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排序方式: 共有232条查询结果,搜索用时 15 毫秒
1.
David M. Lapola José Maria C. da Silva Diego R. Braga Larissa Carpigiani Fernanda Ogawa Roger R. Torres Luis C. F. Barbosa Jean P. H. B. Ometto Carlos A. Joly 《Conservation biology》2020,34(2):427-437
Brazil hosts the largest expanse of tropical ecosystems within protected areas (PAs), which shelter biodiversity and support traditional human populations. We assessed the vulnerability to climate change of 993 terrestrial and coastal-marine Brazilian PAs by combining indicators of climatic-change hazard with indicators of PA resilience (size, native vegetation cover, and probability of climate-driven vegetation transition). This combination of indicators allows the identification of broad climate-change adaptation pathways. Seventeen PAs (20,611 km2) were highly vulnerable and located mainly in the Atlantic Forest (7 PAs), Cerrado (6), and the Amazon (4). Two hundred fifty-eight PAs (756,569 km2), located primarily in Amazonia, had a medium vulnerability. In the Amazon and western Cerrado, the projected severe climatic change and probability of climate-driven vegetation transition drove vulnerability up, despite the generally good conservation status of PAs. Over 80% of PAs of high or moderate vulnerability are managed by indigenous populations. Hence, besides the potential risks to biodiversity, the traditional knowledge and livelihoods of the people inhabiting these PAs may be threatened. In at least 870 PAs, primarily in the Atlantic Forest and Amazon, adaptation could happen with little or no intervention due to low climate-change hazard, high resilience status, or both. At least 20 PAs in the Atlantic Forest, Cerrado, and Amazonia should be targeted for stronger interventions (e.g., improvement of ecological connectivity), given their low resilience status. Despite being a first attempt to link vulnerability and adaptation in Brazilian PAs, we suggest that some of the PAs identified as highly or moderately vulnerable should be prioritized for testing potential adaptation strategies in the near future. 相似文献
2.
Jorge Alberto Vieira Costa Bárbara Catarina Bastos Freitas Camila Gonzales Cruz Jéssica Silveira Michele Greque Morais 《Journal of environmental science and health. Part. B》2019,54(5):366-375
The loss of yields from agricultural production due to the presence of pests has been treated over the years with synthetic pesticides, but the use of these substances negatively affects the environment and presents health risks for consumers and animals. The development of agroecological systems using biopesticides represents a safe alternative that contributes to the reduction of agrochemical use and sustainable agriculture. Microalgae are able to biosynthesize a number of metabolites with potential biopesticidal action and can be considered potential biological agents for the control of harmful organisms to soils and plants. The present work aims to provide a critical perspective on the consequences of using synthetic pesticides, offering as an alternative the biopesticides obtained from microalgal biomass, which can be used together with the implementation of environmentally friendly agricultural systems. 相似文献
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4.
Larissa Stieven Montagna Thaís Larissa do Amaral Montanheiro Fábio Roberto Passador Ana Paula Lemes Mirabel Cerqueira Rezende 《Journal of Polymers and the Environment》2018,26(4):1511-1519
The potential use of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/graphite nanosheets (GNS) as a biodegradable nanocomposite has been explored. PHBV/GNS nanocomposites films were prepared by solution casting at various concentrations of GNS—0.25, 0.50 and 1.00 wt% GNS. The films were exposed to artificial ultraviolet radiation (UV) during 52 h. The effect of GNS on PHBV photodegradation was investigated and compared to neat PHBV film. The artificial photodegradation induced changes in physical (weight loss), chemical carbonyl index by Fourier transform infrared spectroscopy, thermal degree of crystallinity and melting temperature by differential scanning calorimetry and morphological scanning electron microscopy characteristics. Based on the results obtained from aforementioned analyzes it was verified that GNS inhibits the oxidative degradation of PHBV matrix. 相似文献
5.
