The treatment of colored effluents containing Procion Red dye (PR) was investigated using H₂SO₄ and HNO₃ modified avocado shells (Persea americana) as adsorbents. The adsorbent materials (AS–H₂SO₄ and AS–HNO₃) were properly characterized. The adsorption study was carried out considering the effects of adsorbent dosage and pH. Kinetic, equilibrium, and thermodynamic aspects were also evaluated. Finally, the adsorbents were tested to treat simulated dye house effluents. For both materials, the adsorption was favored using 0.300 g L⁻¹ of adsorbent at pH 6.5, where, more than 90% of PR was removed from the solution. General order model was able to explain the adsorption kinetics for both adsorbents. The Sips model was adequate to represent the isotherm data, being the maximum adsorption capacities of 167.0 and 212.6 mg g⁻¹ for AS–H₂SO₄ and AS–HNO₃, respectively. The adsorption processes were thermodynamically spontaneous, favorable (− 17.0 < ΔG ⁰ < − 13.2 kJ mol⁻¹), and exothermic (ΔH ⁰ values of − 29 and − 55 kJ mol⁻¹). AS–H₂SO₄ and AS–HNO₃ were adequate to treat dye house effluents, attaining color removal percentages of 82 and 75%. Avocado shells, after a simple acid treatment, can be a low-cost option to treat colored effluents.

For wastewater-related issues (WRI), life cycle assessment (LCA) is often used to evaluate environmental impacts and derive optimization strategies. To promote the application of LCA for WRI, it is critical to incorporate local impact of water pollutants. Organic pollution, a main type of water pollution, has not been given much consideration in current LCA systems. This paper investigates the necessity of setting a regionalized impact category to reflect the local impact of organic pollution. A case study is conducted concerning an upgraded wastewater treatment plant (WWTP) in China, which is assumed to meet different sewage control strategies. Chemical oxygen demand (COD) is selected to represent the organic pollution and treated as an individual impact category. CML 2002 is used to quantify the environmental impacts of different strategies. Results show that abnormal LCA results are generated with the traditional eutrophication impact category, and after the introduction of COD, more reasonable LCA results are obtained, making the entire comparison of different control strategies more meaningful and compelling. Moreover, BEES, Ecovalue 08, and Chinese factors are adopted here as different weighting methods. Different weighting results exhibited various trade-offs for the increasingly strict control strategies; the results of BEES and Ecovalue08 underlined the potential environmental burden, but the results of Chinese factors only emphasized the local environmental improvement. It is concluded that setting regionalized impact category for organic pollution can make LCA results more reasonable in wastewater treatment, especially in evaluating Chinese cases because of the serious water pollution caused by large quantities of COD emission.

A large number of studies have examined the linkage between income inequality and environmental quality at the individual country levels. This study attempts to examine the linkage between the two factors for the individual BRICS economies from a comparative perspective, which is scarce in the literature. It examines the selected countries (Brazil, India, China and South Africa) by endogenising the patterns of primary energy consumption (coal use and petroleum use), total primary energy consumption, economic growth, and urbanisation as key determining factors in CO₂ emission function. The long-run results based on ARDL bounds testing revealed that income inequality leads to increase in CO₂ emissions for Brazil, India and China, while the same factor leads to reduction in CO₂ emissions for South Africa. However, it observes that while coal use increases CO₂ emissions for India, China and South Africa, it has no effect for Brazil. In contrast, the use of petroleum products contributes to CO₂ emissions in Brazil, while the use of the same surprisingly results in reduction of carbon emissions in South Africa, India and China. The findings suggest that given the significance of income inequality in environmental pollution, the policy makers in these emerging economies have to take into consideration the role of income inequality, while designing the energy policy to achieve environmental sustainability.

