Groundwater quality levels are currently deteriorating in Gulf Cooperation Council (GCC) countries due to excessive surface and subsurface human activities. Agricultural and industrial activities, landfill seepage and seawater intrusion have been attributed to the deterioration of groundwater quality in GCC states. Such a deterioration of groundwater quality could affect water security in the region, including human health and the ecosystem. Therefore, this review aims to identify the key causes of groundwater contamination across the GCC countries from the published literature. In addition, the review summarizes the major components of the groundwater contaminants across the GCC countries. The results have shown that heavy metals, several cations and anions are the leading cause of groundwater pollution. In most cases, the level of metals and ion contaminants exceeds both the local and international water quality standards. The results have observed the presence of high levels of coliform and radioactive elements in groundwater, especially Uranium and Radium, thereby posing additional risk to human health through consumption. Considering the scarcity of freshwater resources in GCC, urgent actions are required from the decision-makers and relevant regulatory bodies to set up and implement long-term mitigation strategies and stringent policies that will protect the groundwater resources from the adverse effects of anthropogenic activities.

This study aims to assess the metallic contamination of soils and water resources in the environment of the Ouixane mining area (North East Morocco). Six metallic elements (Fe, Cu, Pb, Zn, Ni, and Cd) were analyzed by ICP-AES and ICP-MS. To evaluate the contamination of the soils, three contamination assessment methods were used as follows: enrichment factor (EF), pollution index (PI), and geo-accumulation index (Igₑₒ). The results showed that the soils of the studied area are highly enriched in metallic elements Cd, Cu, Zn, and Pb. Thus, the enrichment factor (EF) revealed an anthropogenic contamination of the majority of studied soils with an extreme contamination by Cd (EFₘ = 59.29), Cu (EFₘ = 45.93), and Zn (EFₘ = 44.73). The results of PI revealed extreme contamination by Cu (PIₘ = 7.12) and considerable contamination by Zn (PIₘ = 5.61), Cd (PIₘ = 4.83), Fe (PIₘ = 3.09), and Pb (PIₘ = 3). The Igₑₒ results showed strong contamination for most of the metallic elements and extreme accumulation for Cu and Zn in the Axara-Imnassen lake and the valley located downstream from the Ouixane deposit. Depressions and lakes are highly contaminated by heavy metals due to the leaching phenomenon of surrounding geological formations rich in sulfides. The significant leaching of metallic elements (Cu, Pb, Zn, Ni…) led to significant acid mine drainage (AMD). On the other hand, the geochemistry of the water samples revealed the transfer of metallic pollutants to the water resources which become very acidic locally. Using the contamination degree index (Cd), surface water was found to be highly contaminated by heavy metals (Cd > 3) compared to well water (1 < Cd < 3). Contamination assessment indices combined with the geographic information system (GIS) have been used successfully to identify the most polluted sites.

Deforestation and forest degradation are among the leading global concerns, as they could reduce the carbon sink and sequestration potential of the forest. The impoundment of Kenyir River, Hulu Terengganu, Malaysia, in 1985 due to the development of hydropower station has created a large area of water bodies following clearance of forested land. This study assessed the loss of forest carbon due to these activities within the period of 37 years, between 1972 and 2019. The study area consisted of Kenyir Lake catchment area, which consisted mainly of forests and the great Kenyir Lake. Remote sensing datasets have been used in this analysis. Satellite images from Landsat 1–5 MSS and Landsat 8 OLI/TRIS that were acquired between the years 1972 and 2019 were used to classify land uses in the entire landscape of Kenyir Lake catchment. Support vector machine (SVM) was adapted to generate the land-use classification map in the study area. The results show that the total study area includes 278,179 ha and forest covers dominated the area for before and after the impoundment of Kenyir Lake. The assessed loss of carbon between the years 1972 and 2019 was around 8.6 million Mg C with an annual rate of 0.36%. The main single cause attributing to the forest loss was due to clearing of forest for hydro-electric dam construction. However, the remaining forests surrounding the study area are still able to sequester carbon at a considerable rate and thus balance the carbon dynamics within the landscapes. The results highlight that carbon sequestration scenario in Kenyir Lake catchment area shows the potential of the carbon sink in the study area are acceptable with only 17% reduction of sequestration ability. The landscape of the study area is considered as highly vegetated area despite changes due to dam construction.

