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Effect of oil pollution on the ecological condition of soils and bottom sediments of the arctic region (Yakutia)
2021
Lifshits, Sara | Glyaznetsova, Yuliya | Erofeevskaya, Larisa | Chalaya, Olga | Zueva, Iraida
Oil and petroleum products are known to be among the most widespread soil pollutants. The risk of emergencies is sure to increase greatly in conditions of abnormally low temperatures. Oil and oil products are not only toxic to the environment, but can also have a negative impact on the state of the permafrost zone, accelerating the processes of permafrost degradation. The goal of the research was to study the soils and bottom sediments for oil pollution in the Arctic region of Yakutia. The research was carried out with using the complex of geochemical and microbiological methods of analysis. It had shown that at present oil pollution was mainly concentrated on the objects bearing a high technogenic load. However, some migration of hydrocarbons was observed with melt, seasonal melt and rainwaters, as a result of which the natural background of the nearby territories became technogenic character. In the Arctic conditions for the first time according to the obtained data on geochemical and microbiological studies oxidative destruction of oil pollutants in soil occurred mainly under the influence of physic and chemical environmental factors, not by microbial oxidation. Sluggish processes of mineralization of organic residues and the transformation of oil pollutants by the type of putrefaction led to the colonization of oil-polluted soils of the Arctic with putrefying and pathogenic microorganisms. The purpose of further research will be studying the possibility of intensification of soil remediation processes of technologically disturbed soils at abnormally low temperatures.
Afficher plus [+] Moins [-]Preparation of biochar-interpenetrated iron-alginate hydrogel as a pH-independent sorbent for removal of Cr(VI) and Pb(II)
2021
Zhao, Chenhao | Hu, Linlin | Zhang, Changai | Wang, Shengsen | Wang, Xiaozhi | Huo, Zhongyang
Herein, a pH-independent interpenetrating polymeric networks (Fe-SA-C) were fabricated from graphitic biochar (BC) and iron-alginate hydrogel (Fe-SA) for removal of Cr(VI) and Pb(II) in aqueous solution. Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and scanning electron microscope (SEM) results demonstrated that graphitic BC interpenetration increased surface porosity and distorted surfaces of Fe-SA, which boosted availability of hydroxyl (-OH) group. Fe³⁺ as a cross-linking agent of the alginate endowed Fe-SA-C with positive surfaces (positive zeta potential) and excellent pH buffering capacity, while excessive Fe³⁺ was soldered on Fe-SA-C matrix as FeO(OH) and Fe₂O₃. Cr(VI) removal at pH of 3 by Fe-SA-C (20.3 mg g⁻¹) were 30.3% and 410.6% greater than that by Fe-SA and BC, respectively. Fe-SA-C exhibited minor pH dependence over pH range of 2–7 towards Cr(VI) retention. Greater zeta potential of Fe-SA-C over Fe-SA conferred a better electrostatic attraction with Cr(VI). FTIR and XPS of spent sorbents confirmed the reduction accounted for 98.5% for Cr(VI) removal mainly due to participation of –OH. Cr(VI) reduction was further favored by conductive carbon matrix in Fe-SA-C, as evidenced by more negative Tafel corrosion potential. Reductively formed Cr(III) was subsequently complexed with carboxylic groups originating from oxidation of –OH. Thus, Cr(VI) removal invoked electrostatic attraction, reduction, and surface complexation mechanisms. Pb(II) removal with excellent pH independence was mainly ascribed to surface complexation and possible precipitation. Thus, the functionalized, conductive, and positively-charged Fe-SA-C extended its applicability for Cr(VI) and Pb(II) removal from aqueous solutions in a wide pH range. This research could expand the application of hydrogel materials for removal of both cationic and anionic heavy metals in solutions over an extended pH range.
Afficher plus [+] Moins [-]Stochastic optimisation of organic waste-to-resource value chain
2021
Robles, Ivan | Durkin, Alex | Guo, Miao
Organic fraction municipal solid waste (OFMSW) has a high potential for energy and value-added product recovery due to its carbon- and nutrient-rich composition; however, traditional value chains have treated OFMSW as an undesired by-product. This study focuses on value chain optimisation to assist the transition to resource recovery value chains. To achieve this, this work combined two stage stochastic mathematical optimisation with geographical spatial analysis and time series waste generation analysis. Existing infrastructure in England, including anaerobic digestion plants and road transportation networks, were included in the model. To account for uncertainty in waste generation, multiple scenarios and their associated probabilities were developed based on environmental variables. The optimisation problem was solved to further advance the understanding of economically optimal waste-to-resource value chains under waste generation variability. The pertinent decision variables included sizing, technology selection, waste flows and location of thermochemical treatment sites. The model highlights the potential reduction in system profitability as a result of different operating constraints, such as minimum plant operating capacity factors and landfill taxation. The latter was shown to have the largest impact on profitability as overconservative systems designs were implemented to hedge against the waste variability. Such computer-aided models offer opportunities to overcome the challenges posed by waste generation variability and waste to resource value chain transformation.
