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771.
The results are presented that have been obtained during long-term studies (1991–2009) on the efficiency of natural reproduction
of the beluga, Russian sturgeon, stellate sturgeon, and sterlet in different spawning zones of the Volga. The influence of
major environmental factors on the formation of the offspring of these fishes is analyzed. It is shown that the productivity
of Volga spawning grounds varies depending on the river flow volume during spring floods and the abundance of active spawners.
Practical recommendations are proposed for enhancing sturgeon reproduction in the Volga. 相似文献
772.
Heat waves and floods in urban areas: a policy-oriented review of ecosystem services 总被引:1,自引:0,他引:1
Urbanisation is increasing and today more than a half of the world’s population lives in urban areas. Cities, especially those
where urbanisation is un-planned or poorly planned, are increasingly vulnerable to hydro-meteorological hazards such as heat
waves and floods. Urban areas tend to degrade the environment, fragmenting and isolating ecosystems, compromising their capacity
to provide services. The regulating role of ecosystems in buffering hydro-meteorological hazards and reducing urban vulnerability
has not received adequate policy attention until now. Whereas there is a wide body of studies in the specialised biological
and ecological literature about particular urban ecosystem features and the impacts of hazards upon people and infrastructures,
there is no policy-driven overview looking holistically at the ways in which ecosystem features can be managed by cities to
reduce their vulnerability to hazards. Using heat waves and floods as examples, this review article identifies the aggravating
factors related to urbanisation, the various regulating ecosystem services that buffer cities from hydro-meteorological impacts
as well as the impacts of the hazards on the ecosystem. The review also assesses how different cities have attempted to manage
related ecosystem services and draws policy-relevant conclusions. 相似文献
773.
Adverse effects in wild fish living downstream from pharmaceutical manufacture discharges 总被引:1,自引:0,他引:1
Sanchez W Sremski W Piccini B Palluel O Maillot-Maréchal E Betoulle S Jaffal A Aït-Aïssa S Brion F Thybaud E Hinfray N Porcher JM 《Environment international》2011,37(8):1342-1348
A set of biochemical and histological responses was measured in wild gudgeon collected upstream and downstream of urban and pharmaceutical manufacture effluents. These individual end-points were associated to fish assemblage characterisation. Responses of biotransformation enzymes, neurotoxicity and endocrine disruption biomarkers revealed contamination of investigated stream by a mixture of pollutants. Fish from sampled sites downstream of the industrial effluent exhibited also strong signs of endocrine disruption including vitellogenin induction, intersex and male-biased sex-ratio. These individual effects were associated to a decrease of density and a lack of sensitive fish species. This evidence supports the hypothesis that pharmaceutical compounds discharged in stream are involved in recorded endocrine disruption effects and fish population disturbances and threaten disappearance of resident fish species. Overall, this study gives argument for the utilisation of an effect-based monitoring approach to assess impacts of pharmaceutical manufacture discharges on wild fish populations. 相似文献
774.
Alexandrova M Rozhko T Vydryakova G Kudryasheva N 《Journal of environmental radioactivity》2011,102(4):407-411
The effect of americium-241 (241Am), an alpha-emitting radionuclide of high specific activity, on luminous bacteria Photobacterium phosphoreum was studied. Traces of 241Am in nutrient media (0.16-6.67 kBq/L) suppressed the growth of bacteria, but enhanced luminescence intensity and quantum yield at room temperature. Lower temperature (4 °C) increased the time of bacterial luminescence and revealed a stage of bioluminescence inhibition after 150 h of bioluminescence registration start. The role of conditions of exposure the bacterial cells to the 241Am is discussed. The effect of 241Am on luminous bacteria was attributed to peroxide compounds generated in water solutions as secondary products of radioactive decay. Increase of peroxide concentration in 241Am solutions was demonstrated; and the similarity of 241Am and hydrogen peroxide effects on bacterial luminescence was revealed. The study provides a scientific basis for elaboration of bioluminescence-based assay to monitor radiotoxicity of alpha-emitting radionuclides in aquatic solutions. 相似文献
775.
The activity of 210Po and 210Pb was determined in mussels of the same size (3.5-4.0 cm shell length) sampled monthly over a 17-month period at the Atlantic coast of Portugal. Average radionuclide concentration values in mussels were 759 ± 277 Bq kg−1 for 210Po (range 460-1470 Bq kg−1 dry weight), and 45 ± 19 Bq kg−1 for 210Pb (range 23-96 Bq kg−1 dry weight). Environmental parameters and mussel biometric parameters were monitored during the same period. Although there was no seasonal variation of radionuclide concentrations in sea water during the study period, the concentration of radionuclide activity in mussels varied seasonally displaying peaks of high concentrations in winter and low concentrations in summer. Analysis of radionuclide data in relation to the physiological Condition Index of mussels revealed that 210Po and 210Pb activities in the mussel (average activity per individual) remained nearly constant during the investigation period, while mussel body weight fluctuated due to fat storage/expenditure in the soft tissues. Similar variation of radionuclide concentrations was observed in mussels transplanted from the sea coast into the Tejo Estuary. However, under estuarine environmental conditions and with higher food availability throughout the year, transplanted mussel Condition Index was higher than in coastal mussels and average radionuclide concentrations were 210 ± 75 Bq kg−1 (dry weight) for 210Po and 10 ± 4 Bq kg−1 (dry weight) for 210Pb, therefore lower than in coastal mussels with similar shell length. It is concluded that the apparent seasonal fluctuation and inter-site difference of radionuclide concentrations were mostly caused by mussel body weight fluctuation and not by radionuclide body burden fluctuation. This interpretation can be extended to the apparent seasonal fluctuation in concentrations of lipophilic and lipophobic contaminants in mussels, and provides an explanation for occasional high concentrations of 210Po and man-made contaminants measured in mussels far from pollution sources. 相似文献
776.
