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Airborne Staphylococcus aureus in different environments—a review Texte intégral
2019
Kozajda, Anna | Jeżak, Karolina | Kapsa, Agnieszka
The aim of the literature review was to describe the environments where the presence of airborne Staphylococcus aureus was confirmed and to catalogue the most often used methods and conditions of bioaerosol sampling to identify the bacteria. The basis for searching of studies on S. aureus in the bioaerosol in different environments was PubMed database resources from the years 1990–2019 (May). The review included studies which were carried on in selected environments: hospitals and other health care facilities, large-scale animal breeding, wastewater treatment plants, residential areas, educational institutions, and other public places. The highest concentrations and genetic diversity of identified S. aureus strains, including MRSA (methicillin-resistant S. aureus), have been shown in large-scale animal breeding. The role of the airborne transmission in dissemination of infection caused by these pathogens is empirically confirmed in environmental studies. Commonly available, well-described, and relatively inexpensive methods of sampling, identification, and subtyping guarantee a high reliability of results and allow to obtain fast and verifiable outcomes in environmental studies on air transmission routes of S. aureus strains.
Afficher plus [+] Moins [-]Phytoremediation potential of Miscanthus sinensis for mercury-polluted sites and its impacts on soil microbial community Texte intégral
2019
Zhao, Anqi | Gao, Lingyun | Chen, Buqing | Feng, Liu
Phytoremediation potential of Miscanthus sinensis and its impacts on soil microbial community and nutrients were evaluated by pot experiment at soil mercury concentration from 1.48 to 706 mg kg⁻¹. The changes in biomass yield in dry mass, chlorophyll content, and SOD activity indicated Miscanthus sinensis was tolerant to higher levels of soil mercury exposure, and could grow even if at soil mercury up to 706 mg kg⁻¹. Mercury bioconcentration and translocation factors were close to or greater than 1 when exposed to soil mercury up to 183 mg kg⁻¹, demonstrating Miscanthus sinensis a potential phytoremediator for mercury-polluted soils. Miscanthus sinensis planting could significantly improve the diversity and abundance of soil microbial community, but might cause potential loss of soil nitrogen and phosphorus in the early and middle of its growth. In a word, the study indicated Miscanthus sinensis was a promising energy crop linking biofuel production and phytoremediation of mercury-contaminated sites.
Afficher plus [+] Moins [-]Application of selected life cycle occupational safety methods to the case of electricity production from pyro-oil Texte intégral
2019
Oguzcan, Semih | Tugnoli, Alessandro | Dvarioniene, Jolanta
Life cycle thinking is a necessary component in preventing the shifting of burden along the life cycle and from one impact category to another. For this reason, many have focused on integrating life cycle thinking into occupational risk assessment. The resultant methods have different properties in terms of scope and outcomes. Literature has been reviewed for life cycle occupational risk assessment methodologies, and 3 methods (life cycle inherent toxicity (LCIT) method, work environment characterization factors (WE-CFs) method, and life cycle risk assessment (LCRA) method) have been selected and applied in a case study of electricity production from pyro-oil to identify suitability and research gaps in the existing literature. The results of the LCIT method were highly heterogenous over life cycle of electricity production. For the current case, the major cancer and non-cancer impacts originated from the same life cycles. The results from WE-CFs method were highly heterogenous over the life cycle of electricity production as well. Agriculture contributed the most to the occupational risks. In the LCRA method, averaging caused the information about the frequency of the risks over life cycle to be lost. The method showed the well-known bargaining between accuracy and simplicity when complex systems are considered. Results from this method were quite homogenous among life cycles, due to the averaging effect. Detailed reporting and follow-up of the worker health issues can enable a more accurate application of the WE-CFs method. The overall results showed that it was possible to apply these 3 methodologies for the EU-28 region.
Afficher plus [+] Moins [-]Synthesis of rigid polyurethane foams from phosphorylated biopolyols Texte intégral
2019
de Haro, Juan Carlos | López-Pedrajas, Daniel | Pérez, Angel | Rodríguez, Juan Francisco | Carmona Rodríguez, Manuel
Renewable resources are playing a key role on the synthesis of biodegradable polyols. Moreover, the incorporation of covalently linked additives is increasing in importance in the polyurethane (PU) market. In this work, previously epoxidized grape seed oil and methyl oleate were transformed into phosphorylated biopolyols through an acid-catalyzed ring-opening hydrolysis in the presence of H₃PO₄. The formation of phosphate polyesters was confirmed by FT-IR and ³¹P-NMR. However, the synthesis of a high-quality PU rigid foam was not possible using exclusively these polyols attending to their low hydroxyl value. In that way, different rigid PU foams were prepared from the phosphorylated biopolyols and the commercial polyol Alcupol R4520. It was observed that phosphorylated biopolyols can be incorporated up to a 57 wt.% in the PU synthesis without significant structural changes with respect to the commercial foam. Finally, thermogravimetric and EDAX analyses revealed an improvement of thermal stability by the formation of a protective phosphorocarbonaceous char layer.
