Siwa Oasis groundwater quality: factors controlling spatial and temporal changes.

Siwa Oasis is of great historical, environmental, and scientific importance, as it contains unique archeological and geological features. Groundwater is the main source of freshwater in that oasis. The carbonate aquifer groundwater, used for irrigation, was sampled to evaluate factors controlling quality changes spatially and temporally by applying hydrochemical and statistical analyses. The salinity of the aquifer varied spatially from 1367 to 8645 mg/l based on one hydrogeological condition, with the highest TDS (> 5432.5 mg/l, 25% of samples) at the central part of the study area. Temporally, the salinity changed slightly from 3754.3 mg/l (in 2014) to 4222.4 mg/l (in 2020). The cession of illegal wells, pumping control, and excavation of formed salts have a noticeable impact on salinity (mediate the increase in salinity) and ions. However, about 61% of the studied samples can be considered unsuitable for irrigation owing to salinity and can harm plant yield. The heavy metals studied (Fe, Mn, Cu, Pb), except Cd, were within the permissible limit for irrigation water. Finally, it is proposed to construct desalination stations to enhance water quality for irrigation in the study area and set up many companies for salt extraction.

Multivariate statistics explaining groundwater chemistry, Asyut, Egypt.

Groundwater is an important source for domestic and irrigation purposes in Asyut area. Water quality varied widely due to complex geochemical processes and pollution sources. Understanding the processes controlling groundwater chemistry is necessary to overcome related problems. Multivariate statistics revealed that groundwater is affected by anthropogenic recharge (agricultural/organic pollution), mineralization, and redox processes. Contributions from natural vs. anthropogenic sources explain the variance in hydrochemical data. Shallow wells are relatively higher in bicarbonate content due to oxidation of organic pollutants. Shallow wells anomaly high with iron and organically polluted are most probably owing to pipe corrosion in residential areas. N fertilization impact on natural weathering has been demonstrated. Groundwater is getting more mineralized toward desert fringes due to lithological and hydrogeological characteristics under unconfined conditions. Evaporation factor enhances groundwater salinity under aridity. Fe and Mn contents are relatively higher as the redox potential is getting more reducing. The current study will help in building suitable management plan to protect the aquifer.

Salinization of groundwater during 20 years of agricultural irrigation, Luxor, Egypt.

Groundwater salinization is a global problem accounting for 11-30% of the world's irrigated areas. Luxor region in Upper Egypt is one of such areas affected by salinity. Multivariate statistics indicate that groundwater is affected by intermixed processes; mineralization (salinization), fertilization, domestic wastes, and meteoric recharge. Temporal change in salinity and hydrochemical facies during 1997-2017 revealed aquifer salinization, due to the dissolution of salts from overlain saline soil and marine deposits underneath as well as up-coning of deep saline water. Increasing salinity over time was statistically documented, exhibited temporally high significant differences (P < 0.05), where salinization consumed a quarter of the aquifer during 20 years. Evolution of water facies from less mineralized Ca-Cl, Mg-Cl to highly mineralized Na-Cl species explains the salinization process over time. Elevated content of Na and Cl is associated with the dissolution of marine sediments and saltwater intrusion. The shift from silicate weathering into evaporation dominance confirmed the saltwater intrusion. As a result, groundwater has a high degree of salinity, is not suitable for domestic and other uses. On other hand, fertilization and domestic sewage are probably responsible for the high NO3- and Cd content. Over 80% of Cd exists in mobile species facilitates Cd-plant uptake indicating an alarming environmental situation. Cd mobility is closely related to elevated salinity and chlorinity, allowing competition with major ions and forming of soluble complexes. The present approach will improve the uncertainties of environmental interpretation, as an initial step for aquifers management in reclaimed lands.

Shallow groundwater environmental investigation at northeastern Cairo, Egypt: quality and photo-treatment evaluation.

