首页 | 官方网站   微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
The concentration of tributyltin (TBT) in surface water from Osaka Bay ranged from 0.023 to 0.061 µg l−1 in 1989 and from not detected (ND) to 0.059 µg l−1 in 1990 while the proportion of TBT as a percentage of the total butyltins (BTs) was more than 40%. The concentration of TBT was also surveyed in the Port of Osaka and the Yodo River basin. TBT levels were highest in the estuary (the Port of Osaka), followed by sea areas (Osaka Bay) and rivers (Yodo River basin). A fairly high correlation coefficient between TBT concentration and salinity in water from the estuary and the sea areas was observed. This result shows that the TBT in the estuary water is diluted by seawater. Generally, the TBT concentrations in the water columns were distributed uniformly and the composition of the BTs was also constant. TBT was detected in sediment from Osaka Bay in the range from ND to 0.023 mg kg−1 dry weight with a high ratio of monobutyltin (MBT) to the total BTs. TBT in sediment core was also measured; its concentration decreased with core depth. It was estimated from these measurements that the release of TBT into Osaka Bay began in the 1960s. Copyright © 1998 John Wiley & Sons, Ltd.  相似文献   

2.
Concentrations of tritium in environmental waters (precipitation, rivers, lakes, tap water) have been determined using electrolytic enrichment and liquid scintillation counting. In waters of big rivers (the Vistula and the Odra rivers), lakes and tap water the annual average concentrations were similar to each other being from 1.4 to 1.9 Bq·dm-3. These concentrations were similar to those in the precipitation in which they ranged from 1.7 to 2.2 Bq·dm-3. The lowest tritium concentrations were found in waters of the Seashore Region rivers (average for 1994–1999 was 1.1 Bq·dm-3). The tritium concentrations in surface waters and in precipitation are still higher than that of natural level. The data obtained show that tritium concentration in the water of rivers might depend on the size of drainage area. The observed seasonal variations of tritium concentration in the precipitation collected in Warsaw and at the Mount Sniezka indicate the stratospheric source of tritium. It was found that about 30% of tritium deposited with precipitation is removed to the Baltic Sea with river waters.  相似文献   

3.
Unusual precipitation fell out in the Russian Arctic. There were globally background concentrations of the main components (distilled water) with a ion sum of 1.1–3.6 mg/L, increased amount of chlorides (despite continuous ice cover), and high concentration of trace elements (the sum of heavy metals was 140 μg/L, i.e., 13% of the minimum ion sum, whereas the total mineral content was the lowest). Increased concentration of heavy metals in the Central Arctic was also observed at a higher ion sum (77 mg/L). The highest acidity was estimated at pH 4.7.  相似文献   

4.
The rivers in the Hungarian Upper Tisza Region are frequently polluted mainly due to mining activities in the catchment area. At the beginning of 2000, two major mining accidents occurred in the Romanian part of the catchment area due to the failure of a tailings dam releasing huge amounts of cyanide and heavy metals to the rivers. Surface sediment as well as water samples were collected at six sites in the years 2000–2003, from the northeast-Hungarian section of the Tisza, Szamos and Túr rivers. The sediment pollution of the rivers was compared based on measurements of bulk material and selected single particles, in order to relate the observed compositions and chemical states of metals to the possible sources and weathering of pollution. Non-destructive X-ray analytical methods were applied in order to obtain different kinds of information from the same samples or particles. In order to identify the pollution sources, their magnitude and fate, complementary analyses were carried out. Heterogeneous particulate samples were analyzed from a large geographical territory and a 4-year time period. Individual particles were analyzed only from the “hot” samples that showed elevated concentrations of heavy metals. Particles that were classified as anthropogenic were finally analyzed to identify trace concentrations and chemical states of heavy metals.  相似文献   

5.
Lead concentrations in water and sediment samples near a stationary metal emission source were determined using the lead ion-selective electrode. These results were then verified by use of atomic absorption spectrophotometric methods. Samples were collected at three strategic sites near a local lead company in Southeast Houston, Texas. Accumulated rain water and sediment (soil deep down core) were analyzed in order to estimate lead concentration as a function of depth. Data indicate that the level of lead concentrations in both surface water and water extracted from the sediments exceed the limits for drinking water as established by the Environmental Protection Agency. The lead concentrations of the soil samples were higher in most cases when compared with various soils in the United States. The highest concentrations of lead were found in surface water samples.  相似文献   

