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The Midyan Basin is characterized by arid climate with rare surface water flow. Groundwater is the main water resources in this region. In order to evaluate their suitability for drinking, domestic and irrigation purposes, chemical characteristics of groundwater in the Midyan Basin (northwestern Saudi Arabia) have been investigated and evaluated. A total of 72 water samples were collected from different wells and analyzed for hydrogen ion concentration, total dissolved solids, electrical conductivity, total hardness, Ca2+, Na+, Mg2+, K+, Cl-, HCO3-, NO3- and SO42-. To understand quality of groundwater and their suitability, chemical indices like sodium percentage, sodium adsorption ratio and salinity values have been calculated using analytical techniques. From traditional Piper diagram for water classification, the water quality is placed at Na+-Ca2+-SO42--Cl- type. According to the results of electrical conductivity and sodium adsorption ratio, 37% of the studied samples are regarded as highly saline, while 63% of them are classified as very highly saline. As per the Arab Gulf and international standards, such waters are not suitable for irrigation under normal condition and further action is required to remediate such problem by salinity control. Sodium content in 24% of the studied samples is regarded as high that can't be used for irrigation purposes for any soils. Thus high level of salinity, sodium adsorption ratio and sodium percentage in most water samples have made them unsuitable [ABSTRACT FROM AUTHOR]

This environmental assessment focuses on the coastal sediments of the Al-Khafji area in the Saudi Arabian Gulf, with an analysis of the human health risks posed by lead (Pb) and cadmium (Cd) contamination. Single and integrated indices were used to detect contamination and evaluate these metals' non-carcinogenic and carcinogenic impacts on adults and children through ingestion, dermal contact, and inhalation pathways. Sediment quality guidelines and contamination indices indicated the absence of significant contamination levels. The moderate contamination observed in scattered samples did not imply adverse biological effects due to the presence of these two metals in Al-Khafji sediments. The average values of the chronic daily intake (CDI) for both Pb and Cd were higher in children than adults across all three pathways, with ratios of 9.4, 4.7, and 4.7 folds, respectively. The hazard index (HI) values for Pb and Cd were below 1, confirming that the sediments of Al-Khafji are considered acceptable and safe in terms of these potentially toxic elements (PTEs). The average lifetime cancer risk (LCR) values for Pb and Cd were higher in children compared to adults, with ratios of 9.3 and 9.4 folds, respectively. However, all detected LCR levels do not represent a potential carcinogenic health hazard. Nevertheless, a regular monitoring program aimed at detecting early signals of environmental health depletion is recommended., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

