This study investigates empirically an extended version of the Environmental Kuznets Curve model that controls for tourism development. We find that international tourist arrivals into Turkey alongside income, squared income and energy consumption, cointegrate with CO₂ emissions. Tourist arrivals, growth, and energy consumption exert a positive and significant impact on CO₂ emissions in the long-run. Our results provide empirical support to EKC hypothesis showing that at exponential levels of growth, CO₂ emissions decline. The findings suggest that despite the environmental degradation stemming from tourism development, policies aimed at environmental protection should not be pursued at the expense of tourism-led growth.

Toxicity evaluation is an important segment in sediment quality monitoring in order to protect aquatic organisms and human health. The purpose of this study is to assess the toxicity of sediments from three sediment cores in Yangtze River Estuary, China, using the zebrafish (Danio rerio) embryo tests. Fertilized zebrafish eggs were exposed to both whole sediments and sediment organic extracts prepared from collected sediments, in order to provide a comprehensive and realistic insight into the bioavailable toxicity potential of the sediments. As end points, development parameters (mortality, hatching rate, and abnormality) in the developing embryos were recorded during the 96-h exposure. The results showed that some samples increased mortality, inhibited the hatching of embryos, and induced morphological abnormalities. The embryonic toxicities presented serrated changes and irregular distribution with depth, which may be related to hydrodynamic effect and unstable environmental input. However, lethal and sub-lethal effects were more significant at the sub-surface sediments (10∼40 cm), which indicated that the pollution is more serious in recent decades.

In recent years, the fine particulate matter pollution has become increasingly serious in Beijing, the capital of China. Being considered as an environment-friendly district of Beijing, current research concerning air pollution in Miyun area was relatively less. From August 24, 2013 to September 29, 2013, 24-h samples were collected in the urban and rural areas of Miyun, Beijing, so as to better understand the sources contributing to PM2.5 and the risk to human health in this district. The data obtained showed that daily PM2.5 mass concentrations ranged from 35.33 to 318.71 μg m⁻³ in the urban sampling site, which however were between 12.62 and 292.33 μg m⁻³ in the rural sampling site. At least 23.5 and 41.2 % of the monitoring data, respectively, exceeded the limit value. The mass concentrations of a number of PM2.5 elements fluctuated significantly in the decreasing order of Zn, Ba, Sr, Cu, Pb, Cr, V, Ni, Sb, and Cd. The daily contribution of three cations (NH₄ ⁺, K⁺, and Na⁺) and four anions (F⁻, Cl⁻, NO₃ ⁻, and SO₄ ²⁻) to PM2.5 mass simultaneously varied from 27.51 to 44.04 % and from 29.54 to 46.14 %. In addition, significant linear correlations between main constituents of the ions (SO₄ ²⁻, NO₃ ⁻, and NH₄ ⁺) at both sites indicated that the majority of NH₄ ⁺ was probably in the form of ammonium sulfate and ammonium nitrate. The risk levels of carcinogenic heavy metals detected in survey region occurred in the order of Cr, Cd, and Ni, of which, Cr may have a potential risk to the environment. High risk levels of both carcinogenic and non-carcinogenic heavy metals were easy to occur on haze–fog days.

The European Water Framework Directive aims to achieve a good ecological and chemical status in surface waters until 2015. Sediment toxicology plays a major role in this intention as sediments can act as a secondary source of pollution. In order to fulfill this legal obligation, there is an urgent need to develop whole-sediment exposure protocols, since sediment contact assays represent the most realistic scenario to simulate in situ exposure conditions. Therefore, in the present study, a vertebrate sediment contact assay to determine aryl hydrocarbon receptor (AhR)-mediated activity of particle-bound pollutants was developed. Furthermore, the activity and the expression of the CYP1 family in early life stages of zebrafish after exposure to freeze-dried sediment samples were investigated. In order to validate the developed protocol, effects of β-naphthoflavone and three selected sediment on zebrafish embryos were investigated. Results documented clearly AhR-mediated toxicity after exposure to β-naphthoflavone (β-NF) and to the sediment from the Vering canal. Upregulation of mRNA levels was observed for all investigated sediment samples. The highest levels of all investigated cyp genes (cyp1a, cyp1b1, cyp1c1, and cyp1c2) were recorded after exposure to the sediment sample of the Vering canal. In conclusion, the newly developed sediment contact assay can be recommended for the investigation of dioxin-like activities of single substances and the bioavailable fraction of complex environmental samples. Moreover, the exposure of whole zebrafish embryos to native (freeze-dried) sediment samples represents a highly realistic and ecologically relevant exposure scenario.

