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Resultados 1471-1480 de 6,532
Evaporation rates and pollutants emission from heated cooking oils and influencing factors
2020
Adeniran, Jamiu Adetayo | Yusuf, Rafiu Olasunkanmi | Abdulkadir, Mariam Oyinkansola | Yusuf, Muhammad-Najeeb O. | Abdulraheem, Khadija Abdulkareem | Adeoye, Babatunde Kazeem | Sonibare, Jacob Ademola | Du, Mingxi
The heating of edible oils during cooking activities promotes the emissions of pollutants that have adverse impacts on the health of humans. This study investigated the evaporative emissions of fifteen (15) commonly used cooking oils. Split-plot experimental design under the response surface methodology framework was used to study singular and interaction effects of influencing parameters (temperature, volume of cooking oil and time) on cooking oil evaporation rate and pollutants emissions (i.e. Particulate matter of aerodynamic diameter ≤1 μm (PM₁.₀); ≤2.5 μm (PM₂.₅); ≤10 μm (PM₁₀); Total Suspended Particulate (TSP); Total Volatile Organic Compounds -TVOCs, and Carbon Monoxide- CO) on a groundnut oil sample that served as a case study. Obtained values of density, viscosity, kinematic viscosity, smoke, flash and fire points were; 873–917 kg/m³; 1.12–9.7 kg/ms; 2.4–3.4 m²/s; 96 -100 °C; 124–179 °C and 142–186 °C, respectively. The role of temperature as the most significant parameter influencing the rate of evaporative emissions was established. Evaporation rate and pollutants emission from unrefined samples were the highest. The restricted maximum likelihood (REML) analysis results suggested a strong relationship between the actual values and the predicted values as R-squared values obtained were greater than 0.8 for all the responses. These results suggest that minimal rates of evaporation and pollutants emission from heating cooking oils can be achieved with a high volume of the cooking oil at moderate temperature levels.
Mostrar más [+] Menos [-]The individual and combined effects of cadmium, polyvinyl chloride (PVC) microplastics and their polyalkylamines modified forms on meiobenthic features in a microcosm
2020
Wakkaf, Takwa | Allouche, Mohamed | Harrath, Abdel Halim | Mansour, Lamjed | Alwasel, Saleh | Mohamed Thameemul Ansari, Kapuli Gani | Beyrem, Hamouda | Sellami, Badreddine | Boufahja, Fehmi
A microcosm experiment was carried out to study the ecotoxicity and interactions between heavy metals and polyvinyl chloride microplastics. Fifteen treatments were tested and results were examined after one month. In details, this work aims to study the ecotoxicological effects of cadmium (10 and 20 mg kg⁻¹ Dry Weight DW), polyvinyl chloride (PVC) and its modified forms; PVC-DETA (PD) and PVC-TETA (PT) (20 and 40 mg kg⁻¹ DW), separately and in mixtures, on meiofauna from Bizerte lagoon (NE Tunisia) with focus on nematode features. The results obtained showed that individual treatments were toxic for meiofauna and particularly for free-living nematodes. No clear trends characterized the numerical responses but significant reductions were observed for diversity indices. Moreover, the binary combinations of contaminants have a lesser toxic effect compared to their individual effects. This effect could be related to the high-capacity chelating ability of PVC and its polymers against cadmium.
Mostrar más [+] Menos [-]Physiological effects of toxic elements on a wild nightjar species
2020
Espín, Silvia | Sánchez-Virosta, Pablo | Zamora-Marín, José M. | León-Ortega, Mario | Jiménez, Pedro | Zamora-López, Antonio | Camarero, Pablo R. | Mateo, Rafael | Eeva, Tapio | García-Fernández, Antonio J.
