Given that Turkey has recently committed itself for the first time to reducing its CO₂ emissions in the interest of sustainable growth in not only Turkey but also the world as a whole, this paper examines the relationship between energy consumption, CO₂ emissions, and economic growth in Turkey for the period 1960–2014. In view of the different findings concerning causality and the character of the relationships between these variables revealed in our review of past studies (in most cases using quite different methods), this paper utilizes several different but related methodological approaches for identifying causal relationships. These include both the Toda and Yamamoto (1995) approach, the Fourier Toda-Yamamoto for Cumulative Frequency approach developed by Nazlioglu et al. (2016), vector error correction model (VECM) methodology, and the asymmetric Granger causality test proposed by Hatemi-J (Empir Econ 43:447–456, Hatemi-j 2012). Our results show that, when we apply the popular Toda-Yamamoto model, causality in these relationships is not confirmed even among any of the relevant variables in Turkey. Yet, when the Fourier Toda-Yamamoto tests for cumulative frequency are employed, we find unidirectional causality running from GDP per capita to emissions of CO₂ per capita. Moreover, when we utilize the VECM methodology, the results show that long-run causality exists from GDP per capita and energy to CO₂ emissions. When we apply the asymmetric causality tests, the results provide even stronger evidence for a unidirectional causal relationship from GDP per capita to CO₂ emissions. As a result, the latter sets of results, based on more realistic conditions, suggest very strongly that, if Turkey is to meet the objectives of its ambitious Climate Change Action Plan commitment to the United Nations to reduce its CO₂ per capita emissions relative to its past trends by up to 21% over the coming 2021–2030 decade, it is going to get very serious about the best way to do this as soon as possible.

Microplastics (MP) are transported from land-based sources from rivers to marine waters. However, there is currently little knowledge about MP fate from land sources to marine waters. Traffic is estimated to be one of the largest sources of MP; hence, stormwater is expected to be an important transportation route of MP to marine waters. The aim of this study was to investigate the effect of the size and density of tyre wear particles in road run-off on their fate in the Göta River in Sweden using hydrodynamic modelling. The model of the stretch of Göta River, Sweden’s largest river, passing through Gothenburg (Sweden’s second largest city) and out to the sea, was set up using MIKE 3 FM software. Literature data were used to define the MP characteristics: concentrations in stormwater, prevalent particle sizes, density of MP commonly occurring in road run-off and settling velocities. Results show that higher concentrations of MP are found on the south side of the river, compared with the north side, due to higher annual average daily traffic loads along the south side of the river. The mixing processes in the river and the MP concentrations were generally influenced by the vertical water density gradient caused by saline water from the Kattegat strait. While most MP with higher density and larger size settle in the river, smaller MP with density close to 1.0 g/cm³ do not settle in the river and therefore reach the Kattegat strait and the marine environments. Further research is needed to describe the fate and transport of microplastics in the stormwater system, including treatment facilities, i.e. biofouling, aggregation, degradation and/or further fragmentation and settling.

Manganese sulfate residue (MSR) is a by-product derived from the manganese sulfate production process. In this study, an iron hydroxide adsorbent was prepared from MSR using the hydrothermal conversion method. The adsorbent was characterized and used to remove copper(II) ions from aqueous solution. Batch experiments were performed to investigate the adsorption efficiency of copper ions at different contact times, initial concentrations, solution pH levels, and reaction temperatures. Adsorption equilibrium was observed in 3 h, and the best pH was under natural conditions (pH ∼ 5.5). Increasing the initial Cu²⁺ concentration and reaction temperature can increase the adsorption quantity. The adsorption capacity of iron hydroxide at an initial concentration of 50 mg L⁻¹ was 14.515 mg g⁻¹ Cu(II) under the conditions of a nature pH and room temperature. According to the adsorption data, the pseudo-second-order model can describe the adsorption kinetics of copper ions well, and the Freundlich model provides an excellent fit to the adsorption isotherm. XRD and FTIR were applied to characterize the raw materials and adsorbents to reveal the adsorption mechanism. The results suggest that the adsorbent converted from MSR is a promising material for the removal of Cu(II) in aqueous solutions.

