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1.
Environmental Science and Pollution Research - Aedes aegypti and Culex quinquefasciatus are vectors of diseases that constitute public health problems. The discovery of products capable of...  相似文献   
2.
Monitoring of Phenol in Wastewater Bioremediation by HPLC   总被引:1,自引:0,他引:1  
Bioremediation emphasizes the detoxification and destruction of toxic substances by microorganisms. Wastewater obtained from an industrial concern was solvent extracted with methyl alcohol and dichloromethane and analysed by GC/MS. Besides phenol, a large variety of organic compounds were detected. Under controlled laboratory conditions, the wastewater was innoculated with a mixed culture of microorganisms specially selected for their abilities to degrade phenol. Samples were collected at regular intervals from the stirred tank bioreactor and analysed for phenol by reverse phase HPLC with a C18 column. Results shows that from an initial phenol concentration of 987 ppm, slightly more than 50% was destroyed within 163 hours. The dry weight of the microorganisms and the plate count (CFU/ml) shows a steady increase from 0.5238 gms to 0.5355 gms and from 1.1E+9 to 1.94E+13 respectively over the same period. This suggested that the phenol was consumed by the microorganisms as the sole carbon source.  相似文献   
3.
Environmental Science and Pollution Research - The total cultivated area in Brazil reached to 62 million ha in 2018, with the predominance of genetically modified soybean and corn (36 and 17...  相似文献   
4.
Environmental Science and Pollution Research - In this study, the essential oil (EO) from leaves of Croton linearis Jacq was extracted and characterized by GC/MS. The EO hydrophilic-lipophilic...  相似文献   
5.
Waste from wastewater treatment plants (WWTP) for Helianthus annuus L. production may be a viable solution to obtain biodiesel. This study achieved two objectives: assess the agronomical viability of waste (wastewater and sludge) from the Alcázar de San Juan WWTP in central Spain for H. annuus L. production; use H. annuus L. seeds grown in this way to obtain biodiesel. Five study plots, each measuring 6 m × 6 m (36 m2), were set up on the agricultural land near the Alcázar de San Juan WWTP. Five fertilizer treatment types were considered: drinking water, as the control; treated wastewater; 10 t ha?1 of air-dried sewage sludge; 20 t ha?1 of air-dried sewage sludge; 0.6 t ha?1 of commercial inorganic fertilizer. Soil, irrigation water, sewage sludge, crop development and fatty acid composition in achenes oil were monitored. The 20 t ha–1 dose of sewage sludge proved effective to grow H. annuus L. with similar results to those grown with a commercial fertilizer. However, precautions should be taken when irrigating with wastewater because of high salinity and nutrient deficiency. Sunflower oil was composed mostly of linoleic and oleic acid. The remaining fatty acids were linolenic, estearic, nervonic, palmitoleic, and palmitic.  相似文献   
6.
We utilize life cycle assessment to trace conversion of degradable organic carbon (DOC) contained in organic waste from city markets in Da Nang, Vietnam. Our methodology makes explicit the process of conversion of DOC under aerobic and anaerobic conditions, as well as the balance of nutrients. Greenhouse gas emissions were calculated for six alternative scenarios: (i) anaerobic landfilling (current situation); (ii) semi-aerobic landfilling; (iii) landfill gas capture; (iv) composting; (v) pre-composting before landfill; and (vi) biogas production. We calculate that 1 t of waste in anaerobic landfilling emits 1.70 t CO2-eq. with life-cycle perspective. Lowest emission occurs in biogas scenario with 0.26 t CO2-eq./t. Composting occupies an intermediate position with 0.39 t CO2-eq./t. Likewise, we estimate that cost of emission reduction in solid waste sector of Vietnam is 15.13 US$/t CO2-eq., given by alternative of composting and taking anaerobic landfilling as reference. On the other hand, if social cost of carbon (SCC) is incorporated lowest cost to treat 1 t of waste is given by composting and semi-aerobic landfilling at discount rate of 5 %. However, using lower discount rates, and consequently higher values of SCC, composting and biogas production become the alternatives with lowest treatment costs.  相似文献   
7.
We describe Pliodasypus vergelianus gen. et sp. nov., a Dasypodini armadillo from the middle Pliocene of Venezuela (Vergel Member, San Gregorio Formation). Although scarce, the remains are remarkable because of their geochronologic proximity to the main phase of Great American Biotic Interchange (GABI). The cladistic analysis conducted reveals that Pliodasypus groups with Dasypus and both are sister taxa of Propraopus, whereas Anadasypus is at a basal position. With respect to the records of tribe Dasypodini, after its oldest representative (Anadasypus, middle and late Miocene), the chronologically subsequent form is Pl. vergelianus (middle Pliocene), followed by Dasypus bellus in higher northern latitudes (late Pliocene), and then by widespread occurrences in the Pleistocene of North America (D. bellus) and South America (Propraopus, Dasypus punctatus, and Dasypus novemcinctus). Thus, we infer that Dasypus differentiated in the late Pliocene at low latitudes in the northern South America. It leads to two alternative hypotheses of dispersal: (a) some early Dasypus remained cryptically in South America until the Pleistocene, whereas others dispersed to North America between 2.2 and 2.7 Ma, or (b) they dispersed to North America subsequently to the emersion of the Panamanian isthmus and D. bellus differentiated there; later, during the Pleistocene, D. bellus entered South America and experienced speciation. The same process of re-ingression has been proposed to other xenarthrans, breaking with the traditional assumption that the GABI was unidirectional.  相似文献   
8.
