Re-evaluating the environmental impacts of tourism: does EKC exist? The article Re-evaluating the environmental impacts of tourism: does EKC exist?, written by Jeyhun I. Mikayilov, Shahriyar Mukhtarov, Jeyhun Mammadov and Mayis Azizov

The impact of hot metal temperature on CO 2 emissions from basic oxygen converter Abstract Recycled steel is a key material for sustainable development. However, not all steel demand can be met by recycling, and therefore, new metallic iron must be introduced in the global cycle. The transformation of iron oxides into steel requires carbon which is oxidized into CO2. This paper focuses on the basic oxygen furnace (BOF) where molten iron is converted into liquid steel. In order to assess the effect of molten iron temperature on CO2 emissions, the process has been modelled using mass and energy balances. Model results show that, for a typical converter charge, a slight increase of 10 °C can lead to a direct reduction of 0.006 t of CO2 per ton of liquid steel. A total variation of 0.17 t of CO2 per ton of liquid steel is found depending on plant strategy and process constraints. Finally, different actuation levers for carbon mitigation are assessed. It can be concluded that operation and modelling improvements should be jointly addressed to exploit their full potential for carbon footprint reduction.

Occurrence and removal of sulfonamides and their acetyl metabolites in a biological aerated filter (BAF) of wastewater treatment plant in Xiamen, South China Abstract Most sulfonamides, widely used around the world, are excreted via feces and urine along with their metabolites in humans and animals. Therefore, understanding the potential removal pathway of sulfonamides and their metabolites in wastewater treatment systems is of importance. The occurrence and fate of four sulfonamides and their acetyl metabolites in wastewater and sludge in a biological aerated filter in Xiamen city were evaluated. Six of the target compounds were detected in wastewater, but only parent compounds were detected in sludge. The highest concentration in wastewater was acetyl-sulfamethoxazole (Ac-SMZ) with a concentration of 75.2 ng/L. Removal efficiency and mass load in wastewater treatment systems were calculated. In terms of the overall removal efficiency, they ranged from 24.4 to 100%. The removal efficiencies of sulfamerazine (SM1), sulfamethazine (SM2), and sulfadiazine (SD) were up to 100% while N-acetyl sulfamerazine (Ac-SM1) showed the lowest removal efficiency. Biodegradation was the dominant remove pathway according to the mass balance analysis while SD and SM2 were sludge adsorption. The results can provide an insight into the fate of target sulfonamides in BAF systems and provide data to assess their potential ecological risks.

Monitoring survey of caffeine in surface waters (Lis River) and wastewaters located at Leiria Town in Portugal Abstract Investigation during 11-month period was performed to study the presence of caffeine in the Lis River in Leiria Town in Portugal, and a monitoring during 9-month period was realized to check the contribution of the human pollution of two wastewater treatment plants (WWTPs) that discharge their effluents to the studied river. The samples were collected in five sampling points along the river and in two influents and two effluents of the studied WWTPs. Caffeine was detected in all ninety-one collected samples. The caffeine concentration ranged from 25.3 to 321 ng/L in the river samples, from 112 to 1927 ng/L in the WWTP effluents, and from 9478 to 83,901 ng/L in the WWTP influents. The highest concentration in the river was detected in the two sampling points located after the effluent discharge points and reached 315 and 321 ng/L. Risk assessment was performed for three trophic levels using the risk quotient calculation and revealed that caffeine do not cause toxic effect on Daphnia magna and on fish but could be possibly toxic to algae. The results proved that caffeine can be an effective indicator of human-born pollution.

The impact of globalization on ecological footprint: empirical evidence from the South Asian countries Abstract This study aims to investigate the effect of economic globalization and technological changes on the environmental degradation of the South Asian countries over the time span of 1975–2017. Westerlund (Oxf Bull Econ Stat 69:709–748, 2007) cointegration test is employed to estimate the presence of long-run relationship between globalization, technological changes, and environmental degradation. To determine the validity of the Environmental Kuznets Curve, this study employs panel autoregressive distributional lag (ARDL) model. Empirical findings of this study yield the inverted U-shaped association between globalization, technological changes, and environmental degradation which validate that EKC holds in the South Asian countries. The results indicate that the measures of globalization such as FDI, trade openness, and KOF index have positive and statistically significant effect on ecological footprint. However, technological changes measured as patents registered by residents have an insignificant impact on environmental quality. This study infers that the globalization has increased environmental degradation through unsustainable economic development in South Asian countries. These countries should shift to renewable energy resources to protect the environment and mitigate greenhouse gas emissions.

