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Leaching behavior of polycyclic aromatic hydrocarbons (PAHs) from oil-based residues of shale gas drill cuttings Full text
2021
Xie, Bingxin | Qin, Jihong | Sun, Hui | Wang, Shu | Li, Xin
Cuttings are the main solid residues which are generated from drilling operations. Due to the presence of heavy and radioactive elements, the environment risk posed by cuttings has attracted increasing attention. In this work, a short-term static immersion experiment was carried out to investigate the leaching of polycyclic aromatic hydrocarbons (PAHs) from oil-based residues of shale gas drilling cuttings. Furthermore, the effects of some relevant environmental factors controlling the leaching behavior were evaluated, including the different particle sizes, pH, extraction time, solid-to-liquid (S/L) ratio and dissolved organic matter (DOM) concentration. The results showed that (1) the concentrations of leached PAHs gradually increased with prolonged leaching time, but the cumulative amount of PAHs released during leaching was less than 3% of the total. (2) The Elovich, parabolic diffusion and power function models were found to fit the experimental data better than the first-order kinetic equation, indicating that the leaching of PAHs was controlled by the coupling of diffusion and chemical reactions at the source surface. (3) Different environmental factors had different impacts on the leaching of PAHs: the shaking time and presence of DOM increased leachability, the particle size and S/L ratio decreased leachability, and the pH did not affect the leachability of PAHs. Therefore, PAHs leaching was a complex process, and it is of scientific and environmental interest to conduct the leaching tests under the simulated environmental conditions.
Show more [+] Less [-]Effect of soil cadmium on root organic acid secretion by forage crops Full text
2021
Ubeynarayana, Nilusha | Jeyakumar, Paramsothy | Bishop, Peter | Pereira, Roberto Calvelo | Anderson, Christopher W.N.
The two forage species used in New Zealand pastoral agricultural systems, chicory (Cichorium intybus) and plantain (Plantago lanceolata) show differential ability to absorb and translocate cadmium (Cd) from roots to shoots. Chicory can accumulate Cd from even low Cd soils to levels that might exceed regulatory guidelines for Cd in fodder crops and food. Chicory and plantain were grown in soil-filled rhizocolumns under increasing Cd levels (0 (Control), 0.4, 0.8 and 1.6 mg Cd/kg soil) for 60 days and showed variable secretion of oxalic, fumaric, malic and acetic acids as a function of Cd treatment. Plant roots secrete such Low Molecular Weight Organic Acids into the rhizosphere soil, which can influence Cd uptake. Chicory showed significantly (P < 0.05) lower secretion of fumaric acid, and higher secretion of acetic acid than plantain at all Cd treatments. We propose that the significant secretion differences between the two species can explain the significantly (P < 0.05) higher shoot Cd concentration in chicory for all Cd treatments. Understanding the mechanism for increased uptake in chicory may lead to breeding or genetic modification which yield low Cd uptake cultivars needed to mitigate the risk of Cd accumulation in pastoral agricultural food chains from this increasingly important fodder crop.
Show more [+] Less [-]Arsenic behavior in soil-plant system and its detoxification mechanisms in plants: A review Full text
2021
Khan, Imran | Awan, Samrah Afzal | Rizwan, Muhammad | Ali, Shafaqat | Zhang, Xinquan | Huang, Linkai
Arsenic (As) is one of the most toxic and cancer-causing metals which is generally entered the food chain via intake of As contaminated water or food and harmed the life of living things especially human beings. Therefore, the reduction of As content in the food could be of great importance for healthy life. To reduce As contamination in the soil and food, the evaluation of plant-based As uptake and transportation mechanisms is critically needed. Different soil factors such as physical and chemical properties of soil, soil pH, As speciation, microbial abundance, soil phosphates, mineral nutrients, iron plaques and roots exudates effectively regulate the uptake and accumulation of As in different parts of plants. The detoxification mechanisms of As in plants depend upon aquaporins, membrane channels and different transporters that actively control the influx and efflux of As inside and outside of plant cells, respectively. The xylem loading is responsible for long-distance translocation of As and phloem loading involves in the partitioning of As into the grains. However, As detoxification mechanism based on the clear understandings of how As uptake, accumulations and translocation occur inside the plants and which factors participate to regulate these processes. Thus, in this review we emphasized the different soil factors and plant cell transporters that are critically responsible for As uptake, accumulation, translocation to different organs of plants to clearly understand the toxicity reasons in plants. This study could be helpful for further research to develop such strategies that may restrict As entry into plant cells and lead to high crop yield and safe food production.