This work evaluates the role of a plant community in mercury (Hg) stabilization and mobility in a contaminated Portuguese salt marsh. With this aim, the distribution of Hg in below and aboveground tissues, as well as the metal partitioning between cellular fractions (soluble and insoluble) in four different species (Triglochin maritima L., Juncus maritimus Lam, Sarcocornia perennis (Miller) A.J. Scott, and Halimione portulacoides (L.) Aellen) was assessed. Mercury accumulation, translocation and compartmentation between organs and cellular fractions were related to the plant species.Results showed that the degree of Hg absorption and retention was influenced both by environmental parameters and metal translocation/partitioning strategies. Different plant species presented different allocation patterns, with marked differences between monocots (T. maritima and J. maritimus) and dicots (S. perennis, H. portulacoides). Overall, the two monocots, in particular T. maritima showed higher Hg retention in the belowground organs whereas the dicots, particularly S. perennis presented a more pronounced translocation to the aboveground tissues. Considering cellular Hg partitioning, all species showed a higher Hg binding to cell walls and membranes rather than in the soluble fractions. This strategy can be related to the high degree of tolerance observed in the studied species. These results indicate that the composition of salt marsh plant communities can be very important in dictating the Hg mobility within the marsh ecosystem and in the rest of the aquatic system as well as providing important insights to future phytoremediation approaches in Hg contaminated salt marshes.  相似文献   
9.
This study analyzed water quality in regions around Patos lagoon (Southern Brazil) that are under anthropogenic pressure. Water samples were collected from five different sites, including one used as a source for human consumption (COR) and others known to be influenced by human activities (IP). Danio rerio (Teleostei, Cyprinidae) organisms were exposed for 24 h to these water samples, plus a control group. It was observed that: (1) reactive oxygen species levels were lower in COR and IP than in the control group; (2) glutamate-cysteine ligase (catalytic subunit) expression was higher in COR than in other sites; (3) exposure to all water samples affected long-term memory (LTM) when compared to control group. Thus, some water samples possess the ability to modulate the antioxidant system and to induce a decline in cognitive functions, as measured by LTM. The obtained results indicate that a combination of variables of different organization level (molecular, biochemical and behavioral) can be employed to analyze water quality in impacted regions.  相似文献   
10.
Because of the mutagenic and/or carcinogenic properties, Polycyclic Aromatic Hydrocarbons (PAH), have a direct impact on human population. Consequently, there is a widespread interest in analysing and evaluating the exposure to PAH in different indoor environments, influenced by different emission sources. The information on indoor PAH is still limited, mainly in terms of PAH distribution in indoor particles of different sizes; thus, this study evaluated the influence of tobacco smoke on PM10 and PM2.5 characteristics, namely on their PAH compositions, with further aim to understand the negative impact of tobacco smoke on human health. Samples were collected at one site influenced by tobacco smoke and at one reference (non-smoking) site using low-volume samplers; the analyses of 17 PAH were performed by Microwave Assisted Extraction combined with Liquid Chromatography (MAE–LC). At the site influenced by tobacco smoke PM concentrations were higher 650% for PM10, and 720% for PM2.5. When influenced by smoking, 4 ring PAH (fluoranthene, pyrene, and chrysene) were the most abundant PAH, with concentrations 4600–21 000% and 5100–20 800% higher than at the reference site for PM10 and PM2.5, respectively, accounting for 49% of total PAH (ΣPAH). Higher molecular weight PAH (5–6 rings) reached concentrations 300–1300% and 140–1700% higher for PM10 and PM2.5, respectively, at the site influenced by tobacco smoke. Considering 9 carcinogenic PAH this increase was 780% and 760% in PM10 and PM2.5, respectively, indicating the strong potential risk for human health. As different composition profiles of PAH in indoor PM were obtained for reference and smoking sites, those 9 carcinogens represented at the reference site 84% and 86% of ΣPAH in PM10 and PM2.5, respectively, and at the smoking site 56% and 55% of ΣPAH in PM10 and PM2.5, respectively. All PAH (including the carcinogenic ones) were mainly present in fine particles, which corresponds to a strong risk for cardiopulmonary disease and lung cancer; thus, these conclusions are relevant for the development of strategies to protect public health.  相似文献   
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