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1.
Assessment of persistent toxic substances in the environment of Egypt   总被引:5,自引:0,他引:5  
The objective of this review is to provide a comprehensive assessment of the threats posed by persistent toxic substances (PTS) to the environment and human health in Egypt and to identify priorities, data gaps and recommendations for future intervention to control, reduce or eliminate releases of PTS. Data on available concentrations of persistent toxic substances in the different environmental compartments and their impacts on the ecosystem, and humans have been assembled and summarized. Despite extensive studies, most of the data available deal with limited studies or hot spot situations. Localized inputs of PTS have been identified from freshwater discharges in coastal areas (e.g., Nile estuaries and coastal lakes) and near sewage outfalls from highly industrialized and populated cities. Data are often missing for certain contaminants and in some compartments and geographical areas. The lack of standardized methodologies makes it difficult to compare and use existing data to provide exact conclusions on spatial and temporal trends. In spite of these restrictions, available data indicate that it is unlikely that present levels of cyclodiene pesticides would adversely affect marine organisms. Compounds which are proven to be of concern are DDT, PCBs, gamma-HCH, PAHs, HCB and organotin compounds. Other compounds are suspected to be ubiquitous but data are lacking. Based on few recent data, the reported levels of organochlorine pesticides in fish and human milk samples suggest a concentration decline during the 1990s consistent with the regulatory restrictions on the use of these compounds. It is essential to activate monitoring programs to fill data gaps in appropriate abiotic and biotic. Monitoring programs should be follow standard procedures and include improved QA/QC protocols.  相似文献   

2.
Laboratory experiments were carried out to measure the accumulation of 237Pu by the edible winkle from labelled sea water, food (seaweed), and silt. The equilibrium whole body concentration factor for 237Pu accumulation from sea water at 10°C was estimated as 34 with a biological half-time of 9 d. After 50 d accumulation, 83% of the measured whole body activity was present on the shell. In the flesh, the major sites for accumulation were the head/foot complex and the digestive gland. Depuration was found to be biphasic with components having half-times of 10 and 193 d respectively. Pu loss, following uptake from labelled Fucus spiralis, was biphasic with half-times of 1 and 69 d for the two components. Assimilation efficiency was tentatively estimated as 7%. Pu accumulation from labelled silt was low with an estimated transfer factor of 0.004; Pu loss was biphasic, with half-times similar to those for the seaweed experiment. Comparison of the laboratory-derived results with those for winkles from the environment showed that the food pathway was the main route for Pu accumulation, with the ingestion of silt playing a critical role in determining the final flesh Pu burden.  相似文献   

3.
The data on the ecology of bilberry and cowberry in the West Siberian Plain, Kuznetsk Ala Tau, and highland Altai are presented. Ecological ranges of these plants and amplitudes of their tolerance for some environmental factors are described.  相似文献   

4.
Pollution distribution maps of copper (Cu), zinc (Zn) and lead (Pb) for Erzurum province were developed on the basis of chemical analysis of Scots pine (Pinus sylvestris L.) needles collected from randomly selected sampling points during 2 years. The maps show deposition zones for the studied elements and could help in identification of sources and directions of air pollution dispersion. This study indicated that vegetation in Erzurum was greatly endangered by sulphur dioxide (SO(2)), whereas Zn does not pose an immediate threat to vegetation in most of the country's territory. However, in the city center, main and secondary road agglomeration, very high pollution with Pb and Cu could limit growth. Higher levels of SO(2) measured in some areas of Erzurum might be harmful for human and animal health. Results of this study indicated that Scots pine needles were not contaminated by Zn.  相似文献   

5.
Russian Journal of Ecology - The proportion of jointly visited traps and the frequency of visits to the traps recorded during mark–recapture studies have been compared with the mathematical...  相似文献   

6.
Data on the daily activity and mobility of the common shrew (Sorex araneusL.) were obtained by the method of animal marking and recapturing in test plots. Sex- and age-related differences in the locomotor activity of animals were revealed, which depended on population size and the phase of the population cycle. Under natural conditions, animal activity in the daytime proved to decrease to a lesser extent than in captivity. The mobility (locomotor activity) of shrews was shown to depend on population density, reproductive rate, and weather.  相似文献   