Improving the attractiveness and accessibility of campus green space for developing a sustainable university environment Abstract A growing body of research has investigated the vital effects of urban greening. However, the green space on campus, also recognized as an important element of urban greening and providing many benefits to college students, has gained very limited attention. In developing China, after nearly 20 years of campus construction climax, the speed of expansion has dropped significantly and the focus of a sustainable and optimized green campus has emerged. Improving the accessibility, availability, and attractiveness is a control determining if the green spaces can realize their values. Therefore, this study, taking a case, aims to explore and better understand students’ usage conditions, perceptions, and demands about campus green spaces. On Yijin campus in Hangzhou, China, through the questionnaire among 590 students, and accessibility analysis based on Space syntax theory, we have revealed that the negative usage condition of green spaces: most students rarely or occasionally visit the green space, and the visit time is concentrated in the afternoon and after class but rarely in the morning. Besides, students’ gender and growth surroundings have little influence on the perception of campus green space, but the plant configuration, seasonal color richness, and facilities required at different spaces will affect. In addition, the ranking of accessibility analyzed by Space syntax theory is similar to campus convenience considered by students. In the conclusions, suggestions are made about how to fulfill students’ requirements and improve the attractiveness and accessibility of campus green spaces so that they may inform to the growth of emerging colleges and universities in other cities and countries undergoing campus construction climax.

Role of cost-effective organic carbon substrates in bioremediation of acid mine drainage–impacted soil of Malanjkhand Copper Project, India: a biostimulant for autochthonous microbial populations Abstract Development of an efficient bioremediation strategy for the mitigation of low pH (3.21), high dissolved SO42− (6285 mg/L), and Fe (7292 mg/kg)-rich acid mine drainage–impacted soil (AIS) was investigated through amendment of readily available organic carbon substrates (rice husk, compost, leaf litter, and grass clippings). An organic carbon mixture (OCM) formulated by mixing the test substrates was used to biostimulate microbial processes (SO42−/Fe3+reduction) necessary for efficient attenuation of the hazards imposed by AIS. OCM amendment in calcium carbonate–treated AIS enhanced reductive processes and removed dissolved SO42− and Fe3+ considerably raising the pH close to neutrality. 16S rRNA gene amplicon sequencing performed with total DNA and RNA elucidated the microbial population dynamics of treated AIS. Metabolically active populations comprised of fermentative (Clostridium sensu stricto 1 and Fonticella), iron-reducing (Acidocella, Anaeromyxobacter, and Clostridium sensu stricto 1), and sulfate-reducing (Desulfovibrio, Desulfotomaculum, Desulfosporosinus, and Desulfobacteraceae) bacteria. Microbial guilds obtained highlighted the synergistic role of cellulolytic, fermentative, and SO42−/Fe3+-reducing bacteria in attenuation of hazardous contaminants. Quantitative PCR analysis well supported the role of OCM in stimulating the indigenous bacterial populations, including those harboring the dissimilatory sulfite reductase (dsrB) gene and involved actively in SO42− reduction. The study demonstrated the suitability of locally available organic substrates as a low-cost and efficient biostimulation agent for in situ bioremediation of acid mine drainage (AMD)–impacted soil system.