The Gulf of Suez faces challenges related to contamination, primarily due to industrial, tourism, and shipping activities along its shores. This study aims to record the distribution, concentration, and potential environmental and health risk impacts of heavy metal(loid)s (HMs) in 30 surface sediment samples collected from Ras Sidr coastline, Gulf of Suez. Various contamination and health indices were employed for this study. The average concentrations of HMs (μg/g) were ranked as follows: Fe (3472), Mn (103.3), V (10.41), As (7.94), Cr (6.00), Zn (5.31), Ni (2.94). The spatial distribution of HMs indicated an increase in Mn, Zn, As, and V levels toward the southern part of the study area, potentially linked to the proximity of manganese quarries and their metal association at Abu Zenima. Contamination indices revealed moderately severe enrichment with As, minor enrichment with Mn, and no enrichment for the remaining HMs. Multivariate analysis suggested a natural origin for Cr, Fe, Mn, Ni, Zn, and V, while As were likely anthropogenic. Values of hazard index (HI) for HMs in both adults and children followed the descending order of As > Fe > Cr > V > Mn > Ni > Zn. However, all HI values were below 1.0, indicating no significant non-carcinogenic risk for individuals along the Ras Sidr coastline. 19 samples exhibited lifetime cancer risk (LCR) values exceeding 1 × 10 -4 for As in children, suggesting potential carcinogenic risks. LCR values for As in adults and Cr in adults and children ranged from 1 × 10 -5 to less than 1 × 10 -6 , indicating acceptable or tolerable levels of carcinogenic risk and no significant threats to health., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Surface sediment samples were collected from Ziqlab dam in northwestern Jordan to investigate the spatial distribution of selected trace metals and assess their pollution levels. The results showed that the concentrations of Pb, Cd, and Zn exceeded the environmental background values. Cd, Ni, and Cr contents were higher than the threshold effect level (TEL) in 63, 83, and 60 % of the reservoir sediments, respectively; whereas Pb, Zn, and Cu were less than the TEL limit. The concentrations of trace metals in reservoir sediment varied spatially, but their variations showed similar trends. Elevated levels of metals observed in the western part (adjacent to the dam wall) were coincided with higher contents of clay-silt fraction and total organic matters. Multivariate analysis indicated that Pb, Co, and Mn may be related to the lithologic component and/or the application of agrochemicals in the upstream agricultural farms. However, Cd and Zn concentrations were probably elevated due to inputs from agricultural sources, including fertilizers. Evaluation of contamination levels by the Sediment Quality Guidelines of the US-EPA, revealed that sediments were non-polluted to moderately polluted with Pb, Cu, Zn, and Cr, but non-polluted to moderately to heavily polluted with Ni and non-polluted with Mn. The geoaccumulation index showed that Ziqlab sediments were unpolluted with Pb, Cu, Zn, Ni, Cr, Co, and Mn, but unpolluted to moderately polluted with Cd. The high enrichment values for Cd and Pb (>2) indicate their anthropogenic sources, whereas the remaining elements were of natural origins consistent with their low enrichment levels.

The present study deals with detailed hydrochemical assessment of groundwater within the Saq aquifer. The Saq aquifer which extends through the NW part of Saudi Arabia is one of the major sources of groundwater supply. Groundwater samples were collected from about 295 groundwater wells and analyzed for various physico-chemical parameters such as electrical conductivity (EC), pH, temperature, total dissolved solids (TDS), Na(+), K(+), Ca(2+), Mg(2+), CO3 (-), HCO3 (-), Cl(-), SO4 (2-), and NO3 (-). Groundwater in the area is slightly alkaline and hard in nature. Electrical conductivity (EC) varies between 284 and 9,902 μS/cm with an average value of 1,599.4 μS/cm. The groundwater is highly mineralized with approximately 30 % of the samples having major ion concentrations above the WHO permissible limits. The NO3 (-) concentration varies between 0.4 and 318.2 mg/l. The depth distribution of NO3 (-) concentration shows higher concentration at shallow depths with a gradual decrease at deeper depths. As far as drinking water quality criteria are concerned, study shows that about 33 % of samples are unfit for use. A detailed assessment of groundwater quality in relation to agriculture use reveals that 21 % samples are unsuitable for irrigation. Using Piper's classification, groundwater was classified into five different groups. Majority of the samples show Mix-Cl-SO4- and Na-Cl-types water. The abundances of Ca(2+) and Mg(2+) over alkalis infer mixed type of groundwater facies and reverse exchange reactions. The groundwater has acquired unique chemical characteristics through prolonged rock-water interactions, percolation of irrigation return water, and reactions at vadose zone.

Chemical characteristics of 72 groundwater samples collected from Midyan Basin have been studied to evaluate major ion chemistry together with the geochemical and weathering processes controlling the water composition. Water chemistry of the study area is mainly dominated by Na, Ca, SO4, and Cl. The molar ratios of (Ca + Mg)/total cations, (Na + K)/total cations, (Ca + Mg)/(Na + K), (Ca + Mg)/(HCO3 + SO4), (Ca + Mg)/HCO3, and Na/Cl reveal that water chemistry of the Midyan Basin is controlled by evaporite dissolution (gypsum and/or anhydrite, and halite), silicate weathering, and minor contribution of carbonate weathering. The studied groundwater samples are largely undersaturated with respect to dolomite, gypsum, and anhydrite. These waters are capable of dissolving more of these minerals under suitable physicochemical conditions.