Abdelbaset S. El-Sorogy

Heavy metals contamination of the Quaternary coral reefs, Red Sea coast, Egypt

In order to assess pollutants and impact of environmental changes along the Egyptian Red Sea coast, seven recent and Pleistocene coral species have been analyzed for Zn, Pb, Mn, Fe, Cr, Co, Ni, and Cu. Results show that the concentration of trace elements in recent coral skeletons is higher than those of Pleistocene counterpart except for Mn and Ni. In comparison with recent worldwide reefs, the present values are less than those of Central America coast (iron), Gulf of Aqaba, Jordan (lead, copper), Gulf of Mannar, India (chromium, zinc, manganese), Costa Rica, Panama (chromium, nickel), North-west coast of Venezuela and Saudi Arabia (copper). The present values are higher than those of Gulf of Aqaba, Jordan (iron, zinc, manganese), Gulf of Mannar, India (lead, cobalt, nickel), North-west coast of Venezuela (lead, zinc, chromium, manganese), Australia (copper, nickel, zinc, manganese). The highest values were recorded in Stylophorapistillata (iron, lead and copper), Acroporacytherea (cobalt), Pocilloporaverrucosa (zinc) and the lowest concentrations were recorded in Goniastreapectinata (iron, chromium, copper and nickel), Favitespentagona (lead, zinc and manganese), and Poriteslutea (cobalt). The differences in metals content among the studied species are attributed to differences in microstructure and microarchitecture.

Assessment of toxic metals in coastal sediments of the Rosetta area, Mediterranean Sea, Egypt

The purpose of the present study is to assess the level and distribution of Mg, Co, Cu, Cd, U, Sr, Zn, As, V, Pb, Ti, Mn, Ba, Ce, Ni, P, Cr, Zr, Hf and Fe in coastal sediments of Abu Khashaba beach, Rosetta area, Egyptian Mediterranean coast. The level of pollution was evaluated using enrichment factor, geoaccumulation index and contamination factor. The results indicated that Abu Khashaba coastal sediments were extremely enriched and very strongly polluted with Cd; severely enriched and strongly polluted with As and Pb, and moderately severely enriched and polluted with Ni, Co, Sr and Ce. The highest Fe, Ba, Ce, Ni, Pb, V, Zn, Sr, Co, Cd, U, Cu, Hf, Cr and Zr were recorded along the shoreline. Fe, Mn, Pb, Co, Cd, Cu and Cr values in the Abu Khashaba coastal sediments were much higher than those recorded in the coastal sediments of the Gulf of Aqaba, the Red Sea, the Arabian Gulf and the Daliao River System of China. The enrichment of Cd, As, Pb, Ce, Ni in the sediments could be partially attributed to anthropogenic inputs and also to other already existing naturally occurring metals.

Environmental assessment of coastal surface sediments at Tarut Island, Arabian Gulf (Saudi Arabia)

Thirty eight surface sediments samples have been collected in the area around Tarut Island, Saudi Arabian Gulf to determine the spatial distribution of metals, and to assess the magnitude of pollution. Total concentrations of Fe, Mn, As, B, Cd, Co, Cr, Cu, Hg, Mo, Pb, Se, and Zn in the sediments were measured using ICP-MS (Inductively Coupled Plasma-Mass Spectrometer). Nature of sediments and heavy metals distribution reflect marked changes in lithology, biological activities in Tarut bay. Very high arsenic concentrations were reported in all studied locations from Tarut Island. The concentrations of Mercury are generally high comparing to the reported values from the Gulf of Oman, Red Sea. The concentrations of As and Hg exceeded the wet threshold safety values (MEC, PEC) indicating possible As and Hg contamination. Dredging and land filling, sewage, and oil pollution are the most important sources of pollution in the study area.