Groundwater represents the primary source of freshwater for more than 35% of world people, and its contamination became a worldwide challenge. Egypt is suffering from water quantity and quality, especially in desert areas. El Obour city and environs Northeast Cairo face waterlogging owing to the elevated-shallow groundwater table. In the present research work, the water quality of the shallow groundwater aquifer was studied. The remediation efficiency of polluted water using photocatalytic treatment technique in the presence of modified nano-titania and solar radiation has also been investigated. Twenty-eight representative samples have been collected from different locations, and their microbial, physical, and chemical characteristics were determined. The average contents of Pb (214.96 µg/L), As (1517 µg/L), Cd (8.79 µg/L), total bacterial count (2.22 × 105 CFU/ml), and bacterial indicators (MPN-index/100 ml): total coliform (497.4), fecal coliform (358.3), and fecal streptococci (115.9) were higher than WHO permissible limits for drinking water, possibly due to higher industrialization, agricultural, and urbanization rates. The organic pollutants reached critical concentrations (chemical oxygen demand up to 960.8 mg O2/L). Most of the studied samples contained acceptable concentrations of the major ions, (e.g., K+, Mg2+, HCO3-), for drinking and irrigation purposes. The statistical analyses (e.g., principal component analysis and cluster analysis) pointed out the control of water-rock interaction and anthropogenic activities in water composition. The hydrochemical data show that most of the water samples (96.4%) are Na2SO4 and NaHCO3 type, indicating its meteoric origin. The contamination with human and animal fecal substances, NO3¯, and NH4+ was identified in all samples, which pointed out the control of anthropogenic activities in water pollution. The photocatalytic technique efficiently eliminated more than 82-95% of organic contents and microbial pollutants, respectively, but it was inefficient in reducing heavy metal levels. According to the current results, shallow groundwater injection into the deep aquifer must be constrained and reusable after treatment. Finally, more studies are imperative to disseminate the applied treatment techniques to elude bacteria and organic pollutants from water at a pilot scale.

Chemical and bacterial quality monitoring of the Nile River water and associated health risks in Qena-Sohag sector, Egypt.

The River Nile is the primary source of freshwater for drinking, irrigation, and industrial purposes in Egypt. Thus, the water quality in this river concerns the health of local inhabitants. The present study reveals seasonal variations of various physicochemical and heavy metals parameters and microbial load of water at 15 sites from Qena to Sohag cities, Egypt. The water is fresh with TDS ≤ 270 and 410 mg L-1 in summer and winter, respectively. Fe, Mn, Cd, Cr, Cu, Ni, and Zn concentrations were within drinking water specification in both seasons except Cr and Cd in summer. Viable numbers of total coliform, fecal coliform, and fecal streptococci were recorded in both seasons with fecal streptococci's disappearing in winter. The concentrations of salts and ions in winter were higher than summer due to decreased water quantity and flow rate in this season. On the other hand, heavy metals and bacteria were higher in summer owing to the rain and weathering of upstream rocks and increasing of human activities during the summer. The calculated water quality index (WQI) depicted that the chemical quality of water was poor for drinking and treatment, especially biological treatment, which is required before the water is supplied for drinking. Human health risk assessment factors such as probable daily intake, hazard quotient, and carcinogenic risk indicated high risks of Cr, Cd, and Ni for adults and children in both seasons. The non-carcinogenic and carcinogenic risks are mainly posed by Cr. The WQI values for the other water uses indicated the marginal quality for aquatic life, fair for irrigation, and fair in summer to good in winter for livestock consumption. The irrigation water quality parameters indicated that the water could be used to irrigate all soils and crops except the hazard of biological contamination. The water-rock interaction controls water chemistry besides the contribution of human activities. The agricultural, industrial, and municipal wastewaters were the main contributors to water pollution and should be treated before discharge into the Nile River. Source and drinking water should be monitored continuously to prevent related human waterborne diseases.

Septic arthritis of the knee joint secondary to Prevotella bivia.

Prevotella bivia is an obligatory anaerobic, gram-negative rod, which often produces a detectable beta-lactamase. To date, there has been only 3 descriptions of septic arthritis secondary to this microorganism in a patients pre-existing sever joint disease like rheumatoid arthritis and osteoarthritis or after joint prosthesis. We are reporting the first case of septic arthritis due to Prevotella bivia in a patient with no pre-existing joint symptoms.