Show more [+] Less [-]Citric acid-assisted phytoextraction of trace elements in composted municipal sludge by garden plants Full text
2021
Leng, Yaling | Lu, Minying | Li, Feili | Yang, Boxuan | Hu, Zhong-Ting
Sludge landscaping after compost stabilization is a popular recycling process; however, until trace elements (TEs) are extracted by plants and reduced to safe concentrations, they present a potential exposure risk. Three garden plants, Liriope platyphylla Wang et Tang (L. platyphylla), Iris tectorum Maxim (I. tectorum), and Photinia x fraseri Dress (P. x fraseri), were selected for field experiments, and their ability to phytoremediate TEs and the promotion effect of citric acid (CA) were studied over 3 months of observation. Among the three kinds of plants, L. platyphylla had the highest biomass per unit soil area, and the CA treatment further increased the biomass of this plant per unit soil area as well as the uptake of TEs. When treated with 3 mmol kg⁻¹ CA, L. platyphylla showed increases in the bioconcentration factors of Cu, Zn, Pb, and Cd by 24%, 63%, 27%, and 123%, respectively. Because of the large biomass and high concentrations of TEs, L. platyphylla had high phytoremediation indexes for Zn, Cu, Pb, Ni, and Cd, which reached 18.5, 3.7, 3.2, 2.2, and 0.4 mg m⁻², respectively, and were further improved by 60%–187% by the CA treatment. These advantages indicate the potential usefulness of L. platyphylla for phytoremediation. The results provide basic data and technical support for the use of sludge-based compost and phytoremediation by garden plants.
Show more [+] Less [-]Exposure to nanoplastics affects the outcome of infectious disease in phytoplankton Full text
2021
Schampera, Charlotte | Wolinska, Justyna | Bachelier, Julien B. | de Souza Machado, Anderson Abel | Rossal S., J. Roberto (Julio Roberto Rossal Salazar) | González-Pleiter, Miguel | Agha, Ramsy
Infectious diseases of humans and wildlife are increasing globally but the contribution of novel artificial anthropogenic entities such as nano-sized plastics to disease dynamics remains unknown. Despite mounting evidence for the adverse effects of nanoplastics (NPs) on single organisms, it is unclear whether and how they affect the interaction between species and thereby lead to ecological harm. In order to incorporate the impact of NP pollution into host-parasite-environment interactions captured in the “disease triangle”, we evaluated disease outcomes in the presence of polystyrene NP using an ecologically-relevant host-parasite system consisting of a common planktonic cyanobacterium and its fungal parasite. NP at high concentrations formed hetero-aggregates with phytoplankton and inhibited their growth. This coincided with a significant reduction in infection prevalence, highlighting the close interdependency of host and parasite fitness. Lower intensity of infection in the presence of NP indicates that reduced disease transmission results from the parasite’s diminished ability to establish new infections as NP formed aggregates around phytoplankton cells. We propose that NP aggregation on the host’s surface acts as a physical barrier to infection and, by reducing host light harvesting, may also hamper parasite chemotaxis. These results demonstrate that the consequences of NP pollution go well beyond toxic effects at the individual level and modulate the intensity of species interactions, thereby potentially eliciting diverse cascading effects on ecosystem functioning.