In Hokkaido, northern Japan, there are 12 hybrid subsurface constructed wetlands (HSCWs) and most of them are treating high concentrated organic wastewater. One of these systems is an HSCW situated in Embetsu, northern Hokkaido, and it has been in operation since November of 2006 to treat dairy milking parlor wastewater. The system is composed of two vertical flow beds and a horizontal flow bed. The influent and the effluent flow rates and pollutant concentrations and loads were extremely variable. Throughout its 6 years of operation, most of the pollutant removals were decently high. Removal efficiencies for COD, BOD₅, and SS were ranging in the 90 %. Removal efficiencies for TN, NH₄-N, and BOD₅ were improving because of the development of the soil ecosystem and the Phragmites australis community. However, the removal efficiencies of TP were decreasing, presumably because of the declining adsorption ability. The accumulation of TP in the first and the second vertical beds had reached its plateau. Vertical beds had high removal efficiencies for TN, COD, BOD₅, and SS. These high removal efficiencies of the first vertical bed may be caused from the efficient removal of solid material that is deposited as an organic layer of the first vertical bed. High NH₄-N removal efficiencies exerted by the second vertical bed may be due to the recycling of wastewater. In conclusion, the HSCW was working excellently for its 6 years of operation, and it could be concluded that it has not reached its life yet.

Pseudomonas aeruginosa strain GF31, isolated from a contaminated soil, can effectively degrade β-cypermethrin (β-CP), as well as fenpropathrin, fenvalerate, and cyhalothrin. The highest level of degradation (81.2 %) was achieved with the addition of peptone. Surprisingly, the enzyme responsible for degradation was mainly localized to the extracellular areas of the bacteria, in contrast to the other known pyrethroid-degrading enzymes, which are intracellular. Although intact bacterial cells function at about 30 °C for biodegradation, similar to other degrading strains, the crude extracellular extract of strain GF31 remained biologically active at 60 °C. Moreover, the extract fraction showed good storage stability, maintaining >50 % of its initial activity following storage at 25 °C for at least 20 days. Significant differences in the characteristics of the crude GF31 extracellular extract compared with the known pyrethroid-degrading enzymes indicate the presence of a novel pyrethroid-degrading enzyme. Furthermore, the identification of 3-phenoxybenzoic acid and 2,2-dimethylcyclopropanecarboxylate from the degradation products suggests the possibility that β-CP degradation by both the strain and the crude extracellular fraction is achieved through a hydrolysis pathway. Further degradation of these two metabolites may lead to the development of an efficient method for the mineralization of these types of pollutants.

Bioavailability has been used as a key indicator in chemical risk assessment yet poorly quantified risk factor. Worldwide, the framework used to assess potentially contaminated sites is similar, and the decisions are based on threshold contaminant concentration. The uncertainty in the definition and measurement of bioavailability had limited its application to environment risk assessment and remediation. Last ten years have seen major developments in bioavailability research and acceptance. The use of bioavailability in the decision making process as one of the key variables has led to a gradual shift towards a more sophisticated risk-based approach. Now a days, many decision makers and regulatory organisations ‘more readily accept’ this concept. Bioavailability should be the underlying basis for risk assessment and setting remediation goals of those contaminated sites that pose risk to environmental and human health. This paper summarises the potential application of contaminant bioavailability and bioaccessibility to the assessment of sites affected by different contaminants, and the potential for this to be the underlying basis for sustainable risk assessment and remediation in Europe, North America and Australia over the coming decade.

