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1.
As a contribution to the climatological characterization of the Izaña baseline observatory (Tenerife, Canary Islands, Spain), back-trajectories were calculated and an air mass climatology was developed for a 5-year period. On a daily basis, 5-day back-trajectories were computed for the 850- and 700-HPa levels from January 1983 to December 1987. Trajectories were separated into long- and short-range flows and classified into categories depending on the path followed by the air masses. Flows from the North Atlantic Ocean were much more frequent than flows from continental sectors. In addition, seasonal variations of the sector frequencies were studied and synoptic meteorological patterns were associated with each trajectory category.  相似文献   

2.
Polybrominated diphenyl ethers (PBDEs) as ubiquitous persistent organic pollutants have attracted much attention in recent years. Exposure to PBDEs could induce a high health risk for children. The aim of this study was to investigate the PBDEs exposure of children (9–12 years) from Taizhou, China. Fifty-eight blood samples were collected in one school in a mountainous area in Taizhou. The concentrations of Σ9PBDEs (sum of BDE-28, -47, -99, -100, -153, -154, -183, -197 and -209) ranged from 2.66 to 33.9 ng/g lipid wet (lw) with a median of 7.22 ng/g lw. These concentrations were lower than those of children in USA, but close to European and Asian general population levels. The results showed that children in Taizhou countryside were at a low level of PBDEs exposure. The predominant congener was BDE-209, followed by BDE-28, -47, -197 and -153. High abundance of BDE-209 was consistent with the pollution background of PBDEs in China characterized by high brominated congeners as main pollutants.  相似文献   

3.
The heavy intensification of agriculture in East China since the 1980s caused the decrease of lake area and water storage capacity with impediment of regulation, lake eutrophication and frequent floods. Many restoration projects have been conducted. However, the knowledge of biogeochemical factors that drive nutrient cycles during the early stage of restoration is still limited. We studied the effect of the remediation of a patch of near-shore shallow wetland on the northern bank of Chaohu Lake in the Yangtze-Huaihe region, China, which was used as rice paddy for many years, on the behavior of phosphorus. Redox potential (ORP), temperature and dissolved oxygen were monitored in situ from May 2006 to November 2007. Samples of soil pore water were collected during this time for the determination of different forms of iron and phosphorus. ORP showed a clear transition of the wetland soil from an oxidized state in winter to a reduced state in summer. The decrease of ORP correlated with the release of large amounts of Fe and P. The maxima of total dissolved Fe and total dissolved P in the summer of the second year were (13.8 ± 6.8) mg/L and (0.88 ± 0.27) mg/L, respectively. It is worth noticing that P concentration far exceeded the critical value of lake eutrophication (0.02 mg/L). The pressure of P release to the adjacent lake during the first two years of wetland restoration from rice fields should be taken into account by environmental policy makers.  相似文献   

4.
During January, July and August 1988, two experimental campaigns were carried out in the surroundings of the Castellón industrial area located on the Spanish east coast. The main objective was to study the dispersion of the power plant plume located on this site. This work also forms part of a larger program intended to compose a mosaic of atmospheric mesoscale flows related to air pollution cycles for the whole of the Iberian peninsula.In this program, air pollutants have also been considered as tracers of opportunity of the atmospheric circulations, and the study of ground-level concentration cycles has been used to provide evidence for the meso-meteorological processes. On the Castellón coast, and for most of the year, surface atmospheric dynamics are dominated by local cycles of north-west nocturnal drainage winds and east to south-south-east daytime sea-breeze flows. This regime is particularly marked during the summer, while the effect of large scale synoptic conditions is more noticeable in winter and spring.A mobile laboratory was used to collect 10 min averaged values of O3, NO, NO2, and SO2. This unit was placed in the expected zone of influence of the coastal industries during the sea-breeze regime. Data obtained under summer and winter conditions have been compared and, while the temporal evolution of the concentrations of the compounds studied have similar structures, high ozone values have been detected in association with the onset of the sea-breeze during the summer.  相似文献   

