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Assessment of leaching risk of trace metals, PAHs and PCBs from a brownfield located in a flooding zone Texte intégral
2022
Seidl, Martin | Le Roux, Julien | Mazerolles, Rémi | Bousserrhine, Noureddine
An old industrial site (brownfield) located south of Paris in a flooding plain and containing demolition disposal as well as a burning zone for metal recovery is being regenerated to satisfy local need for public green space. The main objective of the described study was therefore to assess the risk of remobilisation of trace metals, PAH and PCB present. The research focused on vertical migration due to rainfall (non-saturated flow) and to river flooding (saturated flow). To assess the remobilisation risk, representative soil profiles were reconstituted and eluted in columns with artificial rain and filtered river water for 6 weeks with an equivalent of 25 mm d⁻¹. Soil analysis showed that both zones are highly contaminated, exceeding the French environmental standards. Though the superficial metal content was much higher in the burning zone with levels of g kg⁻¹ than that in the demolition zone, most metals showed higher levels in the eluents of the latter. The level of dissolved Zn in the burning zone eluent was 30 μg L⁻¹, while in the demolition zone, it was 300 μg L⁻¹, 40 times the admissible level. Zn was thereby correlated to aromaticity parameter HIX, indicating a link with organic matter transformation. The Cu was only significantly released under saturated condition (up to 80 μg L⁻¹) in the demolition soil, indicating as implicated mechanism manganese and iron oxide reduction rather than organic matter transformation. Despite the high PAH and PCB soil contents, these pollutants were not released. The total PAH content in the effluent was 30 ng L⁻¹ in average and did not significantly differ between the two zones and the types of hydrology. Only Zn and Cu issued from demolition zone presented an eco-toxicological risk. Crossed statistical analysis of the results showed that the role of the soil type is preponderant in the pollutant release and that temporary flooding condition would induce a lower impact on the groundwater quality than an equivalent amount of fallen rain. Though the burning site was far more contaminated in the upper soil than the demolition zone, it presented little risk compared to the demolition zone, more profound and more permeable. The latter showed therefore significative trace metal release, up to 2.1 kg ha⁻¹ year⁻¹ for zinc, doubling the local atmospheric deposition.
Afficher plus [+] Moins [-]The persistence of precious metals and oil during the COVID-19 pandemic: evidence from a fractional integration and cointegration approach Texte intégral
2022
Usman, Nuruddeen | Akadiri, Seyi Saint
In this paper, the behavior of precious metals and oil is examined using a fractionally integrated and cointegrated modeling approach. Using daily data from January 2015 to December 2020 and using both endogenous and exogenous structural breaks, we examine the behavior of the related series before and during the COVID-19 pandemic with the aim of investigating whether the degree of persistence has changed since the onset of COVID-19. We found that precious metals and oil exhibit long memory and are mean reverting regardless of the sample considered as the fractional parameter d < 0.5. However, when structural breaks are taken into consideration, an increase in persistence is found during the COVID-19 as compared to the period before it. In addition, the fractionally cointegrated vector autoregressive (FCVAR) model of Johansen and Nielsen (2010, 2012) is used to examine the existence of long-run relationship among precious metals and oil price. We find the integrated parameters at d < 0.5 for all samples except for the pre-COVID-19 sample. This highlights that the FCVAR is a better fit for the full sample and the COVID-19 and the COVID-19 pandemic period sub-samples, as the fractional parameter is d < 0.5 while the CVAR model is better fit for the pre-COVID-19 period where d> 0.5. Both cointegration techniques alongside the parameter stability tests lend support to the existence of a persistence and stable long-run relationships among the series irrespective of the sample period considered. Attendant policy recommendations for investors and policymakers are recommended.
