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981.
This paper presents data on the concentrations of 5 metals, copper (Cu), cadmium (Cd), iron (Fe), zinc (Zn) and lead (Pb) in Blue Whiting sampled from the Eastern Black Sea coast of Turkey. The highest metal concentrations of Cu, Cd, Fe, Zn and Pb were recorded in Blue Whiting with the values of 2.71, 0.601, 14.137, 15.322 and 1.078 μg g‐1 dry weight, respectively. On average the metal concentrations in Blue Whiting followed the order of Zn > Fe > Cu > Pb > Cd. Temporal differences of concentrations of these metals were significant (p < 0.05). Spatial fluctuations of Cu, Cd, Fe, Zn and Pb concentrations in Blue Whiting were also significant (p < 0.01). It was found that the concentrations of Cu, Cd, Fe, Zn and Pb in the muscle in Blue Whiting were below the limit of Public Health Regulation in Turkey.  相似文献   
982.
Cattle treatment with antiparasitic drugs is associated with an important risk exposure for dung beetles. Previous studies demonstrated the impact of some avermectin and pyrethroid compounds on several species such as Onthophagus gazella and Neomyia cornicina. However, little information is available regarding the elimination of these compounds in faeces 8 days after a pour-on administration in dairy cows. The present study, utilising a dairy cow model with cypermethrin treatment, demonstrated that concentrations in dry faeces can reach levels of 5?mg?kg?1 between the first and fourth day after treatment and were present up to 3 months after a single dose of administration at a concentration around 10?µg?kg?1. Faecal samples were purified with three successive columns (silica gel, anion exchange phase, and basic alumina) and analysed by GC-MS. The limit of quantification of this method was 0.5?µg?kg?1. The high sensitivity of the method permitted one to see that the risk exposure of cypermethrin to dung beetles is longer than what was noted in the literature. According to other studies, repeated treatment with such agents may lead to the local extinction of dung beetles. Even if the impact of pyrethroid largely depends on the conditions of the ecosystem where the treated cattle are living, adverse effects of these agents may still occur.  相似文献   
983.
Hemocytes are main blood components of bivalves playing important roles in toxicological and immune responses. Consequently, a study on these cells may be useful to understand the invertebrate immunological systems. The aim of the present study was to find the best antiaggregant solution, based on its capacity of preserving the natural morphology and viability of hemocytes from the freshwater bivalves, Anodonta cygnea, Unio delphinus, and Corbicula fluminea. Hemocytes from the three species were collected and maintained in different antiaggregant solutions, i.e., ethylenediaminetetraacetic acid (EDTA), EDTA-citrate, modified Alsever solution (MAS), N-ethylmaleimide (NEM), NEM-NaCl, and heparin. The cell morphology and viability were analyzed periodically with light microscopy techniques. Between these assays with various antiaggregant solutions, the best results were obtained with NEM at a concentration of 0.05 mol·L?1. It is also shown that, as expected, the osmolarity of the antiaggregant solutions plays a very important role in cell viability. Based on this study, NEM at 0.05 mol·L?1 was considered an adequate antiaggregant solution for future research on immunological and toxicological responses and other physiological studies of freshwater bivalve hemocytes.  相似文献   
984.
985.
The present study examined the mode and timing of reproduction of poorly understood deep-water octocorals and the environmental factors that may influence their reproductive patterns. Data on reproductive characteristics of the octocoral Drifa glomerata (Alcyonacea: Nephtheidae) collected between 2004 and 2007 at ca. 100–330 m depth off Newfoundland and Labrador (eastern Canada) were compared among years, months and depth ranges. No male gonad was ever observed during the study. The ratio of fertile colonies possessing large pinkish polyps with oocytes/planulae was >50% throughout the year. The number of brooded planula larvae within a single fertile polyp varied between 1 and 10 for a total of approximately 40–3,000 in a whole colony. The size of oocytes and/or planulae was consistently greater in the polyps than in the branchlets, indicating that the development pathway of oocytes to planulae is from the branchlets to the polyps. Although larval production seemed to persist year round, the onset of major planulation events occurred in December–January of two consecutive years, when large mature planulae were released in correlation with the first increase of photoperiod and maximum temperature at 150 m. A second peak in planulation between April and early June followed the phytoplankton bloom. Seasonal trends were more apparent in colonies from <200 m, and the planula index varied among sampling depths and years. Larval release in a live colony under laboratory conditions occurred between January and June 2008, closely following predictions based on field samples.  相似文献   
986.