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The feasibility of copper recovery by induced crystallization in a long period(174 days) was investigated in a seeded fluidized bed reactor(FBR). The process was divided into 3 periods according to different influent conditions, and the period III was separated into III-a and IIIb due to the adjustment of the molar ratio of CO_3~(2-)concentration to copper concentration([CT]/[Cu~(2+)]). The removal efficiency could exceed 95% and the average effluent copper concentration decreased to 3.0 mg/L. The mean particle size of seed grains with copper crystals coating on, raised to 0.36 mm from initial 0.18 mm. During period III-a, the supersaturation exceeded 2.88 × 104, the removal efficiency decreased to 60%–80% and the particle size dropped to 0.30 mm, due to the generation of fines by homogeneous crystallization and seeds breaking. And the morphology of the crystals on the seed grains changed from rod-like to spherical which lead to the particle size decreasing. In period III-b,the supersaturation was modified by adjusting the molar ratio of [CT]/[Cu2+] to 1.2 from 2.The efficiency was back to 95% and the mean particle size grew to 0.36 mm at the end of IIIb, the crystals coating on the seeds turned back to rod-like products of good stability. This study illustrated that the copper salt crystal could keep on growing on the seed grains for over 150 days, the feasibility and controllability of copper recovery by induced crystallization process in FBR were satisfactory, even under the dramatic changes in influent conditions.  相似文献   

7.
El Niño is well known to affect marine fishery. The Southern Oscillation, however, may also have a strong effect on riverine fish production in floodplains via its effect on river discharge. In years with high river discharges larger parts of the floodplain are inundated, increasing the surface area of suitable nursery grounds for young fish stock. In this way high river discharges are thought to have a positive effect on fish production, while low discharges are thought to have a negative effect. The collapse of the sábalo fishery in the Pilcomayo River in Bolivia, for instance, can be attributed to the 1990–1995 El Niño event and subsequent overexploitation of the fish stocks.  相似文献   

8.
Addressing the global challenges of climate change (CC), food security and poverty alleviation requires enhancing the adaptive capacity and mitigation potential of land use systems. To this end, Climate Smart Agriculture (CSA) aims to identify land use practices that sustainably increase productivity, enhance climate change (CC) adaptation and contribute to CC mitigation. A transition towards CSA requires technical, but also socio-institutional changes, for improved smallholder agricultural systems. Such changes may be triggered by stakeholder participation processes that stimulate social learning and collective action. This article evaluates whether a role-playing game (RPG) is an effective participatory tool to encourage social learning and collective action among local stakeholders towards adoption of CSA strategies. We designed and implemented an RPG with three groups of farmers in Apuí (Southern Amazonas), evaluating the game’s impact on social learning by interviewing each farmer before and after the RPG. Our findings show that the RPG induced not only technical learning, but also socio-institutional learning and engagement for collective action, though outcomes varied between different RPG sessions and among farmer participants.  相似文献   

9.
1 Introduction1-1 DiatomsDiatoms(ClassBacillariophyceae)arecommonandwidelydistributedinbothfreshandmarinewaters(Moser,1996).ThesemicroscopicunicellularplantsfixamajorportionoftheEarth○scarbon,generateoxygen,andsupplyfoodtoanimalswhichfeedonthem(Dixit…  相似文献   

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Air pollution causes deleterious effects on human health with aerosols being among the most polluting agents.The objective of this work is the characterization of the PM_(2.5) and PM_(10) aerosol mass in the atmosphere.The methods of analysis include WD-XRF and EDS.Data were correlated with meteorological information and air mass trajectories(model HYSPLIT)by multivariate analysis.A morphological structural analysis was also carried out to identify the probable sources of atmospheric aerosols in the city of Sao Jose do Rio Preto,Brazil.The mean mass concentration values obtained were 24.54 μg/m~3 for PM_(10),above the WHO annual standard value of 20 μg/m~3 and 10.88 μg/m~3 for PM_(2.5) whose WHO recommended limit is10 μg/m~3.WD-XRF analysis of the samples revealed Si and Al as major components of the coarse fraction.In the fine fraction,the major elements were Al and S.The SEM-FEG characterization allowed identifying the morphology of the particles in agglomerates,ellipsoids and filaments in the PM_(10),besides spherical in the PM_(2.5).The analysis by EDS corroborated WD-XRF results,identifying the crustal elements,aluminosilicates and elements of anthropogenic origin in the coarse fraction.For the fine fraction crustal elements were also identified;aluminosilicates,black carbon and spherical particles(C and O) originating from combustion processes were predominant.The use of multivariate analysis to correlate air mass trajectories with the results of the morpho-structural characterization of the particulate matter allowed confirmation of the complex composition of the particles resulting from the combination of both local and long-distance sources.  相似文献   

12.

