewater discharges and combustion activities and decreasing offshore. The levels of PAHs were significantly lower compared to values reported in several coastal/estuarine areas (e.g., in Spain, Italy, USA, and Egypt) receiving substantial anthropogenic inputs from urban and industrial activities. Source ratios indicated that the PAHs were mainly from petrogenic sources in near-shore urban hotspots, with higher contributions of pyrolytic sources in coastal and offshore areas which are little influenced by human activities. Sediment quality guidelines (SQGs) showed that except at one station ...

Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were determined in surface and core sediment samples collected from Manzala Lake, the largest of the Egyptian coastal lakes. Total concentrations of OCPs and ∑7 PCBs (ICES) in sediments ranged from 0.63 to 31.31 ng/g and 0.26 to 31.27 ng/g, respectively. Geographical distribution indicates that levels of contaminants were significantly higher in areas which are mainly influenced by municipal discharge, indicating significant sources of these compounds in urbanised areas. The composition of DDT and its metabolites suggest old input of DDT. The levels of contaminants in Manzala Lake were similar or lower than those observed in comparable areas worldwide. The profiles of ∑OCPs and ∑PCBs in a core from a site heavily impacted by sewage discharge have highest concentrations in the surface core section indicating recent inputs. Assessment of ecotoxicological risk indicated that sediments in two sites were likely to pose potential biological adverse impact.

Organochlorine compounds (OCs) in surface and core sediments collected from Lake Maryut, Egypt, were examined to elucidate their distribution, ecological risk and historical trend. To our knowledge, this is the first study on residue levels of OCs in sediments from Lake Maryut. Concentrations of PCBs and DDTs were higher than other OCs, ranging from 3.06 to 388 and from 0.07 to 106 ng/g dry wt., respectively. The highest concentrations of OCs were found at stations near the discharge point of sewage and close to industrial areas. The distribution of DDT and its metabolites suggest no recent inputs into the lake environment. Contamination levels of sedimentary PCBs and DDTs, can be categorized moderate to high compared to other urbanized regions worldwide. Temporal trends in OCs levels were influenced by input pathways at two sites. Evaluation of ecotoxicological risks suggests that adverse biological effects are expected mainly in the main basin area.

In Egypt, the picture of threats to humans and the environment from the exposure to organic pollutants is still incomplete. Thus the objectives of this study were to assess the occurrence and distribution of polychlorinated biphenyls (PCBs), organochlorine pesticides, and chlorpyrifos in sediments and mussels of Abu Qir Bay and their risks for environment and human health.Twenty-three different compounds organochlorines were determined in 20 surfacial sediment and 10 mussel samples by gas chromatography-electron capture detector. A Screening Level Ecological Risk Assessment (SLERA) and a Human Health Risk Assessment (HHRA) were performed with the data.ΣDDT (DDT, DDE, DDD) (average concentration 27 µg/kg dw) dominated the detected organic pollutants in the sediments, followed by CHLs (chlordane, heptachlor, heptachloro epoxide), hexachlorocyclohexane, chlorpyrifos, endosulfane, dieldrine, Σ6 PCBs, aldrine, hexachlorobenzene, pentachlorobenzene, methoxychlor, and mirex. In general, concentrations of Σ6 PCBs in mussels were higher than their corresponding sediment concentrations reflecting their relatively high bioavailability and bioaccumulative potential. However, concentrations of the organochlorine pesticides in mussels were lower than their corresponding sediment samples. Nevertheless, the SLERA on the bay sediments revealed that adverse ecological effects to benthic species are expected to occur whereas the HHRA showed that adverse health effects are not expected to occur from the consumption of the mussels.With the help of a SLERA, it was possible to indicate which class of chlorinated organic compounds is of highest concern to assess and to improve the environmental quality of the bay. Monitoring of organochlorines and chlorpyrifos would be needed to control the future trend of pollution.