Quaternary coral reefs of the Red Sea coast, Egypt: diagenetic sequence, isotopes and trace metals contamination

This study focuses on the diagenetic sequence under marine and meteoric conditions as well as isotopes and trace metals contamination in Quseir and Gebel Zeit areas along the Egyptian Red Sea coast through a series of modern and fossil corals, Porites lutea and Favites pentagona. The diagenetic sequence begins with deposition of thin fringes of syntaxial aragonite and micritic high-magnesian calcite in the modern corals to completely altered Porites and partially altered Favites to low-magnesium calcite in the oldest Pleistocene unit. Average δ18O and δ13C values of Pleistocene corals in the two studied areas were lower than those of modern corals. Values of modern corals and lower fossil unit indicated coralline limestone, while those of middle and upper fossil units indicated fresh water influences. Average values of trace metals in modern corals were higher than those of Pleistocene counterpart except for Mn. Modern coral samples recorded enrichment in the average values of Pb, Zn, and Mn at Quseir area and enrichment in Co, Cu, and Ni at Gebel Zeit area. This may be attributed mostly to different tourist activities, landfill due to increase urbanization and nearby of Quseir area from the old phosphate harbor at El Hamrawin area, as well as oil exploration and production activities in the Gulf of Suez area. Also, results indicated that most samples of Porites have high concentration of trace metals than in Favites, especially in Cu, Zn, Mn, and Pb. This may due to high amounts of intergranular porosity and high total surface area of Porites in contrast to Favites.

Assessment of metal contamination in coastal sediments, seawaters and bivalves of the Mediterranean Sea coast, Egypt

In order to assess metal contamination on the Mediterranean coast of Egypt, 45 sediment samples, seawaters and bivalve specimens were collected from Rosetta coastal area for Mg, Al, K, Fe, Sr, Zn, Pb, Mn, As, Ce, Ni, Cr and Zr analyses by Inductively Coupled Plasma-Mass Spectrometer. The Enrichment Factor (EF), the Geoaccumulation Index (Igeo) and the Contamination Factor (CF) indicated that the coastal sediments of Rosetta area were severely enriched, strongly polluted with As, Pb and very highly contaminated with As, Pb, Ni, Ce, mostly as a result of anthropogenic inputs. Comparison with other samples from the Arabian Gulf, Red Sea and abroad coasts suggested that the studied samples have higher concentrations of Fe, Pb, As, Zn and Ni. The natural sources of heavy metals in the study area are attributed to weathering and decomposition of mountain ranges of the Sudan and Ethiopia, while the anthropogenic ones are the metals produced from industrial, sewage, irrigation and urban runoff.

Environmental assessment of heavy metal contamination in bottom sediments of Al-Kharrar lagoon, Rabigh, Red Sea, Saudi Arabia

In order to assess the pollution levels of selected heavy metals, 45 bottom sediment samples were collected from Al-Kharrar lagoon in central western Saudi Arabia. The concentrations of the heavy metals were recorded using inductively coupled plasma-mass spectrometer (ICP-MS). The results showed that the concentrations of Pb and Cd exceeded the environmental background values. However, the heavy metal contents were less than the threshold effect level (TEL) limit. The concentrations of heavy metals in lagoon bottom sediments varied spatially, but their variations showed similar trends. Elevated levels of metals were observed in the northern and southern parts of the lagoon. Evaluation of contamination levels by the sediment quality guidelines (SQG) of the US-EPA revealed that sediments were non-polluted-moderately to heavily polluted with Pb; non-polluted to moderately polluted with Cu; and non-polluted with Mn, Zn, Cd, and Cr. The geoaccumulation index showed that lagoon sediments were unpolluted with Cd, Mn, Fe, Hg, Mo, and Se; unpolluted to moderately polluted with Zn and Co; and moderately polluted with Pb, Cr, Cu, and As. The high enrichment factor values for Pb, As, Cu, Cr, Co, and Zn (>2) indicate their anthropogenic sources, whereas the remaining elements were of natural origins consistent with their low enrichment levels. The values of CF indicate that the bottom sediments of Al-Kharrar lagoon are moderately contaminated with Mn and Pb.

