On the occurrence of Campanian rudist biostrome, Aruma Formation, Central Saudi Arabia

780-784The lower limestone Khanasir Member of the Aruma Formation in central Saudi Arabia is characterized by Campanian rudist biostrome at its uppermost part. The most abundant rudist fauna are Eodictyoptychus arumaensis, Durania sp. and Biradiolites sp. Succession is overlying continental siliciclastics of Wasia Formation and comprises shale at the base followed by slightly dolomitized, burrow, nodular limestone and caps with rudist biostrome. Abundant microfacies types are wackestones, packstones, grainstones and floatstones with green algae, benthic foraminifers. The succession in general, indicated shallowing upward sequence and rudist biostrome represents a shallow marine lagoonal environment

Risk Assessment of Potentially Toxic Elements in Agricultural Soils of Al-Ahsa Oasis, Saudi Arabia

Contamination of soil with potentially toxic elements (PTEs) is receiving great attention worldwide due to its apparent toxicity and hazards to local residents. The assessments of soil PTE distribution, sources, and environmental risks are, therefore, the first steps of high-efficiency pollutant degradation and sustainable utilization. The current study used a variety of contamination indicators and multivariate methods to evaluate the environmental risk of As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn in Al-Ahsa soils in eastern Saudi Arabia. For analysis, 30 surface soil samples were collected from palm fields irrigated with groundwater and treated sewage water. Landsat images of Al-Ahsa indicated an increase in the total vegetative area and the residential area, and a decrease in the bare land area from 1985 to 2021. The average concentrations of PTEs (mg/kg−1) were lower than the maximum admissible concentrations and had the following decreasing order: Zn (54.43) > Cr (28.67) > Ni (14.53) > Cu (10.83) > Pb (5.23) > As (2.27) > Hg (0.35) > Cd (0.26). The enrichment factor (EF) findings confirmed that the Al-Ahsa soil is significantly enriched with Hg, moderately to severely enriched with As, and moderately enriched with Cd. The potential ecological risk index (RI) demonstrates a moderate ecological risk, with only certain parts presenting a high risk. The different PTE levels in agricultural soils may be caused partly by the various qualities of groundwater that originate from various aquifers and sewage-treated water. The results of a multivariate analysis showed that most of the anthropogenic sources of Hg, As, and Cd may come from using a lot of fertilizers and insecticides. Levels of the remaining PTEs indicated natural sources from earth crust materials

Health Risk Assessment of Nitrate and Fluoride in the Groundwater of Central Saudi Arabia

High nitrate and fluoride contamination in groundwater cause a variety of disorders, including methemoglobinemia, teratogenesis, and dental and skeletal fluorosis. The present work assesses the non-carcinogenic health risks posed by nitrate and fluoride in infants, children, and adults using the daily water intake (CDI), hazard quotient (HQ), and non-carcinogenic hazard index (HI). Groundwater samples were collected from 36 wells and boreholes in three central Saudi Arabian study areas for nitrate and fluoride analysis using ionic chromatography and fluoride selective electrode, respectively. Nitrate concentrations varied from 0.70 to 47.00 mg/L. None of the 36 studied boreholes had nitrate levels that exceeded WHO guidelines (50.00 mg/L). Fluoride ranged from 0.63 to 2.00 mg/L, and 30.55% of the fluoride samples (11 out of 36) exceeded the WHO recommendations for acceptable drinking water (1.5 mg/L). The average hazard index (HI) values for adults, children, and infants were 0.99, 2.59, and 2.77, respectively. Water samples surpassed the safety level of 1 for adults, children, and infants at 44.44, 97.22, and 100%, respectively. Accordingly, water samples from Jubailah and a few from Wadi Nisah may expose infants, children, and adults to non-cancer health concerns. Infants and children are more vulnerable to non-carcinogenic health risks than adults, possibly due to their lower body weight. Immediate attention and remedial measures must be implemented to protect residents from the adverse effects of F- in the study area

New record of Durania cornupastoris (rudist) from the Campanian of the Aruma Formation, Riyadh, Saudi Arabia: Description and biogeographic remarks

A Radiolitidae (rudist, bivalvia), Durania cornupastoris (Des Moulins) is a well-known species defined as an index fossil from the Turonian (mostly middle-upper) deposits in the Mediterranean Tethys and also in the USA. This study includes new rudist materials and well-preserved samples of the species from the Campanian Khanasir Limestone Member of the Aruma Formation outcropping around the Riyadh (Saudi Arabia) region. Durania cornupastoris is characterized by the many finely ribbed, generally flat, sometimes -slightly or pronounced concave posterior and ventral radial bands and bulge interband with thick costae similar to the external ornament of the rest of the right valve surface. The width of the radial bands are variable. A comparison of the species with the well-known Durania species such as Durania arnaudi (Choffat), Durania gaensis (Dacque) and Durania apula Parona is considered. The broadening of the stratigraphic range up to the Campanian and biogeographic distribution into the eastern part of the Arabo-African plate of the species are also emphasized. (C) 2017 Elsevier Ltd. All rights reserved

Bioerosion and encrustation of the rocky shore dwellers along the Arabian Gulf, Northeast Saudi Arabia

