Multiproxy analyses of paleoenvironmental and paleoceanographic changes during the Danian-Selandian in East Central Sinai: An integrated stable isotope and planktic foraminiferal data

Forty-three planktic foraminifera samples from the Themed section (East Central Sinai; Egypt) spanning the Zone Parvularugoglobigerina eugubina (Pα) to the Subzone Acarinina subsphaerica (P4b) have been studied. Data from δ13C, δ18O, and planktic foraminifera-based species diversity, depth habitat, preference for warm and cool surface waters, and nutrients (oligotrophic, mesotrophic, and eutrophic conditions) are used to infer paleoenvironmental changes throughout the Danian‒Selandian duration. Based on quantitative multivariate analyses (hierarchical cluster and principal component), three distinct intervals were recognized, Interval 1 (Pα‒P1b), Interval 2 (P1c‒P3a), and Interval 3 (P3a‒P4b). Interval 2 is further subdivided into three subintervals, 2a (part P1c), 2b (part P1c), and 2c (P2‒P3a). Two δ13C events are identified, Dan-C2 and Latest Danian Event (LDE) and elaborated concerning paleoenvironmental changes. During the earliest Danian planktic foraminiferal Pα Zone, moderately shallow and eutrophic conditions prevailed with cool surface waters and a shallow thermocline. Comparable conditions were still prevailing during P1a‒P1b, but with slightly deeper and mesotrophic conditions and a somewhat deeper thermocline and reduced stratification. P1b‒P1c exhibits a major shift from Eoglobigerina to Subbotina‒ Parasubbotina with cooler surface waters and moderate mesotrophic conditions. For Subzone P1c (upper part), slightly mesotrophic conditions were inferred, whereas for P2‒P3a (lower part), surface water warming and thermocline shallowing events have inferred with increased oligotrophic conditions. The Latest Danian Event (mid-P3a) is marked by a dramatic negative δ13C excursion, warm waters, increased mesotrophic conditions, and enhanced stratification. The dominance of Morozovella, Acarinina, and Igorina specify warm and oligotrophic conditions for subzones P3b‒P4b

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

Contamination and health risk assessment of potentially toxic elements in agricultural soil of the Al-Ahsa Oasis, Saudi Arabia using health indices and GIS

The current work aimed to assess contamination and human health risk of potentially toxic elements (PTEs) in agricultural soil of the Al-Ahsa Oasis, Saudi Arabia. For the purpose of evaluating the potential risks to human health associated with ingestion, skin contact, and inhalation, the chronic daily intake (CDI), hazard quotient (HQ), hazard index (HI), cancer risk (CR), and total lifetime cancer risk (LCR) were calculated in 30 soil samples. The spatial distribution and possible sources of HMs were investigated using GIS and multivariate analysis. The descending order of PTE averages (dw, µg/g) was Fe (11790) > Mn (176.43) > Zn (54.43) > Cr (28.67) > Ni (14.53) > V (12.33) > Cu (10.83) > Pb (5.23) > Co (2.87) > As (2.27). The average CDI for all PTEs from ingestion pathway in children indicates an increase of approximated 9 times compared to adults. The HI values varied from 1.969 × 10-4 to 2.318 × 10-2 for Adults, and from 1.835 × 10-3 to 2.158 × 10-1 for children, suggesting there is no significant non-carcinogenic risk to the people inhabiting the Al-Ahsa Oasis. The CRs and LCR for Cr, As, and Pb in children was found to be significantly greater than that of adults. LCR values for As, Pb, and Cr varied from lower than 1 × 10-6 to 1 × 10-4, indicating no significant health hazards to acceptable carcinogenic risk

Contamination and Environmental Risk Assessment of Potentially Toxic Elements in Soils of Palm Farms in Northwest Riyadh, Saudi Arabia

Thirty-four surface soil samples were collected from the palm farms of the Al-Ammariah area, northwest Riyadh, Saudi Arabia to assess the contamination and environmental risk of potentially toxic elements (PTEs). Aluminum (Al), arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), mercury (Hg), manganese (Mn), nickel (Ni), lead (Pb), antimony (Sb), strontium (Sr), uranium (U), vanadium (V), and zinc (Zn) were analyzed using inductively coupled plasma–atomic emission spectroscopy (ICP–AES). Several pollution indices were employed to assess contamination and to evaluate the environmental risks of these PTEs. Average values (mg/kg) for Cr (19.97), Pb (5.08), Cu (11.36), Zn (52.16), Ni (26.94), Co (3.89), and V (18.94) were under the values recorded for soils globally, while the average values of Hg (0.50) and U (8.06) were greater than the average values of worldwide soils. Pollution indices indicated that the studied soils exhibited indications of severe enrichment and significant contamination with Hg, and moderately severe enrichment with U and As. The potential ecological (RI) findings indicated a moderate level of risk posed by PTEs in the study area. The potentially toxic elements originated from both natural and human sources, largely due to chemical weathering of the neighboring mountains, in addition to the widespread utilization of insecticides and fertilizers

Contamination and Environmental Risk Assessment of Potentially Toxic Elements in Soils of Palm Farms in Northwest Riyadh, Saudi Arabia