Afficher plus [+] Moins [-]Cobalt speciation and phytoavailability in fluvo-aquic soil under treatments of spent mushroom substrate from Pleurotus ostreatus Texte intégral
2019
Liu, Borui | Huang, Qing | Su, Yuefeng | Xue, Qianhui | Sun, Liuye
Cobalt (Co) is a nutrient for soil microorganisms and crops, as well as a worldwide industrial pollutant. When the level of Co exceeds the acceptable limit, this heavy metal can lead to devastating consequences for soil environments. There is considerable attention and concern about elevated levels of Co contaminating soil and crops. Spent mushroom substrate (SMS) is a potential amendment for the adsorption of pollutants, which has potential for resolving Co-polluted soil that spans the world. To investigate the environmental behavior and risks associated with Co in fluvo-aquic soil under specific treatments of SMS from Pleurotus ostreatus, a lab-scale pot experiment was conducted. SMS and exogenous Co were added to soil, which was retained for approximately 30 days. Pakchois (Brassica chinensis L.) were planted in the treated soil for 28 days until harvest. The Co speciation in soil (modified BCR sequential extraction) and Co accumulation in pakchoi tissue were studied. When the SMS concentration was within a range of 0 to 9 g kg⁻¹ (total amount = 0 to 2.7 g), Co in the acid-soluble fraction was transformed to the oxidizable fraction in soil, resulting from the mesh structure on the surface of SMS, as well as the amide and carboxyl in the SMS molecular structure. In this situation, the Co accumulation levels in the pakchois decreased significantly (P < 0.05), indicating the efficacy of SMS for reducing Co phytoavailability. However, when the SMS concentration reached 12 g kg⁻¹, the phytoavailability increased again (P < 0.05). When the SMS concentration ranged from 8.86 to 9.51 g kg⁻¹, the Co phytoavailability in soil reached a minimum, while the biomass of pakchoi reached a maximum. Conclusively, SMS from Pleurotus ostreatus are effective for reducing the Co phytoavailability, as well as for reducing the chance of Co transferring into a human’s body through crops (i.e., food consumption). In order to achieve the optimum efficacy, the SMS concentration in soil should be maintained at a range of 8.86 to 9.51 g kg⁻¹.
Afficher plus [+] Moins [-]Correction to: Effect of the combined application of fungal residue and chemical fertilizers on the mineralization of soil organic carbon in paddy fields Texte intégral
2019
Shi, Sibo | Wang, Xudong | Ye, Zhengqian | Chen, Wenbo | Li, Ting | Chen, Junhui | Li, Jianwu
The article Effect of the combined application of fungal residue and chemical fertilizers on the mineralization of soil organic carbon in paddy fields.
Afficher plus [+] Moins [-]Cooking fuel decision-making and family structure: a field study in China Texte intégral
2019
Hou, Bingdong | Liao, Hua | Wang, Jin-Wei | Wang, Fangzhi | Zhang, Hongliang
Household air pollution caused by solid fuel use for cooking is prevalent in rural China and generates various environmental and health problems. Various potential impact factors on cooking fuel decision such as income, education, modern energy, and infrastructure are examined. However, the role of family structures has been ignored. A survey on household energy consumption pattern interrelating socio-economic and demographic factors was conducted in ten villages in Northern China using stratified random sampling technique. The number of family member eating together influences households’ cooking fuel decision-making significantly. The numbers of school-age children and family members under 6 and above 60 years old have no significant influence on the household’s cooking fuel decision-making respectively. Compared with families with neither child nor the elderly, those with no child but at least an elderly member have 0.103 lower probability of choosing clean fuels as their primary cooking fuel. Hence, the elderly owns a heavyweight in the household fuel decision-making process in rural China, and the government should formulate policies more in line with the background of the times to deal with rural energy issues.