Afficher plus [+] Moins [-]Separation of virgin plastic polymers and post-consumer mixed plastic waste by sinking-flotation technique Texte intégral
2022
Meneses Quelal, Washington Orlando | Velázquez Martí, Borja | Ferrer Gisbert, Andrés
The main objective of this research is to separate virgin polymers (PA, PC, PP, HDPE; PS, and ABS) and post-consumer plastic waste from municipal solid waste (MSW) using the sinking-flotation technique. Separation was carried out on a pilot scale in an 800-l useful volume container with 160 rpm agitation for one hour. Tap water, ethanol solutions, and sodium chloride at different concentrations were used as densification medium. Virgin polymers were separated into two groups: low-density (HDPE and PP) and high-density polymers groups (PS, ABS, PA, and PC). Polymers whose density was less than that of the medium solution floated to the surface, while those whose density was greater than those of the medium solution sank to the bottom. The experimental results showed that complete separation of HDPE from PP achieved 23% ethanol v/v, whereas high-density polymers separated up to 40% w/v sodium chloride. Polymer recovery ranged from 70 to 99.70%. In post-consumer recycled plastic waste, fractions of 29.6% polyolefins, 37.54% PS, 11% ABS, 8% PA, 12% PC PET, and PVC were obtained. Finally, cast plates were made of the post-consumer waste to properly identify the polymer type present in the separated fractions.
Afficher plus [+] Moins [-]Study of the memory effect of PCDD/F during the combustion of several biomasses in a moving grate boiler Texte intégral
2022
Baraket, Nada | Brandelet, Benoît | Trouvé, Gwenaëlle | Rogaume, Yann
The objective of this work was to study the influence of temperature on the PCDD/Fs behavior stored in biomass ashes issued from an automatic pilot-scale wood boiler. A mixture of these ashes with a dioxin mass ratio dry based of 5.9 μg kg⁻¹ was used for thermal treatment at temperatures ranging between 200 and 500°C. First tests were carried out in a macro thermogravimetric analysis instrument while a couple of other tests were carried out in a quartz-lined crossed fixed-bed reactor. These treated ashes were afterwards analyzed and their dioxin mass ratio was determined. Results obtained from these both experiments are radically different: ashes treated in macro-TGA contain 18 times more PCDD/Fs than the initial non-treated ashes while those from the reactor have 84% less of PCDD/Fs. Ninety-one percent of stored PCDD/Fs in the initial ashes were eliminated after 1h at 400°C in crossed fixed-bed reactor. Macro-TGA experiments are a representation of what happens during the shutdown and cooling phase of the boiler, some areas reaching temperatures for which the formation of PCDD/Fs is optimal. Without cleaning the boiler, a memory effect on further tests is observed.
Afficher plus [+] Moins [-]Water footprint and productivity in broilers and swine production in Brazil from 2008 to 2018 Texte intégral
2022
da Rosa, Gilmar Antônio | Broetto, Luiz F. | Demczuk, Thiago | Viancelli, Aline | Michelon, William
In many countries, the adverse impact of agriculture on water sources has been discussed with more attention recently by the water footprint estimation. Brazil is the second largest animal protein’ exporter, and this demand has a tendency to increase significantly until 2050, and in this context the water management will be crucial. Thus, the present study aimed to evaluate the water footprint and productivity in the broiler and swine slaughtered in Brazil from 2008 to 2018. The results showed that the herds of broiler and swine were concentrated in three main regions: Midwest, Southeast and South, representing 97.1% of the broilers and 99.7% of the swine slaughtered in Brazil. During the studied decade, the slaughter of broiler and swine increased 9.1 and 25.8%, respectively. The broiler and swine water footprint decreased by 15.4 and 3.5%, respectively. The average volume of water needed for the production of broiler and swine meat was 2533 L kg⁻¹ and 3754 L kg⁻¹, respectively. The average water productivity per kg of broiler meat was 0.397 kg m⁻³, while for swine it was 0.269 kg m⁻³. The average water productivity for soybean was 0.497 kg m⁻³, and for corn it was 1.18 kg m⁻³. The decrease in the water footprint is a result of the improvement of management practices, highlighting that it is necessary to improve the knowledge about the use of the water footprint methodology as a tool for water management to help public policies.
