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Are the existing guidelines sufficient for the assessment of bathing water quality? The example of Polish lakes Texte intégral
2021
Pronin, Eugeniusz
The safety of beachgoers and swimmers is determined by the presence or absence of microbial contaminants and cyanobacterial toxins in the water. This study compared the assessment of bathing waters according to the Bathing Water Directive, which is based on the concentration of fecal contaminants, with some modifications, and a new method based on the concentration of chlorophyll-a, which corresponds to the World Health Organization (WHO) guidelines used for determining cyanobacterial density in the water posing threat to people health. The results obtained from the method based on chlorophyll-a concentration clearly showed that the number of bathing waters in Poland with sufficient and insufficient quality were higher in 2018 and 2019, compared to the method based on microbial contamination. The closing of bathing waters based only on the visual confirmation of cyanobacterial blooms might not be enough to prevent the threat to swimmers’ health. The multivariate analyses applied in this study seem to confirm that chlorophyll-a concentration with associated cyanobacterial density might serve as an additional parameter for assessing the quality of bathing waters, and in the case of small water reservoirs, might indirectly inform about the conditions and changes in water ecosystems.
Afficher plus [+] Moins [-]Polycyclic aromatic hydrocarbons, pesticides, and metals in olive: analysis and probabilistic risk assessment Texte intégral
2021
Taghizadeh, Seyedeh Faezeh | Azizi, Majid | Rezaee, Ramin | Giesy, John P. | Karimi, Gholamreza
In the present study, levels of 22 pesticides, eight metals, and 16 polycyclic aromatic hydrocarbons (PAHs) in 1800 Iranian olive samples (20 cultivars from six different cultivation zones), were determined; then, health risk posed by oral consumption of the olive samples to Iranian consumers was assessed. Quantification of PAHs and pesticides was done by chromatography-mass spectrometry (GC-MS), and metal levels were determined using inductively coupled plasma-optical emission spectrometry (ICP-OES). There were no significant differences among the cultivars and zones in terms of the levels of the tested compounds. Target hazard quotients (THQ) were <1.0 for all pesticides, and total hazard indices (HI) indicated di minimis risk. At the 25th or 95th centiles, Incremental Life Time Cancer Risks (ILCRs) for carcinogenic elements, arsenic, and lead and noncarcinogenic metals did not exhibit a significant hazard (HI <1.0 for both cases). At the 25th or 95th centiles, ILCR and margins of exposure (MoE) for PAHs indicated di minimis risk. Sensitivity analysis showed that concentrations of contaminants had the most significant effect on carcinogenic and noncarcinogenic risks.
Afficher plus [+] Moins [-]Influence of polyethylene-microplastic on environmental behaviors of metals in soil Texte intégral
2021
Li, Ming | Wu, Dedong | Wu, Di | Guo, Hongliang | Han, Song
Microplastics (MPs) in terrestrial ecosystems have attracted increasing attention all over the world. The adsorption-desorption behavior and bioavailability of metals in soil would affect its toxicity to organisms. However, the influences of MPs on adsorption-desorption behavior between metals and soil as well as bioavailability of metals in soils are scarcely investigated. Herein, different percentage (0, 0.1%, 1%, 10%) of polyethylene-microplastic (PE-MP) were thoroughly mixed into the soil to investigate the impacts of PE-MP on adsorption-desorption and bioavailability of metals (Zn²⁺, Pb²⁺) in the soil. A series of characterization were carried out to determine the change of PE-MP before and after adsorption to investigate the mechanisms. When MP100 (average size: 129 μm) content in soil increased to 10%, the adsorption capacities of soil with Pb²⁺ and Zn²⁺ were 3.73 and 4.56 mg/g, respectively, which were significantly (p < 0.05) lower than that of pure soil. When MP300 (average size: 293 μm) content in soil increased to 10%, the extraction fraction of Zn²⁺ and Pb²⁺ from soil by diethylenetriaminepentaacetic acid reached 12.35% and 23.96%, respectively, which were significantly (p < 0.05) higher than that of pure soil, indicating high concentration (10%) of MPs in soil would decrease the adsorption capability of soil to metals and increase the mobility of metals in terrestrial environment. However, when MPs content in soil was 0.1%, the extraction fraction of Zn²⁺ and Pb²⁺ showed no significant difference with that of pure soil, indicating that actual MPs in soil is unlikely to bring significant influence on metal bioavailability.