Nightjars are considered human-tolerant species due to the population densities reached in strongly managed landscapes. However, no studies have been done evaluating metal-related effects on physiology, condition or fitness in any nightjar species. The main aim of this study was to evaluate how metal exposure affects physiology and condition in red-necked nightjar (Caprimulgus ruficollis) populations inhabiting three different environments in southeastern Spain: agricultural-urban area (n = 15 individuals), mining area (n = 17) and control area (n = 16).Increased plasma mineral levels (magnesium and calcium) and alkaline phosphatase (ALP) activity were observed in breeding females, and ALP was significantly higher in young birds due to bone growth and development. In the mining-impacted environment, nightjars showed decreased retinol (17.3 and 23.6 μM in the mining area and control area), uric acid (28.8 and 48.6 mg/dl in the mining area and control area) and albumin (16.2 and 19.6 g/l in the mining area and control area), probably impaired by a combination of toxic metal exposure and low prey quantity/quality in that area. Moreover, they showed increased plasma tocopherol levels (53.4 and 38.6 μM in the mining area and control area) which may be a response to cope with metal-induced oxidative stress and lipid peroxidation. Blood concentrations of toxic metals (As, Pb, Cd and Hg) were negatively associated with calcium, phosphorus, magnesium, ALP, total proteins and body condition index. This could lead to metal-related disorders in mineral metabolism and ALP activity that may potentially increase the risk of skeletal pathologies and consequent risk of fractures in the long term, compromising the survival of individuals. Further studies need to be carried out to evaluate potential metal-related effects on the antioxidant status and bone mineralization of nightjars inhabiting mining environments.
Mostrar más [+] Menos [-]Butylated hydroxytoluene induces dysregulation of calcium homeostasis and endoplasmic reticulum stress resulting in mouse Leydig cell death
2020
Ham, Jiyeon | Lim, Whasun | Whang, Kwang-Youn | Song, Gwonhwa
Butylated hydroxytoluene (BHT) is a synthetic phenolic antioxidant that has been used as an additive for fat- or oil-containing foods. The exposure index value increases with extended usage of the chemical. Further, estimated total amount of BHT could exceed standard regulation, considering dietary intake or another exposure. Although BHT may induce side effects in reproductive systems, adequate research had not yet been performed to confirm them. In this study, we investigated the effects of BHT on mouse Leydig cells (TM3), which are components of testis. Our results indicated that BHT suppressed cellular proliferation and induced cell cycle arrest in TM3 cells. Moreover, BHT hampered cytosolic and mitochondrial calcium homeostasis in TM3 cells. Furthermore, BHT treatment led to endoplasmic reticulum (ER) stress and DNA fragmentation, simultaneously stimulating intrinsic apoptosis signal transduction. To elucidate the mode of action of BHT on Leydig cells, we performed western blot analysis and confirmed the activation of the PI3K/AKT and MAPK pathways. Collectively, our results demonstrated that BHT has toxic effects on mouse Leydig cells via induction of calcium dysregulation and ER-mitochondria dysfunction.
Mostrar más [+] Menos [-]Does soil CuO nanoparticles pollution alter the gut microbiota and resistome of Enchytraeus crypticus?
2020
Ma, Jun | Chen, Qing-Lin | O’Connor, Patrick | Sheng, G Daniel
Growing evidence suggests that metallic oxide nanoparticles can pose a severe risk to the health of invertebrates. Previous attention has been mostly paid to the effects of metallic oxide nanoparticles on the survival, growth and physiology of animals. In comparison, the effects on gut microbiota and incidence of antibiotic resistance genes (ARGs) in soil fauna remain poorly understood. We conducted a microcosm study to explore the responses of the non-target soil invertebrate Enchytraeus crypticus gut microbiota and resistomes to copper oxide nanoparticles (CuO NPs) and copper nitrate by using bacterial 16S rRNA gene amplicons sequencing and high throughput quantitative PCR. The results showed that exposure to Cu2+ resulted in higher bioaccumulation (P < 0.05) and lower body weight and reproduction (P < 0.05) of Enchytraeus crypticus than exposure to CuO NPs. Nevertheless, exposure to CuO NPs for 21 days markedly increased the alpha-diversity of the gut microbiota of Enchytraeus crypticus (P < 0.05) and shifted the gut microbial communities, with a significant decline in the relative abundance of the phylum Planctomycetes (from 37.26% to 19.80%, P < 0.05) and a significant elevation in the relative abundance of the phyla Bacteroidetes, Firmicutes and Acidobacteria (P < 0.05). The number of detected ARGs in the Enchytraeus crypticus gut significantly decreased from 45 in the Control treatment to 16 in the Cu(NO3)2 treatment and 20 in the CuO NPs treatment. The abundance of ARGs in the Enchytraeus crypticus gut were also significantly decreased to 38.48% when exposure to Cu(NO3)2 and 44.90% when exposure to CuO NPs (P < 0.05) compared with the controls. These results extend our understanding of the effects of metallic oxide nanoparticles on the gut microbiota and resistome of soil invertebrates.