6.
Summary Radioactivity of water and sediments from the Danube river in its course through Serbia during 2001-2003 years has been tested by alpha- and gamma-ray spectrometry. Except for cesium originating from Chernobyl, the radioactivity level of water and sediment coincide with the content of natural radionuclides in the environment of rivers basin. No increase in the radioactivity of sediments, due to slowing down of the water flow, was observed. The obtained results were analyzed in accordance with the model which considers only naturally occurring radionuclides originating in river sediment. The distribution coefficients for natural radionuclides are determined.  相似文献   

7.
A study is presented on the distribution of thorium and radium isotopes in sediments, suspended matter and water collected along Jucar river (East of Spain), using low-level α-spectrometry. The first aim of this work is to study the thorium and radium activity in water, sediment and suspended matter and their dependence on pH, temperature, conductivity and sediment sizes along Jucar river. The analysis of activity variation with these parameters will provide information about the dynamics of these radionuclides in rivers. The values obtained for the distribution factors between suspended matter and water (K d ) are also discussed.  相似文献   

8.
The Guarapiranga Reservoir is a very important aquatic system due to the fact that it is one of the main water reservoirs for South America’s largest city, São Paulo, Brazil. Guarapiranga basin is located within the Metropolitan Region of São Paulo and the reservoir itself is located in the Northern part of the basin occupying approximately 26 km2. This reservoir is characterized by environmental impacts from urban invasion, industrial and sewage wastes, all of which seriously affect its water quality and, consequently, the sediment quality. Two collection campaigns were undertaken: April 2009 and June 2010. The samples were analyzed by instrumental neutron activation analysis (INAA) in order to determine the following elements: major (Fe, K and Na), trace (As, Ba, Br, Co, Cr, Cs, Hf, Rb, Sb, Sc, Ta, Tb, Th, U and Zn) and rare earths (Ce, Eu, La, Lu, Nd, Sm, Tb and Yb). The organic matter and granulometric distribution were also evaluated and multivariate analysis was applied to the results. The study of elemental ratios indicated that the amount of elements present in the Guarapiranga Reservoir is mainly of detrital origin.  相似文献   

9.
In a framework of a more intensive study of the oceanographic phenomenology of the Northern Adriatic Sea, recently undertaken by the O. G. S. of Trieste, the present paper provides some insight into the determination of trace elements in sea water and bottom sediment matrices. Sampling procedure using continuous pumping and filtering and neutron activation analytical techniques are presented and the obtained results briefly discussed. Accounting for the physiography of the basin, for the oceanographic processes and for the different freshwater input, several samples were collected of filtered water in order to set up their properties. Results were obtained throughout the settlement only for long-lived radionuclides based on routine neutron activation: Cr, Ag, Co, Cs, Rb, Sb, Sc, Sr, Zn, U. For each of them, the concentration range was determined and discussed. Results indicate that the Cs, Rb, Sr and U concentration range is readily comparable with that assessed at open seas. On the contrary, for the other elements such as Cr, Ag, Co, Sc, Sb and Zn concentrations are noticeably higher than those found at open seas, mainly as far as samples collected near the sea bottom are concerned. The concentration increase is surely related to the burden of pollutants suffered by rivers. Moreover, the positive concentration gradient experienced toward the bottom, is fully in agreement with the estuarine character of the investigated area and in accordance with the strong decomposition of organic matter taking place in the bottom layer of the basin. Finally, the complexity of the sedimentary pattern in the Northern Adriatic renders it difficult to properly define the element concentration in bottom sediment. Only four samples were chosen as representative of the different sediments and analysed. Long-lived elements obtained are: Ce, Co, Cs, Cr, Rb, Sc, Tb, Yb. Their concentration was found to be related to the geochemical features of the activated matrix.  相似文献   

10.
The paper aims at the analysis of principal factors affecting the interaction of radiocesium with freshwater solids, important for the migration of radiocesium in rivers. Uptake of radiocesium by bottom sediments and suspended solids from small streams was studied as a function of pH and composition of aqueous phase, of the concentration of cesium in water and of the composition of freshwater solids, using laboratory model experiments. pH had negligible effect on the uptake in the pH range 5–9, the uptake decreased at pH values less than 3–5 depending on the nature and concentration of the solids. Addition of cations suppressed the uptake in the order K+>Na+>Ca2+, the suppression began at 0.001, 0.01 and 0.1 mol.dm?3 concentration, respectively. Increase in cesium concentration in water caused a decrease of radiocesium uptake, but at very low concentrations of cesium combined with higher concentration of sediment (2g·dm?3) the uptake was independent of cesium concentration. Removal of carbonates, oxidic coatings and organic matter from a sediment did not affect the sorption properties of the sediment. The nature of the effects found confirms that cesium is sorbed mainly by clay components of freshwater solids. Results obtained are compared with literature data and conclusions are drawn on the importance of the factors studied for modelling of radiocesium migration in rivers.  相似文献   