Afficher plus [+] Moins [-]A temporal record of microplastic pollution in Mediterranean seagrass soils
2021
Dahl, Martin | Bergman, Sanne | Björk, Mats | Diaz-Almela, Elena | Granberg, Maria | Gullström, Martin | Leiva-Dueñas, Carmen | Magnusson, Kerstin | Marco-Méndez, Candela | Piñeiro-Juncal, Nerea | Mateo Pérez, Miguel Ángel
Plastic pollution is emerging as a potential threat to the marine environment. In the current study, we selected seagrass meadows, known to efficiently trap organic and inorganic particles, to investigate the concentrations and dynamics of microplastics in their soil. We assessed microplastic contamination and accumulation in ²¹⁰Pb dated soil cores collected in Posidonia oceanica meadows at three locations along the Spanish Mediterranean coast, with two sites located in the Almería region (Agua Amarga and Roquetas) and one at Cabrera Island (Santa Maria). Almería is known for its intense agricultural industry with 30 000 ha of plastic-covered greenhouses, while the Cabrera Island is situated far from urban areas. Microplastics were extracted using enzymatic digestion and density separation. The particles were characterized by visual identification and with Fourier-transformed infrared (FTIR) spectroscopy, and related to soil age-depth chronologies. Our findings showed that the microplastic contamination and accumulation was negligible until the mid-1970s, after which plastic particles increased dramatically, with the highest concentrations of microplastic particles (MPP) found in the recent (since 2012) surface soil of Agua Amarga (3819 MPP kg⁻¹), followed by the top-most layers of the soil of the meadows in Roquetas (2173 kg⁻¹) and Santa Maria (68–362 kg⁻¹). The highest accumulation rate was seen in the Roquetas site (8832 MPP m⁻² yr⁻¹). The increase in microplastics in the seagrass soil was associated to land-use change following the intensification of the agricultural industry in the area, with a clear relationship between the development of the greenhouse industry in Almería and the concentration of microplastics in the historical soil record. This study shows a direct linkage between intense anthropogenic activity, an extensive use of plastics and high plastic contamination in coastal marine ecosystems such as seagrass meadows. We highlight the need of proper waste management to protect the coastal environment from continuous pollution.
Afficher plus [+] Moins [-]Assessment of the ability of roadside vegetation to remove particulate matter from the urban air
2021
Kończak, B. | Cempa, M. | Pierzchała, Ł | Deska, M.
The development of urbanised areas together with the growing transport infrastructure and traffic volume are the main cause of air quality deterioration due to the increasing concentrations of particulate matter. Dust pollution is a threat to human health. It can cause the development of lung, larynx or circulatory system cancer. Due to the ability to accumulate dust particles on the leaf surface, the contribution of trees in the process of phytoremediation of air pollution has started to be appreciated. An analysis of the elemental composition of particulate matter (PM) stored on the leaves surface was also carried out, which showed high average concentration of: C > O > Si > Fe (above 8wt.%). It was also observed single particles with a high concentration of heavy metals: Ti, Mn, Ba, Zn, Cr, Pb, Sn, Ni and REE (rare earth elements). The major origin of PM are vehicular emissions, soil and re-suspended road dust. This paper presents also a comparison of selected tree, shrub and vine species differing in their ability to accumulate particulate matter. It was experimentally determined the average leaf surface of individual plant species and established the amount of particulate matter with aerodynamic diameter between 10 and 100 μm, 2.5 and 10 μm, and 0.2 and 2.5 μm deposited on the leaf surface and in waxes.Some species of vines (Parthenocissus quinquefolia), shrubs (Forsythia x intermediata) and coniferous trees, such as Betula pendula ‘Youngii’, Quercus rubra, Cratageus monogyna, Acer pseduoplatanus, Tilia cordata Mill. or Platanus orientalis turned out to be the most efficient in the process of phylloremediation.
