The material discarded by past mining extractive activities is exposed to the action of different environmental agents and constitutes the beginning of a problem that, inevitably, involves the population and the conditions of the environment where it is deposited. Bearing this in mind, a study of the Copaquilla-Chile valley was carried out with a focus on the socio-environmental conflict produced by the accumulation of abandoned mining waste in its vicinity. The objectives were to identify the role of the different actors and the main causes that originated the conflict and to characterize the physical-natural factors that conditioned the susceptibility and physical vulnerability of the studied environment. The methodological approach combined a set of qualitative and quantitative techniques, using participatory action research techniques (PAR) and multi-criteria evaluation models (MCE) through a geographic information system (GIS). The evaluation of the study area revealed quite severe levels in terms of the indices of susceptibility to processes of mass removal and vulnerability of the aquifer, which led us to infer that the morpho-climatic and hydrogeological characteristics of the sector generated the appropriate conditions to produce large damage to the complex socio-ecological system of the Copaquilla territory. This study generated participatory material, a chronology of the conflict, a database of the physical environment of the Copaquilla valley interpreted in thematic cartographies, and physicochemical soil and water samples to monitor contamination levels.

This study examines the potential defending effects of the diatom, Amphora coffeaeformis, as a feed additive versus the deleterious effects (mainly on gonads) caused by microplastics (MPs) in Nile tilapia, Oreochromes niloticus. Groups of male tilapia were pre-fed diets with four different supplementation levels of A. coffeaeformis (0%, 2.5%, 5%, and 7.5%) for 70 days, then exposed to 10 mg/L MPs for 15 days. Thereafter, samples were taken from the four experimental groups and the control fish group, for evaluating blood picture, erythrocytes alterations, biochemical parameters, catalase (CAT), superoxide dismutase (SDO), and total antioxidant capacity (TAC). In addition, male reproductive performance was assessed by quantifying the follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone (T), also testicular sections and GSI% were also assessed. The results showed that the number of leucocytes were significantly (p < 0.05) higher, but the number of red blood cells (RBCs), the level of Hemoglobin (Hb), the percentage of Hematocrit (Ht), the number of platelets, and the eosinophil percentages were significantly decreased (p < 0.05) when fish exposed to MPs. Biochemical parameters (ALP, glucose, uric acid, albumin, and A/G ratio) were significantly increased after MP exposure compared with the control group. Furthermore, MPs induced a significant decline in both serum LH and T levels. Testicular, histological, degenerative changes and testis-ova were found in the MP-exposed fish. Thus, A. coffeaeformis supplementation displayed ameliorative properties that detoxified the negative effects of MPs. This study provides a better understanding of the reproductive injuries caused by MPs exposure and evidence for the use of A. coffeaeformis as a natural remedy in freshwater tilapia.

The volatilization process of contaminants has been shown to play an important role in remediation of VOC-contaminated soils. The aim of this paper is to study the volatilization characteristics of both toluene and water from soil, and to evaluate their interaction mechanism under different conditions. A test system is developed to measure mass loss of contaminants and water from soil by volatilization. It was found that basically the volatilization process could be divided into two stages in clay and one stage in sand. Two main influential mechanisms of water on the volatilization of toluene include molecules’ competitive adsorption and blocking of volatilization channels. In addition, the evaporation process of water was restricted by volatilization of toluene. Volatilization rate of toluene would increase with the increase of water content when the water content was low. But it would decrease with the increase of water content when the water content was higher than 15% in clay. In addition, there existed an optimal water content (15%) under which the maximum volatilization rate could be achieved.

The rising concentration of ground-level ozone (O₃) reduces crop yield via increased oxidative stress. Application of ethylenediurea (EDU) protects plants from O₃ and could thereby serve as a means to estimate the crop yield losses due to ambient O₃ (AO₃). However, no study but a few exceptions has ever compared the yield loss estimates from EDU application with those from O₃ elevation experiments. Here, we estimated yield loss to AO₃ in rice cultivars across the 3 types, indica, japonica, and hybrid, by an EDU application in the field, and compared the yield losses with those estimated with dose-response relationships based on O₃ elevation experiments. Relative yield loss (RYL) in the EDU application was estimated at 16% across the rice types on an assumption of a 100% efficiency for protection of crop yield by EDU. This estimate of RYL was close to the 15% RYL estimated from the O₃ elevation experiments when a common sensitivity to O₃ is assumed across the cultivars. The rice yield loss due to AO₃ was thus consistent between the two approaches supporting the idea of EDU application for the yield loss estimation. When only hybrids are focused, however, the RYL from EDU application (16%) was much lower than the 34% RYL from the O₃ elevation experiments, which indicates only a 37% yield protection by EDU in the hybrid rice. The incomplete protection by EDU and its genetic variability indicates the need to quantify the efficiency of protection from AO₃-induced yield loss as estimated with O₃ manipulating experiments.

