In this study, the spring water quality of a high natural background radiation region in North Iran was evaluated by measuring hydrochemical characteristics and concentration of potentially toxic elements (PTEs) and activity concentration of radioactive elements. The carcinogenicity potential from exposure to PTEs and radioactive elements was also investigated using probabilistic approach. The hydrochemical properties of water samples revealed that there were two different water types in the study area: (1) non-thermal Ca-HCO3 type and (2) thermal Na-Cl type. The concentrations of Al, Cd, Cr, Cu, Pb, Mo, Ni, Sb, Zn, and ⁴⁰K were within the recommended water quality standard set by the World Health Organization (WHO). Elevated concentrations of As, Mn, Hg, ²²⁶Ra, and ²³²Th occur in Na-Cl water type while elevated concentrations of Fe occur in Ca-HCO₃ water type. Also, health complications of dermal contact (via balneology or bathing) are within the safe limits. The major concern regarding the contaminated springs is the possibility of soil and groundwater contamination through uncontrolled runoff and spa effluents. Preventing the spread of toxic constituents in the study area via high-risk spring water requires periodic monitoring, and applying control measures where necessary.

Particulate matter is the key to increasing urban air pollution, and research into pollution exposure assessment is an important part of environmental health. In order to classify PM₁₀ air pollution and to investigate the population exposure to the distribution of PM₁₀, daily and monthly PM₁₀ concentrations of 379 air pollution monitoring stations were obtained for a period from 01/01/2017 to 31/12/2017. Firstly, PM₁₀ concentrations were classified using the head/tail break clustering algorithm to identify locations with elevated PM₁₀ levels. Subsequently, population exposure levels were calculated using population-weighted PM₁₀ concentrations. Finally, the power-law distribution was used to test the distribution of PM₁₀ polluted areas. Our results indicate that the head/tail break algorithm, with an appropriate segmentation threshold, can effectively identify areas with high PM₁₀ concentrations. The distribution of the population according to exposure level shows that the majority of people is living in polluted areas. The distribution of heavily PM₁₀ polluted areas in Germany follows the power-law distribution well, but their boundaries differ from the boundaries of administrative cities; some even cross several administrative cities. These classification results can guide policymakers in dividing the country into several areas for pollution control.

In this study, montmorillonite-supported nanoscaled zero-valent iron (Mt-nZVI) composites were fabricated using a facile liquid-phase reduction method to avoid serious agglomeration of nZVI particles in suspensions due to magnetic effect. The morphology, crystal structure, functional groups, and magnetic properties of as-prepared composites were explored using scanning and transmission electron microscope, X-ray diffractometer, Fourier transform infrared spectroscope, X-ray photoelectron spectroscope, zeta potential analyzer, and superconducting quantum interference device. The fabricated composites were then applied to remove antibiotic oxytetracycline from water. The optimal weight ratio of the Mt particles (mean size, 25 μm) to the nZVI particles (size, 60–100 nm) was first determined to be 2:1 (simply denoted as 2Mt-nZVI). Experimental results showed that 99% of 100 mg/L oxytetracycline at pH 5.0 was removed using 0.6 g/L of the 2Mt-nZVI composite and the mineralization reached 70% after 20 min of reaction. Finally, the transformation products and intermediates were detected and identified by a high-resolution liquid chromatography mass spectrometry (LC-MS) and the pathways were proposed during the degradation of oxytetracycline over the 2Mt-nZVI composite.