Sediment samples were collected from 30 different locations in Abu Qir Bay (Mediterranean Sea), East Alexandria, Egypt and analyzed for trace elements. The highest concentrations of most of the elements were observed in the nearshore stations in the vicinity of the major anthropogenic activities as industrial settlements, wastewater discharges, and agricultural drainage. In addition, mussel samples of Mactra corallina and Tapes decussata were collected corresponding to the sediment samples. Concentrations of As, Cd, Cr, Mn, and Zn in the mussel tissues were higher than concentrations in sediments, thus indicating their relatively high bioavailability. Sequential extraction procedure was performed on selected sediment samples. Significant correlations were observed between the concentrations of Cu, Mn, Pb, and Zn in the exchangeable fraction of the sediments and the corresponding tissues of M. corallina. The output of the risk assessment applied on the sediments revealed that adverse ecological effects to benthic species could occur and that a higher level of risk is expected from the exposure to Cd, Cr, Hg, and Zn. No adverse carcinogenic or non-carcinogenic human health effects are expected from the consumption of the two mussel species from Abu Qir Bay.

Surface and core sediments from Lake Maryut, Egypt, one of the most polluted lakes in Egypt, were analyzed for polycyclic aromatic hydro- carbons (PAHs) using gas chromatography-mass spectrometry. This investigation represents the first extensive study of the distribution and sources of PAHs in sediments from Lake Maryut. The total PAHs concentrations (sum of 39 PAH compounds) in surface sediments varied greatly depending on the sampling location and ranged from 106 to 57,800 ng/g dry weight with a mean concentration of 6,950 ng/g. The most polluted areas are distributed in areas which are mainly influenced by municipal sewage and industrial effluent discharges, suggesting a direct influence of these sources on the pollutant distribution patterns. PAH concentrations were one to two orders of magnitude higher in comparison with those reported for riverine/ estuaries systems around the world. Molecular indices, such as pyrogenic index (PI), methylphenanthrenes to phenanthrene ratio, HMWPAH/LMWPAH, A-PAHs/P- PAHs, FL/FL+PY, BaP/BaP+C, IP/IP+BgP, and Per/ ∑(penta-aromatics) were calculated to evaluate differ- ent hydrocarbon origins and their relative importance. In general, sediments from the main basin and northwest basin of Lake Maryut showed the highest PAH concentrations with petrogenic signatures, indi- cating major sources of petrogenic PAHs in the city. On the other hand, lower levels of PAHs with a pyrogenic signature were widely recorded in areas that are distant from anthropogenic sources. At other locations, both petrogenic and pyrogenic inputs were significant. The concentrations of perylene relative to the penta-aromatic isomers are dominant especially in locations associated with terrestrial inputs and in the deepest core sediments, indicating diagenetic origin for the presence of perylene. Temporal trends of PAH concentrations in both cores sediments were influenced by input pathways and followed the economic development and the environmental policies of the Egyptian Government in the last 15 years. Finally, PAH levels in sediments were compared with Sediments Quality Guidelines (effects range median-effects range low) for evaluation probable toxic effects on organism. Results suggest an ecotoxicological risk for benthic organisms mainly in the main basin area, where high concentrations of PAHs were found in sediments influenced by anthropogenic activities.

To assess the status of polycyclic aromatic hydrocarbon (PAH) contamination in sediments of Hadhramout coastal area, Gulf of Aden, Yemen, 17 surface sediment samples were collected in March–April 2005 and analyzed for PAHs with 2–6 benzene rings by gas chromatography–mass spectrometry (GC-MS). The concentrations of PAHs in surface sediments were in the range of 2.2–604 ng g − 1 (average value: 82.4 ng g − 1 ). PAHs contamination is highest in proximity to harbour activities, near Al-Dhabah petroleum terminal and urban areas. Comparison of the concentration range with a worldwide survey of sedimentary PAH concentrations ranked PAH contamination in Hadhramout coastal sediments as low to moderate. Assessment of PAH sources in Hadhramout coastal sediments suggested that they originated largely from petrogenic sources. PAHs of pyrolytic origin were found in sediments from urbanized areas. Adverse effects on benthic communities are not expected at the levels of PAHs contamination observed from harbour and industrial areas.

