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.

Mining is an important activity for the economic development of many countries. However, this activity produces toxic residues that pollute water and the environment. The heavy metal removal from effluents of acid mine water is crucial to avoid environmental pollution. The microalga Nannochloropsis oculata was cultured in algal medium, with the addition of 1.16, 1.74, 2.32, 3.48, and 4.64 mg Cu²⁺ L⁻¹ coming from acid mine water to assess its removal capacity and the effect of copper content on the cell density and lipid productivity. The results showed that N. oculata removed up to 94.88 ± 0.43% at copper concentration than 1.74 mg Cu²⁺ L⁻¹; additionally, a positive effect on the lipid content was found at copper concentration to be higher, 4.64 mg Cu²⁺ L⁻¹, yielding 77.04 ± 2.60% of lipid content, twice as high as that achieved in the control culture of 33.058 ± 5.398%, thus potentiating the biodiesel production. These findings are favorable because they indicate that microalgae can remove copper added in the culture and present in acid mine water and can yield high lipid content at the same time. The cell density and growth rate decreased with increased concentrations of copper in the culture medium.

Predicting the aggregation tendency of nanoscale zero-valent iron (nZVI), oxidized nZVI, in particular, is crucial for the risk assessment of nZVI in aquatic environments. In this study, the comprehensive effects of the pH and ionic strength (IS) on the aggregation behaviors of two highly oxidized nZVIs (HO-nZVI) were examined. Compared with hematite nanoparticles, HO-nZVI presented a sudden acceleration in aggregation under critical conditions; moreover, the morphology of the HO-nZVI aggregates at pH and IS values higher or lower than the critical conditions was significantly different. Furthermore, owing to the differences in magnetization between the two prepared HO-nZVI samples, their critical coagulation conditions were significantly different. The significant changes in the aggregation behavior of the HO-nZVI samples were analyzed using colloidal theories, and the aggregation tendency of HO-nZVI under specific conditions could be simulated by calculating the theoretical critical conditions of aggregation via a method that takes into account the hydrochemical properties, magnetization, and surface charge of HO-nZVI. To examine the correctness of the method, we compared the experimentally determined colloidal stability of HO-nZVI in water samples collected from nearby rivers with the theoretically predicted value. The results indicated that the method was adequate for most situations, except for those in which the hydrochemical properties of the water samples were close to the critical coagulation conditions. Our study proposes a theoretical approach that is viable for simulating the colloidal stability of magnetic nanoparticles in aquatic environments; we anticipate that it will further facilitate the risk assessment of nanoparticles.

Environmental degradation has become an important global issue due to the extraordinary increase in greenhouse gas emissions in recent years. Therefore, identifying the main determinants of environmental degradation is one of the primary agenda items of researchers and policymakers. In the literature, many social, economic, and sectorial factors related to the main determinants of CO₂ emissions have been studied. Although these studies provide very important information about the causes of CO₂ emissions and environmental degradation, some deficiencies remain in the related literature. The agricultural sector activities, which are an important sector at a global level and have significant potential impacts on CO₂ emissions, have not been adequately studied. In order to fill this gap, the effects of agriculture and renewable energy on CO₂ emissions were examined for lucky-seven countries during the period 1995–2014. The results of panel cointegration reveal the presence of long-run nexus among the variables. While the findings indicate that agriculture increases CO₂ emissions, renewable energy is a very important catalyst in reducing CO₂ emissions in lucky-seven countries. We also found that economic growth and energy consumption enhance CO₂ emissions and trade openness decreases. Panel VECM results indicate that variables are the causes of CO₂ emission in the long run. Also, we find that economic growth is the cause of CO₂ emissions in the short run.

A novel polymer/activated carbon composite was prepared in this study by one-step chemical activation of Sargassum horneri, followed by surface modification with chitosan, a widely abundant biopolymer. The prepared composite was used as adsorbent to remove one of the most toxic metal ions, Cr(VI), from aqueous solution. Surface characterization tests revealed the material to be predominantly mesoporous with the specific surface area of 293.4 m²·g⁻¹ and the average pore diameter of 6.27 nm. Enhanced uptake capacity of Cr(VI) by the prepared composite was obtained due to the presence of more metal-binding functional (amino and hydroxyl) groups on its surface. Extremely fast adsorption rate of Cr(VI) was also achieved due to the porous structure of the prepared composite. This study has clearly shown that Sargassum horneri can be a potential alternative precursor for carbon-based adsorbents and the proper designed polymer/AC composites can be tailor-made adsorbents for heavy metal removal.