Afficher plus [+] Moins [-]Where is the gray side of green growth? Theoretical insights, policy directions, and evidence from a multidimensional approach [Erratum: December 2021, v.28(45), p.63931-63932] Texte intégral
2021
Demiral, Mehmet | Demiral, Ozge
Addressing the geographical relocation of the pollution-intensive gray side of low-carbon green production, our study analyzes potential determinants of green and gray growth performance of industrialized/developed countries (IDCs) and industrializing/emerging economies (IEEs) over the 1996–2015 period. We define green growth by low-carbon output, while we link gray growth to comparative advantages of pollution havens. Green and gray growth models include such predictors as domestic income and foreign direct investment (FDI) together with composite indices for globalization, environmental policy stringency (EPS), industrialization, and control of corruption. Considering non-stationarity, cross-section dependency, endogeneity, and heterogeneity concerns, we employ bootstrap and residual-based cointegration analyses followed by long-run estimations using the Common Correlated Effects Mean Group (CCEMG) and Dynamic Ordinary Least Squares (DOLS) estimators and causality examination through Dumitrescu-Hurlin and Emirmahmutoglu-Kose tests. The key findings of the study are as follows: (i) income is positively associated with green growth for both IEEs and IDCs, whereas the income-gray growth nexus is negative for IEEs. (ii) Although inward FDI stocks are positively related to green and gray growth of IEEs and outward FDI stocks are negatively associated with green and gray growth of IDCs, these relationships are mediated by EPS. (iii) Globalization encourages both green and gray growth for IDCs. (iv) Even though EPS inhibits green growth and encourage gray growth in IEEs, these direct effects widely depend on the indirect effects of control of corruption. (v) IEEs’ higher gray growth performance is substantially explained by their increased industrial competitiveness, whereas the link is negative for IDCs. (vi) Control of corruption fosters both green and gray growth in IEEs. Overall, “growing gray” does not necessarily mean “not growing green” and vice versa. Globally, the low-carbon benefits of greening countries may be counterbalanced by the environmental costs of graying economies. From a policy perspective, IEEs need to reinforce environmental policies by green efficiency, green industrialization, and anti-corruption plans to decouple economic growth from carbon dioxide emissions.
Afficher plus [+] Moins [-]Pilot-scale microaerobic hydrolysis-acidification and anoxic-oxic processes for the treatment of petrochemical wastewater Texte intégral
2021
Chu, Libing | Ding, Pengyuan | Ding, Mingcong
Microaerobic hydrolysis and acidification (MHA), as a promising pre-treatment method of industrial wastewater, is drawing increasing attention to enhance the hydrolysis-acidification rate and inhibit the production of toxic gas H₂S. In the present work, a pilot-scale MHA reactor coupled with anoxic-oxic (A/O) processes for treating the petrochemical wastewater was established and the mechanism and application of the MHA reaction were explored. The results showed that the ratio of VFA/COD was increased by 43–90% and low effluent S²⁻ concentration (less than 0.2 mg/L) was obtained after MHA treatment with 5.5–13.8 L air m⁻³ h⁻¹ supply. The MHA sludge exhibited a good settleability, a higher protease activity and plentiful community diversity. In addition to the dominant anaerobic bacteria responsible for hydrolysis and acidification such as Clostridiales uncultured, Anaerovorax, Anaerolineaceae uncultured and Fastidiosipila, the sulfate reducing bacteria involving Desulfobacter, Desulfomicrobium and Desulfobulbus, the sulphur oxidizing bacteria involving Thiobacillus, Arcobacter and Limnobacter, the nitrifies such as Nitrosomonadaceae uncultured and Nitrospira, and denitrifies Thauera were also identified. MHA pre-treatment guaranteed the efficacy and stability of the following A/O treatment. The removal efficiency of COD and ammonium of the MHA-A/O system remained at around 78.3% and 80.8%, respectively, although the organic load fluctuated greatly in the influent.
Afficher plus [+] Moins [-]The adverse effects of the phenylpyrazole, fipronil, on juvenile white shrimp Litopenaeus setiferus Texte intégral
2021
Al-Badran, Ali Abdulameer | Fujiwara, Masami | Mora, Miguel A. | Gatlin, Delbert M. III
Chemical pesticides are commonly used world-wide, and they can flow into estuaries and affect non-targeted organisms. We evaluated the effects of six concentrations of the phenylpyrazole, fipronil (0.0, 0.005, 0.01, 0.1, 1.0, and 3.0 μg/L), which are environmentally relevant, on white shrimp Litopenaeus setiferus (initially averaging 0.80 ± 0.08 g/shrimp). Compared with the control, survivorship of shrimp over 45 days declined significantly at the higher concentration treatments. Growth was affected at all concentrations, and the percent weight gain decreased significantly. Inter-molt intervals were longer in all treatments. Changes in swimming and feeding behavior of shrimp were observed under all treatments, and change in body color was observed at higher concentration treatments. Lipid content in shrimp decreased significantly while ash content increased with fipronil concentration. Fipronil adversely affected white shrimp under the concentrations observed in the environment and monitoring of fipronil use is needed in coastal areas.
