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571.
Heavy Metals in Littoral Deposits Off Havana City, Cuba 总被引:1,自引:0,他引:1
The content of Al, Cd, Co, Cu, Fe, Hg, Mn, Ni, Pb, Zn, C org and organic matter was investigated in sediment samples taken in the littoral zone off Havana City. the results revealed three areas affected by contamination: (a) Chivo Beach with a submarine sewage outfall, (b) the mouth of the Havana Bay and (c) the estuarine area of the Almendares River. the normalization of the heavy metals contents with respect to aluminium and organic matter combined with multivariate statistical methods was found valuable for a proper interpretation of the analytical results. 相似文献
572.
González Sagrario Mde L Miglioranza KS Aizpún de Moreno JE Moreno VJ Escalante AH 《Chemosphere》2002,48(10):1113-1122
Polychlorinated biphenyls (PCBs) were determined in a aquatic community from Los Padres Lake, Argentina. Twenty four PCB congeners from tri- to octa-chlorinated isomers were detected and quantified using conventional gas chromatography with electron capture detector (GC-ECD). The aim of this study was to investigate the concentrations of PCBs in freshwater organisms from a shallow lake of Argentina. Stems of bulrush (Schoenoplectus californicus), whole tissues of false loosestrife (Ludwigia sp.) and grass shrimp (Palaemonetes argentinus), and liver, gonads, muscle and mesenteric fat (if present) of fish species (Rhamdia sapo) and (Oligosarcus jenynsi) were analyzed. Two areas were selected to macrophytes sampling: the input area, main PCB source of the lake (Station 1), and the output area, a potential anoxic zone (Station 2). Macrophytes from Station 1 bioconcentrated higher total PCB levels than Station 2, showing that the former have received PCBs washed down from upstream areas. Penta- and hexa-congeners were enriched relative to other congeners in animal biota and macrophytes from Station 1, consistent with commercial mixture of Aroclor 1254 used in this region. In bulrush from Station 2 a predominance of tri- and tetra-chlorinated congeners was observed. Grass shrimp showed the lowest PCB values among animal biota. PCB concentrations in fish tissues varied with the species and the gonadal development. Mesenteric fat, only present in post-spawning organisms of R. sapo, had the highest values of PCBs relative to other tissues. A clearance of total PCBs in ovaries of post-spawning females of R. sapo was observed, but not in testes. O. jenynsi/P. argentinus biomagnification factor (BMF) had a mean value of 18.7. Congeners 44, 52 and 151, showed the highest BMF values, being 64, 66 and 62, respectively. These values would be a consequence of the low depuration rate of 44 and 52 congeners with orthochlorine substitution conducted by O. jenynsi and the high depuration rate of congener 151, which lacks 4 4′- chlorine substitution, carried out by grass shrimp. Although the most of congeners have been biomagnified, they did not clearly displayed a concomitantly increasing with log Kow. 相似文献
573.
Organochlorine pesticides accumulation and degradation products in vegetation samples of a contaminated area in Galicia (NW Spain) 总被引:5,自引:0,他引:5
Barriada-Pereira M González-Castro MJ Muniategui-Lorenzo S López-Mahía P Prada-Rodríguez D Fernández-Fernández E 《Chemosphere》2005,58(11):1571-1578
The content of 21 organochlorine pesticides were studied in vegetation samples of a highly contaminated area by isomers of hexachlorocyclohexane (HCH) located close to a former industrial area in Galicia (NW Spain). Five species of plants were collected at different points of the contaminated area and the different parts of the plants were separated in order to study differences in accumulation capabilities. Samples were extracted employing microwave energy followed by a clean-up step using solid phase extraction and finally determined by GC–ECD. The results obtained show that the most abundant pesticides are HCHs isomers, being the main isomers β-HCH and -HCH in all samples whereas δ-HCH and γ-HCH were at lower levels. Some other pesticides such as p,p′-DDT, p,p′-DDD and p,p′-DDE were also present in much lower amount in some of the samples. Several degradation products of HCH were also identified in some samples by GC–MS. 相似文献
574.
The possibility of using organic solvents (OSs) to increase the susceptibility of bioluminescent microorganisms in a bioassay for assessing the toxicity of chemicals dissolved in water was investigated. To conduct the tests acetonitrile, dimethyl sulfoxide, ethanol, methanol, and isopropanol were used as OSs and Cd, Hg, and Zn as reference toxicants. The addition of OSs modified the toxicity of the three metals to Vibrio harveyi, according on the bioluminescence assay used. The sensitivity of the luminescence bioassay for Hg increased in the presence of the five OSs, thus indicating a greater toxic effect. However, the sensitivity of the assay for the other two metals, Cd and Zn, increased or decreased (lesser toxic effect) depending on the concentration at which the OSs were used. No correlation was observed between the concentration of the five OSs and the toxicity of the three reference toxicants. From this it can be deduced that none of these OSs could be recommended for increasing generically the sensitivity of toxicity biotests using V. harveyi. 相似文献
575.
