排序方式: 共有16条查询结果,搜索用时 15 毫秒
1.
Background Worldwide, large amounts of sediments have to be dredged annually from waterways and harbours. These sediments are sometimes
polluted with a variety of toxic compounds. In some countries, including Belgium, the load with the biocide tributyltin (TBT)
from ship coatings prohibits the dumping of harbour sludge into the sea. Land-based dumping is a commonly used alternative.
Objective This research investigated the feasibility to use land-deposited harbour sludge for plant production. In a field trial, the
growth of 38 more or less salt-tolerant plant species on low and high TBT-contaminated sediments was studied. The elimination
of TBT from sludge with and without vegetation was compared. The uptake of TBT and its degradation products di- and monobutyltin
(DBT and MBT) into harvest products under field conditions was determined.
- Experimental Set-up. Sediments dredged in May 2003 from the brackish waters of the port of Antwerp were analysed in the laboratory
for soil texture, pH, electroconductivity, sodium, magnesium, potassium, calcium, ammonium, nitrate, total nitrogen, chloride,
sulphur and the organotins TBT, DBT and MBT. The sediments were lagooned for one year to dewater, desalinate and improve their
structure. Salt-tolerant domestic and wild plants were selected and sown in May 2004. In August 2004, plants were harvested
and the produced biomass was determined. Samples were taken from vegetated and non-vegetated top and bottom sediments and
from plants growing above soil and analysed for TBT, DBT and MBT.
Results The fresh sediments showed a good supply with nutrients and a neutral pH, but were rather saline (EC 14 mS cm-1 of the saturated
paste extract). The salinity decreased to 3.7 mS cm-1 during lagoonation. The high and the low contaminated sediment had initially
43 and 1.6 mg TBT kg-1 dry weight, respectively. Besides TBT, several other contaminants were present in the sediments at
critical levels. The biomass production of the plant species from the field trial ranged from 0.2 to 13 tons dry mass per
hectare. Plants performing excellently were barley, sorghum, rape seed, a clover/grass mix and reed. If at all, a positive
influence of TBT on plant growth was seen. TBT was degraded significantly faster (>40%) below barley. The uptake of TBT, DBT
and MBT into stem and leaves of reed, grass and clover was very low, but measurable and not related to concentrations in soil.
No uptake of TBT or its metabolites into corn of barley was found.
Discussion This study confirmed former results: the toxicity of TBT to higher plants is low, and even high levels in soils would not
be a hindrance for crop production. The removal of TBT seemed to be increased by both lagooning and plant growth, although
the target values for sea dumping in use in certain European countries were not reached. A plausible explanation for the faster
degradation of TBT under vegetation is that oxygen is a limiting factor, and plants dewater the soil, thus aerating it. The
uptake of the organotins TBT, DBT and MBT into harvest products is probably due to attached soil particles.
Conclusions To summarize, barley was the optimal species: it grew very well despite the salinity of the dredged sediments, it had a significantly
positive effect on TBT removal; it showed no measurable uptake of TBT or the other butyltins into the harvested product; and
it is a cash crop well established in European agriculture.
Outlook The amounts of dredged sediments are high, and good soils are becoming increasingly rare. The feasibility of using dredged
sediments for non-food production, such as energy crops, should be investigated by a critical risk assessment. 相似文献
2.
A large number of data (n=488) were acquired from 2003 to 2006 for five Italian harbours and three control areas to determine trace element (Al, As, Cd, Cu, Zn, Pb, Hg, Cr, and Ni) levels in sediments. Results were utilised to evaluate, on a multivariate statistical basis, pollution levels, significant relationships between observed levels and specific factors, and enrichment factors. Of the factors tested, main human use of harbour, was best able to determine segregations in the observed trace element fingerprints. Compared with the concentration limit approach, the evaluation of enrichment factors, even if affected by mathematical approximations, represented a useful tool for environmental studies, allowing evaluation of the presence of sediments enriched by human activities and reducing the occurrence of both false positives and false negatives due to natural differences in aluminosilicate levels. 相似文献
3.
Over the last years, great progress in the research on speciation of butyltins has been made. Many coupling techniques have been successfully developed, with better applications to sediments samples in the environment. Sediments were collected from 1999 to 2000 to elucidate butyltin pollution in Theoule harbour. Most of the analysed samples showed evidence of butyltin compounds. The results show that the concentration of Tributyltin (TBT) was in the range 20–200?µg/kg in March 1999, 20–340?µg/kg in June 1999, 180–1280?µg/kg in July 2000, and 55–820?µg/kg in October 2000. A comparison of the MBT, DBT, and TBT results show that in 1999 the concentrations were in the order TBT?DBT?>?MBT, with some exceptions. The patterns observed in many sediment cores show a great disparity of organotin input concentration among the cores collected during one month and also during two different months, and from one season to the other. This paper provides information on the use of the acetic acid leaching system in the determination of butyltin. The method is applied to evaluate the occurrence of these species in sediments from the Theoule harbour, between 1999 and 2000. In this study, a GC/AES was applied, complemented with acetic acid leaching and monitored using two certified reference materials: PACS-2 reference sediment and BCR 462 (Report EUR 18406 EN, 1998). 相似文献
4.
