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241.
Efficiency of white lupin in the removal of mercury from contaminated soils: Soil and hydroponic experiments 总被引:1,自引:0,他引:1
Pilar Zornoz Roc′?o Mill′an M. Jos′e Sierr Almudena Seco Elvira Esteban 《环境科学学报(英文版)》2010,22(3):421-427
This study examined the ability of the white lupin to remove mercury (Hg) from a hydroponic system (Hg concentrations 0, 1.25, 2.5, 5 and 10 μmol/L) and from soil in pots and lysimeters (total Hg concentration (19.2 ± 1.9) mg/kg availability 0.07%, and (28.9 ± 0.4) mg/kg availability 0.09%, respectively), and investigated the accumulation and distribution of Hg in different parts of the plant. White lupin roots efficiently took up Hg, but its translocation to the harvestable parts of the plant was low. The Hg concentration in the seeds posed no risk to human health according to the recommendations of the World Health Organization, but the shoots should not be used as fodder for livestock, at least when unmixed with other fodder crops. The accumulation of Hg in the hydroponically-grown plants was linear over the concentration range tested. The amount of Hg retained in the roots, relative to the shoots, was almost constant irrespective of Hg dose (90%). In the soil experiments, Hg accumulation increased with exposure time and was the greater in the lysimeter than in the pot experiments. Although Hg removal was the greater in the hydroponic system, revealing the potential of the white lupin to extract Hg, bioaccumulation was the greatest in the lysimeter-grown plants; the latter system more likely reflects the true behaviour of white lupin in the field when Hg availability is a factor that limits Hg removal. The present results suggest that the white lupin could be used in long-term soil reclamation strategies that include the goal of profitable land use in Hg-polluted areas. 相似文献
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244.
Teresa Pamatz-Bolaños Denis A. Cabrera-Munguia Horacio González Rosa E. Del Río José L. Rico Gabriela Rodríguez-García 《International Journal of Green Energy》2018,15(8):465-472
Caesalpinea eriostachys seed oil, as a source of triglycerides with potential application for biodiesel production in Mexico is introduced. Its lipid profile obtained by Gas Chromatography-Mass Spectrometry (GC-MS) revealed saturated and unsaturated glycerol esters as the constituents. Therefore, heterogeneous and homogeneous catalyzed transesterification reactions were assayed employing ZnAl hydrotalcites and KOH, as the catalysts, respectively. The transesterification reactions yielded 59% for Zn/Al(2), 79% for Zn/Al(4), and 90% for KOH, depicting typical behavior, as in biodiesel production data from literature, where Zn-Al hydrotalcites or KOH were assayed. The caloric, density, viscosity values, and fatty acid methyl esters profile from reaction products were concordant to EN 14214, suggesting C. eriostachys as a promising feedstock for biodiesel production. 相似文献
245.
José María Navas Helmut Segner 《Environmental science and pollution research international》1998,5(2):75-82
A number of natural and man-made chemicals possess antiestrogenic activity, i.e. they antagonize a broad spectrum of estrogen-induced
responses in vertebrates. Examples of antiestrogens include dioxin, furan and PCB congeners, certain PAHs, pesticides and
indol-3-carbinol derivatives. Major mechanisms of antiestrogenicity are antagonistic action of chemicals at the estrogen receptor,
or binding of chemicals to the arylhydrocarbon (Ah) receptor and subsequent interaction with estrogen-responsive genes. Toxicological
consequences resulting from antiestrogenic activity have not been conclusively demonstrated to date, although antiestrogenic
compounds could critically affect sensitive reproductive and developmental processes. 相似文献
246.
Rodolfo Paranhos André P. Pereira Letícia M. Mayr 《Environmental monitoring and assessment》1998,50(2):131-141
The objective is to describe and quantify the diel variability of water quality in a tropical coastal system, Guanabara Bay, Brazil. Water samples were collected in spring and neap tide cycles over 24 h periods at three strategic sites. A pollution gradient was evident between the sampling sites. The average fecal coliform values decreased from 106 (site 3, most polluted) to 101 (site 1, less polluted). Organic matter mineralization was found in a similar gradient to organic pollution. However, complete nitrification was only found associated to regions where the water quality was better. Variability in this data set was determined mostly by the pollution gradient observed, and by tidal influence as well. The poor water quality indicates that the bay undergoes severe environmental stress. However water renewal promoted by tidal action was an important mechanism in diluting the pollution, improving water quality even in ebb tides and in the inner channels. The significance of micro-scale changes in water quality assessment in Guanabara Bay was confirmed, as well as the importance of these strategic sampling sites, reinforcing the importance of these measurements in monitoring programs. 相似文献
247.
Eduardo Soto-Galera Joel Paulo-Maya Eugenia López-López José Angel Serna-Hernández John Lyons 《Environmental management》1999,24(1):133-140
Chirostoma charari and C. compressum, and they are presumed extinct. Twelve (63%) of the remaining species had declines in distribution. Sixteen (80%) of the 20
localities sampled had lost species. The greatest declines occurred in Lago de Cuitzeo proper and in the lower portion of
the Río Grande de Morelia watershed. Species losses from the lake were attributable to drying and hypereutrophication of the
lake because of substantial reductions in the amount and quality of tributary inputs, whereas losses from the Río Grande de
Morelia watershed were the result of pollution from agricultural, municipal, and industrial sources, especially in the region
around the city of Morelia. Three localities in the upper portion of the Río Grande de Morelia watershed—Cointzio reservoir,
La Mintzita spring, and Insurgente Morelos stream—contained most of the remaining fish species diversity in the basin and
deserve additional protection. Fish faunal changes indicated major declines in the health of aquatic ecosystems in the Morelia–Cuitzeo
basin. 相似文献
248.