Non-alcoholic fatty liver disease (NAFLD), the most common form of liver disease, affects over 30% of the US population. Our group and others have previously demonstrated that low-level environmental pollutant exposures were associated with increased odds ratios for unexplained alanine aminotransferase (ALT) elevation, a surrogate biomarker for NAFLD, in the adult National Health and Nutrition Examination Survey (NHANES). However, recently, more sensitive and lower ALT cutoffs have been proposed. The objective of this observational study is to utilize these ALT cutoffs to determine new associations between environmental chemicals and the surrogate NAFLD biomarker. Adult NHANES 2003–2004 participants without viral hepatitis, hemochromatosis, or alcoholic liver disease were analyzed in this cross-sectional study. ALT elevation was defined as > 30 IU/L in men and > 19 IU/L in women. Odds ratios adjusted for potential confounders for ALT elevation were determined across exposure quartiles for 17 pollutant subclasses comprised of 111 individual pollutants. The overall prevalence of ALT elevation was 37.6%. Heavy metal and organochlorine insecticide subclasses were associated with dose-dependent increased adjusted odds ratios for ALT elevation of 1.6 (95% CI 1.2–2.3) and 3.5 (95% CI 2.3–5.5) respectively, for the highest vs. lowest exposure quartiles (pₜᵣₑₙd < 0.01). Within these subclasses, increasing whole blood levels of lead and mercury, and lipid-adjusted serum levels of dieldrin, and the chlordane metabolites, heptachlor epoxide, and trans-nonachlor, were associated with increased odds ratios for ALT elevation. In conclusion, organochlorine insecticide, lead, and mercury exposures were associated with ALT elevation and suspected NAFLD in adult NHANES 2003–2004.

Adhesive-free wood-plastic composite panels made with lignocellulosic wastes, and recycled plastics can be a sustainable option for generating useful “green” products. The present work assessed the physical-mechanical properties of adhesive-free panels produced with Qualea sp. sawdust and recycled polypropylene (PP). Discarded PP packaging was used. The packages were washed and ground with a laboratory knife mill until particle size of 10 to 14 mesh. Qualea sp. sawdust was sieved to select particle size of 14 to 30 mesh. Four experimental treatments were assessed by varying the percentages of PP and sawdust, as follows, 60 and 40%, 70 and 30%, 80 and 20%, and 90 and 10%, in an entirely randomized design with 3 panels per treatment, totaling 12 panels. The mats were hot-pressed at 180 °C during 20 min, the first 10 min under pressure of 1.0 MPa and the remaining 10 min at 42 MPa. Physical-mechanical properties of the panels were obtained as follows: density, moisture content, water absorption, thickness swelling, moduli of elasticity and rupture, and Rockwell hardness. In general, an increase of the percentage of PP provided higher dimensional stability to the panels, but there was no significant influence on mechanical strength.

There is a lack of studies on whether market distortions inhibit the ecological efficiency. This study introduces the ecological efficiency based on the bootstrap-data envelopment analysis (DEA) method as the indicator of environmental performance in China, uses the transcendental logarithmic production function to calculate factor price distortion, and further identifies whether the factor price distortion has a negative impact on the ecological efficiency using the system generalized method of moments (GMM) method. Meanwhile, institutional quality is considered a threshold variable to examine the relationship between factor price distortion and ecological efficiency based on the threshold model. The result shows that factor price distortion significantly inhibits the improvement of ecological efficiency. Moreover, institutional quality is considered to be the threshold of factor price distortion affecting ecological efficiency. Further investigation of heterogeneity effect suggests that the inhibitory impact of factor price distortion on ecological efficiency is more significant in the central and western regions. This study provides a supplement to the study on environmental performance from the perspective of factor distortions and expands the framework of the influence mechanism of factor price distortion affecting ecological efficiency.

Water-energy nexus is a cornerstone in modern societies, with significant impacts at social, environmental, and economic levels. In addition to the issue of water scarcity that several regions of the world already face or are forecasted to face in the near future due to demand increase and availability reduction (e.g. pollution, climate changes), water consumption in buildings entails substantial energy consumption. In most cases, part of this energy is produced from non-renewable sources, encompassing greenhouse gas emissions. The present research effort presents a generic methodology to assess the cascade impact of water efficiency measures in buildings in terms of water, energy and emissions reduction. The methodology is applied to the Mediterranean climate zone context for two different types of non-residential buildings: university buildings and hotels, with very distinct water end use and consumption patterns. Lastly, are performed sensitivity analyses between the proposed methodology and simplified approaches. Is observed that assuming a linear relationship between flow rate and water consumption can lead to overestimations of up to 64% in water savings. Is also explored the relevance of the water consumption and energy mix seasonality typical of climates with marked dry and wet seasons, such as the Mediterranean region. The importance of the seasonality is discussed in terms of the time scale considered to apply the methodology, revealing that adopting a simplified (annual) approach, instead of the proposed approach, can lead to relative differences between − 62 and 233% in the presented case studies.