Afficher plus [+] Moins [-]Long-term exposure to particulate matter and roadway proximity with age at natural menopause in the Nurses’ Health Study II Cohort
2021
Li, Huichu | Hart, Jaime E. | Mahalingaiah, Shruthi | Nethery, Rachel C. | Bertone-Johnson, Elizabeth | Laden, Francine
Evidence has shown associations between air pollution and traffic-related exposure with accelerated aging, but no study to date has linked the exposure with age at natural menopause, an important indicator of reproductive aging. In this study, we sought to examine the associations of residential exposure to ambient particulate matter (PM) and distance to major roadways with age at natural menopause in the Nurses’ Health Study II (NHS II), a large, prospective female cohort in US. A total of 105,996 premenopausal participants in NHS II were included at age 40 and followed through 2015. Time-varying residential exposures to PM₁₀, PM₂.₅₋₁₀, and PM₂.₅ and distance to roads was estimated. We calculated hazard ratios (HR) and 95% confidence intervals (CIs) for natural menopause using Cox proportional hazard models adjusting for potential confounders and predictors of age at menopause. We also examined effect modification by region, smoking, body mass, physical activity, menstrual cycle length, and population density. There were 64,340 reports of natural menopause throughout 1,059,229 person-years of follow-up. In fully adjusted models, a 10 μg/m³ increase in the cumulative average exposure to PM₁₀ (HR: 1.02, 95% CI: 1.00, 1.04), PM₂.₅₋₁₀ (HR: 1.03, 95% CI: 1.00, 1.05), and PM₂.₅ (HR: 1.03, 95% CI: 1.00, 1.06) and living within 50 m to a major road at age 40 (HR: 1.03, 95%CI: 1.00, 1.06) were associated with slightly earlier menopause. No statistically significant effect modification was found, although the associations of PM were slightly stronger for women who lived in the West and for never smokers. To conclude, we found exposure to ambient PM and traffic in midlife was associated with slightly earlier onset of natural menopause. Our results support previous evidence that exposure to air pollution and traffic may accelerate reproductive aging.
Afficher plus [+] Moins [-]Deposition and mobilization of viruses in unsaturated porous media: Roles of different interfaces and straining
2021
Zhang, Wenjing | Wu, Shengyu | Qin, Yunqi | Li, Shuo | Lei, Liancheng | Sun, Simiao | Yang, Yuesuo
The vadose zone is the first natural layer preventing groundwater pollution. Understanding virus transport and retention in the vadose zone is necessary. The effects of different interfaces and mechanisms on virus transport and retention were investigated by studying Escherichia coli phage migration in laboratory-scale columns under unsaturated conditions. The E. coli phage was used as a model virus. Colloid filtration theory, extended Derjagin–Landau–Verwey–Overbeek theory and two−site kinetic deposition model were used to calculate fitted parameters and interaction energies to assess virus retention at different interfaces. The collector diameters and the size of E. coli phages in the influent and effluent were compared to assess the effect of straining. The results indicated that the roles of solid–water interfaces (SWIs) and air–water interfaces (AWIs) in retaining E. coli phages are strongly controlled by the moisture content and hydrochemical conditions. Decreasing the moisture content and increasing the ionic strength (IS) of the suspension increased E. coli phage retention. At suspension ISs of 0.01 or 0.03 M and various moisture contents, E. coli phages were mainly retained at the SWIs rather than AWIs. When the IS was increased to 0.06 M, the viruses were strongly retained by becoming attached to both SWIs and AWIs. The role of straining in virus retention could not be ignored. Viruses were retained more at the SWIs and less straining occurred under acidic conditions than under neutral or alkaline conditions. This was mainly because of the effects of the pH and IS on surface charges and the model virus particle size. This study has important implications for modeling and predicting virus transport in soil affected by rainfall, snowmelt, and human activities (e.g., irrigation and artificial groundwater recharging).