7.
The geographic variation of the water vole Arvicola terrestris L. has been analyzed with respect to two linear combinations of craniometric characters with the highest additive heritability (h 2 = 0.59 and h 2 = 0.52). The greatest differences have been revealed between the territorially close montane and piedmont populations. The lowland and montane populations have proved to differ to the smallest extent, despite their spatial and altitudinal separation. Selection under extreme conditions that leads to similar phenotypic results may be based on the common genetic background of these populations, irrespective of considerable distances between them and different environmental conditions in their habitats.  相似文献   

8.
The abundance of moles has been studied in 2007–2010 along the gradient of pollution by emissions from the Middle Ural (Middle Urals) and Karabash (Southern Urals) Copper Smelters. It has been estimated by the routing method with regard to the number of inhabited burrows per 1 km. Not a single mole has been recorded in heavily polluted areas near these copper smelters. Under conditions of moderate pollution, the abundance of moles decreased 1.5–1.8 times. The smallest “mole desert” near the source of emissions extends for 90–100 km2. A dramatic decrease in the abundance of earthworms, which are the main food object of moles, is considered a possible reason for these changes.  相似文献   

9.
In Belarussian Polesye, characteristics of reproduction, population dynamics, and factors responsible for a decrease in the abundance of the pond turtle were studied. The main factors limiting pond turtle reproduction in Polesye include the focal distribution of its populations and limited areas of reproductive biotopes. The pond-turtle popuation itself is characterized by a high potential for reproductive growth; in the current situation, the population growth is mainly limited by a high pressure of oophagous predators and anthropogenic destruction of reproductive sites.  相似文献   

10.
11.
The state of the population, biotopic distribution, and population dynamics of the field vole are analyzed on the basis of long-term studies performed in 1956–2012 in taiga ecosystems of Eastern Fennoscandia affected by anthropogenic transformations. General trends and regional and landscape-related specific features of the effects of forest exploitation on the structure of habitats, abundance, and spatial distribution of the field vole are discussed in comparative ecological aspect.  相似文献   

12.
The remote effect of the nuclear polyhedrosis virus on the gypsy moth was studied for the first time under natural conditions. In the generation that developed from infected eggs, the weight of pupae was reduced, sex ratio was altered, and female fecundity and egg fertility were lower than in control individuals. The F1 progeny of these moths were characterized by an increased rate of latent virus carriage and high mortality caused by the combined effect of polyhedrosis and insect parasites.  相似文献   

13.
The communities of intestinal helminths found in the winter sample of ide (December–May, 45 fish) and in the summer sample (August–September, 42 fish) were compared. They consisted of 10 and 11 species, respectively, with Sphaerostomum globiporum being dominant in both communities. The species Parasymphylodora markewitschi and Capillaria tomentosa were found only in the summer community. Dominance and diversity (the Simpson and Brillouin indices) in the winter community were higher. All helminth species in the intestinal community of ide were of broad specificity. Therefore, host specialization does not play an important role in the forming of intestinal helminth community in this fish species.  相似文献   

14.
Studies on speckled alder trees in an alder forest of grass-herb type in the northern taiga subzone of Northern Karelia have shown that specific features of the seasonal growth of shoots, leaves, and stems in these trees depend on a number of ecological factors, with air temperature playing the main role.  相似文献   

15.
A hydroponic experiment was carried out to investigate the effects of iodine species and solution concentrations on iodine uptake by spinach (Spinacia oleracea L.). Five iodine concentrations (0, 1, 10, 50 and 100 microM) for iodate (IO(3)(-)) and iodide (I(-)) were used. Results show that higher concentrations of I(-) (> or =10 microM) had some detrimental effect on plant growth, while IO(3)(-) had little effect on the biomass production of spinach plants. Increases in iodine concentration in the growth solution significantly enhanced I concentrations in plant tissues. The detrimental effect of I(-) on plant growth was probably due to the excessively high accumulation of I in plant tissues. The solution-to-spinach leaf transfer factors (TF(leaf), fresh weight basis) for plants treated with iodide were between 14.2 and 20.7 at different solution concentrations of iodide; TF(leaf) for plants treated with iodate decreased gradually from 23.7 to 2.2 with increasing solution concentrations of iodate. The distribution coefficients (DCs) of I between leaves and roots were constantly higher for plants treated with iodate than those treated with iodide. DCs for plants treated with iodide increased with increasing solution concentrations of iodide, while DCs for plants treated with iodate (around 5.5) were similar across the range of solution concentrations of iodate used in this experiment. The implications of iodine accumulation in leafy vegetables in human iodine nutrition are also discussed.  相似文献   

