International Journal of Environmental Research最新文献

Environmental regulations can effectively mitigate environmental degradation, yet their impact on energy efficiency remains unclear. This study contributes to the existing literature by examining how the Environmental Protection Tax Law (EPTL) drives energy efficiency and demonstrating its environmental and economic dividends. Empirical evidence from a dataset of 271 Chinese prefecture-level cities from 2011 to 2020 reveals that EPTL significantly enhances energy efficiency by 3.8%, and it has a positive spatial spillover effect. The underlying mechanisms are improvements in environmental governance and economic development. Heterogeneity analysis highlights a particularly prominent positive impact in the eastern and western regions. Our study confirms the effectiveness of EPTL in promoting energy efficiency and supports the double dividend hypothesis, providing policymakers with insights for formulating differentiated policies.

Micro and nano plastics (MNPs) have emerged as significant environmental pollutants globally, with numerous research findings extensively addressing the environmental and biohazards resulting from the bioavailability of contaminants. Rice, serving as the staple carbohydrate source for more than half of the global population, demands a concrete understanding of MNPs' toxicity in rice plants. However, the literature pertaining to the impact of MNPs on rice plant growth and development is limited and the future research scope related to MNPs exposure in rice plants is poorly defined. Thus, this review aims to synthesize current research findings regarding MNPs exposure in rice plants and identify existing research gaps. Furthermore, this review article comprehensively discusses up-to-date findings on various impacts on rice plant growth and development, covering key areas such as morphological, biochemical, physiological, metabolic, molecular, and microbial alterations. In addition, it explores MNP sources, uptake and translocation mechanisms, potential health risks, and available remedial approaches to alleviate MNPs bioavailability in rice plants. The review concludes that addressing the current research gaps related to MNPs in paddy fields requires further studies in the future. This would contribute to a more comprehensive understanding of the impact of MNPs on rice plants and aid in developing effective mitigation strategies.

Arsenic in drinking water threatens public health worldwide. Phytoremediation has brought new vitality to solve this problem. The aim of this work was to study the role of emergent macrophyte sweet flag (Acorus calamus L.) in phytoremediation of arsenate [As(V)] and arsenite [As(III)] from polluted water. For that, the methods of analytic chemistry and physiology were used. The results showed that As(III) could be removed by A. calamus more efficiently than As(V). The removal efficiencies of As(V) and As(III) both reached more than 95%. In As(V)- and As(III)-exposed A. calamus, the arsenic contents were much higher in root than in stem and leaf. The translocation factors of As(V) and As(III) were no more than 0.152. Both As(V) and As(III) were found in the whole plant, whereas dimethylarsinic acid (DMA, 0.06‒0.13 mg kg^‒1) was only present in the aboveground part. As(V) was the main species in the As(V)-exposed plants (45.86–70.21%). As(III) was the main species in stem and leaf of As(III)-exposed plants (55.76–85.52%), while As(V) was still dominant in root. A. calamus could keep its green leaves during the 31 days of inorganic arsenic (iAs) exposure. However, iAs had a little inhibitory effect on biomass accumulation, and high-concentration iAs was beneficial to promote root growth. The concentrations of malondialdehyde (MDA) and hydrogen peroxide (H₂O₂), as well as the activity of catalase (CAT) were significantly higher in root than those in stem and leaf. The oxidative stress response of A. calamus to As(III) was more than that to As(V). The findings of this study indicated that A. calamus was regarded as a promising material for the phytoremediation of arsenic from water.

Due to imperfect environmental regulation system, developing countries may be treated as “Pollution Havens” by firms from developed countries, imposing impacts on the local and even global environment. Thus, this paper examines the following questions at the country and city levels, respectively: First, whether China’s environmental regulation system (i.e., government and civil environmental regulations) has an impact on the M&A location choices of developed-country acquirers and what the moderating role will the acquirers’ carbon risks play. Second, whether the carbon risks of acquirers from developed countries entering China have an impact on carbon emissions in target regions and what moderating role will the environmental regulation system in the target regions play. By collecting 810 M&A deals from 2002 to 2021 in BvD_Zephyr database and conducting empirical analysis based on logistic, time series, and panel fixed effect regressions, we find that: first, environmental regulations at the country level often have a greater deterrent effect than those at the city level. Second, environmental regulations in China suffer from the problem of a “top down” system, i.e., although government environmental regulations have many measures and thus a high deterrent effect, the effects of civil environmental regulations are poor. Third, attracting foreign investment may help reduce carbon emissions.