The increasing number of applications of nanoparticles (NPs) in various fields has led to negative effects on the environment. In this study, the effects of CuO nanoparticles (CuO NPs) on Arabidopsis root tips were investigated. Significant growth inhibition on Arabidopsis roots was observed after treatment with both CuO NPs (10 mg/L) and the correspondingly released Cu²⁺ (0.80 mg/L). Scanning electron microscope images demonstrated that NPs primarily deposited on the surface of root tips and penetrated intercellular spaces after CuO NP exposure. Light and fluorescence microscope visualization revealed that the root tips were damaged severely after CuO NP exposure, with swelling of the hair zone, splitting of the cell wall junction, and disordered cell arrangement in the root tip. Semiquantitative analysis by Fourier transform infrared spectroscopy demonstrated that the cell wall xyloglucan and esterified pectin contents in the roots were decreased. Similar but weaker effects on the roots were detected after Cu²⁺ treatment. Additionally, some genes related to cell wall organization were downregulated by CuO NP stress, partially contributing to the cell wall component change. The results demonstrated that CuO NPs produced phytotoxicity to the cell wall through both physical damage and biochemical disruption, causing loosening of the tethers between cellulose microfibrils in the cell wall and the disruption of cell adhesion. The phytotoxicity of CuO NPs in the plant cell wall was mainly caused by NPs and was partially related to the released Cu²⁺. These findings are helpful to understand better the negative effects of CuO NPs on plant regarding the cell wall.

This study investigates the spatial influence and spillover effects of foreign direct investment (FDI) on environmental pollution (EP) by using panel spatial data in 1970–2016 for 12 selected Arab countries. It employs the STochastic Impacts by Regression on Population, Affluence, and Technology (STIRPAT) model. The spatial econometric approach is applied to examine the validity of the pollution haven hypothesis (PHH) and the pollution halo hypothesis (P-HH) (from now on, we will use the acronyms PHH and P-HH to denote the pollution haven hypothesis and pollution halo hypothesis, respectively). The Sustainable Development Goals (SDGs) are linked to the study results with a focus on cleaner production practices. The global Moran’s I, local Moran’s I, and Lagrange multiplier (LM) tests are used to ascertain the existence of spatial autocorrelation (SAR) and determine its trend. We also apply the spatial lag model (SLM), the spatial error model (SEM), and the spatial Durbin model (SDM) to achieve the study objectives. Data are analyzed by using the SDM on the basis of the results of the Wald and likelihood ratio tests. The results of the LM and global and local Moran’s I tests confirm the existence of SAR. The SDM results reveal that a slight increase in CO₂ is an influence of the FDI on EP. Findings support the existence of PHH in the Arab countries. The direct effect of the FDI is increased CO₂ and environmental degradation, and the spatial spillover effects are statistically insignificant. This study suggests a set of policies for managing and directing FDI toward clean technology-based industries and reduced CO₂ emissions. Such policies may contribute to the achievement of some SDGs and balancing economic development and environmental sustainability according to the cleaner production practice perspective in the Arab countries and other states with similar conditions.

In several countries, mining generates a high volume of tailing deposits, significantly impacting on soils. One of the non-metallic elements found in high concentrations in mine tailings is sulphur (S), in the form of sulphide minerals, whose oxidation causes acid drainage and metal mobility. The absorption of S in plants cultivated in mine tailings has been scarcely investigated. The objective of this study was to evaluate the extent to which a commercial humic substances and a vegetable waste compost can enhance the phytoremediation capacity of Atriplex nummularia for S and metals (Cu, Mo) in mine tailings. The plants were cultivated for 120 days under greenhouse conditions in pots with mine tailings (MT), with the addition of vegetable waste compost (VC) and a commercial humic substance (HS) in a 5% dose (W/W). At the end of the assay, the concentration of S in the aerial parts of plants cultivated in mine tailings, without amendments, reached 19,538 ± 4554 mg kg⁻¹, indicating a potential thiophore plant. In MT in which HS were applied, S and Cu concentration decreased significantly in aerial parts, while VC significantly increased Mo. The addition of HS generated significantly greater dry weight, reaching 11.55 ± 1.92 g in the aerial parts versus 2.08 ± 0.52 g in MT, which increased significantly S and Cu content in plant root and therefore favourable to phytostabilization. Regarding organic amendments, their chemical characteristics, availability, cost and quality in relation to organic matter are very important aspects for phytoremediation of mine tailings.