16.
The radial and vertical distributions of radiocaesium, potassium and calcium were determined in two Scots pine stands (17 and 58 yr old) similarly affected by the Chernobyl fallout. For both age classes, concentrations are always the lowest in the stemwood, highest in the inner bark and intermediary levels were observed for the outer bark. Due to the cumulative character of its biomass. however. stemwood is a long-term major reservoir of 137Cs. With tree development, changes in the 137Cs radial distribution are well described by variations in the sap ascent pattern and reveal an important transfer between tree rings. It is shown that. both the biomass evolution and knowledge of the evolution of the 137Cs radial gradient are important to predicting 137Cs accumulation in wood with time. According to the common transfer factor (TF) approach, one would expect a decrease in radiocaesium accumulation with time (from 0.0047 +/- 0.0013 to 0.0035 +/- 0.0008 m2kg(-1) for the 17 and 58 yr old trees, respectively). With the wood immobilisation potential (WIP) approach, it was, however, clearly shown that additional annual uptake was highest for the older stand (3.12 +/- 0.23 Bq cm(-3) yr(-1) for the 58-year-old stand compared to 1.99 +/- 0.30 Bq cm(-3) yr(-1) for the younger stand). Following the WIP approach, it was moreover possible to distinguish between the 137Cs incorporated via the root uptake process and a possible lasting effect of interception. It is shown that, whereas for the younger stand (5 yr old at the time of the accident) root uptake contributed exclusively to the wood contamination, the former process explained only 48% of the measured total 137Cs content in the wood of the older tree.  相似文献   

17.
The activity of antioxidant enzymes and electrophoretic protein spectra were studied in sand smelt larvae inhabiting from five Sevastopol bays with different degrees of anthropogenic impact. The activity of antioxidant enzymes and the heterogeneity of electrophoretic protein spectra proved to increase in the larvae from the most polluted waters. The possibility of using these parameters as biological markers for assessing the influence of pollution on the early stages of fish ontogeny and the marine environment are discussed.  相似文献   

18.
Specific features of larval feeding in two geographic populations of the gypsy moth are considered. It is shown that in larvae reared on an artificial diet, trophic indices depend on several factors, including the age and sex of larvae and the food plant on which the parental generation developed in nature. It is shown that larval micropopulations belonging to the same geographic population but feeding in nature on different plant species differ from each other to a greater extent than those of different geographic populations feeding on the same species.  相似文献   

19.
The uptake and retention of technetium from sea water by juvenile lobsters, and the effects of moulting on these processes, has been studied using 95mTc as a tracer.Accumulation was rapid with whole body concentration factors of over 2000 being measured in some lobsters. Uptake was highest immediately before a moult; post-moult there was a fall in accumulation. No simple mathematical equation for technetium accumulation with time was found.The technetium concentration in the moulted exoskeleton increased with time of exposure of the lobsters but never exceeded 2% of the whole body value.The highest percentage of the whole body activity was found in the digestive gland; the green gland had the highest concentration factor.Technetium excretion, following 64 d of accumulation, could be expressed as an exponential rate of loss. The biological half-time was calculated as 53 d. Moulted exoskeletons from these lobsters contained approximately 0·6% of the day zero whole body activity.  相似文献   

20.
Changes in the survival parameters of the red fox were analyzed at different phases of the population cycle. It was found that the survival rate in all age classes, including newborns, drastically increased at the phase of population growth. The relationship between the general mortality rate and population size was determined. A hypothesis concerning the mechanism of these changes in the general mortality rate is suggested.  相似文献   

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