Spatial and temporal rainfall variability and its controlling factors under an arid climate condition: case of Gabes Catchment,Southern Tunisia

Environment, Development and Sustainability - Precipitation is the principal component of the hydrologic cycle. This study examines the spatial and temporal rainfall variability in Gabes Catchment...     

The effect of titanium dioxide nanoparticles on neuroinflammation response in rat brain

Titanium dioxide nanoparticles (TiO₂ NPs) are widely used for their whiteness and opacity in several applications such as food colorants, drug additives, biomedical ceramic, and implanted biomaterials. Research on the neurobiological response to orally administered TiO₂ NPs is still limited. In our study, we investigate the effects of anatase TiO₂ NPs on the brain of Wistar rats after oral intake. After daily intragastric administration of anatase TiO₂ NPs (5–10 nm) at 0, 50, 100, and 200 mg/kg body weight (BW) for 60 days, the coefficient of the brain, acethylcholinesterase (AChE) activities, the level of interleukin 6 (IL-6), and the expression of glial fibrillary acidic protein (GFAP) were assessed to quantify the brain damage. The results showed that high-dose anatase TiO₂ NPs could induce a downregulated level of AChE activities and showed an increase in plasmatic IL-6 level as compared to the control group accompanied by a dose-dependent decrease inter-doses, associated to an increase in the cerebral IL-6 level as a response to a local inflammation in brain. Furthermore, we observed elevated levels of immunoreactivity to GFAP in rat cerebral cortex. We concluded that oral intake of anatase TiO₂ NPs can induce neuroinflammation and could be neurotoxic and hazardous to health.     

Aluminum position in Rb-feldspar as determined by X-ray photoelectron spectroscopy

Al/Si configurations in some natural and synthetic Rb-feldspars have been examined carefully by EMPA and XPS analyses. Our results indicate that a small amount of H₂O and excess Si and Al are incorporated in hydrothermally synthesized Rb-feldspar. The quantities of excess Al are 0.056 atoms per formula unit and are negatively correlated with those of the Rb, suggesting the presence of excess Al occupying non-tetrahedral sites in feldspar structures. This leads to incorporation of Al(Al₃Si)O₈ endmember into Rb-feldspars, estimated as one appropriate endmember indication for unusual chemistry of feldspars. In addition, Si2p, Al2p and O1s XPS signals of Rb-feldspars shift drastically toward the higher energy side than those of any natural feldspars. These provide conclusive evidence not only for existence of perceptible excess Si and Al, but also for Al at both extra-framework and tetrahedral sites in feldspar structures.     

Photosynthesis and growth responses of pea Pisum sativum L. under heavy metals stress

The present work aimed to study the physiological e ects of cadmium (Cd) and copper (Cu) in pea (Pisum sativum). Pea plants were exposed to increasing doses of cadmium chloride (CdCl2) and copper chloride (CuCl2) for 20 d. The examined parameters, namely root and shoot lengths, the concentration of photosynthetic pigments and the rate of photosynthesis were a ected by the treatments especially with high metals concentrations. The analysis of heavy metals accumulation shows that leaves significantly accumulate cadmium for all the tested concentrations. However, copper was significantly accumulated only with the highest tested dose. This may explain the higher inhibitory e ects of cadmium on photosynthesis and growth in pea plants. These results are valuable for understanding the biological consequences of heavy metals contamination particularly in soils devoted to organic agriculture.     

Management of toxic cyanobacteria for drinking water production of Ain Zada Dam

Blooms of toxic cyanobacteria in Algerian reservoirs represent a potential health problem, mainly from drinking water that supplies the local population of Ain Zada (Bordj Bou Arreridj). The objective of this study is to monitor, detect, and identify the existence of cyanobacteria and microcystins during blooming times. Samples were taken in 2013 from eight stations. The results show that three potentially toxic cyanobacterial genera with the species Planktothrix agardhii were dominant. Cyanobacterial biomass, phycocyanin (PC) concentrations, and microcystin (MC) concentrations were high in the surface layer and at 14 m depth; these values were also high in the treated water. On 11 May 2013, MC concentrations were 6.3 μg/L in MC-LR equivalent in the drinking water. This study shows for the first time the presence of cyanotoxins in raw and treated waters, highlighting that regular monitoring of cyanobacteria and cyanotoxins must be undertaken to avoid potential health problems.     

