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551.
The theory of parental investment and brood sex ratio manipulation predicts that parents should invest in the more costly sex during conditions when resources are abundant. In the polygynous great reed warbler, Acrocephalus arundinaceus, females of primary harem status have more resources for nestling provisioning than secondary females, because polygynous males predominantly assist the primary female whereas the secondary female has to feed her young alone. Sons weigh significantly more than daughters, and are hence likely to be the more costly sex. In the present study, we measured the brood sex ratio when the chicks were 9 days old, i.e. the fledging sex ratio. As expected from theory, we found that female great reed warblers of primary status had a higher proportion of sons in their broods than females of lower (secondary) harem status. This pattern is in accordance with the results from two other species of marsh-nesting polygynous birds, the oriental reed warbler, Acrocephalus orientalis, and the yellow-headed blackbird Xanthocephalus xanthocephalus. As in the oriental reed warbler, we found that great reed warbler males increased their share of parental care as the proportion of sons in the brood increased. We did not find any difference in fitness of sons and daughters raised in primary and secondary nests. The occurrence of adaptive sex ratio manipulations in birds has been questioned, and it is therefore important that three studies of polygynous bird species, including our own, have demonstrated the same pattern of a male-biased offspring sex ratio in primary compared with secondary nests. Received: 1 June 1999 / Received in revised form: 10 January 2000 / Accepted: 12 February 2000  相似文献   
552.
The ever increasing impact of the marine industry and transport on vulnerable sea areas puts the marine environment under exceptional pressure and calls for inspired methods for mitigating the impact of the related risks. We describe a method for preventive reduction of remote environmental risks caused by the shipping and maritime industry that are transported by surface currents and wind impact to the coasts. This method is based on characterizing systematically the damaging potential of the offshore areas in terms of potential transport to vulnerable regions of an oil spill or other pollution that has occurred in a particular area. The resulting maps of probabilities of pollution to be transported to the nearshore and the time it takes for the pollution to reach the nearshore are used to design environmentally optimized fairways for the Gulf of Finland, Baltic Proper, and south-western Baltic Sea.  相似文献   
553.
A repository of 14 gaseous organic compounds at parts-per-billion levels (7-430 ppb) in compressed gas cylinders has been established by the Environmental Protection Agency. This repository was established to provide audit materials for use in conducting performance audits to assess the accuracy and precision of principal organic hazardous constituent (POHC) measurements, especially those performed during hazardous waste trial burn tests. Five- and nine-component mixtures In a balance gas of nitrogen were prepared in aluminum cylinders for use in the performance audit program. The five-component mixtures contain carbon tetrachloride, chloroform, perchloroethylene, vinyl chloride, and benzene. The ninecomponent mixtures contain trichloroethylene, 1,2-dichloroethane, 1,2-dibromoethane, acetonitrile, trichlorofjuoromethane, dichlorodifluoromethane, bromomethane, methyl ethyl ketone and 1,1,1-trichloroethane.

Studies of all 14 gaseous organic compounds were performed to determine the stability of the compounds and the feasibility of using them in performance audits. Results indicate that ail of the 14 compounds were adequately stable to be used as reliable audit materials. Also, the estimation of specific uncertainties associated with the analysis of these audit materials and how those uncertainties are used to assign a total uncertainty to the final analyte concentration for 14 organics Is described.

Subsequent to completion of the stability studies, several performance audits were conducted using the repository gases to assess the accuracy and precision of the volatile organic sampling train (VOST) and bag measurement methods. The audit results indicate that laboratories can use these methods to analyze POHC with accuracy usually to within ± 50 percent of the audit concentrations.  相似文献   
554.
Air pollution abatement policies must be based on quantitative information on current and future emissions of pollutants. As emission projections uncertainties are inevitable and traditional statistical treatments of uncertainty are highly time/resources consuming, a simplified methodology for nonstatistical uncertainty estimation based on sensitivity analysis is presented in this work. The methodology was applied to the “with measures” scenario for Spain, concretely over the 12 highest emitting sectors regarding greenhouse gas and air pollutants emissions. Examples of methodology application for two important sectors (power plants, and agriculture and livestock) are shown and explained in depth. Uncertainty bands were obtained up to 2020 by modifying the driving factors of the 12 selected sectors and the methodology was tested against a recomputed emission trend in a low economic-growth perspective and official figures for 2010, showing a very good performance.