Show more [+] Less [-]Bisphenol F induces nonalcoholic fatty liver disease-like changes: Involvement of lysosome disorder in lipid droplet deposition Full text
2021
Wang, Jun | Yu, Pengfei | Xie, Xuexue | Wu, Linlin | Zhou, Manfei | Huan, Fei | Jiang, Lei | Gao, Rong
Epidemiological studies have demonstrated that the general population’s exposure to bisphenol A (BPA) substitutes is ubiquitous. Bisphenol F (BPF), one of the main BPA substitutes, is increasingly replacing BPA in plastics for food and beverage applications. Accumulating evidence suggests that BPA exposure is associated with nonalcoholic fatty liver disease (NAFLD)-like changes. However, the potential effects of BPF on lipid homeostasis remain poorly understood. In the present study, an epidemiological analysis with LC-MS-MS revealed that the BPF concentrations in the serum of NAFLD patients were significantly higher than those in a control group. Supporting this result, using Oil Red O, BODIPY 493/503, LipidTox Deep Red staining and gas chromatography-time-of-flight mass spectrometry (TOF-MS) assays, we found that BPF exposure induced NAFLD-like changes, with obvious lipid droplet deposition, triglyceride (TG) and fatty acids increase in mouse livers. Meanwhile, lipid droplet deposition and TG increase induced by BPF were also observed in HepG2 cells, accompanied by autophagic flux blockade, including autophagosome accumulation and the decreased degradation of SQSTM1/p62. Using adenoviruses dual-reporter plasmid RFP-GFP-LC3, RFP-GFP-PLIN2 transfection, AO staining, and EGFR degradation assays, we demonstrated that BPF treatment impaired lysosomal degradative capacity, since BPF treatment obviously impaired lysosomal acidification, manifested as decreased lysosomal hydrolase cathepsin L (CTSL) and mature cathepsin D (CTSD) in HepG2 and mouse liver issues. Additionally, v-ATPase D, a multi-subunit enzyme that mediates acidification of eukaryotic intracellular organelles, significantly decreased after BPF exposure in both the vitro and in vivo studies.This study ascertained a novel mechanism involving dysfunctional of lysosomal degradative capacity induced by BPF, which contributes to lipophagic disorders and causes lipid droplet deposition. This work provides evidence that lysosomes may be a target organelle where BPF exerts its potential toxicity; therefore, novel intervention strategies targeting lysosome are promising for BPF-induced NAFLD-like changes.
Show more [+] Less [-]Improving sustainability and mitigating environmental impacts of agro-biowaste compost fertilizer by pelletizing-drying Full text
2021
Sarlaki, Ehsan | Kermani, Ali Mashaallah | Kianmehr, Mohammad Hossein | Asefpour Vakilian, Keyvan | Hosseinzadeh-Bandbafha, Homa | Ma, Nyuk Ling | Aghbashlo, Mortaza | Tabatabaei, Meisam | Lam, Su Shiung
The use of agro-biowaste compost fertilizers in agriculture is beneficial from technical, financial, and environmental perspectives. Nevertheless, the physical, mechanical, and agronomical attributes of agro-biowaste compost fertilizers should be engineered to reduce their storage, handling, and utilization costs and environmental impacts. Pelletizing and drying are promising techniques to achieve these goals. In the present work, the effects of process parameters, including compost particle size/moisture content, pelletizing compression ratio, and drying air temperature/velocity, were investigated on the density, specific crushing energy, and moisture diffusion of agro-biowaste compost pellet. The Taguchi technique was applied to understand the effects of independent parameters on the output responses, while the optimal pellet properties were found using the iterative thresholding method. The soil and plant (sweet basil) response to the optimal biocompost pellet was experimentally evaluated. The farm application of the optimal pellet was also compared with the untreated agro-biowaste compost using the life cycle assessment approach to investigate the potential environmental impact mitigation of the pelletizing and drying processes. Generally, the compost moisture content was the most influential factor on the density and specific crushing energy of the dried pellet, while the moisture diffusion of the wet pellet during the drying process was significantly influenced by the pelletizing compression ratio. The density, specific crushing energy, and moisture diffusion of agro-biowaste compost pellet at the optimal conditions were 1242.49 kg/m³, 0.5054 MJ/t, and 8.2 × 10⁻⁸ m²/s, respectively. The optimal biocompost pellet could release 80% of its nitrogen content evenly over 98 days, while this value was 28 days for the chemical urea fertilizer. Besides, the optimal pellet could significantly improve the agronomical attributes of the sweet basil plant compared with the untreated biocompost. The applied strategy could collectively mitigate the weighted environmental impact of farm application of the agro-biowaste compost by more than 63%. This reduction could be attributed to the fact that the pelletizing-drying processes could avoid methane emissions from the untreated agro-biowaste compost during the farm application. Overall, pelletizing-drying of the agro-biowaste compost could be regarded as a promising strategy to improve the environmental and agronomical performance of farm application of organic biofertilizers.