Due to the rapid pace of urbanization in China, there has been a significant increase in construction work, which has resulted in the generation of more waste. Reducing the waste at source is the most efficient way to reduce its negative impacts, and prefabrication is a construction method that does exactly that. Since prefabricated construction generates less waste compared to conventional cast-in-situ construction, it is being promoted by the Chinese government. This study investigates the benefits of prefabrication and quantifies the percentage of construction waste reduction through its application in China. It does so by using a 26-storey concrete-brick residential building as a case study, and by conducting uncertainty analysis with Oracle Crystal Ball simulation software to assess the reduction of waste when using prefabricated components in place of cast-in-situ elements. Simulation results demonstrated that the waste generation rate for in-situ timber formwork and masonry work was 10.52 and 4.77 kg/m² respectively, and that the use of prefabricated components reduced those figures by 36.04% and 25.53% respectively. This study quantifies the benefits of prefabrication as a method for reducing the generation of construction waste in China. Not only would extensive use of prefabrication decrease the cost related to construction waste management in China, but it could also mitigate the environmental and social impacts of construction waste globally.

The aim of this study was to access the Mn contamination in soil, forages, and animals. Heavy metal pollution is a matter of prime significance in natural environment. Through food chain, toxicity of heavy metals and their bioaccumulation potential are transferred into humans. Higher concentrations of metallic compounds are toxic to living organisms but these are essential to maintain body metabolism. Intake of food crops polluted with heavy metals is chief food chain channel for human exposure. Animals are exposed to heavy metal stress by the intake of richly contaminated food crops; those are chief part of food chain. Samples of soil, plant, animal blood, hair, and feces were collected to find contamination through wet digestion process in lab and metal analysis. Different forages were collected to study Mn content that was our major concern in this study. The present findings also emphasized on the assessment of bio-concentration factor (BCF). Other significant indices of mobility and pollution of metal were also calculated, i.e. pollution load index (PLI), daily intake of metal (DIM), health risk index (HRI), and enrichment factor (EF). The experimentation result showed different concentrations of metal in different seasons. The Mn concentration in forages was 20.01–28.29 mg/kg and in soil was 5.27–8.90 mg/kg. Soil samples showed higher level of (PLI) Pollution load index. Bio-concentration of MN was 2.59–4.21 mg/kg. It can be concluded that regular monitoring of the metal is essential to evaluate the contamination status. Mn contents were in the safe limits in soil and plants; however, its toxic level was observed in animals.

Sewage treatment and water reuse are, undoubtedly, one of the main points on scientific agenda of the 21ˢᵗ century. Many technologies for sewage treatment are available; however, it is still as an open issue that deserves much attention in order to facilitate their application, develop more effective methods and propose alternative treatment for unusual situations. Developing high performance materials for sewage treatment fits the idea of the development of efficient and alternative methods for microorganism removal and the high organic load of wastewater and is of fundamental importance. In this paper, a heterojunction with perovskite-type strontium stannate (SrSnO₃) and graphitic carbon nitride (g-C₃N₄) — SrSnO₃/g-C₃N₄ — was synthesized and used for photocatalytic treatment of domestic sewage using only sunlight. Results were accompanied by assessing the total organic carbon decrease and removal of pathogenic microorganisms. X-ray diffraction and X-ray excited photoelectron spectroscopy demonstrated that a heterostructure was successfully formed and photocatalytic tests showed an important activity in the visible range, i.e., under sunlight. Exposing raw sewage to 240 min (from 11 a.m. until 3 p.m.) in the presence of SrSnO₃/g-C₃N₄, led to a 56.1% mineralization. This process was 2.5 more efficient than photolysis under sunlight. Moreover, the treated sewage showed no coliform growth (either fecal or total) or heterotrophic bacteria. This simple treatment makes sewage suitable and safe for reuse, for example, for agriculture purposes according to Brazilian regulations criteria and could be an alternative for isolated areas in which sewage treatment plants are not available.