Afficher plus [+] Moins [-]Procaine penicillin alters swimming behaviour and physiological parameters of Daphnia magna Texte intégral
2019
Bownik, Adam | Ślaska, Brygida | Bochra, Justyna | Gumieniak, Katarzyna | Gałek, Kinga
Procaine penicillin (PP) is a β-lactam antibiotic widely used in human and veterinary medicine. Although PP is detected in surface water, little is known on its effects on aquatic invertebrates. Our aim was to determine the influence of PP on swimming behaviour (track density, swimming speed, turning angle, hopping frequency) and physiological activity (oxygen consumption, heart rate, thoracic limb movement) of a freshwater invertebrate Daphnia magna exposed to PP at concentrations of 11.79 mg/L, 117.9 mg/L and 1179 mg/L for 2 h and 24 h. The results showed no mortality; however, reduction of swimming activity manifested by the decreased track density, swimming speed and turning angle noted in Daphnia exposed to all the concentrations of PP. Increase of oxygen consumption was observed after 2-h exposure; however, decrease of this parameter was found after 24 h. PP also reduced heart rate and thoracic limb movement in a concentration-dependent manner. The results suggest that the antibiotic should not induce mortality; however, it may affect swimming behaviour and physiological parameters of Daphnia magna particularly inhabiting aquaculture facilities with intensive antibiotic treatment. On the basis of the present results, we also suggest higher sensitivity of behavioural and physiological parameters of cladocerans than the commonly used endpoints: mortality or immobilisation and their possible application as a part of early warning systems in monitoring of surface water toxicity.
Afficher plus [+] Moins [-]Characteristics of heavy metals in soils and grains of wheat and maize from farmland irrigated with sewage Texte intégral
2019
Xue, Peiying | Zhao, Quanli | Sun, Hongxin | Geng, Liping | Yang, Zhengzheng | Liu, Wenju
The farmland irrigation with the sewage is a common and better pathway to save the resource of groundwater in Northern China. The investigation was conducted in the farmland along the Fuhe River to explore characteristics of heavy metals in soils and grains of wheat and maize from a long-term sewage-irrigated area of Baoding region. The results showed that the topsoil with long-term sewage irrigation accumulated more Cd, Pb, and Hg compared with that of soil irrigated with groundwater and their corresponding natural background values. Cd concentrations in 48% of sewage-irrigated soil samples exceeded the Chinese safety limitation at 0.6 mg/kg, but less Cd accumulated in crop grains and did not pose the potential health risk. On the contrary, Pb levels in soils irrigated with sewage were lower than the safety limitation but Pb concentrations in 24% of wheat grain samples exceeded the Chinese national safety limit. Long-term sewage irrigation did not increase As, Cr, and Ni concentrations in soils or crop grains. The target hazard quotient (THQ) of heavy metals in edible grains of crops was selected to assess their risk to human health. Total THQ values were higher than 1.0 for the wheat samples from sewage-irrigated area and both sewage-irrigated and smelter-impacted areas, and As is the main contributor to the total THQ and posed the potential risk to human health. Therefore, the accumulation of Cd, Pb, Hg, and As in soils and crops in sewage-irrigated area should be monitored continuously to ensure food safety and security.
Afficher plus [+] Moins [-]Anthropogenic impacts in the Changbai Mountain region of NE China over the last 150 years: geochemical records of peat and altitude effects Texte intégral
2019
Bao, Kunshan | Wang, Guoping | Jia, Lin | Xing, Wei
Geochemical records from peatlands are important tools for the interpretation of environmental signals preserved in the peat and the understanding anthropogenic impacts on remote mountain regions. In this paper, six ²¹⁰Pb-dated peat cores located at 500–1900 m above sea level (asl) in the Changbai Mountains were used to reconstruct the pollution history over the past 150 years in northeastern (NE) China. The cores physicochemical parameters and 10 key chemical elements were analyzed by inductively coupled plasma atomic emission spectroscopy (ICP-AES). Results from loss on ignition (LOI), total organic carbon (TOC), and lithogenic element (Ti, Fe, and Mn) analysis show that the peatlands (Ch, Yc1 and Jb) over 900 m asl are ombrotrophic and the lower altitude peatlands (Dng, Jc, and Ha) are minerotrophic. There is a decreasing trend of trace element distribution with the altitude, mainly due to the local source input. The content of the magnetic particles and trace elements (Cu, Ni, Pb and Zn) as well as their accumulation rates document 150 years of pollution history in the Changbai Mountain region. There is a significant elevated pattern of the geochemical records after the New China, which might mark the start date of Anthropocene since the 1950s in this region. The peatlands at the lower altitude (i.e., Dng and Ha) record the earliest fingerprints of metal contamination due to the starting period of massive reclaiming and immigrating in the Changbai Mountain region. The major increase of trace elements since the 1980s probably suggests a significant deterioration of the local environment due to the fast industrial and urbanization development after the Reform and Opening up in China.
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