The cost of host egg damage caused by a brood parasite: experiments on great spotted cuckoos (Clamator glandarius) and magpies (Pica pica) 总被引:2,自引:0,他引:2
Manuel Soler Juan José Soler Tomás Pérez-Contreras 《Behavioral ecology and sociobiology》1999,46(6):381-386
Adult great spotted cuckoos, Clamator glandarius, frequently damage one or more eggs of their magpie host, Pica pica, without removing or eating them. The presence of damaged host eggs could signal parasitism thereby increasing the probability
that the parasitic egg is ejected. This hypothesis was tested by experimentally introducing a model cuckoo egg with or without
damaged host eggs. Magpie responses to experimental parasitism did not differ significantly between treatments implying that
damaged host eggs are not used by magpies to assess parasitism. We followed the fate of magpie eggs naturally damaged by the
great spotted cuckoo or experimentally damaged by us. Host response was very similar for naturally or experimentally damaged
host eggs, but varied significantly according to the type of egg damage, eggs being removed more frequently when pecked than
crushed, while cracked eggs were never removed. However, the egg damage that most readily causes egg removal is albumen leakage.
Received: 30 November 1998 / Received in revised form: 7 June 1999 / Accepted: 12 June 1999 相似文献
249.
Effects of paternal care on reproductive success in the polygynous spotless starling Sturnus unicolor 总被引:2,自引:0,他引:2
J. Moreno José P. Veiga Pedro J. Cordero Eduardo Mínguez 《Behavioral ecology and sociobiology》1999,47(1-2):47-53
For males of socially polygynous avian species like the spotless starling, there may exist a trade-off between investing in
paternal care and controlling several nests. To determine how the intensity of paternal care affects reproductive success
per brood sired or expressed as the total number of young raised in all nests controlled by the same male, it is necessary
to manipulate paternal care. Testosterone (T) has been shown to depress the tendency for males to care for their young, and
induces them to acquire more mates. The effects of paternal care on reproductive success were studied by treating certain
male starlings with exogenous T and others with the antiandrogen cyproterone acetate (CA), and comparing the parental behavior
of T- and CA-males throughout the breeding season with that of controls. CA-males fed their chicks more during the first week
after hatching than T-males, with controls feeding at intermediate rates, both on a per nest basis and as total effort for
all nests controlled by the same male. Paternal feeding rates during the first week of chick life had a significant positive
effect on the number of fledged young. The hormone treatment significantly affected the number of chicks raised per nest,
CA-males having a higher breeding success per nest than T-males, and controls showing intermediate levels of success. There
was no significant effect of treatment on total reproductive success attained by males throughout the season. In the polygonous
spotless starling, the intensity of paternal care of young affects reproductive success per nest positively but not on a seasonal
basis.
Received: 6 February 1999 / Received in revised form: 30 June 1999 / Accepted: 11 July 1999 相似文献
250.
José A. Donázar Alejandro Travaini Olga Ceballos Alejandro Rodríguez Miguel Delibes Fernando Hiraldo 《Behavioral ecology and sociobiology》1999,45(1):55-65
Phenotype-limited interference models assume competitive asymmetries among conspecifics and unequal sharing of resources.
Their main prediction is a correlation between dominance status and patch quality: dominant individuals should preferentially
exploit better-quality habitats. We tested assumptions and predictions of the phenotype-limited interference model in Andean
condors (Vultur gryphus), a New World vulture with strong sexual size dimorphism (males are 30–40% heavier than females). We recorded searching birds
in habitats differing in quality: mountains and plains. We also observed scavenging behaviour at 20 sheep carcasses, and videotaped
5 of them. Intraspecific hierarchy at carcasses was based on size: males dominated females and, within each sex, older birds
dominated younger ones. Adult males and juvenile females occupied extreme positions in the feeding hierarchy. Aggression was
directed at those individuals belonging to lower hierarchical levels. In high-quality areas (mountains), more condors arrived
at carcasses. Juvenile females were more often observed searching in low-quality areas (plains), far from breeding areas and
main roost sites. GLM analyses of individual behaviour showed that the hierarchy did not influence time of arrival, but low-ranking
individuals spent more time at carcasses, especially if the number of condors at arrival was high. Additionally, low-ranking
condors spent less time feeding at carcasses when individuals of higher hierarchical levels were present. On the other hand,
the number of condors present had a positive effect on feeding rates of dominant individuals, probably because of a reduction
in individual vigilance. These results support most of the assumptions and predictions of the phenotype-limited distribution
model, although a spatial truncated distribution between phenotypes was not observed. Asymmetric feeding pay-off, unequal
parental roles and sexual selection constraints could favour sexual divergence in body size in Andean condors.
Received: 6 April 1998 / Accepted after revision: 11 July 1998 相似文献