In this study, the high-gravity technique is used to intensify the heterogeneous catalytic ozonation with activated carbon (AC) as the catalyst for removal of phenol from wastewater in a rotating packed bed (RPB), and the effects of high-gravity factor, inlet O₃ concentration, liquid–gas ratio, and initial pH on the degradation and mineralization of phenol at room temperature are investigated. It is revealed that the degradation rate of phenol reaches 100% at 10 min and the removal rate of total organic carbon (TOC) reaches 91% at 40 min under the conditions of high-gravity factor β = 40, inlet O₃ concentration = 90 mg·L⁻¹, liquid flow rate = 80 L·h⁻¹, and initial pH = 11. Compared with the bubbling reactor (BR)/O₃/AC and RPB/O₃ systems, the mineralization rate of phenol by the RPB/O₃/AC system is increased by 24.78% and 34.77%, respectively. Free radical quenching experiments are performed using tertiary butanol (TBA) and benzoquinone (BQ) as scavengers of ·OH and O₂⁻, respectively. It is shown that the degradation and mineralization of phenol are attributed to the direct ozonation and the indirect oxidation by ·OH generated from the decomposition of O₃ adsorbed on AC surface, respectively. ·OH and O₂·⁻ are also detected by electron paramagnetic resonance (EPR). Thus, it is concluded that AC-catalyzed ozonation and high-gravity technique have a synergistic effect on ·OH initiation, which in turn can significantly improve the degradation and mineralization of organic wastewater.

Heavy metal contamination plays a major role in water pollution. It needs remediation without raising the issues of secondary waste generation and their related issues. Heavy metal residues adversely affect soil and water quality. Their leachate would disturb the whole ecological system. It needs remediation to avoid the effect on soil and water. Azospirillium biofertilizer has the ability to reduce hazardous components without disturbing the growth of the plant. Hence, the use of low-cost biosorbent was proposed for heavy metal removal. The investigations showed excellent removal of heavy metals like copper (Cu) and chromium (Cr) using Azospirillium biofertilizer. These materials showed efficient removal of Cu and Cr at 94% and 70%, respectively. Separation was dependent upon the interaction between sorbent and sorbate, which makes separation tunable for the removal of the desired material from effluent or other streams. Parameter optimization like temperature, adsorbent dose, time, pH, and agitation speed was studied for both metals. At optimum parameters, Langmuir capacity was found to be 35.71 mg/g and 5.58 mg/g of copper and chromium. Experimental data was best fitted to Langmuir isotherm, and the pseudo-second-order kinetic model was suitable for the study of both metals.

The seasonal burning of crop residue significantly affects the environment, leading to poor air quality over Indo-Gangetic Plain (IGP) in India. Hence, there have been significant efforts to minimize crop residue burning through policy, innovations, and awareness measures. However, an abrupt increase in paddy residue burning was observed over IGP during 2020. Hence, the study explores the factors leading to this sharp rise. The business as usual trends analysis revealed that paddy crop residue burning activities increased significantly (60%) in 2020 compared to the previous year. The massive increase in crop residue burning consequently seems to be linked with the COVID-19 pandemic, which affected the farmer’s income, including the poor compliance by the regulatory authorities. The study also highlights the issues and prospects for sustainable crop residue management and explores the solutions to minimize crop residue burning. There are few crops in India that have guaranteed minimum sale price and are also subsidized. These provisions encourage farmers to grow those particular crops, resulting in the generation of large amounts of crop residue from these specific crops. There have been several efforts by the Indian government, including based on recent court intervention. Still, there is no respite from burning activities and the occurrence of Delhi winter smog every year. Hence, the study emphasizes a need to adopt integrated approaches having in situ eco-friendly solutions, which enhances the farmer’s income and focuses on employability, capacity building, awareness generation, and in situ economically viable solutions.