A pot trial was conducted to investigate the effects of three arbuscular mycorrhizal (AM) fungi species, including Glomus geosporum BGC HUN02C, G. versiforme BGC GD01B, and G. mosseae BGC GD01A, on grain yield and arsenic (As) uptake of upland rice (Zhonghan 221) in As-spiked soils. Moderate levels of AM colonization (24.1–63.1 %) were recorded in the roots of upland rice, and up to 70 mg kg⁻¹ As in soils did not seem to inhibit mycorrhizal colonization. Positive mycorrhizal growth effects in grain, husk, straw, and root of the upland rice, especially under high level (70 mg kg⁻¹) of As in soils, were apparent. Although the effects varied among species of AM fungi, inoculation of AM fungi apparently enhanced grain yield of upland rice without increasing grain As concentrations in As-spiked soils, indicating that AM fungi could alleviate adverse effects on the upland rice caused by As in soils. The present results also show that mycorrhizal inoculation significantly (p < 0.05) decreased As concentrations in husk, straw, and root in soils added with 70 mg kg⁻¹ As. The present results suggest that AM fungi are able to mitigate the adverse effects with enhancing rice production when growing in As-contaminated soils.

We present here observations on diurnal and seasonal variation of mixing ratio and δ¹³C of air CO₂, from an urban station—Bangalore (BLR), India, monitored between October 2008 and December 2011. On a diurnal scale, higher mixing ratio with depleted δ¹³C of air CO₂ was found for the samples collected during early morning compared to the samples collected during late afternoon. On a seasonal scale, mixing ratio was found to be higher for dry summer months (April–May) and lower for southwest monsoon months (June–July). The maximum enrichment in δ¹³C of air CO₂ (−8.04 ± 0.02‰) was seen in October, then δ¹³C started depleting and maximum depletion (−9.31 ± 0.07‰) was observed during dry summer months. Immediately after that an increasing trend in δ¹³C was monitored coincidental with the advancement of southwest monsoon months and maximum enrichment was seen again in October. Although a similar pattern in seasonal variation was observed for the three consecutive years, the dry summer months of 2011 captured distinctly lower amplitude in both the mixing ratio and δ¹³C of air CO₂ compared to the dry summer months of 2009 and 2010. This was explained with reduced biomass burning and increased productivity associated with prominent La Nina condition. While compared with the observations from the nearest coastal and open ocean stations—Cabo de Rama (CRI) and Seychelles (SEY), BLR being located within an urban region captured higher amplitude of seasonal variation. The average δ¹³C value of the end member source CO₂ was identified based on both diurnal and seasonal scale variation. The δ¹³C value of source CO₂ (−24.9 ± 3‰) determined based on diurnal variation was found to differ drastically from the source value (−14.6 ± 0.7‰) identified based on seasonal scale variation. The source CO₂ identified based on diurnal variation incorporated both early morning and late afternoon sample; whereas, the source CO₂ identified based on seasonal variation included only afternoon samples. Thus, it is evident from the study that sampling timing is one of the important factors while characterizing the composition of end member source CO₂ for a particular station. The difference in δ¹³C value of source CO₂ obtained based on both diurnal and seasonal variation might be due to possible contribution from cement industry along with fossil fuel / biomass burning as predominant sources for the station along with differential meteorological conditions prevailed.

Major endogenous biochemical properties can make plants ideal agents for metal/metalloid-contaminated site cleanup. This study investigates the biochemistry of Juncus maritimus (Lam) roots for its high mercury (Hg) stabilization potential in the sediments of the Ria de Aveiro coastal lagoon (Portugal), which received Hg-rich effluents from a chlor–alkali industry between 1950 and 1994. J. maritimus plants were collected at a reference (R) site and three sites with the highest (L1), moderate (L2), and the lowest (L3) Hg contamination levels. The highest Hg-harboring/stabilizing J. maritimus roots at L1, exhibited significantly elevated damage endpoints (H₂O₂; lipid peroxidation, LPO; electrolyte leakage, EL; protein oxidation, PO; proline) which were accompanied by differential changes in H₂O₂-metabolizing defense system components (ascorbate peroxidase, catalase, glutathione peroxidase, glutathione S-transferase), glutathione reductase and the contents of both reduced and oxidized glutathione. Trends in measured endpoints reached maximum levels at L1 followed by L2 and L3. Cross-talks on root–Hg status and the studied biochemical traits revealed (a) high Hg-accrued elevations in oxidative stress as an obvious response; (b) Hg-stabilization potential of J. maritimus roots as a result of a successful mitigation of elevated high Hg-induced H₂O₂, and its anomalies such as LPO, EL, and PO; and (c) the induction of and a fine synchronization between non-glutathione and glutathione-based systems. Overall, the study unveiled biochemical mechanisms underlying root tolerance to Hg burden-accrued anomalies which, in turn, helped J. maritimus during Hg-stabilization.