Contribution to the scleractinian corals of Hanifa Formation, Upper Jurassic, Jabal Al-Abakkayn, central Saudi Arabia

Eighteen scleractinian coral species belonging to 13 genera, 8 families and 4 suborders have been identified from the lower and upper parts of the Upper Jurassic (Oxfordian) Hanifa Formation at Jabal Al-Abakkayn, central Saudi Arabia. Actinastrea bernensis, A. crassoramosa, Coenastraea hyatti, Stylina kachensis, Cryptocoenia slovenica, C. wegeneri, Isastrea hemisphaerica, I. bernensis, Montlivaltia cornutiformis, M. frustriformis, Collignonastraea jumarensis, Ovalastrea michelini and Vallimeandropsis davidsoni are believed to be recorded for the first time from the Jurassic rocks of central Arabia. Most corals have massive hemispherical and globular forms, and few corals have dendroid and conical growth forms. They occur as small, isolated patches, about 0.5 m thick and about 10–30 m wide, in argillaceous reefal limestones. The identified corals show Africa, north America, northern, southern and western Europe, and southern or eastern Asia corals. The low diversity and abundance as well as the small size of colonies are attributed to inimical palaeoecological factors throughout the reefoids formation such as muddy substratum, water turbidity, high rate of sedimentation.

Metal pollution in Al-Khobar seawater, Arabian Gulf, Saudi Arabia

In order to assess heavy metals pollution along the Al-Khobar coastline, 30 seawater samples and 15 sediment ones were collected for Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Sr, Mo, Cd, Hg and Pb analysis by Inductively Coupled Plasma-Mass Spectrometer (ICP-MS). The analysis indicated a southward decreasing pattern in most heavy metal concentrations and the average values of Zn, Fe, Mn, Cu, As and Cr were higher than the ones reported from some worldwide seas and gulfs. Most of the highest levels were recorded within the bays and were related with in situ under sediments especially that composed of clays and very fine sands, and in localities characterized with anthropogenic activities like landfilling, desalination plants, fishing boats, oil spills and solid rubbish. The results of the present study provide useful background for further marine investigation and management in the Arabian Gulf region.

Paleoecology of benthic foraminifera in coral reefs recorded in the Jurassic Tuwaiq Mountain Formation of the Khashm Al-Qaddiyah area, Central Saudi Arabia

Thirty three benthic foraminiferal species belong to 23 genera and 16 families have been recorded from the coral reefs of the Callovian Tuwaiq Formation, Khashm Al-Qaddiyah area, Central Saudi Arabia. Three species: Astacolus qaddiyahensis, Nodosaria riyadhensis, Siderolites jurassica are believed to be new. Nearly all identified foraminifera are of Atlantic-Miditeranean affinity. The foraminiferal assemblage recorded in the present work is mixed of open marine, moderately deep marine conditions associations and shallow to deep lagoon. The reefal part of upper Twiaq Formation may have been deposited in shallow water of lower to middle shelf depth (20–50 m) as indicated by abundant corals and benthic foraminifera. The coral fauna and bearing benthic foraminifera indicated moderate water energy.

Diagenetic alterations of the upper Jurassic scleractinian corals, Hanifa Formation, Jabal Al-Abakkayn, central Saudi Arabia

During diagenetic stages, the aragonitic skeletons and the inter/intra-corallite cement of the upper Jurassic corals of Hanifa Formation either dissolved or subjected to diagenetic alterations including cementation, micritization, recrystallization, silicification, dolomitization and dedolomitization. The proposed sequence of diagenetic stages is as follows: early marine diagenesis, early meteoric and mixing zone diagenesis, late meteoric diagenesis, and shallow burial diagenesis. Each stage is characterized by certain diagenetic processes. The source of sulfate solutions for dedolomitization in the studied corals is the dissolved anhydrite deposits of the Arab–Hith Formations, sometime before their erosion. A possible source of silica, needed for the formation of chert and chalcedony, is the sponge spicules dispersed in many carbonates of the Hanifa Formation.