International trade in connection with carbon dioxide (CO₂) emissions has been well studied, but export quality in this context has not widely been considered yet. Hence, in this study, we fill this gap by exploring the effects of export quality, economic growth, urbanization, trade openness, and total energy use on CO₂ emissions in 63 developed and developing countries around the world. To achieve our objectives, we have used the recent techniques of panel quantile estimators as proposed in Powell (2016) and Canay. Econ J 14 (3): 368-386, (2011), along with several other estimation methods. Our overall empirical evidence shows that the existence of the Environmental Kuznets Curve (EKC) hypothesis depends heavily on the estimation method and on the development stage of the economies considered. Emissions are influenced by the same factors as in the EKC specification, as explored in sensitivity analysis. The results from the panel quantile regression model show that economic growth and total energy use are highly CO₂ emissions conducive, while urbanization increases environmental degradation at the higher quantiles, as does export quality, depending on the countries’ income levels. Consequently, improvements in export product quality should be prioritized through the production of cleaner products mainly in the lower and upper middle-income countries. There should also be a decrease in total energy use in countries of all income levels. Particularly, policy makers should promote a decrease in export products intensive of fossil fuel energy by prioritizing the use of more renewable energy sources.

Permanganate (PM) has shown to be able to oxidize a range of organic contaminants including perfluorooctane sulfonate (PFOS). However, mechanisms of PFOS removal by PM have been questioned. To provide clarity to what may be happening to PFOS in PM systems, here we evaluated the ability of PM on PFOS destruction by conducting studies similar to previous studies that reported PFOS destruction which included PM solutions and PM combined with persulfate (PS). We also evaluated if addition of various soluble catalysts could enhance PM’s potential to breakdown PFOS. We observed no PFOS destruction by PM. We also show that the F⁻ and SO₄²⁻ generation reported in a published study as evidence that PM was breaking bonds in PFOS were found below or not significantly higher than reported limits of quantitation and that SO₄²⁻ impurities in technical PM approach the reported SO₄²⁻ levels. For PM-PS systems, heterogeneous PFOS distribution was observed when subsampling reaction vessels at different depths and “salting-out” of PFOS was evident. In addition, subsequent sonication and filtering of the samples led to the apparent disappearance of most of the PFOS, which was an artifact arising from the behavior of PFOS aggregates or potential hemi-micelle formation. Given these findings, addition of salts may have application for collecting or concentrating PFOS and other PFAAs in a remediation or water treatment strategy.

This study explores the possibility of developing an eco-friendly adsorbent for effective remediation of groundwater fluoride, a well-known health hazard affecting more than 25 nations on the various continents. A facile and milder approach has been adopted to synthesize chitosan-modified ZnO/ZnFe₂O₄ nanocomposites. The synthesized materials have been characterized by different spectroscopic, microscopic, and diffractometric techniques. X-ray photoelectron spectroscopy and X-ray diffraction studies have confirmed the formation of pure and highly crystalline ZnO/ZnFe₂O₄ nanocomposites. The presence of surface-adsorbed chitosan in the modified ZnO/ZnFe₂O₄ has been confirmed by FT-IR and thermogravimetric analysis. The results from microscopic and BET surface area analysis of ZnO/ZnFe₂O₄ nanocomposites indicated that chitosan plays a crucial role in modulating the surface morphology and surface properties of the nanocomposites. The nanocomposites exhibit excellent adsorption performance in the remediation of groundwater fluoride. Experimental conditions have been systematically designed to evaluate the optimum adsorption condition for fluoride, and the results have been analyzed with various non-linear models to describe the kinetics and isotherms of adsorption. The adsorption primarily follows Lagergren pseudo-first-order kinetics, and the Langmuir adsorption capacity is varied from 10.54 to 13.03 mg g⁻¹ over the temperature range 293–323 K. The thermodynamics study reveals that the adsorption process is endothermic and spontaneous. The mechanism of adsorption has been proposed based on the spectroscopic analysis of the fluoride-loaded adsorbent. The adsorption is non-specific in nature as co-existing anion can reduce its fluoride removal capacity. The effect of the co-existing anions on adsorption of fluoride follows the trend PO₄³⁻ > CO₃²⁻ > SO₄²⁻ > Cl⁻. The adsorbent can be reused successfully for the 5th consecutive cycles of adsorption-desorption study. This study offers a very promising material for remediation of groundwater fluoride of affected areas.