Anabela Rebelo Isabel Ferra Albertina Marques Manuela Moreira Silva 《Environmental science and pollution research international》2016,23(24):24560-24566
The chloroform is a substance that presents a significant risk to or via the aquatic environment. Thus, the emissions, discharges and losses of this substance need to be controlled during wastewater disinfection for reclamation and reuse purposes. Due to its carcinogenetic potential, multiple studies have been carried out on drinking and surface/natural waters but less consideration has been directed to the wastewater disinfection. The focus of this work studied the formation of chloroform during chlorination in prepared waters or artificial matrices that intended to simulate wastewaters stored in landscape ponds for green areas irrigation. The relation between reaction time, chlorine dose, and chloroform formation and the variation of the dissolved organic carbon (DOC) content during the reaction was assessed. A two-variant model was proposed to simulate breakpoint chlorination practices (when chlorine dose is equal or lower than chlorine demand) and super chlorination techniques (when chlorine dose tends to surpass chlorine demand). The model was validated by the application of actual data from working conditions of six wastewater treatment plants located in Algarve, Portugal, including other data obtained in previous research studies that were not used in the model development, and by comparing the predicted values with real measured ones. 相似文献
6.
Alexandre Bevilacqua Leoneti Valquiria Aragão-Leoneti Simone Vasconcelos Ribeiro Galina Geciane Silveira Porto 《Environment, Development and Sustainability》2017,19(2):637-651
Brazil is considered one of the world’s leading producers of biofuels given the predominance of ethanol fuel in its energy matrix. However, despite the prominence of Brazil in ethanol production, the vast majority of biodiesel production plants in Brazil use methanol instead of ethanol as the alcohol for transesterification reaction, as is generally the case in the rest of the world. The aim of this paper is therefore to examine the transesterification process in the Brazilian biodiesel production in terms of sustainability. In this regard, it was necessary to evaluate the way in which the industrial process is currently carried out, the role of government incentives or subsidies for the use of ethanol to produce biodiesel, and the investments of companies in technology development for the same purpose. This study presents indications that the development of the biodiesel market in Brazil is still oriented toward a production model which is inconsistent with the environmental and social aspects of sustainability. 相似文献
7.
José Thales da Motta Portillo Vinícius Londe Francisco Wagner Araújo Moreira 《Journal of Coastal Conservation》2017,21(1):139-144
In Brazil, few studies have been conducted about the assimilation of carbon and biomass accumulation in mangroves despite its great role as a carbon sink. In this sense, this study aimed to estimate the aboveground biomass (AGB) and carbon stocked by mangrove species in a stretch along the Piraquê-Açu River in southeastern Brazil, and to verify their relation with some soil parameters. For such, the height and diameter of all trees inside six plots of 100 m2 were measured and used to quantify AGB through an allometric equation, and soil samples were collected to calculate granulometry, humidity, time of infiltration and permeability. Multiple regressions were used to identify relations between AGB and soil parameters. A total of 296 trees were found in the area and the AGB and carbon assimilated were 2.92 t ha?1 and 1.46 t ha?1, respectively. Laguncularia racemosa was the most abundant species and contributed with 61% of these values. Only a positive relation between AGB/carbon of L. racemosa and soil humidity was found, probably due to the substrate characteristics which contain a large concentration of silt/clay, and may store more water and do not yet provide firmness to the roots. By comparison, this mangrove had a low amount of AGB and carbon stocked and has yet to develop structurally. Along with other ecological functions and its associated ecosystem services such as supplying food for the local community, these features highlight the importance to conserve the studied mangrove and the interlinked coastal ecosystems. 相似文献
8.
do A Kehrig H Seixas TG Palermo EA Baêta AP Castelo-Branco CW Malm O Moreira I 《Environmental science and pollution research international》2009,16(1):10-24
Background, aim, and scope Selenium (Se) has been shown to reduce mercury (Hg) bioavailability and trophic transfer in aquatic ecosystems. The study
of methylmercury (MeHg) and Se bioaccumulation by plankton is therefore of great significance in order to obtain a better
understanding of the estuarine processes concerning Hg and Se accumulation and biomagnification throughout the food web. In
the western South Atlantic, few studies have documented trace element and MeHg in fish tissues. No previous study about trace
elements and MeHg in plankton has been conducted concerning tropical marine food webs. Se, Hg, and MeHg were determined in
two size classes of plankton, microplankton (70–290 μm) and mesoplankton (≥290 μm), and also in muscle tissues and livers
of four fish species of different trophic levels (Mugil liza, a planktivorous fish; Bagre spp., an omnivorous fish; Micropogonias furnieri, a benthic carnivorous fish; and Centropomus undecimalis, a pelagic carnivorous fish) from a polluted estuary in the Brazilian Southeast coast, Guanabara Bay. Biological and ecological
factors such as body length, feeding habits, and trophic transfer were considered in order to outline the relationships between
these two elements. The differences in trace element levels among the different trophic levels were investigated.