Abstract

Eutrophication of fresh waterbodies is a global phenomenon that is exacerbated by increases in agricultural activities, industrialization, and urbanization, all driven by the global increase in human population. This paper reviews the state of inland waterbodies in South Africa, identifying the major drivers of eutrophication and discussing how different sectors of the economy are negatively impacted by eutrophication. Data indicate that up to 76% of major water impoundments and approximately 70% of major river systems are eutrophic to hypereutrophic and experience protracted periods of cyanobacterial blooms, particularly in the summer months. Negative impacts of eutrophication on the agricultural sector, potable water supply and tourism are well documented and are becoming more explicit. Evidently, nutrient loading patterns into water bodies have changed and become more complex. Although wastewater treatment plants remain the major contributors of nutrient loads to most waterbodies, non-point sources including agricultural runoff, untreated sewage from leaking and overflowing sewer systems, as well as runoff from informal settlements, also make substantial contributions. As a result, the strategies employed to prevent eutrophication, including within-waterbody remediation programs have fallen short in reducing the trophic status of water impoundments and thus ameliorating the symptoms of eutrophication. Tailor-made, integrated management initiatives that target point source, non-point source, and internal nutrient loads are, therefore, required.

Salinity and drought stress pose critical challenges to crop productivity, including roselle (Hibiscus sabdariffa L.). Using waste agriculture as a natural source of fertilizer to promote the activity of beneficial soil microorganisms has the potential to help agriculture in abiotic stress-affected areas by increasing plant nutrient uptake and ecological sustainability. We investigate the ability of BioSoy⁺ biofertilizer, which contains salt and drought stress-tolerant plant-growth-promoting rhizobacteria (PGPR) and soybean meal, to improve roselle growth under unfavorable conditions. Rhizobacteria tolerant to salt and drought stress were isolated, and evaluated for growth-promoting traits and pathogen inhibition under stress, and their identity confirmed by 16s rRNA gene sequencing. The impact of BioSoy⁺ on roselle growth and soil stability index during salt and drought stress was evaluated. Salt- and drought-tolerant PGPR strains Pseudomonas nicosulfuronedens AP01 and Bacillus velezensis CC03 were identified as the major component for biofertilizers. Under 2% NaCl stress, Pseudomonas nicosulfuronedens AP01 displayed outstanding phosphate solubilization and robust Sclerotium rolfsii pathogen suppression. BioSoy⁺ biofertilizer application significantly enhanced roselle growth under salt and water-limited conditions. BioSoy⁺ treatment, for example, boosted biomass by 194.74% and 68.29% at 25% field capacity and 100 mM NaCl conditions, respectively. BioSoy⁺ also increased relative water content, microbial activity, proline accumulation, and chlorophyll content, indicating stress reduction and better photosynthetic efficiency. This study highlights the importance of PGPR in alleviating the negative impacts of salt and drought stress. Furthermore, it emphasizes the feasibility of soybean meal as a biofertilizer carrier, fostering sustainable agricultural practices.

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Abstract

This article presents a method for evaluating the environmental benefits of implementing Product-Service Systems (PSSs) and Smart PSS with application to the heating systems field. The proposed PSS-oriented life cycle assessment method aims at addressing the specificities of PSS and Smart PSS, representing PSS variety and dealing with uncertainty sources resulting from the PSS context. Besides environmental analysis, the method supports decision-making by comparing different PSS scenarios. This study focuses on the challenges of a generic configuration of the life cycle assessment method and the rigorous handling of uncertainty sources, while an industrial case study reports a real case of PSS design decision-making.