This paper presents the characterization of municipal solid waste (MSW) randomly collected from two material recovery facilities in São Paulo city, before (input — recyclables) and after (output — rejects) the sorting processes. Geo-environmental and geotechnical tests were performed on shredded samples and a digestion method was applied to detect the metals As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn concentrations using an ICP OES. The objective was to assist future activities of integrated solid waste management and soil pollution. Results showed different particle sizes comparing the input (44.6%) and the output MSW (75.1%) passing through the 100-mm sieve. Organic matter and ash contents indicated the influence of inorganic carbon due to the plastics’ presence, with values varying between 6 and 13%. The pH values obtained were neutral and the electrical conductivity of the MSW rejects suggested a higher amount of ions, with values above 1000 µS/cm. Metals analyses show that Cd, Cu, Ni, Pb, and Zn are present in high concentrations, depending on the types of the materials. Standard Proctor compaction curves yielded maximum dry unit weight varying from 6.6 to 10.0 kN/m³ and optimum moisture contents from 20 to 42%. Cohesion ranged from 1.3 to 31.3 kPa and friction angle from 3.2 to 42.9°. The results are comparable with those obtained for other countries using different MSW treatments and contribute to the data basis for MSW from the selective collection, aiming the integrated solid waste management, serving for other countries that adopt MSW sorting and recycling.

Heavy metal and metalloid pollution is a matter of concern in animal, human and environmental health (One Health) and also in wildlife conservation worldwide. Studying wild mammals in toxicology has been contributing significantly to our knowledge, namely to find out the most critical regions, to understand bioaccumulation and biomagnification phenomena or to evaluate their toxic effects. However, not all the animal tissues and organs provide the same information or should be interpreted in the same way. The best sample to use will depend on the objectives and conditions of the study. This review aims to compare invasive and non-invasive samples to biomonitor heavy metals, providing a brief resume of their advantages, limitations and examples of use. Further research, using a wider range of mammalian species, is required to establish what information can be obtained in biomonitoring studies that use non-invasive samples (such as hair, faeces and parasites) and/or invasive samples (such as blood, liver, kidney, bone and other organs).

The exploration of oil and gas contributes to green-house-gas. While exploring countries ensures economic growth, their activities also contribute to environmental pollution through carbon emissions. The 13-member states of the Organization of the Petroleum Exporting Countries (OPEC) are the world’s most important oil-producing and exporting countries. Since the safety of a country’s oil and gas resources is related to the country’s economic growth and environmental protection, this study aims at assessing the impact of oil and gas trading, foreign direct investment inflows, and economic growth on carbon emission for OPEC member countries. Using secondary data from 2000 to 2018, the authors utilized Stata and EViews statistical software for the empirical studies. The fully modified least squares (FMOLS) and the generalized methods of moments estimators were used for the multiple regression. The findings from the multiple regression analysis revealed a positive but statistically insignificant relationship between oil and gas export and carbon emissions. On the contrary, an inverse relationship that is statistically significant was found between foreign direct investment inflows and carbon emissions. Also, a positive and statistically significant relationship was found between economic growth and carbon emissions for OPEC member countries. The research findings contribute to previous literature on petroleum exploration activities and give clues to policy-makers and stakeholders in putting in measures to ensure economic growth while promoting environmental protection for OPEC member countries.

Prenatal and postnatal exposures to heavy metals have been suggested to interfere with neurodevelopment, but the neurotoxicity of lead (Pb), arsenic (As), and cadmium (Cd) is still unclear. In this study, we aimed to assess the associations between the levels of As, Cd, and Pb and children’s neurodevelopment. A total of 299 mother–infant pairs were recruited in this study and their meconium were collected. After three years, 53 children underwent the Bayley Scales of Infant and Toddler Development (Bayley-III) examinations and provided hair and fingernail specimens. The levels of As, Cd, and Pb in the meconium, hair, and fingernail were measured by inductively coupled plasma mass spectrometry; the median levels were the following: meconium, 42.7, 5.57, and 25.6 ng/g, respectively; hair, 0.19, 0.05, and 3.61 μg/g, respectively; and fingernail, 0.29, 0.04, and 0.84 μg/g, respectively. After adjusting for potential confounding factors, we found that the log-transformed levels of As in the hair samples was negatively associated with gross motor development (β = − 0.032; 95% confidence interval: − 0.061 to − 0.004). We conclude that postnatal exposure to As is a crucial period for gross motor development in children, while the effects of Cd and Pb on neurodevelopment are less clear.

