Previous studies of neustonic debris have been limited to surface sampling. Here we conducted two trawl surveys, one before and one shortly after a rain event, in which debris and zooplankton density were measured at three depths in Santa Monica Bay, California. Surface samples were collected with a manta trawl, mid-depth samples with a bongo net and bottom samples with an epibenthic sled, all having 333 micron nets. Density of debris was greatest near the bottom, least in midwater. Debris density increased after the storm, particularly at the sampling site closest to shore, reflecting inputs from land-based runoff and resuspended matter. The mass of plastic collected exceeded that of zooplankton, though when the comparison was limited to plastic debris similar to the size of most zooplankton, zooplankton mass was three times that of debris. 相似文献
Different levels of eutrophication and pollution in the Baltic coastal waters in general, and in estuaries particularly define variations in the buffering capacity of ecosystems of these important filter zones between rivers and the adjacent Baltic Proper. Phyto- and zooplankton in the estuaries form important components of the pelagic food webs that participate in producing and structuring the matter, energy, and information fluxes in the ecosystems. Due to salinity gradients, estuaries provide a large variety of aquatic habitats for native populations of marine, brackish and fresh water plankton species. Non-indigenous planktonic species that expand their bio-geographical range and invade the Baltic coastal ecosystems also find favourable environments, establish permanent populations there, and impact aboriginal ecosystems. The dynamics of abundance, species diversity, population structure, productivity of planktonic communities, and peculiarities of trophic interactions in different Baltic estuaries are influenced by a number of common environmental factors. Being measured on the unified basis and monitored, changes (or stability) of structural and functional parameters of plankton communities can serve as indicators of alterations to the ecosystems. Comparative analyses and quantitative estimates of long-term changes in phyto- and zooplankton can contribute to evaluation of functional response of Baltic coastal ecosystems to anthropogenic stress. Both theoretical (modeling) and empirical studies of interactions within plankton communities aimed at the assessment of the role of planktonic organisms in water quality regulation, and applicability of these data for the evaluation of the status of ecosystems and their management can be considered as major goals for the future investigations in Baltic estuaries. 相似文献
Various human activities threaten the groundwater quality and resource under urban areas, and yet residents increasingly depend on it for their livelihood. The anticipated expansion of the worlds urban population from 3 to 6 billion in the coming 50 years does not only pose a large water management threat but also provides an opportunity to conserve groundwater in a better way than up to now. The authors argue for a new way to manage urban activities in order to conserve the precious groundwater resource. The focus is on the quality of the discharged water after use in households. Restrictions on what is added to water while using it, e.g. detergents, excreta, paint residues, oils, and pharmaceuticals, are important to simplify the treatment and reuse of used water. Avoiding mixing different wastewater flows has the same positive effect. If increased volumes of wastewater can be treated and reused, the demand on the groundwater resource is reduced, as also occurs with demand management measures. Reduced discharge of polluted water to the environment from households and utilities also conserves the quality of groundwater and reduces sophisticated treatment costs.
Resumen La urbanización lleva a una demanda elevada y concentrada de agua de calidad adecuada, acompañada por el vertido de volúmenes análogamente mayores de aguas residuales. Los alimentos se importan a ciudades donde los microorganismos y nutrientes de los excrementos humanos son descargados a ríos, lagos y, también, aguas subterráneas. Más aún, gran número de los bienes de consumo son eliminados vía las tuberías de las cloacas. Las deudas medioambientales, es decir, el empobrecimiento de las condiciones medioambientales, que requerirán de aportaciones humanas y económicas para rehabilitarlas, son comunes a todas las ciudades, sobretodo en el Hemisferio Sur, donde, según la Valoración Global de Suministro de Agua y Saneamiento (OMS y UNICEF), la mayor parte de las aguas residuales urbanas no son tratadas (65% en Asia, 86% en Latinoamérica, 100% en África). La tarea pendiente consiste en proteger los recursos de aguas subterráneas para que estén disponibles de forma rápida para los habitantes urbanos también el futuro. En los próximos 50 años, se espera que la población urbana aumente de 3,000 a 6,000 millones de personas, según estimaciones de las Naciones Unidas, por lo que es imperativo dejar de contaminar las aguas subterráneas existentes bajo las nuevas áreas urbanas en construcción. En este artículo, se escudriña la calidad de las aguas subterráneas y su protección a la luz de los cambios recientemente introducidos en las políticas del agua, esto es, desde la gestión de los abastecimientos de agua a la gestión de la demanda y, eventualmente, hastaa la gestión de la reutilitzación.