PUMPING ELEPHANT: The COVID-19 pandemic has adversely affected the lives of people around the world in millions of ways . Due to this severe epidemic, all countries in the world have been affected by all aspects, mainly economic. It is widely discussed that the COVID-19 outbreak has affected the world economy. When considering this dimension, this study aims to examine the impact of the COVID-19 pandemic on the world economy, socio-economics, and sustainability. In addition, the research focuses on multiple aspects of social well-being during the pandemic, such as employment, poverty, the status of women, food security, and global trade. To this end, the study used time series and cross-sectional analysis of the data. The second-hand data used in this study comes from the websites of major international organizations. From the analysis of secondary data, the conclusion of this article is that the impact of the pandemic is huge. The main finding of the thesis is that the social economy is affected by the pandemic, causing huge losses in terms of economic well-being and social capital.

The release of liquid effluents containing radionuclides from radioactive plants in urban areas has been the subject of discussions related to the environmental issue. This study presents the analysis of the activity concentrations (AC) of ¹³¹I and ⁹⁹ᵐTc in sewage samples collected in a nuclear medicine facility (NMF), associated with an university hospital situated in Rio de Janeiro, Brazil. The analyzes and measurements by gamma spectrometry of the collected sewage samples were performed, whose the estimated values (EV) for AC obtained for ¹³¹I in July (8.78 × 10³ Bq m⁻³) and September 2016 (9.80 × 10³ Bq m⁻³) and in February 2017 (1.14 × 10⁴ Bq m⁻³) were lower than the exemption level (EL = 1.90 × 10⁴ Bq m⁻³). For ⁹⁹ᵐTc, the EV for AC obtained from August (4.77 × 10² Bq m⁻³ and 2.96 × 10⁴ Bq m⁻³) to September 2017 (2.18 × 10³ Bq m⁻³) were lower than the EL (1.90 × 10⁹ Bq m⁻³). From an environmental point of view, the presence of ¹³¹I in the sewage treatment unit (STU), even if below the legal release limit, points out the greater importance of this radionuclide, as it requires special precautions in its adequate storage for the radioactive decay in the NMF and the dilution effect to reduce its AC minimizing the environmental impact after the effluent release to the environment. The presence of ¹³¹I in the STU was not expected pointing to the need and evaluation of the waste management system (WMS) of the NMF.

The diminution of the natural sources in the form of dredging the riverbanks and blasting the mountain ranges has always dented the balance of the ecosystem which in turn results in disasters as well at times. This alarming situation accelerates the global warming, threatens the biota life in riverbanks, diminishes the ground water level, harms the aquatic life, and affects the growth of agriculture. This study is an attempt to synthesis fine aggregates from the industrial byproducts, namely, fly ash and GGBS through the process of geopolymerization. This enables the formation of aluminosilicate networks upon the addition of the alkaline activator solution (Na₂ SiO₃ + NaOH) into the byproducts. The dry mix is then allowed for oven drying as well as air drying to accelerate the geopolymerization process. The fly ash-geopolymerized fine aggregate (F-GFA) and the GGBS-geopolymerized fine aggregate (G-GFA) were noted to exhibit adequate physiochemical and mechanical properties in par with the natural sand. The production of GFA is considered eco-friendly process since it ceases the extensive usage of river sand and incorporates the effective usage of industrial byproducts (fly ash and GGBS), thereby minimizing the land pollution and its consequent harmful hazards. Though the F-GFA and G-GFA showcased higher water absorption ratio than the natural sand due to the presence of unreacted fly ash and GGBS particles, the complete replacement of fine aggregate with geopolymerized sand initiated the adequate compressive strength attainment up to 90% of natural sand, by reacting with the lime expelled out of the hydration process of cement in the mortar specimens developed in this experimental study. The geopolymer itself is hydrophilic in nature, and it will also aid for the higher water absorption ratio of the polymer sand. The microstructure of the samples was further examined through optical microscope, scanning electron microscope, and X-ray diffraction analysis in order to corroborate the experimental results of this study. The results thus obtained strongly recommend the potential of the F-GFA and G-GFA as an ideal replacement material for natural sand.