The vertical distribution of the 236U/238U isotopic ratio was investigated in soil samples from three different locations on La Palma (one of the seven Canary Islands, Spain). Additionally the 240Pu/239Pu atomic ratio, as it is a well establish tool for the source identification, was determined. The radiochemical procedure consisted of a U separation step by extraction chromatography using UTEVA® Resin (Eichrom Technologies, Inc.). Afterwards Pu was separated from Th and Np by anion exchange using Dowex 1x2 (Dow Chemical Co.). Furthermore a new chemical procedure with tandem columns to separate Pu and U from the matrix was tested. For the determination of the uranium and plutonium isotopes by alpha spectrometry thin sources were prepared by microprecipitation techniques. Additionally these fractions separated from the soil samples were measured by Accelerator Mass Spectrometry (AMS) to get information on the isotopic ratios 236U/238U, 240Pu/239Pu and 236U/239Pu, respectively. The 236U concentrations [atoms/g] in each surface layer (∼2 cm) were surprisingly high compared to deeper layers where values around two orders of magnitude smaller were found. Since the isotopic ratio 240Pu/239Pu indicated a global fallout signature we assume the same origin as the probable source for 236U. Our measured 236U/239Pu value of around 0.2 is within the expected range for this contamination source. 相似文献
777.
Fatih Matyar Tamer Akkan Yasemin Uçak Buse Eraslan 《Environmental monitoring and assessment》2010,167(1-4):309-320
We studied the susceptibility patterns to 15 different antibiotics and six heavy metals in Aeromonas spp. and Pseudomonas spp. isolated from Iskenderun Bay, Turkey (northeast Mediterranean Sea). A high percentage of Aeromonas isolates showed resistance to cefazolin (66.6%) and trimethoprim–sulphamethoxazole (66.6%). Amongst the Pseudomonas isolates, there was a high incidence of resistance to nitrofurantoin (86.2%), cefazolin (84.8%) and cefuroxime (71.7%). Most isolates showed tolerance to different concentrations of heavy metals, and minimal inhibition concentrations ranged from 25 to >3,200 μg/ml. The Aeromonas spp. and Pseudomonas spp. showed high resistance to copper of 98.3% and 75.4%, respectively, and low resistance to lead of 1.7% and 7.2%, respectively. Our results show that antibiotic and heavy metal resistant Aeromonas spp. and Pseudomonas spp. were widespread in Iskenderun Bay in 2007 and 2008. The increasing presence of antibiotic and heavy metal resistant Aeromonas spp. and Pseudomonas spp. may become a potential human health hazard. 相似文献
778.
Bruno Nunes Ana Raquel Barbosa Sara C. Antunes Fernando Gonçalves 《Environmental science and pollution research international》2014,21(9):6258-6262
The simultaneous presence of distinct compounds in the aquatic environment can be causative of various toxicological interactions. This scenario challenges ecotoxicologists, since the assessment of toxicological effects caused by the simultaneous presence of multiple substances is by far more complicated. An illustrative example can be given by mentioning the anticholinesterasic compounds: by studying the level of cholinesterase impairment of an exposed organism, it is possible to ascertain the level of exposure to all anticholinesterasics (despite their chemical classes and natures) that the organism was subjected to. In this work, we describe the effects of three chemically different, albeit mechanistically, and toxicologically similar compounds (copper, chlorfenvinphos, and pyridostigmine) on cholinesterases of the fish Gambusia holbrooki. The results showed that the combinatorial effects may be of considerable extent, even for levels of exposure that are close to the ones already reported in the wild, for each isolated compound. 相似文献
779.
780.
S. Mohapatra A. K. Ahuja M. Deepa G. K. Jagadish N. Rashmi D. Sharma 《Journal of environmental science and health. Part. B》2013,48(3):264-271
Flubendiamide is a new insecticide that has been found to give excellent control of lepidopterous pests of tomato. This study has been undertaken to develop an improved method for analysis of flubendiamide and its metabolite des-iodo flubendiamide and determine residue retention in tomato and soil. The analytical method developed involved extraction of flubendiamide and its metabolite des-iodo flubendiamide with acetonitrile, liquid-liquid partitioning into hexane-ethyl acetate mixture (6:4, v v?1) and cleanup with activated neutral alumina. Finally the residues were dissolved in gradient high pressure liquid chromatography (HPLC) grade acetonitrile for analysis by HPLC. The mobile phase, acetonitrile-water at 60:40 (v v?1) proportion and the wavelength of 235 nm gave maximum peak resolution. Using the above method and HPLC parameters described, nearly 100 % recovery of both insecticides were obtained. There was no matrix interference and the limit of quantification (LOQ) of the method was 0.01 mg kg?1. Initial residue deposits of flubendiamide on field-treated tomato from treatments @ 48 and 96 g active ingredient hectare?1 were 0.83 and 1.68 mg kg?1,respectively. The residues of flubendiamide dissipated at the half-life of 3.9 and 4.4 days from treatments @ 48 and 96 g a.i. ha?1, respectively and persisted for 15 days from both the treatments. Des-iodo flubendiamide was not detected in tomato fruits at any time during the study period. Residues of flubendiamide and des-iodo flubendiamide in soil from treatment @ 48 and 96 g a.i. ha?1 were below detectable level (BDL, < 0.01 mg kg?1) after 20 days. Flubendiamide completely dissipated from tomato within 20 days when the 480 SC formulation was applied at doses recommended for protection against lepidopterous pests. 相似文献