Agroforestry practices coupled with wastewater irrigation systems are sustainable strategies for water management. The performance of these practices could be improved by rhizobioaugmentation. This approach would be particularly useful in developing countries where it can be used as a low-cost tool to control widespread environmental contaminations. The main objectives of the present study are to (1) determine the effects of wastewater on metal/nutrient contents in soils, (2) assess the pattern of metals in Casuarina glauca, and (3) analyze the effects of rhizobioaugmentation of C. glauca growing in industrial wastewater–irrigated agricultural soil using N-fixing Frankia symbionts. Overall, the wastewater treatment significantly increases the levels of total Pb, B, Cr, Mn, Na, Sr, Zn, As, Co, Sb, Sn, and Fe. Only a small portion of total metals/nutrients were phytoavailable. The bioaccumulation in roots of all the metals/nutrients measured was high while the translocation from roots to aerial parts showed insignificant level of movement of the elements tested. Based on bioavailable metals/nutrients, the bioaccumulation factors were 34, 41, 94, 196, 584, 587, 1859, and 9917 for Mg, As, Ni, Mn, Cu, Co, Cr, and Pb, respectively. Hence, C. glauca is classified as a metal excluder. Rhizobioaugmentation with Frankia resulted in an increase or a decrease of metals/nutrients in soil depending on the bacterial strain used and the metal/nutrient element. It also increased significantly the bioaccumulation in roots of some metals and the uptake of key nutrients such as Ca, Na, and K by Casuarina plants. Overall, the results of the present study showed that C. glauca is suitable for phytoremediation of metal-contaminated soils. The use of Frankia represents a potential approach of managing Casuarina glauca wastewater–irrigated soil system.

Several studies were carried out and drought coexistence technologies were developed to deal with the problem of drought in semiarid regions, such as the construction of underground dams, which became a tool for rural development, mainly for family agriculture. However, there are still scarce informations regarding technical studies on the water security level of underground dams, especially about trace metal contamination due to the use and agricultural occupation of the soils downstream of the dams. In this work, the level of contamination of trace metals in waters of underground dams, during two hydrological years, was evaluated around of the sub-basin of the Cobras river, in the Rio Grande do Norte state, Brazil. The analysis of the results indicated that the water samples stored in the Alexandre and Ginaldo underground dams are within the permitted drinking patterns and did not suffer, on the other hand, any alteration in their quality that requires treatment for human consumption, fitting into Class 1. Most of the samples from the waters of the Boa Vista and Ademar dams are above the maximum allowable value for iron (Fe), lead (Pb), chromium (Cr), and nickel (Ni), requiring a differentiated treatment for human consumption, and can be classified as Class 2. The probable contamination of the waters stored in the underground dams may be of geological origin, since the largest accumulation of trace metals occurred in the lower area of the river course greater drained area, leading to believe that the metals come from the rock weathering that make up the geological framework of the region.

In the present work, the interaction between temperature, relative humidity, wind speed, and wind direction was studied in the atmosphere of Patras port, and the following were found: The interaction between temperature and air particle concentration was synergistic in the absence of wind direction, this result being however false. The actual effect of temperature in the presence of wind direction was antagonistic in line with most of the authors of the international bibliography; i.e., increase of the temperature level resulted in a decrease of particle concentration per unit volume (cm³). On the other hand, increase of the relative humidity increased the particle concentration per cm³, while the interaction between temperature and relative humidity was also antagonistic; i.e., increase of temperature decreased accordingly the relative humidity, and vice versa. Similarly, the interaction between wind speed and relative humidity was also antagonistic and statistically significant. It is emphasized that the wind direction played an important role in determining the antagonistic or synergistic nature of the interactions between the meteorological factors, and especially, in controlling quantitatively the results (or outcomes), of the above interactions.

The impregnation process has successfully prepared a novel composite of iron oxide/carbon from black liquor (CA-BL/Fe) as an adsorbent for the removal of tripolyphosphate ions. Black liquor is a secondary product of the bioethanol pre-treatment process. X-ray diffraction results showed that the main iron oxide species present in the CA-BL/Fe was goethite (α-FeOOH). Interestingly, the specific surface area of CA-BL/Fe was 504 m²/g higher than that of commercial activated carbon of 356 m²/g. The adsorption performance showed that tripolyphosphate ion removal efficiency increased by increasing the adsorbent dosage, pH, and contact time. At the same time, it decreased with an increase in the initial concentration of tripolyphosphate. By controlling the environment pH value, the optimum removal efficiency of tripolyphosphate ions with CA-BL/Fe was 96.87%, with the adsorption capacity of 1.5922 mg/g for 1 h measurement. In this study, the dominant mechanisms of tripolyphosphate adsorption are electrostatic attraction and ion exchange. The result of this study is expected to be the basis for further promising adsorbent material for tripolyphosphate ion.

Many coastal communities rely on individual onsite wastewater treatment (i.e., septic) systems to treat and disperse wastewater. Proper wastewater treatment in these systems depends on sufficient volume of unsaturated soil below the drainfield’s infiltrative surface. This is governed by the vertical separation distance—the distance between the groundwater table and the drainfield infiltrative surface—which is specified in (regulatory jurisdictions’ onsite wastewater system) regulations. Groundwater tables along the southern New England coast are rising due to sea-level rise, as well as changes in precipitation and water use patterns, which may compromise the functioning of existing septic systems. We used long-term shallow groundwater monitoring wells and ground-penetrating radar surveys of 10 drainfields in the southern Rhode Island coastal zone to determine whether septic system drainfields have adequate separation distance from the water table. Our results indicate that only 20% of tested systems are not impaired by elevated groundwater tables, while 40% of systems experience compromised separation distance at least 50% of the time. Surprisingly, 30% of systems in this study do not meet separation distance requirements at any time of the year. Neither age of system nor a system’s geographical relationship to a tidal water body was correlated with compromised separation distance. The observed compromised separation distances may be a result of inaccurate methods, specified by the regulations, to determine the height of the seasonal high water table. Our preliminary results suggest that enacting changes in the regulatory permitting process for coastal zone systems may help protect coastal drinking and surface water resources.