In recent years, a growing number of scholars have employed various proxies of environmental degradation to understand the reasons behind rising environmental degradation. However, very few studies have considered consumption-based carbon emissions, even though a clear understanding of the impact of consumption patterns is essential for redirecting the pattern to more sustainable consumption. Thus, this study takes a step forward by using consumption-based carbon emissions (CCO₂) as a proxy of environmental degradation using the novel non-linear ARDL technique for Chilefrom 1990 to 2018. To the best understanding of the investigators, no prior studies have investigated the drivers of consumption-based carbon emissions utilizing non-linear ARDL. The study employed ADF and KSS (non-linear) tests to check the data series’ stationary level. Additionally, the symmetric and asymmetric ARDL approaches are utilized to explore cointegration and long-run linkages. According to the results, there is no symmetric cointegration among the variables; however, the empirical estimates reveal a long-run asymmetric connection between the indicators and CCO₂ emissions. The novel results from the asymmetric ARDL indicate that negative and positive changes in economic growth deteriorate the quality of the environment. Interestingly, a reduction in economic growth makes a more dominant contribution to environmental degradation. Moreover, positive changes in renewable energy usage improve the quality of Chile’s environment, inferring that the country can achieve a reduction in environmental degradation by boosting renewable energy consumption. Surprisingly, the study found that technological innovation is ineffective in reducing consumption-based carbon emissions, which implies that Chile’s technological innovation is not directed towards manufacturing green technology. Finally, the policy implications are discussed with respect to reducing consumption-based carbon emissions.

Arsenic exposure to the population leads to serious health problems like neurotoxicity, nephrotoxicity, and cardiovascular abnormality. In the present study, the work has been commenced to discover the prospect of rolipram a phosphodiestrase-4 (PDE-4) inhibitor against sodium arsenite (SA)–induced vascular endothelial dysfunction (EnDF) leading to dementia in rats. Wistar rats were treated with SA (5 mg/kg body weight/day orally) for 44 days for induction of vascular EnDF and dementia. Learning and memory were evaluated using Morris water maze (MWM) test. Vascular EnDF was evaluated using aortic ring preparation. Various biochemical parameters were also evaluated like brain oxidative stress (viz. reduced glutathione and thiobarbituric acid reactive substances level), serum nitrite/nitrate activity, acetylcholinesterase activity, and inflammatory markers (viz. neutrophil infiltration in brain and myeloperoxidase). SA-treated rats showed poor performance in water maze trials indicating attenuated memory and ability to learn with significant rise (p < 0.05) in brain acetylcholinesterase activity, brain oxidative stress, neutrophil count, and significant decrease (p < 0.05) in serum nitrite/nitrate levels and vascular endothelial functions. Rolipram (PDE-4 inhibitor) treatment (0.03 mg/kg and 0.06 mg/kg body weight, intraperitoneally daily for 14 days) significantly improved memory and learning abilities, and restored various biochemical parameters and EnDF. It is concluded that PDE-4 modulator may be considered the prospective target for the treatment of SA-induced vascular EnDF and related dementia.

This study assesses association between occupational and environmental pesticide exposure on pesticide applicators directly exposed to pesticides and inhabitants of the Cukurova region by analyzing blood and hair samples. Hair and blood samples were collected from 132 volunteers, 66 of whom are pesticide applicators, and the rest are non-farmer residents, in 10 villages nearby the Ceyhan River between March and June in 2017. Samples were then analyzed via the liquid chromatography-tandem mass spectrometer. As the analysis result, a total number of 31 pesticides were detected in hair samples, whereas a total number of 15 pesticides were observed in blood samples. Twenty of the pesticides (64.5%) detected in the hair and 3 (20%) detected in the blood were significantly higher in the applicators than the non-farm residents. Also, 5 pesticides (16.1%) observed in the hair and 7 observed (46.6%) in the blood were banned pesticides. This study investigated the pesticide exposures on people living in the region via hair and blood samples. Our study revealed that, in addition to individuals who are occupationally exposed to pesticides, individuals from all parts of the society, especially those living in the agricultural region, have a certain level of pesticide exposure.