Afficher plus [+] Moins [-]Reductions of migrant population reduces the number of COVID-19 epidemic: a case study in China Texte intégral
2021
Han, Lizhen | Jia, Jinzhu
The novel coronavirus disease (COVID-19) broke out worldwide in 2020. The purpose of this paper was to find out the impact of migrant population on the epidemic, aiming to provide data support and suggestions for control measures in various epidemic areas. Generalized additive model was utilized to model the relationship between migrant population and the cumulative number of confirmed cases of COVID-19. The difference of spatial distribution was analyzed through spatial autocorrelation and hot spot analysis. Generalized additive model demonstrated that the cumulative number of confirmed cases was positively correlated with migration index and population density. The predictive results showed that, if no travel restrictions are imposed on the migrant population as usual, this number of COVID-19 would have reached 27,483 (95% CI 16,074, 48,097; the actual number was 23,177). The increase in one city (Jian) would be 577.23% (95% CI 322.73%, 972.73%) compared with the real confirmed cases of COVID-19. The average increase in 73 cities was 85.53% (95% CI 19.53%, 189.81%). Among the migration destinations, the number of cases in cities of Hubei province, Chongqing, and Beijing was relatively high, and there were large-scale high-prevalence clusters in eastern Hubei province. Without restrictions on migration, the high prevalence areas in Hubei province and its surrounding areas will be further expanded. The reduced population mobility and population density can greatly slow down the spread of the epidemic. All epidemic areas should suspend the transportation between cities, strictly control the population travel, and decrease the population density, so as to reduce the spread of COVID-19.
Afficher plus [+] Moins [-]Exploring the influence of contributing factors and impact degree on bus emissions in real-world conditions Texte intégral
2021
Wang, Chao | Ye, Zhirui | Bi, Hui
Buses in urban have environmental problems because they are mostly having higher emission factors and pollution levels. This study analyzed the contributing factors on bus emissions including NOX, CO, HC, and CO₂ and further evaluated the impact degree of these factors. A back-propagation neural network (BPNN) was applied, and the results showed that the composition of pollutant emissions for different fuel types was various. BPNN can be utilized to solve the multifactor, uncertainty, and nonlinearity problems without making any prior presumptions about the data distribution. Among them, diesel buses under EURO-IV and EURO-V emission standards were more likely to produce higher emissions of CO and NOX. By contrast, the emission level of CO and NOX for compressed natural gas bus was lower, but the emission level of CO₂ and HC was heavier. In this study, nine variables, namely, speed, acceleration, passenger load, past speed, past acceleration, acceleration time, delay time, stops, and location were selected to investigate their effects on bus emissions. The results showed that factors delay time, location, and stops had the strongest impacts on bus emissions. By contrast, bus emissions were not sensitive to past speed and passenger load. In addition, to fully understand the influence of contributing factors, the impact degree of all these factors on bus emissions was summarized in this study.
Afficher plus [+] Moins [-]Effects of substrates containing different concentrations of sewage sludge on physiological parameters and quality of Alibertia edulis (Rubiaceae) seedlings Texte intégral
2021
da Silva Santos, Jaqueline | da Silva Pontes, Montcharles | dos Santos Nobrega, Michele Aparecida | Santiago, Etenaldo Felipe
Sewage sludge (SS), a solid residue of effluent treatment, is rich in organic matter and nutrients, while also containing heavy metals and other potential contaminants. The feasibility of employing SS as a substrate component for seedling production depends on its composition and dose, as well as on the tolerance limit of individual plant species. To expand the knowledge base on the use of SS in the production of plants native to the Brazilian Cerrado biome, we evaluated the physiological responses and quality of Alibertia edulis seedlings grown under distinct SS concentrations. Chlorophyll a fluorescence (ChlF), stomatal conductance (gs), leaf temperature (Lt), biomass, growth, and seedling quality were investigated. At 25%, SS improved growth, biomass, and seedling quality, while substrates containing 50% or more SS affected gs, Lt, and ChlF. Seedling quality was strongly worsened by SS at 75% and 100%, as shown by lower biomass and impaired growth, including leaf symmetry loss and leaf deformities possibly related to contaminants, particularly heavy metals. Accordingly, we conclude that SS exhibited potential as a fertilizer at concentrations below 50%, but exerted a toxic effect on seedlings at higher concentrations.
Afficher plus [+] Moins [-]Reuse of waste tyre products as a soil reinforcing material: a critical review Texte intégral
2021
Mistry, Mohit K. | Shukla, Shruti J. | Solanki, Chandresh H.
All over the globe, the generation of industrial waste has been increased due to the increasing demand for modern civilisation. In the developing countries like India, it is growing vigorously which eventually increases the production of vehicles and results in the more number of waste tyres. Despite the dumping such hazardous waste in landfills, stockpiling, and burning, their feasible utilisation in the modification of soil and concrete can be a good alternative option for their disposal. This paper enlightens the published work carried out by various researchers to enhance the mechanical properties of clayey soil using various forms of waste tyres. The effects of different forms of waste tyres on consistency limits, compaction characteristics, strength characteristics, compressibility characteristics, permeability and California-bearing ratio of cohesive soils have been reviewed. The review results show that the use of waste tyre products in ground improvement can be an economical solution for the construction industries and optimistic future as its disposal option. Still, further investigations and more research studies are required to consolidate the remarks drawn by the past researchers for its utilisation in the construction of highway/railway embankments and other field applications.
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