Thirty-four surface soil samples were collected from the palm farms of the Al-Ammariah area, northwest Riyadh, Saudi Arabia to assess the contamination and environmental risk of potentially toxic elements (PTEs). Aluminum (Al), arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), mercury (Hg), manganese (Mn), nickel (Ni), lead (Pb), antimony (Sb), strontium (Sr), uranium (U), vanadium (V), and zinc (Zn) were analyzed using inductively coupled plasma–atomic emission spectroscopy (ICP–AES). Several pollution indices were employed to assess contamination and to evaluate the environmental risks of these PTEs. Average values (mg/kg) for Cr (19.97), Pb (5.08), Cu (11.36), Zn (52.16), Ni (26.94), Co (3.89), and V (18.94) were under the values recorded for soils globally, while the average values of Hg (0.50) and U (8.06) were greater than the average values of worldwide soils. Pollution indices indicated that the studied soils exhibited indications of severe enrichment and significant contamination with Hg, and moderately severe enrichment with U and As. The potential ecological (RI) findings indicated a moderate level of risk posed by PTEs in the study area. The potentially toxic elements originated from both natural and human sources, largely due to chemical weathering of the neighboring mountains, in addition to the widespread utilization of insecticides and fertilizers

Contamination and health risk assessment of potentially toxic elements in Al-Ammariah agricultural soil, Saudi Arabia

The purpose of this study is to determine the potentially toxic elements (PTEs) in the agricultural land of Al-Ammariah their potential non-carcinogenic and carcinogenic risks for residents’ health due to exposure to PTEs. As, Cu, Co, Cr, Fe, Mn, Ni, Zn, V, and Pb were measured in 34 soil samples collected from palm and citrus plantations using Inductively Coupled Plasma - Atomic Emission Spectroscopy. The values of the chronic daily intake “CDI”, the hazard index “HI”, and the life cancer risk “LCR” can be used to predict the health risks via ingestion and dermal pathways. The following was the order of the average HM levels (μg/g): Fe (11581) > Mn (180) > Zn (52.17) > Ni (26.94) > Cr (19.97) > V (18.94) > Cu (11.36) > Pb (5.08) > Co (3.89) > As (3.78). Our average levels were mostly lower than those reported in worldwide soils. HI decreased in the order of Fe > As > Cr > V > Pb > Ni > Mn > Cu > Co > Zn for adults and children, and was less than 1.0, indicating its insignificance on the human body. The carcinogenic risks for As and Pb, as well as their LCR, were less than (1 × 10−6), implying no significant health risks. Values of LCR due to exposure for Cr in the ingestion pathway in children were higher than (1 × 10−4) implying unacceptable risk

Campanian-Maastrichtian unconformities and rudist diagenesis, Aruma Formation, central Saudi Arabia

The Upper Cretaceous Aruma Formation is widely distributed in central Saudi Arabia and consists of three members, from base to top, the Khanasir Limestone Member, the Hajajah Limestone Member, and the Lina Shale Member. It disconfomably overlies the Cenomanian Wasia Formation (middle Turonian, the Wasia-Aruma break). Two unconformities were recorded within and at the top of the Aruma Formation: (a) the lower Campanian unconformity between the Khanasir Limestone Member and the Hajajah Limestone Member and (b) the pre-Cenozoic unconformity between the Lina Shale Member and the Paleogene Umm er Radhuma Formation. The comparison between these unconformities and those recorded on the Arabian Plate was emphasized. A lenticular rudist biostrome in the uppermost part of the Khanasir Limestone Member consists mainly of the radiolitids and sparse canaliculated rudists in life position. However, rudists are entirely fragmented in the lower limestone and are very rare in the upper limestone of the Hajajah Limestone Member. Loose right valves of radiolitids from the Campanian Khanasir Member have underwent diagenetic alterations, such as fragmentation and compaction, micritization, bioerosion, and micritic calcite cement, which indicates marine diagenetic stage, while very limited silicification, dolomitization, and dissolution suggest the meteoric diagenetic environments with arid climates. Isopachus and equant calcite cement and neomorphism may be showed the fresh pharetic zone related with subaerial unconformities

Mechanisms of nitric oxide involvement in plant-microbe interaction and its enhancement of stress resistance

As a highly active signaling molecule, nitric oxide (NO) is a key factor in regulating plant growth and development. Nitric oxide can promote the formation of symbionts between plant roots, rhizobia and AMF, which improves plant access to nitrogen and phosphorus nutrients in the soil. As a signaling molecule, NO regulates plant resistance to biological and abiotic stresses through the following mechanisms: 1) NO interacts with ROS to regulate reactive oxygen levels and mitigate the damage of oxidative stress response on plants; 2) NO regulates plant immunity and stress resistance through post-translational modification of proteins; 3) NO interacts with various plant hormones and is involved in the regulation process of plant growth and development by hormones. In addition, NO can promote the expression of genes related to the formation and development of the symbionts, inhibit the expression of immune genes, and maintain the REDOX level and energy state of the symbionts through the cycle of NO and phytoglobin, thereby enhancing the plant microbial symbiosis. Previous studies on NO have mainly focused on the first three aspects, and there have been few studies on the mechanism of NO in plant-microbe interaction, therefore the involvement of NO in the mechanism of plant-microbe interaction should be strengthened. It is of great theoretical and practical importance to uncover the mechanism of NO enhancement of plant stress resistance and regulation of root development and to study the mechanism of NO regulation of plant-microbe interactions, responses to abiotic stresses, stomatal regulation, and a range of developmental processes. Combined with recent advances in plant NO biology, this review will highlight some key aspects that need further attention