Abstract

Ecological concrete has excellent water and air permeability, which not only is conducive to plant growth but also allows surface water to infiltrate underground and intercept pollutants. The performance of ecological concrete is largely determined by the nature of the raw materials and their relative content. Therefore, mastering the optimal design method for the mix proportion of ecological concrete is crucial to achieving good performance. In the current research, there is a lack of systematic intelligent decision-making models for predicting performance and optimizing mix proportions. In this paper, four factors, namely mechanical properties, water permeability, decontamination properties, and planting properties of ecological concrete, were considered when evaluating the comprehensive performance of ecological concrete. The evaluation was conducted using the analytic hierarchy process (AHP). The gray wolf optimizer (GWO) was introduced to enhance the backpropagation (BP) neural network, and an optimization model for finding the optimal ecological concrete mix proportion was established. The optimal mix proportion of two types of typical ecological concrete, one for filtration and one for plant growth, was discussed. The results indicate that the AHP-GWO-BP model calculates the optimal mixing proportion of filtration ecological concrete as follows: The diameter of coarse aggregate is 10–15 mm, with adsorbed coarse aggregate accounting for 49.7%, a component ratio is 118%, the water–cement ratio should be 28.7%, and the silica fume mix ratio should be 32.1%. According to the given parameters, the performance test of ecological concrete is conducted, with a coarse aggregate size of 12 mm. The results showed that under these parameters, the compressive strength was 12.3 MPa, the flexural strength was 3.35 MPa, the water permeability coefficient was 14.87 cm s⁻¹, the porosity was 27.23%, the removal rate of total nitrogen was 80.56%, the removal rate of total phosphorus was 67.33%, the pH was 9.16, and the plant dry weight was 9.37 g. The optimal mix proportion of the planting ecological concrete is as follows: The diameter of the coarse aggregate is 20–25 mm, the adsorbed coarse aggregate accounts for 49.7%, its component ratio is 138%, the water–cement ratio should be 27.3%, and the silica fume mix ratio should be 34.1%.

One of the basic strategies to reduce vulnerability in social systems facing fluctuations or climate change is to increase the resilience of communities to the disturbance and turmoil created in ecological systems. The aim of this study was to investigate multi-level resilience based on social heterogeneity under climate fluctuations in Nodooshan watershed of Yazd province. The survey method and the questionnaire were used to determine the resilience of local beneficiaries. The sample size was calculated using the Cochran sampling formula, and 102 people were selected by random sampling method from 6 villages in Nodooshan watershed. In order to determine the degree of resilience of users in Nodooshan watershed, social network analysis (SNA) was used by the full network method in three ties of social capital (trust, collaboration, and information exchange). The result of the highest effect size in the collaboration network of Nodoushan watershed beneficiaries is 57.75, in the trust network is 45.41 and in the information exchange network is 44.17. Findings show that social capital has led to more resilience of beneficiaries in drought conditions, and the rate of resilience in villages that are more exposed to drought is higher than in villages less exposed to drought. However, the results, in general, show the unfavorable situation of beneficiaries in terms of social capital. In addition, the effect of social network metrics on resilience in the face of climate change in different layers of social heterogeneity, as well as the structure of the exploitation system, is distinct. As a result, developing trust-building programs that address priority issues, resolving people's conflicts through increased and established inter-sectoral communication, and implementing multilevel governance are strongly advised. Therefore, by exploiting these results, planners and policymakers can help and plan to improve the resilience of rural communities faced with drought, self-reliance, and rural development.

Partial nitritation is a promising technology for wastewater treatment systems and, in symbiosis with other nitrogen removal approaches (i.e., Anammox bacteria), is attractive for reducing costs compared to conventional technologies. However, the intrinsic problems related to the different characteristics of the effluent induce unstable process conditions, including the subsequent accumulation of nitrate, which also reduces the partial yield of nitritation. Several studies highlight the persistent obstacles in preventing nitrate accumulation by nitrite-oxidizing bacteria, identified as the main challenge in the partial nitritation process. Consequently, this study conducted a comprehensive literature review, exploring various strategies to overcome these bottlenecks. Addressing the suppression of ammonia-oxidizing bacteria and the inhibition of nitrite-oxidizing bacteria involved consideration of operational strategy. Notably, pH emerged as an essential factor affecting microbial activity and process stability, influencing the efficiency of biochemical reactions. In addition, other interferents, such as organic compounds and metals, can influence the health and activity of microorganisms, affecting the overall effectiveness of the nitrogen removal process. The systematic control of various environmental and operational variables is essential for the stability of the process, demonstrating that a single strategy does not define the control of partial nitritation in wastewater. To date, maintaining dissolved oxygen in the range of 0.4 to 1 mg O₂ L⁻¹ and temperatures between 25 and 35 °C remains the most viable strategy for promoting stable partial nitritation. Finally, it is imperative to carry out further studies to develop control strategies and technologies, guaranteeing the efficiency of large-scale nitrogen removal systems and maintaining environmental safety standards.