Phosphate (PO₄³⁻) and nitrate (NO₃⁻) contamination causes the threatening issue of eutrophication. A major waste from seafood industries of various seashells including Anadara inaequivalvis, Saccostrea commercialis, Perna viridis, Tegillarca granosa, Filopaludina martensi, Babylonai areolate and Meretrix lusoria was thermally modified and investigated for PO₄³⁻ and NO₃⁻ removal from synthetic and domestic wastewater. It was found that some raw seashells could remove ≥85% of PO₄³⁻, whereas their NO₃⁻ removal efficiency was poor. However, after calcination, among others, only M. lusoria pyrolysed at 800 °C (M. lusoria F800) was found as a novel adsorbent for both PO₄³⁻ and NO₃⁻ removal. An increase in temperature and increased Ca(OH)₂ content enhance the removal of PO₄³⁻ and NO₃⁻ by precipitating with calcium ions (Ca²⁺). M. lusoria F800 was the best for PO₄³⁻ and NO₃⁻ removal compared with commercial lime and other calcined seashells. The maximum adsorption capacity (Qₘₐₓ) of M. lusoria F800 for PO₄³⁻ and NO₃⁻ was 700 mg/g and 170 mg/g, respectively, which was higher than the Qₘₐₓ of PO₄³⁻ and NO₃⁻ by commercial lime Ca(OH)₂ which was about 465 mg/g and 18 mg/g, respectively. The crystals of calcium phosphate-hydroxide and calcium nitrate-hydroxide complexes were mainly found in M. lusoria F800 that adsorbed PO₄³⁻ and NO₃, respectively, as confirmed by X-ray diffractometer (XRD). Also, M. lusoria F800 could completely remove PO₄³⁻ and NO₃⁻ from domestic wastewater. Hence, easily handled and cost-effective M. lusoria F800 would increase the value of this waste material, increase water quality and mitigate eutrophication.

The objective of this study is to evaluate the water quality of the Lien Son irrigation system in Vietnam and identify the critical pollutants that affect the system’s water quality. Firstly, the water quality at fifteen locations distributed along the main Lien Son drainage and irrigation canals was monitored in the dry season (from January to March) for 3 consecutive years (2018, 2019, and 2020) to collect nine physical, chemical, and microbiological parameters. And then, principal component analysis (PCA) and factor analysis (FA) were applied to extract and identify the critical pollutants which helps to preliminarily detect the potential pollution sources to the irrigation system. Results of PCA and FA showed the principal groups of pollutants which had a significant influence on the water quality of the system. Sampling locations LS7 and LS8 had the heaviest pollution. The primary factors that influenced the pollution of the system were organic matter (COD and BOD₅), nutrients (N-NH[Formula: see text] and P-PO[Formula: see text]), sediment transport (turbidity and TSS), and coliform. These factors are usually associated with the sources of domestic wastewaters and agricultural runoff from the vicinity. This suggested that urgent actions should be taken to control domestic wastewaters and agricultural runoff from the vicinity so that they could not deteriorate the water quality of the system.

The composition and structure of dissolved organic matter (DOM) play vital roles in the material cycle of river ecosystems. Based on ultraviolet-visible absorption spectroscopy, excitation-emission matrix fluorescence spectroscopy, and ultrahigh-resolution electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry technology, this study comprehensively characterized the composition and structure of DOM in the overlying water of the Chaobai River in order to determine the potential environmental impact of DOM on the water quality. The results showed that the DOM content of the overlying water in the Chaobai River was between 10.94 and 28.13 mg/L. The main DOM component of the overlying water was humus (70.94%). The relative abundance of CHOS compounds in the Chaobai River was lower than Maozhou River (urbanized river) and significantly higher than Xiangxi Bay (suburban river). In addition, the DOM composition and structure of the overlying water were closely related to anthropogenic input, microbial activity, and phytoplankton. In particular, chlorophyll a can indirectly reflect fresh autochthonous DOM content and composition in the overlying water. The results of this study further reveal the characteristics of suburban rivers and provide theoretical basis and guidance for the water quality evaluation and pollution control of the Chaobai River and other suburban rivers worldwide.