Implications:?A solid understanding and quantification of uncertainties related to atmospheric emission inventories and projections provide useful information for policy negotiations. However, as many of those uncertainties are irreducible, there is an interest on how they could be managed in order to derive robust policy conclusions. Taking this into account, a method developed to use sensitivity analysis as a source of information to derive nonstatistical uncertainty bands for emission projections is presented and applied to Spain. This method simplifies uncertainty assessment and allows other countries to take advantage of their sensitivity analyses.  相似文献   
555.
In this study the levels and distribution of some persistent toxic substances (PTS) were investigated in soils, superficial water, and snow along an altitudinal gradient in the Laja River Basin (South Central Chile). The principal objective was to establish the basin's contamination status. The working hypothesis was that PTS levels and distribution in the basin are dependent on the degree of anthropogenic intervention. Fifteen PAHs, seven PCBs congeners, and three organochlorine pesticides were studied in superficial soil and water samples obtained along the altitudinal gradient and from a coastal reference station (Lleu-Lleu River). Soil samples were extracted using accelerated solvent extraction with acetone/cyclohexane (1:1) for PAHs and organochlorine compounds. Contaminants were extracted from water and snow samples by liquid-liquid extraction (LLE). PAH and organochlorine compound quantification was carried out by HPLC with fluorescence detection and GC-MS, respectively. PCBs in soils presented four different profiles in the altitudinal gradient, mainly determined by their chlorination degree; these profiles were not observed for the chlorinated pesticides. In general, the detected levels for the analyzed compounds were low for soils when compared with soil data from other remote areas of the world. Higher summation operator PAHs levels in soils were found in the station located at 227 masl (4243 ng g-1 TOC), in a forestry area and near a timber industry, where detected levels were up to eight times higher than the other sampling sites. In general, PAH levels and distribution seems to be dependent on local conditions. No pesticides were detected in surface waters. However, congeners of PCBs were detected in almost all sampling stations with the highest levels being found in Laja Lake waters, where 1.1 ng/l were observed. This concentration is two times higher than values reported for polluted lakes in the Northern Hemisphere. The presence of organochlorine compound in snow sampled at the highest elevation point of the basin is indicative of the transport and atmospheric deposition phenomena of alpha-HCH, gamma-HCH and PCB 52, with values being similar to the levels reported in Canadian snow samples. We conclude that environmental PTS substance levels are in general relatively low, although PAHs may be of concern in some areas of the basin.  相似文献   
556.
Pharmaceuticals in the river Elbe and its tributaries   总被引:13,自引:0,他引:13  
Medicinal drugs were found to be ubiquitous in the river Elbe, its tributary the river Saale and in other tributaries at their points of entry into the Elbe. The distribution of concentration peaks along the investigated river stretches provides an indication that they are mainly due to the emission of treated waste water from municipal sewage treatment works. This leads to the conclusion that medicinal substances can be regarded as faecal indicators for water pollution caused by human activity. The main substances found in the Elbe in 1998 were diclofenac, ibuprofen and carbamazepine as well as various antibiotics and lipid regulators in the concentration range of <20-140 ng/l. The more thorough investigations carried out in 1999 and 2000 show that in addition to the drugs (phenazone, isopropyl-phenazone and paracetamol) metabolite concentrations contributed significantly to the total concentration of pharmaceuticals in the Elbe. The metamizole metabolites N-acetyl-4-aminoantipyrine (AAA) and N-formyl-4-aminoantipyrine (FAA) were found in concentrations from <20 to 939 ng/l. A multivariate statistical analysis revealed a high correlation in respect of the distribution of persistent substances. The metoprolol distribution throughout the Saale demonstrated that the tributaries cause either an increase (Weisse Elster, Unstrut, Ilm) or a reduction (Wipper, Bode) in the concentration, depending on the respective load of waste water. Wide scale sampling in Saxony during 2002 showed the ubiquitous occurrence of carbamazepine in surface waters. The ecotoxicological effects of this contamination cannot be assessed at present. This is due to the fact that no legal framework in respect of these medicinal drugs for human consumption has been established and therefore little research and no risk assessment has been carried out. Therefore it is urgently necessary to include at least the quantitatively most significant substances in the new assessment concept of the EC White Paper.  相似文献   
557.
A new setup has been developed and built to measure number size distributions of exhaust particles and thermodynamic parameters under real traffic conditions. Measurements have been performed using a diesel and a gasoline passenger car driving with different speeds and engine conditions. Significant number of nucleation mode particles was found only during high load conditions, i.e. high car and engine speeds behind the diesel car. The number concentration of soot mode particles varied within a factor of two for different engine conditions while the concentration of nucleation mode particles varied up to two orders of magnitude. The results show that roadside measurements are still quite different from those behind the tailpipe. Beside dilution transformation processes within the first meter behind the tailpipe also play an important role, such as nucleation and growth. Emission factors were calculated and compared with those obtained by other studies. Emission factors for particles larger than 25 nm (primary emissions) varied within 1.1 × 1014 km?1 and 2.7 × 1014 km?1 for the diesel car and between 0.6 × 1012 km?1 and 3.5 × 1012 km?1 for the gasoline car. The advantage of these measurements is the exhaust dilution under atmospheric conditions and the size-resolved measurement technique to divide into primary emitted and secondary formed particles.  相似文献   
558.