The aim of this study was to determine the origin (human, bovine or porcine) and the concentration of the fecal sources of contamination in waters from Santa Lucía basin and Uruguay River in Uruguay by using host-specific viral markers (adenoviruses and polyomaviruses) as microbial source tracking (MST). Between June 2015 and May 2016, monthly collections of surface water samples were performed in six sites in Santa Lucía basin and four sites in Uruguay River (n = 120 samples). Viral concentration was carried out using an absorption-elution method. Detection and quantification of human and porcine adenovirus (HAdV and PAdV, respectively) and human and bovine polyomavirus (HPyV and BoPyV, respectively) were performed by quantitative PCR (qPCR). To evaluate the infectivity of circulating HAdV, an integrated cell culture-qPCR (ICC-qPCR) was used. A logistic regression analysis was carried out to estimate the influence of environmental variables on the virus presence in surface waters. Overall, HAdV was the prevalent (18%; 21/120) followed by BoPyV (11%; 13/120) and HPyV (3%; 3/120), whereas PAdV was not detected in this study. The mean concentration ranged from 1.5 × 104 genomic copies/L (gc/L) for HAdV to 1.8 × 102 gc/L for HPyV. Infective HAdVs were observed in two out of ten analyzed samples. A significant effect of environmental temperature (p = 0.001) and river (p = 0.012) on the presence of human viruses was found. These results suggest that fecal contamination could affect the water quality of these rivers, showing deficiencies in the procedure of sewage discharge from regional cities, livestock and dairy farms.

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13.
A water bloom sample collected from Lake Dishui in Shanghai was characterized. The morphological identification showed that Micorcystis wesenbergii and Micorcystis smithii were the main component of the bloom. Five strains of M. smithii were successfully isolated. Their 16S rRNA gene sequences based phylogenetic tree showed that the five strains of M. smithii intermixed with strains of other morphospecies in Microcystis. A fragment of mcy gene encoding for microcystin synthetase was detected in one of the five M. smithii strains (CHAB 2183), indicating its potential of microcystin production. High performance liquid chromatography analysis confirmed M. smithii CHAB 2183 to produce microcystin-RR as 1550 g per gram dry weight cells. The present investigation, for the first time, reported the isolated strains of M. smithii and microcystin production from M. smithii.  相似文献   

14.
A water bloom sample collected from Lake Dishui in Shanghai was characterized.The morphological identification showed that Micorcystis wesenbergii and Micorcystis smithii were the main component of the bloom.Five strains of M.smithii were successfully isolated.Their 16S rRNA gene sequences based phylogenetic tree showed that the five strains of M.smithii intermixed with strains of other morphospecies in Microcystis.A fragment of mcy gene encoding for microcystin synthetase was detected in one of the five M....  相似文献   

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Introduction B isphenol A (2, 2-bis (4-dihydroxydiphenyl) propane) (BPA ) is w idely used as a raw m aterial for polycarbonate and epoxy resins. In previous studies, the residue level of B PA w as detected to be at a rather high level in natural w ater en…  相似文献   