This study reports how adding a membrane filter (0.45-μm cellulose nitrate filter) between a glass fibre filter and the solid phase extraction (SPE) cartridge affected the GC/MS analysis of 48 emerging organic micropollutants in wastewater. Most of them are widely used as active pharmaceuticals, cosmetic and packaging material ingredients including classes of parabens, benzophenones and bisphenols among other chemicals tested. A high artificial organic carbon (OC) content in wastewater (DOC = 280 ± 14 mg/L) was investigated to gain insight into micropollutants/colloidal OC filter cake interactions. The results show that even with the use of matrix-matched calibration, the introduction of a second (membrane) filtration step can affect the analysis. Both positive, negative and no effects on the theoretical concentrations calculated from the calibration curves with and without additional filtration were observed. Positive effects on the concentration for the same analyte peak area relative to its surrogate standard were the consequence of a reduced signal for the same concentration, while the negative effects are the consequence of increasing signal for the same concentration. Effect types were dependent on the concentration and the nature of the analytes. Results show that bisphenols and parabens significantly interact with colloidal OC. Statistical analysis of molecular descriptor distribution with effect type showed that micropollutants that have a stronger interaction with colloidal OC have significantly higher ability to act as hydrogen bond donors (HBD) and have larger molar volume (MV). All compounds that experienced either positive or negative effects have a significantly higher median logD. However, further exploration within a single class of compounds (parabens, benzophenones and bisphenols) revealed that selected descriptors are unrelated to an effect type. Pearson’s correlations showed that a correlation exists for certain concentration levels and groups of compounds between a negative effect and MV and logD and a positive effect with MV, MW and rotatable bond (RB) count.

Studies around the world have revealed reduced levels of atmospheric particulate matter in periods of greatest human mobility restriction to contain the spread of SARS-CoV-2 during the COVID-19 pandemic. The present study aimed to carry out a health impact assessment in Recife, Brazil, hypothesizing a scenario in which the levels of PM₁₀ and PM₂.₅ remained, throughout the year, as in the most restrictive period of human mobility. Particular material data (PM₁₀ and PM₂.₅) were measured during the pandemic and population and health (mortality, hospital admissions for heart and respiratory problems) data from 2018 were used. We observed a reduction in the concentration of PM₂.₅ in up to 43.7% and PM₁₀ up to 29.5% during the period of social isolation in the city of Recife. The reduction in PM₂.₅ would avoid 106 annual deaths from non-external causes and 58 annual deaths from cardiovascular diseases. In this scenario, $ 294.88 million would be saved ($ 114.88 million from heart problems and $ 180 million from non-external causes). When considering hospitalizations avoided by the decrease in PM₁₀, we observed 57 fewer hospitalizations for respiratory diseases, 42 for heart diseases and a reduction of 37 deaths due to non-external causes. The reduction in spending on respiratory and cardiovascular hospitalizations would exceed $ 330,000. Therefore, the reduction of particulate matter could prevent hospital admissions, deaths and consequently there would be a reduction in disease burden in developing countries where economic resources are scarce. In this sense, governments should seek to reduce levels of pollution in order to improve the life quality and health of the population.

Since the developed world’s economic prosperity has been heavily reliant on excessive fossil-based energy consumption, it has posed severe environmental quality challenges. This research attempts to revisit the relationship between income and anthropogenic emissions in the context of the environmental Kuznets curve (EKC) theory by considering electric power consumption, urbanization, and democratic accountability index in the Gulf Cooperation Council (GCC) region. It employs annual frequency panel data from 1990 through 2019 and three alternative advanced econometric estimation techniques. The main findings are as follows: Firstly, the EKC results for the whole sample strongly support the proposition of an inverse U-shaped connection between anthropogenic emissions and affluence in the long run. Secondly, the country-specific results confirm EKC only in Saudi Arabia and Bahrain, while the remaining countries demonstrate a U-shaped connection. Thirdly, the democratic accountability promoted anthropogenic emissions implying that it failed to contribute to environmental protection. It means that democratic setup in the GCC region performs poorly in accomplishing climate change mitigation and Sustainable Development Goals (SDGs). Fourthly, electric power consumption and urbanization impart positive and negative impacts on anthropogenic emission, respectively. These findings are found robust across the fully modified ordinary least square (FMOLS), bias-corrected LSDV (least squares dummy variable) (LSDV), and pooled mean group (PMG) estimators. Finally, Dumitrescu-Hurlin panel causality shows that (i) income and urbanization establish a two-way causality with the anthropogenic emissions. (ii) However, a unidirectional causal connection is revealed from electric power consumption and democratic accountability index to anthropogenic emissions. The findings suggest that the GCC region should prioritize environmental protection and SDGs across the political aims’ recipe since it would direct the region on the path of climate change mitigation.