Résumé Lurbanisation conduit à une demande élevée et concentrée deau de qualité adéquate, accompagnée du rejet dimportants volumes correspondants deaux usées. La nourriture est importée dans les villes tandis que les micro-organismes et les nutriments provenant des excrétas humains sont rejetés dans les rivières, les lacs et aussi les eaux souterraines. De plus, une large gamme de biens de consommation est évacuée par les égouts. Les créances environnementales, cest-à-dire lappauvrissement des conditions environnementales qui demandera des apports humains et économiques pour la réhabilitation, sont habituelles dans toutes les villes, et pas seulement dans lhémisphère sud, comme cela est indiqué dans le rapport sur lalimentation en eau et la santé publique du monde (publié par lOMS et UNICEF), établissant que la plupart des eaux résiduaires des zones urbaines reste non traitée (65% en Asie, 86% en Amérique latine et 100% en Afrique). La tâche à réaliser pour lhomme est de protéger les ressources en eau souterraine en sorte quelle reste disponible pour les habitants des villes dans le futur. Dans les prochaines 50 années, il faut sattendre à ce que la population urbaine saccroisse de 3 à 6 milliards de personnes selon les estimations des Nations Unies; aussi il est impératif de ne pas continuer à polluer les eaux souterraines sous les nouvelles zones urbaines en cours de construction. Dans cet article, nous analyserons la qualité des eaux souterraines et leur protection à la lumière des récents changements de politique de leau, cest-à-dire de la gestion de lalimentation en eau jusquà une gestion de la demande et en abordant éventuellement la période de gestion du recyclage.
The Pb contents and 206Pb/207Pb and 208Pb/206Pb isotopic ratios were studied in the soils and wines (2004 harvest) of three vineyard areas of the Czech Republic. The areas differ in their geological basements and anthropogenic loading. The isotopic compositions of wine in areas with intensive industry (Most, North Bohemia 206Pb/207Pbwine = 1.178 ± 0.004) and the agricultural areas of Central Bohemia (Roudnice nad Labem 206Pb/207Pbwine = 1.176 ± 0.007) are similar to the Pb isotopic composition of airborne particulate material typical of polluted and industrial environments (206Pb/207Pb = 1.17–1.19). The isotopic composition of wine from Prague (206Pb/207Pbwine = 1.174 ± 0.003) is different from that of the soil, which was severely contaminated in the past by vehicular Pb (206Pb/207Pbsoil = 1.147–1.168). This fact shows that interception of airborne Pb by plants is greater than its uptake by the root system. 相似文献
The impact that volcanic eruptions may have upon environments far from the volcanic source is conventionally assumed to depend on climatic modification by emitted gases. However, recent research has suggested that the damage caused by the direct impact of volcanic gases, mainly H2SO4, may be profound. This paper highlights the severity of this mechanism by reference to human sickness and death in France and contiguous with the eruption of the Laki fissure in Iceland in 1783. This work demonstrates the gains which may be made by interdisciplinary teams of researchers and illustrates the valuable knowledge that remains to be revealed by further research in the French historical record. To cite this article: J. Grattan et al., C. R. Geoscience 337 (2005).相似文献
This paper is based on the premise that research into the environmental impact of continental flood basalt (CFB) volcanism has paid insufficient attention to the potential ecosystem damage that would result from the direct deposition of hundreds of megatons (Tg) of sulphur and other volatiles. The environmental impacts of the 1783 Laki Fissure eruption are reviewed in outline. It is shown that in a relatively brief period of volcanic activity, volatiles emitted by the eruption damaged and destroyed vegetation from the Arctic Ocean to the Mediterranean. Air pollution was so intense that human health was affected and the national death rate increased dramatically in both England and France.
It is proposed that the events of 1783 may be used as a paradigm for the environmental impacts of a CFB lava flow, and the emissions of 1783 are scaled up to illustrate this point. Thus, if a Laki style event were to erupt for a year it would approach the physical scale of a single episode of the Roza flow in the Columbia River CFB and potentially yield 576 Tg of sulphur gases which could have been oxidised into approximately 945 Tg of aerosol. This could generate a tropospheric aerosol mass of approximately 708 Tg H2SO4.
The ecosystem impact of the deposition of acids on this scale would be profound and, as with the actual Laki event, be continental in scale. All parts of the plant life cycle would be disrupted, including photosynthesis and fruiting. Inevitably, with the disruption of food webs animals would also be affected. Poorly buffered inland waters would be acidified, as would Boreal soils, reducing their biodiversity.
In our already polluted and interdependent world, any future event on this scale would have serious consequences for human health and trade. 相似文献
To determine selected water pollution parameters of the Anyang River (one of the biggest contributory branches of the Han
River in Korea) and its main tributaries, the geological and topographical and rainfall features in its basin were investigated,
and the resulting data were tabulated. Samples were collected at the upper, mid and down parts of the Anyang River and its
branches and were analyzed based on biochemical and chemical methods, Korean biotic index (KBI) and Saprobien systems. Selected
parameters of concern include BOD, heavy metals, nonpoint pollution and sewage discharge. The Anyang River basin has a torrential
heavy rainfall; however, the rate of rainfall significantly varies from season to season. Water pollution levels in the dry
season increase dramatically. The mainstream of the Anyang River is classified as fifth grade polysaprobic water according
to Saprobien system. In addition, the biotic index is over 2.5 in overall. General pollution at the junction of the Anyang
River and each branch stream varies. Possible countermeasures to improve the water quality of the river include intercept
the non-treated waste water and sewage at the Anyang River junction and each branch stream, enforcement of water management
during the rainy season, and continuous investment on environmental restoration. 相似文献