The aliphatic and aromatic fractions of the extracts of ten street dust (SD) samples collected from eight cities covering a wide geographic area of Egypt were analyzed using gas chromatography with flame ionization detector (GC-FID) and GC–MS to compare their hydrocarbon distributions. To identify their sources, the extracts of the possible source materials were also analyzed. The impact of SDs on the marine environment was investigated in a marine sediment collected from the Western Harbor of Alexandria. The GC-FID profiles of the aliphatic fractions showed considerable differences in the n -alkane distribution that permits the classification of the SDs into five groups. This grouping reflects the environments of the cities in which they are collected. The carbon preference index and the unresolved complex mixture relative to the total resolved peaks values revealed that automobile exhaust is the main source of the hydrocarbons in these SDs with a significant contribution from terrestrial higher plant waxes to group 1 (Nile Delta cities). The sterane and hopane profiles supported this conclusion. The total polycyclic aromatic hydrocarbon (PAH) concentrations ranged from 27 to 379 ng/g (dry wt.) and showed clear differences between the SDs. The lowest and highest concentrations were found in samples from Shebeen and Port Said, respectively. The PAH distribution patterns and the ratio of the sum of combustion specific PAHs to total PAHs in samples from Alexandria, Port Said and Cairo were similar, implying similar sources. PAH ratios indicated a mixture of pyrogenic and petrogenic sources of PAHs in all samples where asphalt and automobile fuel exhaust were the major contributors of PAHs in Alexandria, Port Said, Cairo and Sharm El Sheikh cities. These ratios also indicated the predominance of diesel-operated vehicles to the PAHs signatures of Alexandria, Port Said and Cairo while gasoline emissions influence more strongly the PAH distributions in the SDs from Shebeen, Kafr El Sheikh and Sharkea. The PAH fingerprints excluded fresh oil and tire particles as major contributors. Both SDs and petrogenic sources significantly contributed to the hydrocarbon signature of the marine sediment from the Western Harbor of Alexandria.

Little data are available on the levels of polycyclic aromatic hydrocarbons (PAHs) in the sediments of the Mediterranean Sea Coast of Egypt in general and the Alexandria coastal zone in particular. It was therefore deemed necessary to set up a monitoring programme to determine the current concentrations of PAHs in bottom sediments, and to identify any area where high concentrations of these potential hazardous contaminants were present in the Western Harbour of Alexandria. The composition, distribution and the source of PAHs in surficial sediments of the harbour were investigated. To document the spatial PAH input, surficial sediment samples from 23 locations throughout the harbour were analysed. as]Results and Discussion The total PAH load determined in the surficial sediment samples ranged from 8 to 131150 ng g1 dry wt, generally with most of the samples having total concentrations of PAHs greater than 5000 ng g1 dry weight. The highest concentration of total PAHs was recorded in sediments of the inner harbour. Ratio values of specific compounds such as phenanthrene to anthracene, fluoranthrene to pyrene, methyl-phen-anthrene to phenanthrene, methyl-dibenzothiophenes to dibenzothiophenes, alkylated to non-alkylated and high molecular weight to low molecular weight PAH, were calculated to evaluate the possible source of PAH contamination in the harbour sediments. Two main sources of PAH in the study area have been found: pyrolytic and petrogenic. Interferences of rather petrogenic and pyrolytic PAH contaminations were noticed for most samples. The dominant sources of PAH appear to be the combustion processes through run-off, industrial and sewage discharges, and atmospheric input. The concentrations of PAHs were generally above levels expected to cause adverse biological effects. Information from this study and any other relevant studies should be useful in designing future strategies for environmental protection and management of the harbour.

To assess the contamination of polycyclic aromatic hydrocarbons (PAHs) in the Mediterranean coastal environment of Egypt, 26 sediment samples from the coastline, harbours, estuaries and coastal lakes were collected and analyzed. The sediment PAH concentrations of thirty-nine 2–6 ring PAHs ranged from 13.5 to 22,600 ng/g. PAH profiles varied according to the nature of the site and its proximity to sources. Industrialized and urbanized region showed high level of PAHs contamination. In general, the contamination levels of PAHs were similar to those observed in contaminated and slightly contaminated sediments of the Mediterranean Sea. Molecular indices based on ratios of selected PAH concentrations were used to differentiate PAHs from pyrogenic and petrogenic and mixed origins. Good correlations were observed between the petrogenic index, MP/P, A-PAHs/P-PAHs and HMW/LMW. Finally, PAH levels in sediments were compared with Sediments Quality Guidelines (ERM–ERL) for evaluation of probable toxic effects on organism.