Ebensperger LA Hurtado MJ Soto-Gamboa M Lacey EA Chang AT 《Die Naturwissenschaften》2004,91(8):391-395
Communal nesting is a fundamental component of many animal societies. Because the fitness consequences of this behavior vary with the relatedness among nest mates, understanding the kin structure of communally nesting groups is critical to understanding why such groups form. Observations of captive degus (Octodon degus) indicate that multiple females nest together, even when supplied with several nest boxes. To determine whether free-living degus also engage in communal nesting, we used radiotelemetry to monitor spatial relationships among adult females in a population of O. degus in central Chile. These analyses revealed that females formed stable associations of > 2–4 individuals, all of whom shared the same nest site at night. During the daytime, spatial overlap and frequency of social interactions were greatest among co-nesting females, suggesting that nesting associations represent distinct social units. To assess kinship among co-nesting females, we examined genotypic variation in our study animals at six microsatellite loci. These analyses indicated that mean pairwise relatedness among members of a nesting association (r=0.25) was significantly greater than that among randomly selected females (r=–0.03). Thus, communally nesting groups of degus are composed of female kin, making it possible for indirect as well as direct fitness benefits to contribute to sociality in this species. 相似文献
576.
Impact of nickel mining and metallurgical activities on the distribution of heavy metals in sediments of Levisa, Cabonico and Nipe Bays, Cuba 总被引:1,自引:0,他引:1
At MayarÕ zone, northeast Cuba, important lateritic deposits have been exploited since 1943. The mineral is used as raw material in a nickel-processing plant which discharges its untreated solid and liquid wastes into Levisa Bay. Similarly to the adjacent Nipe and Cabonico bays, fluvial currents from the mining areas convey a significant mineral load into this bay. To assess the environmental impact caused by the mining and the metallurgical activities, the distribution of Ni, Co, Fe, Mn, Cu, Pb and Zn was investigated in surface and core sediment samples. Uni- and multivariate statistical methods as well as different indices and pollutant factors were used to interpret results. These revealed significant environmental impacts in some areas of the three bays with high concentrations of Ni, Co, Fe and Mn, whose values are up to two orders of magnitude greater than the zone baseline levels. The metal concentrations decreased with increasing distance from discharges. A comparison with other Cuban bays and coastal zones, confirmed that the main source of metal pollution in these three bays was not urban and industrial activities, but lateritic mining and metallurgy. 相似文献
577.
Ana Marçalo Luísa Mateus José Henrique Duarte Correia Pedro Serra Rob Fryer Yorgos Stratoudakis 《Marine Biology》2006,149(6):1509-1518
Observations from the purse seine fishery off northern Portugal are used to describe the early dynamics of sardine (Sardina pilchardus) stress reactions and identify likely stressors during the commercial fishing operation. Sardine blood and muscle were sampled from the onset of fishing (school identification and encircling) to the end of fish transfer onboard (90–120 min later). The evolution of haematocrit, haemoglobin, cortisol, glucose, ionic concentrations, ATP and its catabolites were modelled using linear mixed models as a function of time spent in the net, biological (sex, reproductive state and condition) and operational variables (catch, light level and phase of fishing operation). Significant linear trends with time were detected for most stress variables and mean concentrations after 2 h in the net were similar to literature values corresponding to acute stress reactions for teleosts. Biological variables were rarely significant and explained a small proportion of variation, while operational variables were never significant. For each stress variable, levels varied considerably between trips but the temporal evolution was common across trips. Random trip effects were uncorrelated among most biochemical variables, suggesting that distinct factors affected each stress variable during the sampled trips. However, the linear trend with time spent in the net observed for most stress variables indicates that the duration of the fishing operation is an important stressor in purse seine fishing due to the progressive water volume restriction, crowding and manipulation associated to the fishing method. 相似文献
578.
Site-Selection Algorithms and Habitat Loss 总被引:13,自引:0,他引:13
579.
Mirady Sebastiani Sara Elena González María Mercedes Castillo Pablo Alvizu María Albertina Oliveira Jorge Pérez Antonio Quilici Martín Rada María Carolina Yáber Miguel Lentino 《Environmental management》1994,18(5):647-661
In Venezuela, large-scale shrimp farming began in the 1980s. By 1987, the Ministry of Environment and Natural Resources (MARNR)
had received 14 proposals for approval. A developer illegally started the construction of ponds at the Píritu Lagoon in the
State of Anzoátegui before the authorization process was completed. This action triggered a land-use conflict. This study
identifies the causes for public protest and determines the consequences of this conflict for land-use management. The results
show that public protest was based on the impacts of the partial construction of ponds. These impacts were related to direct
removal of wetlands, interruption of natural patterns of surface flows, and alteration of feeding grounds of some bird species
with migratory status. Consequences were identified in relation to the role that nongovernmental organizations (NGOs) play
in land-use conflicts and the actions that MARNR could take in the future to prevent and solve similar situations. 相似文献
580.
Alejandro Rivera Jorge Silvio González Raúl Carrillo José María Martínez 《Journal of Cleaner Production》2009,17(2):137-142
The development and implementation of new procedures and operational changes in the production processes constitutes a powerful tool for the practical application of Cleaner Production in industries. In this work an operational change (new procedure) was developed for the elaboration of a type of beer which uses sugar as malt adjunct. The change consists in processing separately the three main components of the beer wort: malt extract, sugar and water, and use them properly in a different sequence than that used up to date in the traditional process. The new procedure was successfully assayed on industrial scale in Tínima brewery, located in Camagüey, Cuba, obtaining a good quality beer, technological and economical advantages with benefits for the environment, registering significant savings in energy (49%), sugar (4%), water (7%) and caustic soda (3%) consumption; and diminishing the surplus hot water (74%), waste generation (11%) and greenhouse gases emission (21%). Beer production capacity is increased also almost three times. With the application of the new technology to the Cuban beer type of 8 °P, it was achieved a total saving of US$ 481.83/1000 hL of beer produced. 相似文献