At present, water pollution becomes a very significant environmental issue. Heavy metals and organic dyes present at higher concentrations in water are dangerous for aquatic life and humanity. Chitosan nanocomposites have been used for the adsorptive removal of heavy metals and dyes due to their improved chemical activity. This paper encompassed the synthesis of chitosan-nSiO₂ nanocomposites and was used to examine Cu(II) ion removal capability. The chitosan/nSiO₂ nanocomposite (CSNC) adsorbents were synthesized with different weight ratios. The nanocomposites are characterized by using SEM, EDX, BET apparatus, FTIR, XRD, and TGA. The experiment is performed in batch mode by varying the operating parameters like pH, contact time, temperature, adsorbent dosage, and initial metal ion concentration. The optimum pH is 6.5 for all adsorbents. Different kinetic and isotherm models are tried. The removal efficiency was greater than 98% for the adsorbent CSNC2–1. The pseudo-2nd-order model described the kinetic process better than other models. Equilibrium data fit the best in Fritz and Schluender (IV) isotherm model for the adsorbents CWS and CSNC2–1 and Vieth and Sladek isotherm model CSNC1–1. The adsorption process was spontaneous and endothermic. Industrial effluent is also tested successfully. The application of statistical and GA modeling has also been performed successfully.

Advanced processing of low C/N sewage faces the carbon sources shortage, while quantities of agricultural biomass wastes need to be disposed. This study investigated the potential of quantitative modified biomass addition in constructed wetlands (CWs) filled with polyethylene fillers. Results showed that the lignin in NaOH-heating pretreated corn stalks (NH-CSs) was destroyed, and the wrinkles on the stalks increased and became more soft after pretreatment, which was more conducive to the utilization of carbon sources and attachment of microorganisms. Compared with glucose and sodium acetate, the denitrification with mixed carbon source (glucose and NH-CSs) had the highest effective utilization percentage (61.37%) and NH-CSs were expected to become stable and fast-release carbon sources. After adding 30 g NH-CSs to the rear unit of CW with polyethylene fillers (CW-A), TN removal efficiency was increased by 18.21%, and the average removal efficiency of COD, NH₄⁺-N, TN, and TP reached 54.83%, 89.95%, 64.11%, and 45.04%, respectively. Compared with the traditional CW (CW-B), CW-A had a significant denitrification advantage (P < 0.05), but the removal efficiency and effluent stability of phosphorus were inferior to CW-B. These results indicate that the biomass carbon sources such as corn stalks and polyethylene fillers have a good potential to improve the denitrification in CWs.

Extensive attention has been paid to the treatment and disposal of dredged material, and there is a need to clarify the feasibility of recycling dredged material by using it as backfill in soil-bentonite vertical cutoff walls. By setting the dredged material in the Baimao storage yard of Meiliang Bay in Taihu Lake and bentonite as the research objects, this paper studied the influences of bentonite content, confining pressure and pore size distribution on the permeability of dredged material-bentonite backfills. According to the test results, from the perspective of medium-term and short-term permeability, it is feasible to recycle dredged material by using it as backfill in a vertical cutoff wall. The permeability of the dredged material-bentonite soil mixture decreases with increasing bentonite content, but the degree of decrease is not significant. At the same time, the higher the confining pressure is, the smaller the variation in hydraulic conductivity with bentonite content. The permeability of the soil mixture decreases with increasing confining pressure, and the range of reduction is within a certain order of magnitude. Moreover, the confining pressure has a similar impact on the decrease in the permeability of the soil mixtures with different bentonite contents. The hydraulic conductivity of the dredged material-bentonite mixture decreases because the addition of bentonite changes the pore size distribution and reduces the porosity and characteristic pore size D₅₀ of the soil mixture.

Energy consumption is an indispensable element for the purpose of achieving economic growth. Clean energy sources must be put into use to achieve a sustainable environment. The aim of this study is to investigate the relationship among growth, energy consumption, employment, education, and inflation with PVAR, FMOLS, and DOLS analysis in BRICS countries. The study that covers the 2001–2018 observation period included growth as the dependent variable in the equation. The only common result of the three coefficient estimates is that there is no significant relationship between education and growth. However, the increase in income has a decreasing effect on the level of education. The direction of causality between the two variables is from growth to education. Contrary to the PVAR estimate, according to FMOLS and DOLS, energy consumption and employment have a positive contribution towards growth. However, according to PVAR regression results, income growth has a positive effect on employment. Moreover, a unidirectional causal relation from energy consumption to growth and a bidirectional relation between growth and employment have been determined. This one-way relationship between energy consumption and GDP depicts that the growth hypothesis is valid. Furthermore, an energy poverty problem does not exist in BRICS countries. According to FMOLS, DOLS, and PVAR forecasts, the relationship between inflation and growth is complex. In accordance with PVAR estimates, the increase in growth reduces inflation, and the causality from growth to inflation also supports the PVAR results. According to the outcome of the research, energy poverty is not observed in the panel countries. It would be wise for BRICS countries to increase their energy consumption and employment levels in order to increase growth. However, considering the air pollution caused by fossil fuel consumption, it is key that they employ renewable energy sources.