A sectorial approach for assessing heavy metal pollution in rivers neglects the inter-relationship between its environmental compartments and thus fails to report realistic pollution status and associated ecological and human health risks. Therefore, a systems approach was adopted to assess heavy metal pollution and associated risks in the Yamuna River (Delhi, India), one of the world’s most polluted and populated river–city pairs. Sampling sites selected along the river with distinct land use were uncultivated natural floodplain vegetation, marshy area, invasive community, arable land, and human settlements. The multivariate analysis identified sources of pollutions (Pb, Cd, Cr, and Ni [anthropogenic]; Fe and Zn [geogenic]). Across the land use, a high log Kₚ value of Zn and Pb in water–soil phase than in water–sediment phase indicates their long-range transfer, whereas low log Kₚ (water–soil) of Cd suggests river sediments as its reservoirs. Comparison of pollution indices of Cd, Cr, and Pb in water, sediment, and soil across the land use suggested the role of vegetation in reducing pollution in the environment. Ecological risk also gets reduced progressively from water to sediment to the soil in naturally vegetated sites. Similarly, in river water, Cr, Cd, Ni, and Pb pose carcinogenic and non-carcinogenic risks to adults and children, which are also reduced in sediments and soil of different vegetation regimes. This study showed the eco-remediation services rendered by natural vegetation in reducing pollution and associated ecological and human health risks. To conclude, using a systems approach has significance in assessing pollution at the ecosystem level, and focusing on riverbank land use remains significant in developing methods to reduce pollution and ecological and human health risks for sustainable riverbank management.

The Mexican maquiladora industry is applying Lean Manufacturing Tools (LMT) in its production lines; however, few studies have investigated its relationship with sustainability (social, economic, and environmental). This paper presents a second-order structural equation model (SEM) relating 8 LMT integrated into three independent latent variables: continuous improvement (Kaizen and Gemba), supporting tools (Andon, visual management, and Poka-yoke), and machinery and equipment (total productive maintenance, overall equipment effectiveness, and Jidoka) that are related to social, economic, and environmental sustainability as dependent variables. The model is validated with information obtained from 249 companies using partial least squares. Findings show that the application of LMT in the Mexican maquiladora industry avoids the generation of waste and reprocessing. Likewise, the improvement of production processes reduces the waste emitted into the environment and reduces energy consumption. Also, when companies have environmental programs, the work environment is safe, and labor relations are improved, increasing morale and the commitment to work for the company, gaining economic and ecological benefits.

It is necessary to effectively separate photocatalytic materials from water bodies and reuse catalysts for industrial wastewater treatment. Herein, a novel nanofiber membrane with enhanced light absorption and reusability of photocatalytic materials was prepared. The three-dimensional porous structure of the nanofibers helps the photocatalyst efficiently degrade pollutants. Specifically, a high-efficiency photocatalyst carrier with a nanofiber structure (PAN/PU/β-CD@Ag nanofiber membrane) was prepared by electrospinning and a simple silver plating process, and then ZnO NPs were synthesized in situ on the nanofiber membrane during the hydrothermal process. Under visible-light irradiation, the ZnO-loaded PAN/PU/β-CD@Ag nanofiber membranes exhibited excellent photocatalytic performance for the degradation of methylene blue (MB, 71.5%) and tetracycline hydrochloride (TCH, 70.5%). Additionally, a possible pathway of charge migration in this system was proposed. This design may provide a new idea for the preparation of visible-light photocatalytic nanofiber membranes and their treatments of wastewater containing dyes and hormones.