Afficher plus [+] Moins [-]Farmed tilapia as an exposure route to microcystins in Zaria-Nigeria: A seasonal investigation
2021
Chia, Mathias Ahii | Abdulwahab, Rabiu | Ameh, Ilu | Balogun, J Kolawole | Auta, Jehu
Several studies have reported the contamination of farmed fish by microcystins, however, alternations in levels of contamination resulting from seasonal changes are infrequently described. This investigation is focused on the seasonal accumulation of microcystins in farmed Nile Tilapia muscle tissue across three farms located in Zaria, Nigeria, as a means of assessing the health risks associated with the consumption of contaminated fish. Total microcystins and cyanobacteria content, respectively, in muscle tissue and gut of tilapia varied, seasonally in the farms. Microcystin levels were higher in fish tissues analyzed in the dry season than the rainy season at Nagoyi and Danlami ponds. Correlating with the levels of microcystins found in fish tissues, the highest dissolved microcystins levels in all the fish farms occurred in the dry season, where the Bal and Kol fish farm had the highest concentration (0.265 ± 0.038 μgL⁻¹). Gut analysis of fish obtained from the ponds, revealed a predominance of Microcystis spp. among other cyanobacteria. Estimation of total daily intake of consumed contaminated Nile tilapia muscles reveal values exceeding WHO recommended (0.04 μg kg⁻¹ body weight) total daily intake of MC-LR. Consumption of tilapia from Danlami pond presented the greatest risk with a value of 0.093 μg kg⁻¹ total daily intake. Results of the present study necessitate the implementation of legislation and monitoring programs for microcystins and other cyanobacteria contaminants of fish obtained from farms and other sources in Zaria and indeed several other African countries.
Afficher plus [+] Moins [-]HVAC filtration of particles and trace metals: Airborne measurements and the evaluation of quantitative filter forensics
2021
Mahdavi, Alireza | Dingle, Justin | Chan, Arthur W.H. | Siegel, Jeffrey A.
Filters installed in the heating, ventilation, and air-conditioning (HVAC) systems can serve as air-cleaning and sampling devices for indoor particles. The purpose of this article is to evaluate these dual roles. An occupied home with a central HVAC system equipped with a Minimum Efficiency Reporting Value (MERV, from ASHRAE Standard 52.2) 11 filter was monitored for six weeks. Weekly airborne gravimetric and real-time sampling was performed to measure the particle size distribution and the concentration of total suspended particles (TSP), PM₁₀, PM₂.₅, PM₁, and 12 trace metals. The weekly system runtimes were intentionally changed to provide a wide range of weekly filtration volumes. The quantitative filter forensics (QFF) concentrations of particulate matter (PM) and trace metals were calculated using the analysis of the dust collected on the HVAC filter, the filtration volume, and filter in-situ efficiency. The results indicated that filtration was not influential to remove PM and trace metals as the concentrations during the weeks with continuous HVAC operation were not consistently lower than those during the other weeks. This suggests the dominance of other particle and trace metal source and loss mechanisms weakens the influence of filtration in this home. The QFF evaluation results indicated that the concentration of TSP and over half of the tested trace metals (e.g., Pb, Cd, Ni, V, Sb, K, and Sr) could be estimated by QFF within a factor of two when compared to airborne sampling results. PM₁₀, PM₂.₅, and PM₁ concentrations were significantly underestimated by QFF potentially due to the limitations of size distribution analysis by a laser diffraction particle sizer (LDPS) for the detection of <1 μm particles. Overall, while QFF was promising for TSP and some trace metals, improvement in size distribution analysis could extend the application of QFF for airborne sampling.
Afficher plus [+] Moins [-]Differential mitochondrial dysregulation by exposure to individual organochlorine pesticides (OCPs) and their mixture in zebrafish embryos
2021
Lee, Hyojin | Ko, Eun | Shin, Sooim | Choi, Moonsung | Kim, Ki-Tae
Organochlorine pesticides (OCPs) have been reported to cause mitochondrial dysfunction. However, most studies reported its mitochondrial toxicity with respect to a single form, which is far from the environmentally relevant conditions. In this study, we exposed zebrafish embryos to five OCPs: chlordane, heptachlor, p,p’-dichlorodiphenyltrichloroethane (p,p’-DDT), β-hexachlorocyclohexane (β-HCH), and hexachlorobenzene (HCB), as well as an equal ratio mixture of these OCPs. We evaluated mitochondrial function, including oxygen consumption, the activity of mitochondrial complexes, antioxidant reactions, and expression of genes involved in mitochondrial metabolism. Oxygen consumption rate was reduced by exposure to chlordane, and β-HCH, linking to the increased activity of specific mitochondrial complex I and III, and decreased GSH level. We found that these mitochondrial dysfunctions were more significant in the exposure to the OCP mixture than the individual OCPs. On the mRNA transcription level, the individual OCPs mainly dysregulated the metabolic cycle (i.e., cs and acadm), whereas the OCP mixture disrupted the genes related to mitochondrial oxidative phosphorylation (i.e., sdha). Consequently, we demonstrate that the OCP mixture disrupts mitochondrial metabolism by a different molecular mechanism than the individual OCPs, which warrants further study to evaluate mitochondrial dysregulation by chronic exposure to the OCP mixture.
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