Show more [+] Less [-]Long Island enhanced aerosol event during 2018 LISTOS: Association with heatwave and marine influences Full text
2021
Zhang, Jie | Mak, John | Wei, Ziran | Cao, Cong | Ninneman, Matthew | Marto, Joseph | Schwab, James J.
The co-occurrence of enhancement in aerosol concentration, temperatures, and ozone mixing ratio was observed between June 29 and July 4, 2018 (enhanced period, EP) on Long Island (LI) and the greater NYC metropolitan area during part of the 2018 Long Island Sound Tropospheric Ozone Study (LISTOS). Two aerosol formation pathways were identified during the EP, the first being the condensation of semi- and intermediate volatility oxidation products of anthropogenic volatile organic compounds (AVOCs) under stagnant synoptic flow conditions, high temperatures and afternoon sea-breeze circulation. While this first pathway was prevalent, the most abundant organic aerosol factor was less oxidized oxygenated organic aerosol or LO-OOA. The second formation pathway occurred during a period of more persistent (synoptic) on-shore flow transporting more aged aerosol which consisted of an internal mixture of more oxidized oxygenated organic aerosol (MO-OOA), methanesulfonic acid (MSA) and sulfate. It was estimated that 35% of the sulfate observed during the mature period (an average of about 1.2 μg m⁻³) originated from oceanic dimethyl sulfide (DMS) emissions. These two formation pathways helped elucidate the sources of fine particle pollution, highlighted the interaction between human emissions and natural DMS emission, and will help our understanding of pollution affecting other urban areas adjacent to large bodies of water during hot and stagnant periods.
Show more [+] Less [-]Nanoplastics in aquatic systems - are they more hazardous than microplastics? Full text
2021
Gaylarde, Christine C. | Baptista Neto, José Antonio | da Fonseca, Estefan Monteiro
The fragmentation of plastic materials into nanoparticles of less than 1000 nm (secondary nanoplastics) and their possible accumulation in the environment is a recent matter of concern. There are still no suitable standard methods for determining the concentrations and chemical makeup of these particles in aquatic systems and the fate and effect of nanoplastics in the aquatic environment has been little explored, although there has been research using engineered nanoparticles as models. In this review, we give a summary of the (mainly laboratory-based) studies on the influences of nanoplastics. We aim to provide an updated overview of this emerging topic, reviewing the literature mainly from 2018 onwards and considering the effects of nanoplastics on ecosystems, their uptake and transport of polluting molecules, and the challenges that are faced by workers in this area. The review includes 119 references.
Show more [+] Less [-]Strategies to reduce ammonia emissions from livestock and their cost-benefit analysis: A case study of Sheyang county Full text
2021
Wang, Haodan | Zhao, Zhanqing | Winiwarter, Wilfried | Bai, Zhaohai | Wang, Xuan | Fan, Xiangwen | Zhu, Zhiping | Hu, Chunsheng | Ma, Lin
Ammonia (NH₃) emissions, the majority of which arise from livestock production, are linked to high concentration of PM₂.₅ and lower air quality in China. NH₃ mitigation options were well studied at the small-scale (laboratory or pilot), however, they lack of a large-scale test in China. This study fills this crucial gap by evaluating the cost-benefit of pioneering NH₃ mitigation projects carried out for a whole county – Sheyang, Jiangsu province, China. Measures were implemented in 2019 following two distinct strategies, improved manure treatment for industrial livestock farms, and collection and central treatment for traditional livestock farms. Emission reductions of 16% were achieved in a short time. While this is remarkable, it falls short of expectations from small-scale studies. If measures were fully implemented according to purpose and meet expectations from the small scale, higher emission reductions of 42% would be possible. The cost benefit analysis presented in this study demonstrated advantages of central manure treatment over in-farm facilities. With improved implementation of mitigation strategies in industrial livestock farms, traditional livestock farms may play an increasing role in total NH₃ emissions, which means such farms either need to be included in future NH₃ mitigation policies or gradually replaced by industrial livestock farms.The study found an agricultural NH₃ reduction technology route suitable for China's national conditions (such as the “Sheyang Model”).
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