Background, aim and scope  

After the discovery of chloroform in drinking water, an extensive amount of work has been dedicated to the factors influencing the formation of halogenated disinfections by-products (DBPs). The disinfection practice can vary significantly from one country to another. Whereas no disinfectant is added to many water supplies in Switzerland or no disinfectant residual is maintained in the distribution system, high disinfectant doses are applied together with high residual concentrations in the distribution system in other countries such as the USA or some southern European countries and Romania. In the present study, several treatment plants in the Somes river basin in Romania were investigated with regard to chlorine practice and DBP formation (trihalomethanes (THMs)). Laboratory kinetic studies were also performed to investigate whether there is a relationship between raw water dissolved organic matter, residual chlorine, water temperature and THM formation.  相似文献   
559.
In Sweden, leaching tests with deionized water (D.W.) are utilized in risk assessment of materials entering landfills, but implementation of these results to evaluate the risk of spreading of pollutants in the environment is difficult. One problem is that most leaching procedures only consider heavy metals release, whereas organic pollutants are left out. The aim of the present study was to assess the possible pollutant mitigation in four remediated soils, three with heavy metals and one with polycyclic aromatic hydrocarbons (PAH) contamination. The mitigation was evaluated by standardized batch and column leaching tests utilizing three different leaching solutions: D.W., a weak ionic solution (0.001 M CaCl2) and an artificially made soil water (ASW). In general, batch leaching tests implied larger contaminant removal than column leaching test, possibly due to the more rough treatment of the soil particles, and guidelines would at times be exceeded by the batch leaching test but not by column leaching tests. Utilization of CaCl2 was found to release less heavy metal than D.W., whereas the metals mobilized by ASW were removed from solution by the filtration of soil leachates. Low molecular weight PAH was most efficiently mobilized by CaCl2, while D.W. worked better for high molecular weight PAH. Despite very low initial PAH-concentrations, tap- and groundwater criteria were exceeded by all leaching solutions.  相似文献   
560.
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