Effect of moisture gradient on rice yields and greenhouse gas emissions from rice paddies Abstract Fluxes of methane (CH4) and nitrous oxide (N2O) from two rice varieties, Huayou 14 and Hanyou 8, were monitored using closed chamber/gas chromatography method. Huayou 14 is a commonly grown variety of rice whereas Hanyou 8 is a water-saving and drought-resistant rice (WDR) variety. Low soil volumetric water content (VWC) existed in the treatments on the slope (W5 < W4 < W3 < W2). On the slope, rice yields of Hanyou 8 decreased by 12–39%, and Huayou 14 by 11–46% as compared to the plots on the flat. The total compatible solutes in Hanyou 8 had a greater variational range than Huayou 14. Compared to W1, CH4 emissions from W2–W5 decreased by 58–86% in Hanyou 8 and 38–86% in Huayou 14, whereas those of N2O increased by 26–121% in Hanyou 8 and 49–189% in Huayou 14 across both two seasons, which was mainly because the VWC varied in W2–W5 treatment. Under the treatments in the slope (W2, W3, W4, and W5), the global warming potential (GWP) was dominated by N2O emissions, which accounted for 69–90% of the GWP. Hanyou 8 had greater tolerance for water stress than Huayou 14 did, as evident from the smaller reductions in rice yield and greater variational range of total compatible solutes content. Water stress could reduce CH4 emissions but decrease N2O emissions for both rice varieties. This results suggest that planting WDR varieties under water shortage irrigation (such as W4, W5) will be able to maintain rice yields and reduce the GWP with less water.

Identifying the environmental footprint by source of supply chains for effective policy making: the case of Spanish households consumption Abstract Household consumption has been identified to have an essential role in influencing ultimately the environmental pressures generated by human activities. This study assesses the indirect environmental footprint of the Spanish households applying a combination of consumer expenditure surveys with environmentally extended multi-regional input–output analysis. A total of fourteen environmental impact categories are studied from 2006 to 2015. All the impact categories present a similar trend, particularly affected by the economic crisis. The impacts decreased from 2008 to 2013 and finally slightly started rising again from 2014 to 2015. Results show that the dominant categories influencing the indirect environmental footprint in 2015 are (1) food and beverages, (2) housing, and (3) furnishings. From the intensity perspective, housing, transport, and food and beverages appear to be the most intensive consumption clusters in the Spanish household indirect environmental footprint. In relation to the indirect water impacts embodied in the Spanish households’ imports, the largest amount is from European countries and the highest virtual water (59%) corresponds to food and agriculture, in particular from wheat, fruit, vegetables, and dairy products. The findings obtained in relation to the sources generating indirect impacts from household consumption could aid the implementation of future mitigation policies.

Sub-chronic exposure to Tris(1,3-dichloro-2-propyl) phosphate induces sex-dependent hepatotoxicity in rats Abstract As the application and environmental release of tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) are being increased rapidly, serious concerns have been raised regarding its adverse effects on human health. Exposure to TDCIPP has been implicated in hepatotoxicity, but the molecular mechanisms remain unclear. Here, both male and female Sprague Dawley rats were administered TDCIPP with 125, 250, or 500 mg/kg/day for 12 weeks. Then the ultrastructure of liver, biochemical indicators in serum and liver, and hepatic gene expression were analyzed to reveal molecular mechanisms of hepatotoxicity induced by TDCIPP. Continuous TDCIPP exposure decreased body weight, particularly in 500 mg/kg/day TDCIPP-exposed males, and dose dependently increased the ratio of liver to body weight in both genders. The decreased levels of triglyceride, cholesterol, and transaminase in the serum and livers were observed in both genders after TDCIPP exposure, which indicated dysfunction in the hepatic metabolism. Liver histopathology revealed hepatocellular damages in males and females after TDCIPP exposure. The transcriptomic analysis indicated that TDCIPP exposure significantly changed pathways of bile acid metabolism, inflammatory response, oxidative phosphorylation and carcinogenicity in 250 and 500 mg/kg/day TDCIPP-exposed males and 500 mg/kg/day TDCIPP-exposed females, and there was no statistical significance in any other TDCIPP-exposed groups. The transcriptional analysis showed that TDCIPP exposure led to oxidative stress in the livers of rats, thereby increasing the inflammatory response and promoting mechanisms of carcinogenesis in both genders. Finally, TDCIPP led to more severe adverse phenotypic effects in male than female rats.