A ‘coastal-hazard GIS’ for Sri Lanka   总被引:1,自引:1,他引:0  
Following the 2004 tsunami disaster in Sri Lanka, it was apparent that mapping the coast’s vulnerability was essential for future protection of the local populations. We therefore developed a prototype ‘Coastal-hazard GIS’ for Sri Lanka so as to provide an effective tool for decision makers to limit the impact of natural coastal hazards such as sea level rise, tsunamis, storm surges and coastal erosion, and thus protect the exposed assets (population, property, settlements, communications networks, etc.). The prototype was developed on a pilot site in Galle through building up homogeneous data on the land/sea interface from studies conducted on the exposure of the coastal populations, the aim being to enable an evaluation of the hazards combined with the vulnerability and thus an analysis of the risks. Coastal risk scenarios are developed so as to estimate the impacts and consequences of an event (tsunami, storm, etc.) on the assets, the principle behind this being that if, in general, the coastal hazard cannot be decreased, then a better knowledge of it through simulation should make it possible to limit the vulnerability and thus the risk. The Coastal-hazard GIS will also provide a planning tool in terms of locating new settlements, expanding urban areas, siting coastal protection works, etc.  相似文献   
987.
14C-labelled simazine was composted together with biowaste on a pilot (m3) scale. The herbicide was quickly bound to the compost matrix. By aqueous extraction of 29 and 200 days old compost (equivalent to thermophilic and mesophilic phase of composting) only 4.2% and 3.1% respectively of the radioactivity in the compost samples could be extracted with water. Analysis of the extracts using high-performance size exclusion chromatography (HPSEC) revealed that the dissolved organic matter (DOM) had molecular weights ranging between 2 and 28 kDa. The amount of DOM-associated radioactivity increased from 53% (day 29) to 65% (day 200) of total extractable radioactivity. The type of binding of the 14C-labelled residues and the DOM was elucidated by silylation of humic matter and subsequent HPSEC. The data demonstrated that besides polar metabolites also intact simazine was bound to the DOM. A distinct shift from rather weak interactions to strong covalent linkages of simazine and its metabolites with increasing age of the compost was observed. The results showed that only low amounts of free simazine and its degradates can be extracted with water. We concluded that the shift towards stable covalent linkages is equivalent to a detoxification of the contaminant in aged compost. Consequently, the use of the analysed compost in its mature stage should not pose an environmental risk to the groundwater or the subsoil.  相似文献   
988.
A rare case of extrahepatic biliary atresia was diagnosed by a combination of prenatal ultrasound and measurements of fetal digestive enzymes in amniotic fluid. Ultrasound at 15 and 18 weeks' gestation failed to detect the gall bladder, and amniotic fluid digestive enzyme values were below the fifth percentile. The patient decided to terminate the pregnancy. Post-abortal pathological examination confirmed the diagnosis. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   
989.
Even when present at sub‐lethal levels, toxic compounds have an effect on the dynamics of a population, expressed through altered growth and reproduction rates. We explore some of the potential effects of toxicants on populations, using a simple model that considers a generic toxicant and populations of two species, a primary producer, and a consumer living under food‐limited conditions. The toxicant is assumed to affect the consumers only, and it may enter them either directly from the environment or via their food, the latter opening the possibility of biomagnification. The initial response of the consumer to introduction of a toxicant is invariably a decline in its fecundity and density. However, in the longer term, the equilibrium densities of both producer and consumer may increase or decrease, depending on parameter values and ambient toxicant levels. The surprising case of an increased equilibrium in response to the toxicant occurs if, in the absence of toxicant, the consumers held the producers at a very low level, analogous to ‘overfishing’ in fishery studies. If the toxicant enters the consumer via food, multiple, non‐trivial equilibria are possible. The complex, but interpretable, dynamics exhibited by these simple models will be used to guide studies with more realistic models, for whose development this study forms a prelude.  相似文献   
990.
Several barriers impede the free flow of environmental information in the government's hands to the public. The most important of these are the compartmentalization of environmental information among several departments, the manipulation of information to protect vested bureaucratic or political interests and, lastly, the withholding of information. The media's ineffective coverage of environmental issues and the small number of well-funded environmental groups constitute two additional institutional barriers to the broader dissemination of environmental information. Solutions proposed to reduce these barriers include the creation of an independent Commissioner on the environment reporting publicly to Parliament about the government's performance and the development of a widely-available system of indicators to inform the public about changes in environmental quality.  相似文献   
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