Afficher plus [+] Moins [-]Enantioselective hydrolysis and photolysis of mandipropamid in different aquatic environments — evaluation of influencing factors Texte intégral
2022
Li, Jianmin | Han, Jiahua | Lan, Tingting | Mu, Shiyin | Hu, Deyu | Zhang, Kankan
The hydrolysis and photolysis of the chiral fungicide mandipropamid were investigated, and the potential enantioselectivity of mandipropamid in solutions was further assessed. The aqueous solutions were filtered and directly injected into the liquid chromatography with tandem mass spectrometry. In the hydrolysis experiments, mandipropamid enantiomers hydrolyzed slowly in aquatic solutions with half-lives > 200 days; nevertheless, rise of the pH and incubation temperature could increase the hydrolysis rates more than 1.1 times (half-lives decreased from 495.1 to 216.6 days). Compared with the hydrolysis results, photolysis was found to be the main degradation pathway for mandipropamid in different solutions (half-lives < 14 h, except in pH = 5.05 buffer solution). Organic solvents were able to accelerate the photolysis of mandipropamid, but acidic solutions and the addition of flavonoids or inorganic salts significantly inhibited the photolysis of mandipropamid. During the hydrolysis and photolysis processes, the configuration of mandipropamid enantiomers was stable and five possible transformation products were identified by high resolution mass spectrometry. Due to the enantiomeric fraction values > 0.5, the hydrolysis and photolysis of mandipropamid were enantioselective, and S-(+)-mandipropamid preferentially disspated in certain aqueous solutions. The systematic evaluation of the hydrolysis and photolysis of mandipropamid enantiomers may provide more accurate data for better assessment of environmental and ecological risks in aquatic ecosystems.
Afficher plus [+] Moins [-]Microfiber shedding from nonwoven materials including wipes and meltblown nonwovens in air and water environments Texte intégral
2022
Kwon, Soojin | Zambrano, Marielis C. | Venditti, Richard A. | Frazier, Ryen | Zambrano, Franklin | Gonzalez, Ronalds W. | Pawlak, Joel J.
Nonwoven products are widely used in disposable products, such as wipes, diapers, and masks. Microfibers shed from these products in the aquatic and air environment have not been fully described. In the present study, 15 commercial single-use nonwoven products (wipes) and 16 meltblown nonwoven materials produced in a pilot plant were investigated regarding their microfiber generation in aquatic and air environments and compared to selected textile materials and paper tissue materials. Microfibers shed in water were studied using a Launder Ometer equipment (1–65 mg of microfibers per gram material), and microfibers shed in air were evaluated using a dusting testing machine that shakes a piece of the nonwoven back and forth (~ 4 mg of microfibers per gram material). The raw materials and bonding technologies affected the microfiber generation both in water and air conditions. When the commercial nonwovens contained less natural cellulosic fibers, less microfibers were generated. Bonding with hydroentangling and/or double bonding by two different bonding methods could improve the resistance to microfiber generation. Meltblown nonwoven fabrics generated fewer microfibers compared to the other commercial nonwovens studied here, and the manufacturing factors, such as DCD (die-to-collector distance) and air flow rate, affected the tendency of microfiber generation. The results suggest that it is possible to control the tendency of microfiber shedding through the choice of operating parameters during nonwoven manufacturing processes.
Afficher plus [+] Moins [-]Main and added effects of heatwaves on hospitalizations for mental and behavioral disorders in a tropical megacity of Vietnam Texte intégral
2022
Vietnam is highly vulnerable to climate change-related extreme weather events such as heatwaves. This study assesses the association between heatwaves and hospitalizations due to mental and behavioral disorders (MBDs) in Ho Chi Minh City (HCMC). We collected daily MBD hospital admissions data at the HCMC Mental Health Hospital from 2017 to 2019. Heatwaves effects were characterized into the main effect (i.e., the intensity of temperature during heatwaves) and the added effect (i.e., the duration of heatwaves). Time series Poisson regression coupled with a distributed lag linear model (DLM) was used to quantify the 14-day lags effect of heatwaves. Confounders including long-term trend, seasonality, days of the week, holidays, and relative humidity were included in the model. Heatwaves increased all-cause MBD hospitalization by 62% (95%Cl, 36–93%) for the main effect and by 8% (95% Cl, − 3% to 19%) for the added effect. Noticeably, the group aged 18–60 years old was affected by the main effect of the heatwave, while the group aged 61 years and older was affected by the added effect of the heatwave. The effects of heatwaves differed among groups of MBD hospitalizations. The mental and behavioral disorder group due to psychoactive substance use was significantly affected by the main effect of heatwaves (RR:2.21; 95%Cl:1.55–3.15). The group of schizophrenia, schizotypal and delusional disorders were highly vulnerable towards both the main and the added effect of heatwaves with RR = 1.50 (95%CI, 1.20–1.86) and RR = 1.14 (95%CI, 1.01–1.30), respectively.