Drought is a natural hazard that can inflict significant damage to agriculture, society, economy, and ecosystems. The assessment of the persistence of drought severity (PDS) assists in understanding the characteristics of droughts better and enables the development of associated prediction tools and models. This work explores the persistence and spatial–temporal variability of drought severity (DS) in the diverse dryland of Iran. Using monthly precipitation and temperature data of 44 synoptic stations from 1989 to 2018, relationships between DS coefficient of precipitation variation, aridity, and the persistence percentage are determined by the application of the standardized precipitation index (SPI), the dryland index, and the Hurst exponent (H). The results confirm the persistence of droughts in Iran as H exceeded the 0.5 threshold for all stations. The PDS average in Iran is 0.78 with high regional variability reflective of different climatic conditions and geographical locations. An inverse relationship exists between the long-term coefficient of variation of monthly precipitation and PDS in the hyper-arid and arid regions of watersheds. Higher PDS values and increasing trend in the DS are detected in dry-subhumid areas. Also, the effect of the El Niño–Southern Oscillation (ENSO), a teleconnection metric, on the DS displays high spatial and temporal variability in Iran. The results show that the PDS is consistent with the spatial variation of DS changes during the period of 2009–2018.

UV-visible spectroscopy and synchronous fluorescence spectroscopy (SFS) combined with two-dimensional correlation spectroscopy (2D-COS) were applied for extracting fluorescence components, tracing organic functional groups, and revealing variations of dissolved organic matter (DOM) in Puhe River. Water samples were collected from the mainstream and two tributaries (Nanxiaohe River and Huangnihe River). DOM in three rivers was composed of protein-like fluorescent (PLF), microbial humus-like fluorescent (MHLF), fulvic-like fluorescent (FLF), and humic-like fluorescent components, which were relative to aromatic groups, phenolic groups, carboxylic groups, and microbial products. The PLF and MHLF were dominated in DOM fractions in the rivers, and the average content of the PLF was the highest in Nanxiaohe River. Humification degree of DOM was the highest in Puhe River, followed by Huangnihe River and Nanxiaohe River. However, molecular mass of DOM in Puhe River was the lowest, followed by Huangnihe River and Nanxiaohe River. Based on the 2D-COS of the SFS and UV-visible spectra, the variation order of DOM fractions in Puhe River was PLF → MHLF → FLF, and the PLF was consistent with the phenolic groups, aromatic groups, and carboxylic groups, but the adverse trend with the microbial products. The variation order in Nanxiaohe River was MHLF → PLF → FLF, and the MHLF was consistent with the aromatic groups, phenolic groups, carboxylic groups, and microbial products. The variation order in Huangnihe River was MHLF → PLF → FLF too, and the PLF was consistent with the carboxylic groups and aromatic groups. The results of the present study demonstrate that UV-visible spectroscopy and SFS combined with 2D-COS are useful methods to characterize structural composition of DOM from urban black and stinky rivers so as to investigate their pollution status.

This study aimed to investigate the effects of endocrine disruptors 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) on Nile tilapia (Oreochromis niloticus) development, focusing on gonadal histological factors. Concentrations of estrogens E2 and EE2 ranging from 250 to 1000 ng·L⁻¹ can produce intersex individuals, significantly decreasing the condition factor as the concentrations increased. These concentrations could also induce the development of morphological anomalies. Increasing the concentration of estrogens by one order of magnitude (µg·L⁻¹) was lethal for Nile tilapia larvae, with no effect on the incubation time and percentage of larvae hatching. Additionally, morphological anomalies and developmental problems were observed. Estrogens applied at a concentration of 160 µg·L⁻¹ for 28 days caused the birth of a small number of intersex individuals in Nile tilapia, but generated almost entirely female populations in hormonal treatments. Furthermore, the gonads of fish exposed to the estrogens were smaller and less developed, without any significant difference between E2 and EE2. Variation in the exposure time (one to 4 weeks) of Nile tilapia to estrogens (160 µg·L⁻¹) resulted in the appearance of intersex individuals and the development of morphological anomalies, regardless of the exposure time.

G20 countries are responsible for more than 80% of global energy consumption and the largest CO₂ emissions in the world. Literature related to the energy consumption-environmental quality-subjective wellbeing nexus is limited and lacks consensus. This paper analyses the impact of energy consumption and environmental quality on subjective wellbeing in G20 countries from 2006 to 2019 using a panel-corrected standard error (PCSE) model. Cantril life ladder data is used as a proxy of subjective wellbeing. For robustness, the Newey-West standard error model is used. The findings reveal that renewable energy consumption and environmental quality, i.e. lesser carbon emissions, enhance subjective wellbeing in G20 countries. In contrast, non-renewable energy consumption degrades subjective wellbeing. Moreover, the study also finds bidirectional causality between renewable energy consumption, non-renewable energy consumption, and economic growth. The policymakers of these countries should encourage renewable energy production and its consumption to reduce carbon emissions for conserving the environment and enhancing their people’s subjective wellbeing.