Materials and methods Fish were collected from July 2004 to August 2005 at Guanabara Bay. Plankton was collected from six locations within the bay
in August 2005. Total mercury (THg) was determined by cold vapor atomic absorption spectrometry (CV-AAS) with sodium borohydride
as a reducing agent. MeHg analysis was conducted by digesting samples with an alcoholic potassium hydroxide solution followed
by dithizone-toluene extraction. MeHg was then identified and quantified in the toluene layer by gas chromatography with an
electron capture detector (GC-ECD). Se was determined by AAS using graphite tube with Pin platform and Zeeman background correction.
Results and discussion Total mercury, MeHg, and Se increased with plankton size class. THg and Se values were below 2.0 and 4.8 μg g−1 dry wt in microplankton and mesoplankton, respectively. A large excess of molar concentrations of Se in relation to THg was
observed in both plankton size class and both fish tissues. Plankton presented the lowest concentrations of this element.
In fish, the liver showed the highest THg and Se concentrations. THg and Se in muscle were higher in Centropomus undecimalis (3.4 and 25.5 nmol g−1) than in Micropogonias furnieri (2.9 and 15.3 nmol g−1), Bagre spp (1.3 and 3.4 nmol g−1) and Mugil liza (0.3 and 5.1 nmol g−1), respectively. The trophic transfer of THg and Se was observed between trophic levels from prey (considering microplankton
and mesoplankton) to top predator (fish). The top predators in this ecosystem, Centropomus undecimalis and Micropogonias furnieri, presented similar MeHg concentrations in muscles and liver. Microplankton presented lower ratios of methylmercury to total
mercury concentration (MeHg/THg) (34%) than those found in mesoplankton (69%) and in the muscle of planktivorous fish, Mugil liza (56%). The other fish species presented similar MeHg/THg in muscle tissue (of around 100%). M. liza showed lower MeHg/THg in the liver than C. undecimalis (35%), M. furnieri (31%) and Bagre spp. (22%). Significant positive linear relationships were observed between the molar concentrations of THg and Se in the
muscle tissue of M. furnieri and M. liza. These fish species also showed significant inverse linear relationships between hepatic MeHg and Se, suggesting a strong
antagonistic effect of Se on MeHg assimilation and accumulation.
Conclusions Differences found among the concentrations THg, MeHg, and Se in microplankton, mesozooplankton, and fishes were probably related
to the preferred prey and bioavailability of these elements in the marine environment. The increasing concentration of MeHg
and Se at successively higher trophic levels of the food web of Guanabara Bay corresponds to a transfer between trophic levels
from the lower trophic level to the top-level predator, suggesting that MeHg and Se were biomagnified throughout the food
web. Hg and Se were positively correlated with the fish standard length, suggesting that larger and older fish bioaccumulated
more of these trace elements. THg, MeHg, and Se were a function of the plankton size.
Recommendations and perspectives There is a need to assess the role of selenium in mercury accumulation in tropical ecosystems. Without further studies of
the speciation of selenium in livers of fishes from this region, the precise role of this element, if any, cannot be verified
in positively affecting mercury accumulation. Further studies of this element in the study of marine species should include
liver samples containing relatively high concentrations of mercury. A basin-wide survey of selenium in fishes is also recommended. 相似文献
9.
10.
This paper presents an overview of cell phone recycling programs currently available in the United States. At the same time, it also provides analyses of the current recycling situation and possible recycling alternatives for Brazil. Although there are several recycling options in the United States, collection rates are still only 10% of all potential devices because customers are not aware of these possibilities. The whole system is financially based on reselling refurbished cell phones and recycled materials to developing countries which represent an effective and strong market. Several recyclers offer funds to collection partners who are either charities or who work with charities while obtaining the materials that they need in order to run their operations. A mobile phone recycling system for Brazil considering the United States experience and the Extended Producer Responsibility (EPR) principle is suggested. A deposit/refund/advance-recycling fee is proposed which might be implemented as a voluntary industrial initiative managed by PRO Brazil, a producer responsibility organization. One widespread public–private agreement will integrate all mobile phone stakeholders, and environmental education actions and promotional events will promote citizen’s participation. 相似文献