Afficher plus [+] Moins [-]Biostimulants decreased nitrogen leaching and NH3 volatilization but increased N2O emission from plastic-shed greenhouse vegetable soil Texte intégral
2022
Biostimulant application is an effective strategy to enhance soil fertility and plant growth. However, its comprehensive impacts on nitrogen (N) uptake and reactive N (Nr) losses via leaching, ammonia (NH₃) volatilization, and nitrous oxide (N₂O) emission from plastic-shed greenhouse vegetable system are still little known. Therefore, a field experiment was conducted with cauliflower-tomato growth rotation (from September 6, 2018, to July 17, 2019) receiving three biostimulants, i.e., humic acid (HA), algae extract (AE), and chitosan (CT), as well as a control without stimulant. The cumulative Nr losses over the cauliflower-tomato growth cycle via leaching, NH₃ volatilization, and N₂O emission were 104–175 kg N ha–¹, 2.32–3.85 kg N ha–¹, and 0.70–0.85 kg N ha–¹, respectively. Biostimulant application significantly (P < 0.05) retarded the total N leaching by 17–44% in tomato season, while suppressed the NH₃ volatilization by 18–38% in cauliflower season. Overall, AE showed the best inhibition efficiency on Nr losses by significantly (P < 0.05) decreasing total N leaching and NH₃ volatilization by 36–44% and 38–52% in both vegetable seasons, compare to the control. However, all three biostimulants stimulated the N₂O emission under both vegetable cycles. Interestingly, all biostimulant-added treatments promote the cauliflower and tomato yield, particularly following the HA and AE amendments, which bring local farmers approximately 4,384–10,035 yuan RMB ha–¹ more income. Enhanced yield under biostimulant treatments was due to higher N uptake capacity and enhanced root morphology. In summary, biostimulants have a contrasting influence on three major Nr lost pathways in greenhouse vegetable production. We recommend that AE is the most optimal biostimulant as it increases vegetable yield and decreases total N leaching and NH₃ volatilization while not dramatically increase the N₂O emission.
Afficher plus [+] Moins [-]Integrating water quality index, GIS and multivariate statistical techniques towards a better understanding of drinking water quality Texte intégral
2022
Groundwater is considered as an imperative component of the accessible water assets across the world. Due to urbanization, industrialization and intensive farming practices, the groundwater resources have been exposed to large-scale depletion and quality degradation. The prime objective of this study was to evaluate the groundwater quality for drinking purposes in Mewat district of Haryana, India. For this purpose, twenty-five groundwater samples were collected from hand pumps and tube wells spread over the entire district. Samples were analyzed for pH, electrical conductivity (EC), total dissolved solids (TDS), total hardness (TH), turbidity, total alkalinity (TA), cations and anions in the laboratory using the standard methods. Two different water quality indices (weighted arithmetic water quality index and entropy weighted water quality index) were computed to characterize the groundwater quality of the study area. Ordinary Kriging technique was applied to generate spatial distribution map of the WQIs. Four semivariogram models, i.e. circular, spherical, exponential and Gaussian were used and found to be the best fit for analyzing the spatial variability in terms of weighted arithmetic index (GWQI) and entropy weighted water quality index (EWQI). Hierarchical cluster analysis (HCA), principal component analysis (PCA) and discriminant analysis (DA) were applied to provide additional scientific insights into the information content of the groundwater quality data available for this study. The interpretation of WQI analysis based on GWQI and EWQI reveals that 64% of the samples belong to the “poor” to “very poor” bracket. The result for the semivariogram modeling also shows that Gaussian model obtains the best fit for both EWQI and GWQI dataset. HCA classified 25 sampling locations into three main clusters of similar groundwater characteristics. DA validated these clusters and identified a total of three significant variables (pH, EC and Cl) by adopting stepwise method. The application of PCA resulted in three factors explaining 69.81% of the total variance. These factors reveal how processes like rock water interaction, urban waste discharge and mineral dissolution affect the groundwater quality.
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