Mostrar más [+] Menos [-]Investigating arsenic impact of ACC treated timbers in compost production (A case study in Christchurch, New Zealand)
2020
Safa, Majeed | O’Carroll, Daniel | Mansouri, Nazanin | Robinson, Brett | Curline, Greg
The arsenic concentration is an important issue in compost production. The main inputs of a compost factory, including kerbsides, green wastes, food industry wastes, and river weeds are investigated in this study. Also, this study investigated how treated timbers, ashes, and other contamination can impact arsenic concentration in compost production. The results showed that most treated timbers and all ashes of treated and untreated timbers contained significant amounts of arsenic. These results revealed that the presence of a small amount of treated timber ashes can significantly increase the arsenic concentration in composts. The results of the study show the arsenic concentration in compost increase during cold months, and it dropped during summer, which would be mostly because of high arsenic concentration in ashes of log burners. This study shows ashes of burning timbers can impact arsenic contamination mostly because of using Copper-Chrome-Arsenic wood preservatives (CCA). Also, the lab results show the arsenic level even in ashes of untreated timber is around 96 ppm. The ashes of H3, H4, and H5 treated timbers contain approximately 133,000, 155,000, and 179,000 ppm of arsenic, which one kg of them can increase arsenic concentration around 10 ppm in 13.3, 15.5 and 17.9 tons of dry compost products. The main problem is many people look at ashes and treated timber as organic materials; however, ashes of treated and untreated timbers contained high concentrations of arsenic. Therefore, it was necessary to warn people about the dangers of putting any ashes in organic waste bins.
Mostrar más [+] Menos [-]The imidacloprid remediation, soil fertility enhancement and microbial community change in soil by Rhodopseudomonas capsulata using effluent as carbon source
2020
Wu, Pan | Zhang, Xuewei | Niu, Tong | Wang, Yanling | Liu, Rijia | Zhang, Ying
The effects of Rhodopseudomonas capsulata (R. capsulata) in the treated effluent of soybean processing wastewater (SPW) on the remediation of imidacloprid in soil, soil fertility, and the microbial community structure in soil were studied. Compared with the control group, with the addition of effluent containing R. capsulata, imidacloprid was effectively removed, soil fertility was enhanced, and the microbial community structure was improved. Molecular analysis indicated that imidacloprid could exert induction effects on expression of cpm gene and regulation effects on the synthesis of cytochrome P450 monooxygenases (P450) by activating HKs gene in two-component system (TCS). For R. capsulata, this induction process required 1 day. The synthesis of P450 occurred 1 day after inoculation, because R. capsulata are a type of archaea and imidacloprid is an environmental stress. Before expression of the cpm gene and synthesis of P450, R. capsulata need a period of time to adapt to external imidacloprid stimulation. However, the lack of organic matter in the soil cannot sustain R. capsulata growth for more than 1 day. In four groups with added effluent, the remaining organic matter in the effluent provided a sufficient carbon source and energy for R. capsulata. Five days later, the microbial community structure was improved by R. capsulata in the soil. The new technique could be used to remediate imidacloprid, enhance soil fertility, treat SPW and realize the recycling and reuse of wastewater and R. capsulata cells.
Mostrar más [+] Menos [-]Geospatial assessment of oil spill pollution in the Niger Delta of Nigeria: An evidence-based evaluation of causes and potential remedies
2020
Akinwumiju, Akinola S. | Adelodun, Adedeji A. | Ogundeji, Seyi E.