Tropospheric ozone (O₃) is a naturally occurring gas in the atmosphere. However, the concentration of O₃ increased in the twentieth century. Although the effects of O₃ on vegetation have been extensively studied since the 1950s, limited information exists regarding the effects of O₃ on insect herbivores. In particular, evidence is lacking regarding the effects of O₃ on the biology of insect herbivores. Agelastica coerulea Baly (1874) is a coleopteran species that grazes on Betulaceae plants. In this study, to investigate the effects of O₃ on A. coerulea biology for the first time, female adult insects were collected from Japanese white birch trees grown in a Free Air Controlled Exposure System (FACE) in Sapporo, Japan. These beetles inhabited trees exposed either to ambient or to elevated O₃ for 23 days. After collection, the enzyme activities in the beetles were measured. Elevated O₃ led to a greater total antioxidant activity and lower α- and β-esterase activities, a phenomenon that may suggest an increased resistance of the beetles to stress. Our results are further discussed with regard to biological and toxicological aspects. Collectively, our findings indicate that total antioxidants and α- and β-esterase activities can serve as effective O₃ biomarker systems in this beetle species. This adaptive response of the beetle, which was induced by moderate O₃ exposure, should be further tested across generations and for its protection against greater exposure.

Nanotechnology is a novel arena with promising applications in the field of medicine, industry, and agriculture including fisheries. Cross-disciplinary interactions and the application of this technology in biological systems have led to the innovation of novel nanoparticle antioxidants, which are the subject of our study. In context with above background, we designed an experiment on nano-silver to elucidate its role for mitigation of abiotic and biotic stress. Three diets were formulated viz. silver nanoparticles (Ag-NPs) incorporated at 0.5 and 1 mg/kg diet and control diet (Ag-NPs at 0 mg/kg). Fish were exposed to sublethal level of 1/25th of LC₅₀ (4 ppm) of lead (Pb) and temperature at 34 °C. The effect of Ag-NPs on productive performance (weight gain %, feed conversion ratio, protein efficiency ratio, and specific growth rate), stress biomarkers (catalase, super oxide dismutase, glutathione-s-transferase, acetylcholine esterase, cortisol, heat shock protein), biochemical and immunological response (protein and carbohydrate metabolic enzymes, phagocytic activity, serum total protein and albumin: globulin ratio), histopathology alterations in the liver and gill as well as survival of Channa striatus, following challenge with pathogenic bacteria were evaluated. Dietary Ag-NPs at 0.5-mg supplementation improved growth performance, immunity, survival, and reduced stress biomarker such as HSP 70, cortisol, and blood glucose in various fish tissues. Exposure to Pb and high temperature and group fed with Ag-NPs (1 mg/kg diet) demonstrated remarkable changes in the histo-architect of liver such as pyknotic nuclei, pyknosis, leucocyte infiltration, hemorrhage and karyokinesis, blood vessels with nucleated, lipid vacuoles in the liver tissue. Histology of gill displayed hyperplasia, aneurism, blood congestion, severe telengiectiasis, epithelial lifting, curling of secondary lamella, hyperplasia of epithelial cell of secondary lamella in the group exposed to lead and high temperature and supplemented with Ag-NPs at 1 mg/kg diet. In addition to histopathology, feeding with Ag-NPs at 1 mg/kg diet deteriorated and altered all studied parameters including reduced growth performance. Results obtained in the present study suggest that supplementation of Ag-NPs at 0.5 mg/kg diet has a definitive role to play in the mitigation of abiotic and biotic stress in C. striatus.

With growing population and urbanization, there is an increasing exploitation of natural resources, and this often results to environmental pollution. In this review, the levels of heavy metal in lentic compartments (water, sediment, fishes, and aquatic plants) over the past two decades (1997–2017) have been summarized to evaluate the current pollution status of this ecosystem. In all the compartments, the heavy metals dominated are zinc followed by iron. The major reason could be area mineralogy and lithogenic sources. Enormous quantity of metals like iron in estuarine sediment is a very natural incident due to the permanently reducing condition of organic substances. Contamination of cadmium, lead, and chromium was closely associated with anthropogenic origin. In addition, surrounding land use and atmospheric deposition could have been responsible for substantial pollution. The accumulation of heavy metals in fishes and aquatic plants is the result of time-dependent deposition in lentic ecosystems. Moreover, various potential risk assessment methods for heavy metals were discussed. This review concludes that natural phenomena dominate the accumulation of essential heavy metals in lentic ecosystems compared to anthropogenic sources. Amongst other recent reviews on heavy metals from other parts of the world, the present review is executed in such a way that it explains the presence of heavy metals not only in water environment, but also in the whole of the lentic system comprising sediment, fishes, and aquatic plants.