11.
Concentrations of heavy metals (Cd, Cr, Cu, Ni and Pb) were measured in sediment and water from a representative Western Mediterranean basin in South Spain: Guadalhorce River. In the later twentieth century, cities such as Málaga (capital of the Costa del Sol), have suffered the impact of the mass summer tourism. The ancient industrial activities, abandoned mine sites and the actual urbanisation and coastal development, recreation and tourism, wastewater treatment facilities, have been sources of pollution. This river has been heavily modified, with three dams for volume regulation purposes owing to the climatic cycles, with some years very dry and others with torrential rains. In this study, different indices to assessment of sediment contamination, statistical tools (Kruskall–Wallis test, Conglomerate analysis), sequential extraction methods and environmental quality guidelines have been employed to assess the possible contamination of this basin. Other physical–chemical parameters as chloride concentration, pH and conductivity were also measured. The results indicated that Ni and Cu were the most troublesome metals because they were more easily mobilisable than Cr and Pb; Ni exceeds the SQGs guidelines, and Cu presents considerable contamination. These metals were derived from lithogenic and anthropogenic sources, respectively, according to the enrichment factors (EF) values. Ni was the most dangerous because Ni concentrations exceeded the threshold effect concentration (TEC) below which harmful effects are unlikely to be observed, in 96.6% of the samples analysed and even the probable effect concentration (PEC) above which harmful effects are likely to be observed, in 56.6%. The cause of this pollution was postulated to be by abandoned Ni mines, which indicates that the pollution from mining persists during several decades. Multivariate analyses used in this study provide important tools for better understanding of the pollution source identification.  相似文献   

12.
<正>1 Introduction Areca catechu L.(Palmae), commonly known as an important economical seed crop, is widely culti-vated in tropical and subtropical areas, including India, Southeast Asia, East Africa and New Guinea. Areca nut(frequently known as betel nut) is the ripe fruit of  相似文献   

13.
A group of dissolved-bioavailable organochlorine (OC) pesticides and inorganic anions in water and total OC pesticides in sediments were measured in the Malheur Watershed, a semi-arid region in the western United States, over a 2-year period. OC pesticide levels were compared with those from a 1990 study of the lower section of the river, the most recent data available. After calculating the dissolved fraction from the 1990, study it seems that DDD and dieldrin levels have decreased in the water by 50-70%, while DDE and DDT have changed little. Although banned nearly 30 years ago, DDT is still persistent throughout the Malheur River basin/watershed because it was found in all water samples tested. All of the OC pesticides tested during the 2-year study are well below the criterion continuous concentration for aquatic community exposure as defined by the U.S. Environmental Protection Agency (EPA). OC pesticides appear to be decreasing, however, at lower Ontario there remains a human health risk (EPA Human Health Risk Water Quality Criteria) for DDT, because this criteria includes daily consumption of water and fish from the river. Overall, although the upper forest watershed sites have lower OC pesticide concentrations, they represent an important contribution to the total DDT load to this watershed, a source not previously acknowledged. The large increase in DDT and sigmaDDT between the Ontario sites may indicate a possible historical point source of contamination or historical preferential deposition of contamination. Normalized sediment (sigmaDDT/organic carbon) strongly correlates with dissolved water sigmaDDT.  相似文献   

14.
Statistical aspects of sediment sampling are discussed. Sampling sites at two selected rivers in East Germany were investigated using various sampling models. In the sediment samples the contents of 13 metals (As, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Se and Zn) were analyzed by means of atomic spectroscopy. Large differences in the contents of the analyzed metals were already found at small distances. The application of an overall error analysis shows that independent of the analyzed grain size fraction, sampling is the main source of variance. Two-dimensional variance analysis and a geostatistical method were applied because of homogeneity considerations. In contrast to the investigated longitudinal profiles, concentration gradients and spatial dependences of the metal contents were detected at the cross section. Finally, two approaches are described to determine the number of samples required for the representative assessment of loads. Weighting the result according to a critical value is shown as a way to reduce the expenditure of sampling.Dedicated to Professor Dr. K. Doerffel on the occasion of his 70th birthday  相似文献   