17.
This paper compares the life cycle global warming potential of three of Australia’s important agricultural production activities – the production of wheat, meat and wool in grazed subterranean clover (sub-clover) dominant pasture and mixed pasture (perennial ryegrass/phalaris/sub-clover/grass and cape weed) systems. Two major stages are presented in this life cycle assessment (LCA) analysis: pre-farm, and on-farm. The pre-farm stage includes greenhouse gas (GHG) emissions from agricultural machinery, fertilizer, and pesticide production and the emissions from the transportation of these inputs to paddock. The on-farm stage includes GHG emissions due to diesel use in on-farm transport and processing (e.g. seeding, spraying, harvesting, topdressing, sheep shearing), and non-CO2 (nitrous oxide (N2O), and methane (CH4)) emissions from pastures and crop grazing of lambs.The functional unit of this life cycle analysis is the GHG emissions (carbon dioxide equivalents – CO2 -e) from 1 kg of wheat, sheep meat and wool produced from sub-clover, wheat and mixed pasture plots. The GHG emissions (e.g. CO2, N2O and CH4 emission) from the production, transportation and use of inputs (e.g. fertilizer, pesticide, farm machinery operation) during pre-farm and on-farm stages are also included. The life cycle GHG emissions of 1 kg of wool is significantly higher than that of wheat and sheep meat. The LCA analysis identified that the on-farm stage contributed the most significant portion of total GHG emissions from the production of wheat, sheep meat and wool. This LCA analysis also identified that CH4 emissions from enteric methane production and from the decomposition of manure accounted for a significant portion of the total emissions from sub-clover and mixed pasture production, whilst N2O emissions from the soil have been found to be the major source of GHG emissions from wheat production.  相似文献   

18.
PCDD/Fsinsodiumpentachlorophenate(Na-PCP)andhumanblood,milkandsedimentsamplesfromChineseschistosomiasisareasJiangKe;ChenYudon...  相似文献   

19.
Nowadays, more people tend to spend their recreational time in large national parks, and trace metal(loid)s in soils have attracted long-term attention due to their possible harm to human health. To investigate the pollution levels, potential sources and health risks of trace metal(loid)s in road soils, a total of eight trace metal(loid)s (including As, Cd, Cr, Cu, Ni, Pb, Zn and Hg) from 47 soil samples along roads were studied in the Huangshan National Park in Southeast China. The results showed that the concentrations of As, Cd, Pb, Zn and Hg appeared different degrees of pollution compared with their corresponding background values. According to the pollution indices, Hg and Cd were recognized as significant pollutants presenting moderate to high ecological risk. Combining principal component analysis and positive matrix factorization model, the results showed that traffic, industrial, agricultural and natural sources were the potential origins of trace metal(loid)s in this area, with contribution rates of 39.93%, 25.92%, 10.53% and 23.62%, respectively. Non-carcinogenic risks were all negligible, while the carcinogenic risk of As was higher than the limit (1 × 10−6). Moreover, children were more susceptible to trace metal(loid)s by ingestion which appeared to be a more important exposure pathway than dermal contact and inhalation. The contribution rates of different sources to non-carcinogenic risks and carcinogenic risks were similar among children and adults, while traffic and industrial sources have a significant impact on health risks. This study will give more insights to control the environmental risks of trace metal(loid)s in national parks.  相似文献   

20.
A heavy metal contaminated soil sample collected from a mine in Chonnam Province of South Korea was found to be a source of heavy metal adsorbing biosorbents. Chemical analyses showed high contents of lead (Pb) at 357 mg/kg and cyanide (CN) at 14.6 mg/kg in the soil. The experimental results showed that Penicillium sp. MRF-1 was the best lead resistant fungus among the four individual metal tolerant fungal species isolated from the soil. Molecular characterization of Penicillium sp. MRF-1 was determined using ITS regions sequences. E ects of pH, temperature and contact time on adsorption of Pb(II) by Penicillium sp. MRF-1 were studied. Favorable conditions for maximum biosportion were found at pH 4 with 3 hr contact time. Biosorption of Pb(II) gradually increased with increasing temperature. E cient performance of the biosorbent was described using Langmuir and Freundlich isotherms. Adsorption kinetics was studied using pseudo first-order and pseudo second-order models. Biosorbent Penicillium sp. MRF-1 showed the maximum desorption in alkali conditions. Consistent adsorption/desorption potential of the biosorbent in repetitive cycles validated the e cacy of it in large scale. SEM studies given notes on surface modification of fungal biomass under metal stress and FT-IR results showed the presence of amino groups in the surface structure of the biosorbent. In conclusion, the new biosorbent Penicillium sp. MRF-1 may potentially be used as an inexpensive, easily cultivatable material for the removal of lead from aqueous solution.  相似文献   

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