Regional averages of radon, thoron, and associated decay product concentration are reported to be higher than their respective global averages in recent studies conducted in Indian Himalayan belt. The present study explores another region in Indian Himalayan belt by conducting measurements of radon, thoron, and decay product’s activity concentration in 92 dwellings of Bageshwar district. The year-long measurements were performed in all 3 seasons distinguishing dwellings as per their construction material. The average radon and thoron concentration for the study region was measured as 57 Bq/m³ and 66 Bq/m³, respectively. Analysis of the measured data in terms of seasonal effects and construction material led to well established inferences, i.e., higher concentration for mud houses and for winter season. In addition, the present study focuses on lesser probed statistical inferences. One of them is related to the appropriateness of frequency distribution function for the measured data and other dwells upon the correlation analysis of inter-related factors for high concentration cases. Three distribution functions (Lognormal, Weibull, and Gamma) were found to be following the trend of frequency distribution curve of the measured data. For mud houses in winter season, variations of radon/thoron concentration were attempted to correlate with mass/surface exhalation rate, emanation rate, and source term content. More than 80% of the dwellings of the study region were found to have gas and decay product’s concentration levels, higher than the respective global average values. However, these values were mostly within the reference levels for residential environments. Nevertheless, this region requires further studies to pinpoint the causes for elevated levels and suggest simple remedial modifications if required.

This paper assesses the potential impact of reduced Nile water due to the construction of Grand Ethiopian Renaissance Dam (GERD) on flow and contaminant transport pattern in Ismailia Canal and its surrounding area. The groundwater/surface water system has been characterized, conceptualized, and modeled numerically and analytically, with assessing the response against this expected reduced discharge. The isotopic signature of seventeen samples helped in the identification of different recharge sources in the study area and demarcates the boundary conditions that might encounter the conceptualization of the study area. Based on the inflow/outflow components from MODFLOW under present-day conditions and reducing surface water discharge in the studied area, it was revealed that at the end of the year 2024, the contribution from the canal to the modeled groundwater system will be decreased by 6%, 8%, and 11%, by decreasing 20%, 30%, and 40% of the original canal flow according to three proposed scenarios. This reduced flow would increase the contaminate load of ¹³⁷Cs in the groundwater system by 2.5-fold than that expected in case of the non-reduced flow in Ismailia Canal at the end of the simulation (year 2038). Furthermore, the impact of surface water conditions (flow, velocity, dispersion) on ¹³⁷Cs dispersion and temporal/spatial distribution has been analyzed, revealing the side effect of GERD on Ismailia Canal, as a response to the decrement in the Nile flow.

The removal of residual organics from manganese (Mn) electrochemical solution using combined Fenton oxidation process with adsorption over activated carbon (AC) was investigated. The effect of operating conditions such as dosage of H₂O₂, H₂O₂/Fe²⁺ ratio, initial pH value, reaction temperature, and reaction time on Fenton oxidation was studied. Experimental results indicated that a maximum chemical oxygen demand (COD) of 83.2% was obtained under the optimized set of conditions: H₂O₂ concentration of 0.15 mol/L, H₂O₂/Fe²⁺ molar ratio of 3, initial pH value of 3, reaction temperature of 50 °C, and reaction time of 90 min. The leaching solution was furthered treated over AC and COD removal rate increased to 93.1% under 3.75 g/L dosage of AC, adsorption temperature of 70 °C, and adsorption time of 120 min. The adsorption mechanism of Mn over AC was detailly investigated, while the porous texture of AC was studied by nitrogen adsorption isotherm.

Tunnel boring muds, coming from underground works, are considered as specific materials due to their intrinsic characteristics (granularity, clay content, water content, presence of heavy metals). In order to determine if they can be valorized in road construction or civil engineering, a complete characterization, including their environmental behavior, is necessary. Thus, the aim of this study is to characterize a tunnel boring mud sample from chemical, mineralogical, and environmental point of view. The studied material, a limestone mud, was characterized using different analytical techniques. Some pollutants and heavy metals were identified, such as sulfates and molybdenum (Mo), and specific analyses were performed to identify molybdenum speciation. As molybdenum was detected as traces in the studied material, it was necessary to increase its concentration. Thus, a nitric acid extraction was specifically developed at a laboratory scale with the aim to remove its high-calcium carbonate content. Then, synchrotron analyses were performed, allowing to obtain data on the oxidation state of molybdenum.