15.
The water consumption characteristics and water use efficiency (WUE) of poplar (Populus simonii) were investigated under the condition of three different soil water regimes, which were 70%, 55% and 40% of field capacity (FC), respectively. The results showed that water potential, water content, photosynthetic rate, WUE of leaves, and plant growth rate decreased significantly with reduction in soil water content. At the level of adequate and medium soil water content, rapid growth and biomass accumulation in poplar occurred during May and June, whereas this phenomenon occurred only during May under severe soil drought condition. Total water consumption and biomass growth were the greatest under adequate soil water condition, decreased under medium soil drought condition, and lowest under severe soil drought condition. Total WUE was the highest under medium soil water condition and lowest under severe soil condition. Changing patterns of water consumption for daily rate, every 10-day rate, and month rate were quite different under these three soil water regimes. For all these three treatments, the highest monthly water consumption rate occurred during July and June. The highest water consumption over a 10-day period was during in the second 10 days of July, the first 10 days of July, and the last 10 days of June for these three treatments, respectively. The day for the highest water consumption in the medium and severe drought treatments occurred 1 or 2 months earlier than the adequate soil water treatment. The daily time for the greatest water consumption was different throughout the life span of poplar under these soil water levels. According to these results, we concluded that poplar did not have the characteristics of drought-resistance plants, and we do not recommend that this tree species be planted over a wider range of the Loess Plateau in China.  相似文献   

16.
Tributyltin (TBT), a biocidal antifoulant in many marine paints, was measured in near-surface and near-bottom water over a 25 h period at the entrance to a marina in San Diego Bay, USA. Surface water concentrations varied from 20 to 225 nanograms per liter (ng dm?3) as TBT chloride and bottom water varied from non-detectable (<1 ng dm?3) to 77 ng dm?3. Surface water concentrations varied, with highest concentrations associated with ebbing tides, and lowest concentrations with flooding tides, indicating that the yacht basin is a source of TBT. Bottom water TBT concentrations were almost always lower than corresponding surface water concentrations. The highest bottom water concentrations were associated with flooding tides and lowest surface water TBT concentrations. Physical water column measurements indicate that vertical stratification developed during ebbing tides and dissipated during flooding tides. This accounted for maximum bottom water and minimum surface water TBT concentrations during flooding tides, due, at least in part, to vertical mixing and dilution during flood tides.  相似文献   

17.
Measurement of tritium in water of rains, springs, wells, mud volcanoes and rivers, lakes of the Western Caucasus (Krasnodar region) has been carried out since 1997 for hydrogeology, engineering geology, ecology and seismology. Electrolytic cells with spiral electrodes and the big multiwire proportional chamber were used for low tritium concentration measurements on expeditions. With the new design of the cell the enrichment factor of 64.0 ± 1.5 % was obtained during the electrolytic process. Correlation of tritium concentration is observed in mud volcanoes and spring water with regional seismicity. The long-term tritium data are shown in natural waters in South Russia.  相似文献   

18.
A New Alkaloid from Sinomenium acutum   总被引:2,自引:0,他引:2  
Sinomenium acutum is widely used in East and South Asia for the treatment of many diseases, especially rheumatoid arthritis (RA). The chemical research on Sinomenium acutum led to the isolation of a new alkaloid compound (1). On the basis of chemical evidences and spectral analysis, 1 was identified as N-(1, 7-dimethoxylphenanthren-2-yl)acetamide.  相似文献   

19.
Gas chromatography–mass spectrometry was used for the determination of 16 priority polycyclic aromatic hydrocarbons (PAHs) in surface soils from seventeen areas in Southeast Romania, including sites placed in the vicinity of Galati iron and steel plant and Lower Prut Meadow natural reserve in Galati County. The total concentration of PAHs (TPAHs) in the investigated soils ranges from 0.003 mg/kg to 38.524 mg/kg dry weight. According to Romanian legislation for trace organic compounds in soils of different uses, the amounts of PAHs in soils from the industrial zone exceed the normal values for the majority of individual PAHs. The lowest concentrations were found in soils sampled from the protected area of Lower Prut Meadow natural reserve and the highest near a zootechnique farm in the Prut River basin, where the alert levels exceeded for the less sensitive area in the case of TPAHs and benzo[b]fluoranthene and for the sensitive area in the case of chrysene, benz[a]anthracene, benzo[k]fluoranthene and benzo[g,h,i]perylene. The sources of PAH contaminating soils are complex, being of both pyrogenic and petrogenic origins.  相似文献   

20.
Seasonal changes in sea level, tidal range, wind, riverine discharges, nearshore SSC (suspended sediment concentration) and bed-level of intertidal flat at 4 different sites were shown. In addition, the statistical relationships between the dynamics and the behavior of the sediment surface were examined. The average intertidal elevation seems negatively correlated to sea level while positively correlated to nearshore SSC. The effect of wind on seasonal cycle of average intertidal elevation is not evident although wind is an important factor governing short-term erosion/accretion events. The influence of riverine discharges on seasonal cycle of deltaic intertidal flats is masked by other factors. It is concluded that seasonality on mudflats is more complicated than on beaches.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号