The extract from Cinnamomum cassia Presl bark was obtained with supercritical CO₂ fluid extraction (SFE). Chemical components of the SFE extract were characterized by GC-MS spectrometry. The repellency and contact toxicity of the SFE extract were evaluated against the adults of Tribolium castaneum and Lasioderma serricorne along with those of its two main compounds. The results of GC-MS analysis indicated that 33 volatile constituents were identified from the extract. The main components included trans-cinnamaldehyde (32.1%), 3,3-dimethylhexane (10.6%) and 2,4-di-tert-butylphenol (7.9%). Testing results showed that the SFE extract had potent contact toxicity against T. castaneum and L. serricorne with LD₅₀ values of 3.96 and 23.89 μg/adult, respectively. LD₅₀ values of trans-cinnamaldehyde against T. castaneum and L. serricorne were 5.78 and 3.24 μg/adult, respectively. Additionally, percentage repellency values of the SFE extract and trans-cinnamaldehyde against T. castaneum and L. serricorne were rather high (PR = 100% and PR > 90%, respectively) at 78.63 and 15.73 nL/cm² at 2 h post-exposure. 2,4-Di-tert-butylphenol showed some repellency against both beetle species. Considering its insecticidal and repellent effects, the SFE extract from C. cassia bark might be used in integrated pest management programs for T. castaneum and L. serricorne.

Anthracite is a natural inorganic-organic hybrid environmentally friendly material, which often is used as a filter medium in water treatment. In this study, we processed anthracite particles using potassium hydroxide (KOH) with different concentrations. The anthracites, before and after treatments, were characterized by Brunauer-Emmett-Teller analysis, scanning electron microscopy, Fourier transform infrared spectrometer, X-ray diffraction, X-ray photoelectron spectroscopy, and Boehm titration. The specific surface area and the amount of total alkalinity of anthracite were 23.73 m² g⁻¹ and 0.38 mmol g⁻¹ (increased by 101 and 217%, respectively) for 4 M KOH treatments, but decreased to 10.09 m² g⁻¹ and 0.12 mmol g⁻¹ for 10 M KOH treatments. We selected 4 M KOH-modified anthracite particles to remove 17α-ethinylestradiol (EE2) and bisphenol A (BPA) from water with unmodified anthracite used in control experiments. The pseudo-second-order model fitted well for the whole adsorption process, and intraparticle diffusion was not the unique rate-controlling step. The equilibrium adsorption data fitted well with the Langmuir-Freundlich model, and the adsorption capacities of EE2 and BPA on anthracite particles after 4 M KOH treatments were 0.7914 and 0.4327 mg g⁻¹ (increased by 138 and 97%, respectively), because the active sites markedly increased. The ligand exchange, hydrogen bonds, and π-π electron donor-acceptor interactions were the main adsorption mechanisms. The 4 M KOH-modified anthracite could be promising in large-scale applications, both as filter medium and adsorbent for organic contaminants.

In this study, a novel inexpensive biosorbent of pine cone powder was used for the treatment of wastewater contaminated with phenol and chlorophenols (CPhs). The biosorbent was thoroughly characterized by using CHN and BET measurements, as well as FTIR, SEM, and XRD analyses. Kinetic and equilibrium biosorption experiments showed that the uptake was more than 80% within the first 30 min of contact time at pH 5.0. The biosorption of 4-CPh onto pine cone powder was higher than those of phenol and 2-CPh. The kinetic data were consistent with the pseudo-first-order kinetic model, and the Langmuir isotherm model best represented the equilibrium data. The maximum biosorption capacities of phenol, 2-CPh, and 4-CPh were 164.51, 189.44, and 220.12 mg/g, respectively, at 30 ± 1 °C. Therefore, the pine cone powder is an effective low-cost adsorbent for the removal of phenol and CPhs from the contaminated water.

A good water supply and wastewater management is essential for a local sustainable community development. This is emphasized in the new global goals of the UN Sustainable Development, where the sixth objective is to: “Ensure availability and sustainable management of water and sanitation for all” (United Nations 2015). This obviously raises the question of how this can be achieved considering the very different conditions and cultures around the globe. This article presents the Greenlandic context and elucidates the current Greenland water supply system and wastewater management system from a socio-technical approach, focusing on the geographic, climatic and cultural challenges. The article identifies a diverse set of system constellations in different parts of Greenland and concludes with a discussion of health and quality of life implications.