国外松飞子成林能力较强,在人工促进措施下进行天然更新,幼树的地径和树高生长速度达到人工造林水平,而每亩可节约造林成本34.95元,经济效益显著。值得大力推广。 相似文献
5.
6.
污水处理厂的建立可避免污水直排对受纳水体的污染,但污水处理厂尾水的集中排放也会对水体造成污染,科学规划污水处理厂尾水排污口及排放标准尤其重要。以黄海北部地区某港口待建污水处理厂为研究对象,基于EFDC(Environmental Fluid Dynamics Code)建立水动力及污染物输移扩散模型,定量评估不同排污口位置及排放标准下,尾水对港内水环境的影响。结果表明:港池内水体自净能力较差,排放口位于A点时,最适宜方案是GB 18918—2002《城镇污水处理厂污染物排放标准》一级排放标准。 相似文献
7.
文中叙述了1988 ̄1990年间,我国4个港湾-大连湾、天津港、深圳湾及珠江河段各疏浚区疏浚物中油类污染调查及分布状况。文中介绍了站位布设原则,样品采集、样品处理、分析测试方法。进行了沾污疏浚物油类出溶出实验,认为油类溶出实验是估价疏浚物油类污染的程度的重要手段。讨论了4港湾疏浚物油类污染水平。大连湾海域疏浚物石油污染明显,珠江河段,深圳湾及天津港疏浚物稍受影响,基本上是清洁的。 相似文献
8.
Sources of hydrocarbons in sediments of the Mandovi estuary and the Marmugoa harbour, west coast of India 总被引:5,自引:0,他引:5
Surface sediments were collected from various locations of the Mandovi estuary and the Marmugoa harbour. Sediments were analysed for organic carbon (OC), total lipids, n-alkanes concentration and composition. Concentrations of OC, total lipids and n-alkanes varied spatially and ranged from 1 to 2.5%, 176 to 1413 microg/g dry weight (dw) sediments, and 0.8 to 3.2 microg/g dw sediments of the Mandovi estuary, respectively; and from 0.6 to 2.9%, 233 to 1448 microg/g dw sediments, and 1.6 to 10.7 microg/g dw sediments in the Marmugoa harbour, respectively. Long chain, odd carbon n-alkanes (C(23)-C(33)) in the Mandovi estuary, whereas short chain, even carbon n-alkanes (C(11)-C(21)) in the Marmugoa harbour sediments were more abundant. The total HC concentrations, n-alkane composition, CPI, UCM and other evaluation indices suggest the dominance of terrestrial hydrocarbons in the estuarine while petroleum derived hydrocarbons in the harbour sediments. This conclusion was further supported by the abundance of hopanes with C(29) to C(34) alpha, beta compounds and steranes with C(27), C(28) and C(29) compounds in the harbour sediments. 相似文献
9.
Environmental effects of enlargement works in Puerto Calero (Lanzarote, Canary Islands) were analysed in the sediments using abiotic variables (total hydrocarbons, polyaromatic hydrocarbons, organic matter and granulometry) and three biotic indexes (AMBI, M-AMBI and BENTIX). A before–after/control–impact (BACI) design was developed with four sampling campaigns, before (November 2004), during (March and July 2005) and after (July 2006) works. Inner stations were characterised by high concentrations of pollutants (total hydrocarbons and polyaromatic hydrocarbons). A temporal trend (2004–2006) was observed in macrofaunal assemblage structure, and thus in AMBI, M-AMBI and BENTIX indexes. Macrobenthic assemblages also mirrored the pollution gradient, with bioindicator species in inner stations (the polychaete Pseudopolydora paucibranchiata and the mollusc Abra alba), sensitive species (the sipunculid Aspidosiphon muelleri, the crustacean Pariambus typicus and the polychaete Aponuphis bilineata) in outer stations and ubiquitous species (the polychaetes Aricidea assimilis and Armandia polyophthalma) in both stations (inner and outer). 相似文献
10.
An approach for defining the quality of surface sediments of limited areas in terms of heavy metal contents is proposed. Sediments were taken on a bi‐dimensional mapping, for checking possible different sources of pollution in the case study, a harbour zone. Non residual metals were determined by ICP‐AES in cold diluted hydrochloric acid leachates of sediments. An “enrichment factor”;, r, can be computed for each metal: metals with r values exceeding unity can be considered as indicators of metal pollution. A “total enrichment factor”;, R, was proposed in order to assess the degree of pollution of sediments for each site. R is an adimensional value that accounts for the presence of metals that exceed threshold values determined by background concentrations. 相似文献