The coastal area between Al-Khafji and Al-Jubail, Arabian Gulf, Saudi Arabia is characterized by natural and artificial rocky shores, which inhabited by intensive dwellers. The present work aimed to shed light on the taxonomy, distribution, and environmental factors affecting the abundance of the invertebrate borers and encrusters in the study area. A total of 614 specimens of bivalve, gastropod, coral, and lithified rocky shores were collected from 13 sites. Eighteen ichnospecies of 8 ichnogenera were identified and illustrated. These traces were produced by clionid sponges (31.75%), endolithic bivalves (26.19%), naticid gastropods (24.60%), polychaete annelids (15.08%), acrothoracican barnacles (1.85%), and vermitid gastropods (0.53). The rocky shore dwellers act as hard substrate for colonization by serpulids, barnacles, bryozoans, and other cemented invertebrates. Most of the thick invertebrates and lithified rocky grounds were bioeroded by endolithic bivalves, clionaid sponges, polychaete annelids, and acrothoracican barnacles, while the thin walled invertebrate dwellers were bioeroded by naticid gastropods and clionaid sponges. Barnacles, serpulid worms and some molluscs were intensively covered the rocky shore blocks and solid rubbish in intertidal area facing wave action to comb microscopic food from the water

Contamination and health risk assessment of surface sediments along Ras Abu Ali Island, Saudi Arabia

The coastline of the Arabian Gulf attracts people throughout the year for tourism and fishing activities. The present work aimed to document the contamination and human health assessment of heavy metals (HMs) in 34 surface sediment samples collected along Ras Abu Ali coastline, Saudi Arabia. Enrichment factor (EF), contamination factor (CF), and sediment quality guideline (SQG) were calculated to estimate the sediment contamination, while the hazard index (HI), cancer risk (CR), and total lifetime cancer risk (LCR) were determined for human health assessment via ingestion and dermal contact pathways on both adults and children. The averages of the HMs (μg/g dry weight) were in the following order: Fe (4808) > Ni (13.00) > Zn (6.89) > Cr (7.86) > V (6.67) > Cu (4.14) > Pb (3.50) > As (2.47) > Co (1.43). Results of EF indicated minor enrichment with Ni, Pb, and As, and no enrichment with the remaining HMs. Based on CF, the coastal sediments of Ras Abu Ali showed low contamination with HMs. Reported values of As, Cr, Cu, Pb, and Zn were lower than the ISQG-Low values, however, 4 samples of Ni reported values between the ISQG-Low and ISQG-High values, indicating some anthropogenic effects with Ni. HI values were higher among children in comparison to adults, suggesting that children were at higher risk of non-carcinogenic exposure than adults. LCR values indicated that no significant health hazards for people inhabited the study area from the carcinogenic Pb, Cr, and As

Benthic foraminifera as bioindicators of anthropogenic pollution in the Red Sea Coast, Saudi Arabia

The concentrations of Fe, Mn, Cu, Ni, Zn, Pb, Cr, Co, and Cd were measured in the tests of two foraminiferal species (Sorites orbibulus and Peneroplis planatus) using ICP-MS to assess the marine contamination. Iron was the most abundant metal (3294 μg/g), followed by Mn (133 μg/g), Cu (34.7 μg/g), Zn (28.3 μg/g), Cr (25 μg/g), Ni (18.9 μg/g), Pb (12.2 μg/g), Co (9.5 μg/g), and Cd (0.85 μg/g). The values enrichment factor, geo-accumulation index, and contamination factor show that the foraminiferal shells are enriched in (Cd, Cu, Pb) posing an ecological risk. Iron shows highest concentration amongst the heavy metals recorded in the study shells, however, shows low concentration in comparison with surrounding areas of Red Sea coast in Saudi Arabia and Egypt. Other heavy metals show higher concentrations than those recorded in Egypt and Saudi Arabia. The elevated heavy metal concentrations in the foraminiferal tests may be attributed to the industrial and urban activities along Yanbu coast

Groundwater quality assessment in western Saudi Arabia using GIS and multivariate analysis

In arid and semi-arid regions, assessment of groundwater quality and potentially toxic elements is essential issue for health of the human being. Groundwaters were collected from sixty-eight wells in Harrat Khaybar, Saudi Arabia to evaluate their suitability for drinking and irrigation purposes and to document the potential sources of contamination. Several contamination indices and inverse distance weighted technique were applied for assessing contamination and generate spatial maps for the potentially toxic elements (PTEs). The results showed that the average values of the ions, Cl–, SO42–, HCO3–, NO3–, Na+, Ca2+, Mg2+, and the total dissolved solids (TDS) were greater than the permissible limit for drinking water while the average values of PTEs were less than the permissible limit, with exceeding limits of Cr, Se, As, Zn, and Pb in some individual samples. Piper diagram indicated that 47.10% of the water samples are of Na-K-SO4-Cl type, 23.51% of Ca-Mg-CO3-HCO3 type, 23.51% of Ca-Mg-SO4-Cl type, and 5.88% of Na-K-CO3-HCO3 type. Based on the groundwater quality index (GWQI), 29 of the groundwater wells were categorized as excellent and good water for drinking purposes, while 29 wells fell under poor, very poor water, and unsuitable for drinking. Additionally, results of heavy metal pollution index (HPI) indicated that all waters fell within the low pollution category, while results of the metal index (MI) indicated that 35 wells fell within very pure, pure, and slightly affected categories, while 33 wells fell in the moderately, strongly, and seriously affected categories. Results of sodium adsorption ratio (SAR), sodium percentage (%Na), and magnesium ratio (MR) revealed that 33.82–98.5 % of the water samples are suitable for irrigation depending on the parameter type. Ions exchange reactions and dissolution of rock forming minerals, as well as industrial and domestic effluents and intensive use of fertilizers and pesticides were the natural and anthropogenic factors controlling the groundwater geochemistry in the study area and PTE contamination in some wells