Based on the archival data on oil facilities, oil spill incidents, and environmental conditions, we researched the plausible causes of oil spill disasters in the Niger Delta of Nigeria between 2006 and 2019. The data were analyzed for geospatial and statistical patterns, using ArcGIS and R programming platforms, respectively. A fuzzy logic algorithm was employed to generate three oil spill disaster models (hazard, vulnerability, and risk). Ordinary Least Square algorithm was adopted to model the relationships between oil spill and two sets of predictor variables: oil facilities (oil well, flow station, and pipeline) and disaster models. We found that, during the 23 years, the Niger Delta experienced 7940 oil spill incidents, of which 67% occurred onshore. A total of 4,950, 501, 855 episodes were attributed to sabotage, corrosion, and equipment failure, with 87%, 62%, and 45% occurring onshore, respectively. Besides, 81% of the 5320 onshore oil spill cases were attributed to sabotage, while corrosion and equipment failure accounted for mere 6% and 7% of the incidents, respectively. The estimated average risk index (R = 0.20) shows that the risk of an oil spill disaster in the Niger Delta is low. Whereas, 5% of the region is characterized by a high risk of oil spill disaster. Furthermore, the regression model infers that the oil spillages exhibit a positive relationship with disaster models and oil facilities at α = 0.10. However, only 16% of the incidents were explained by disaster models, while the oil facilities account for 23% of the total cases, indicating the influence of other factors. To avert further socio-environmental damage in the Niger-Delta, oil theft and sabotage should be curbed, polluted areas are remediated, and an all-inclusive socio-economic development is prioritized.
Mostrar más [+] Menos [-]Diurnal and temporal changes in air pollution during COVID-19 strict lockdown over different regions of India
2020
Singh, Vikas | Singh, Shweta | Biswal, Akash | Kesarkar, Amit P. | Mor, Suman | Ravindra, Khaiwal
Lockdown measures to contain COVID-19 pandemic has resulted in a considerable change in air pollution worldwide. We estimate the temporal and diurnal changes of the six criteria air pollutants, including particulate matter (PM₂.₅ and PM₁₀) and gaseous pollutants (NO₂, O₃, CO, and SO₂) during lockdown (25ᵗʰ March – 3ʳᵈ May 2020) across regions of India using the observations from 134 real-time monitoring sites of Central Pollution Control Board (CPCB). Significant reduction in PM₂.₅, PM₁₀, NO₂, and CO has been found in all the regions during the lockdown. SO₂ showed mixed behavior, with a slight increase at some sites but a comparatively significant decrease at other locations. O₃ also showed a mixed variation with a mild increase in IGP and a decrease in the South. The absolute decrease in PM₂.₅, PM₁₀, and NO₂ was observed during peak morning traffic hours (08–10 Hrs) and late evening (20–24 Hrs), but the percentage reduction is almost constant throughout the day. A significant decrease in day-time O₃ has been found over Indo Gangetic plain (IGP) and central India, whereas night-time O₃ has increased over IGP due to less O₃ loss. The most significant reduction (∼40–60%) was found in PM₂.₅ and PM₁₀. The highest decrease in PM was found for the north-west and IGP followed by South and central regions. A considerable reduction (∼30–70%) in NO₂ was found except for a few sites in the central region. A similar pattern was observed for CO having a ∼20–40% reduction. The reduction observed for PM₂.₅, PM₁₀, NO₂, and enhancement in O₃ was proportional to the population density. Delhi’s air quality has improved with a significant reduction in primary pollutants, however, an increase in O₃ was observed. The changes reported during the lockdown are combined effect of changes in the emissions, meteorology, and atmospheric chemistry that requires detailed investigations.
Mostrar más [+] Menos [-]Leaching of herbicidal residues from gravel surfaces – A lysimeter-based study comparing gravels with agricultural topsoil
2020
Albers, Christian Nyrop | Jacobsen, Ole Stig | Bester, Kai | Jacobsen, Carsten Suhr | Carvalho, Pedro N.
Evidence from the past shows that pesticide use in populated areas may impact groundwater quality. The approval of herbicides such as diflufenican and glyphosate for use on paved and unpaved gravel surfaces in the European Union is based on their behaviour and fate in agricultural soils. However, this might be very different from their fate in gravel surfaces. We therefore conducted an outdoor study with 21 small lysimeters containing different gravel types and a sandy arable topsoil as control. The lysimeters were sprayed with a commercial product for gardening, containing diflufenican and glyphosate. The concentrations of the herbicides and their relevant degradation products in the outlet was followed for 19 months. Diflufenican, glyphosate and AMPA did not leach from any of the lysimeters. However, one diflufenican degradation product (AE-0) leached from two of the gravel types for more than a year and a second degradation product (AE-B) leached from all gravels for up to one year. Concentrations in the leachate peaked at 0.5–3 μg/L, with highest concentrations over the longest periods observed with rock chippings on top of the gravel. We conclude, that the different properties of gravel compared to those of agricultural soils may lead to very different herbicide leaching patterns but also that the leaching depends highly on the type of gravel and type of herbicide.
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