Microplastic sources,formation, toxicity and remediation: a review

Microplastic pollution is becoming a major issue for human health due to the recent discovery of microplastics in most ecosystems. Here, we review the sources, formation, occurrence, toxicity and remediation methods of microplastics. We distinguish ocean-based and land-based sources of microplastics. Microplastics have been found in biological samples such as faeces, sputum, saliva, blood and placenta. Cancer, intestinal, pulmonary, cardiovascular, infectious and inflammatory diseases are induced or mediated by microplastics. Microplastic exposure during pregnancy and maternal period is also discussed. Remediation methods include coagulation, membrane bioreactors, sand filtration, adsorption, photocatalytic degradation, electrocoagulation and magnetic separation. Control strategies comprise reducing plastic usage, behavioural change, and using biodegradable plastics. Global plastic production has risen dramatically over the past 70 years to reach 359 million tonnes. China is the world's top producer, contributing 17.5% to global production, while Turkey generates the most plastic waste in the Mediterranean region, at 144 tonnes per day. Microplastics comprise 75% of marine waste, with land-based sources responsible for 80–90% of pollution, while ocean-based sources account for only 10–20%. Microplastics induce toxic effects on humans and animals, such as cytotoxicity, immune response, oxidative stress, barrier attributes, and genotoxicity, even at minimal dosages of 10 μg/mL. Ingestion of microplastics by marine animals results in alterations in gastrointestinal tract physiology, immune system depression, oxidative stress, cytotoxicity, differential gene expression, and growth inhibition. Furthermore, bioaccumulation of microplastics in the tissues of aquatic organisms can have adverse effects on the aquatic ecosystem, with potential transmission of microplastics to humans and birds. Changing individual behaviours and governmental actions, such as implementing bans, taxes, or pricing on plastic carrier bags, has significantly reduced plastic consumption to 8–85% in various countries worldwide. The microplastic minimisation approach follows an upside-down pyramid, starting with prevention, followed by reducing, reusing, recycling, recovering, and ending with disposal as the least preferable option.

     

Removal of carbamazepine from urban wastewater by sulfate radical oxidation

The occurrence of bioactive trace pollutants such as pharmaceuticals in natural waters is an emerging issue. Numerous pharmaceuticals are not completely removed in conventional wastewater treatment plants. Advanced oxidation processes may represent an interesting alternative to completely mineralize organic trace pollutants. In this article, we show that sulfate radicals generated from peroxymonosulfate/Co^II are more efficient than hydroxyl radicals generated from the Fenton’s reagent (H₂O₂/Fe^II) for the degradation of the pharmaceutical compound, carbamazepine. The second-order rate constant for the reaction of SO₄ ^·− with carbamazepine is 1.92·10⁹ M⁻¹ s⁻¹. In laboratory grade water and in real urban wastewater, SO₄ ^·− yielded a faster degradation of carbamazepine compared to HO^· . Under strongly oxidizing conditions, a nearly complete mineralization of carbamazepine was achieved, while under mildly oxidizing conditions, several intermediates were identified by LC–MS. These results show for the first time in real urban wastewater that sulfate radicals are more selective than hydroxyl radicals for the oxidation of an organic pollutant and may represent an interesting alternative in advanced oxidation processes.     

Detoxification of 4-chlorophenol in TiO2 sunlight system: effect of raw and treated solution on seed germination and plants growth of various sensitive vegetables

The mineralization and detoxification of 4-chlorophenol (4-CP) were studied using a TiO₂-paper/sunlight system. The possibility of reusing the photocatalyst was examined to determine the cost effectiveness of the method. Experiments were performed to establish optimum conditions for 4-CP removal. Phytotoxicity of photo-treated and raw 4-CP (100 mg L^?1) solutions on seed germination and plant growth were carried out with the aim of water reuse and environment protection. The seeds irrigated with raw 4-CP solution showed lower sprout length while increase in sprout length was observed with the photo-treated solution for tomato (Lycopersicon esculentum), lettuce (Lactuca sativa), onion (Allium cepa), and turnip (Brassica rapa). Plant growth tests with the photo-treated 4-CP solution did not affect the leaf numbers compared to those irrigated with tap water. Photo-treated 4-CP solution can be used for irrigation in agriculture.