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61.
Accumulation of heavy metals from contaminated soil to plants and evaluation of soil remediation by vermiculite 总被引:18,自引:0,他引:18
We evaluated the distribution of 15 metal ions, namely Al, Cd, Cu, Cr, Fe, La, Mn, Ni, Pb, Sc, Ti, V, Y, Zn and Zr, in the soil of a contaminated site in Piedmont (Italy). This area was found to be heavily contaminated with Cu, Cr and Ni. The availability of these metal ions was studied using Tessier’s sequential extraction procedure: the fraction of mobile species, which potentially is the most harmful for the environment, was much higher than that normally present in unpolluted soils. This soil was hence used to evaluate the effectiveness of treatment with vermiculite to reduce the availability of the pollutants to two plants, Lactuca sativa and Spinacia oleracea, by pot experiments. The results indicated that the addition of vermiculite significantly reduces the uptake of metal pollutants by plants, confirming the possibility of using this clay in amendment treatments of metal-contaminated soils. The effect of plant growth on metal fractionation in soils was investigated. Finally, the sum of the metal percentages extracted into the first two fractions of Tessier’s protocol was found to be suitable in predicting the phytoavailability of most of the pollutants present in the investigated soil. 相似文献
62.
Otones V Álvarez-Ayuso E García-Sánchez A Santa Regina I Murciego A 《Environmental pollution (Barking, Essex : 1987)》2011,159(10):2637-2647
A mining area affected by the abandoned exploitation of an arsenical tungsten deposit was studied in order to assess its arsenic pollution level and the feasibility of native plants for being used in phytoremediation approaches. Soil and plant samples were collected at different distances from the polluting sources and analysed for their As content and distribution. Critical soil total concentrations of As were found, with values in the range 70-5330 mg kg−1 in the uppermost layer. The plant community develops As tolerance by exclusion strategies. Of the plant species growing in the most polluted site, the shrubs Salix atrocinerea Brot. and Genista scorpius (L.) DC. exhibit the lowest bioaccumulation factor (BF) values for their aerial parts, suggesting their suitability to be used with revegetation purposes. The species Scirpus holoschoenus L. highlights for its important potential to stabilise As at root level, accumulating As contents up to 3164 mg kg−1. 相似文献
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Ochoa-Hueso R Allen EB Branquinho C Cruz C Dias T Fenn ME Manrique E Pérez-Corona ME Sheppard LJ Stock WD 《Environmental pollution (Barking, Essex : 1987)》2011,159(10):2265-2279
We review the ecological consequences of N deposition on the five Mediterranean regions of the world. Seasonality of precipitation and fires regulate the N cycle in these water-limited ecosystems, where dry N deposition dominates. Nitrogen accumulation in soils and on plant surfaces results in peaks of availability with the first winter rains. Decoupling between N flushes and plant demand promotes losses via leaching and gas emissions. Differences in P availability may control the response to N inputs and susceptibility to exotic plant invasion. Invasive grasses accumulate as fuel during the dry season, altering fire regimes. California and the Mediterranean Basin are the most threatened by N deposition; however, there is limited evidence for N deposition impacts outside of California. Consequently, more research is needed to determine critical loads for each region and vegetation type based on the most sensitive elements, such as changes in lichen species composition and N cycling. 相似文献
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为了解15种药物及个人护理用品(PPCPs)在中小型污水处理厂中的分布及其去除效果,采用液相色谱-串联质谱(LC-MS/MS)技术对3座A2/O工艺的污水处理厂水样进行分析研究。结果显示,除普萘洛尔、吉非罗平和吲哚美辛在3座中小型污水处理厂各个工艺单元中均未被检出外,其余12种目标化合物的检出频率在90%~100%之间。进水水样中PPCPs的平均检出浓度为2 285.4 ng/L,其中咖啡因(CF)的平均检出浓度最高为973.3 ng/L,酮洛芬(KP)的平均检出浓度次之为844.7 ng/L,两者之和占进水水样中PPCPs平均含量的79.5%,表明污水处理厂的主要污染物为CF和KP。3座污水处理厂对CF的去除效果最为显著,平均去除率为95.3%,对15种PPCPs总去除效率在39.3%~82.8%之间。 相似文献
67.
新的《火电厂大气污染物排放标准》和新《环境保护法》实施后,燃煤火电企业的依法治企自觉性不断提高,但由于不同的环保管理文件对超标处罚依据和处罚手段不同,造成政府对企业处罚的自由裁量权加大,对企业造成一定的压力与困惑。结合企业实际运行情况对燃煤电厂大气污染物排放考核时间间隔提出建议。 相似文献
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In many locations, regulatory agencies do not permit tree planting above landfills that are sealed with a capping clay, because
roots might penetrate the clay barrier and expose landfill contents to leaching. We find, however, no empirical or theoretical
basis for this restriction, and instead hypothesize that plant roots of any kind are incapable of penetrating the dense clays
used to seal landfills. As a test, we excavated 30 trees and shrubs, of 12 species, growing over a clay-lined municipal sanitary
landfill on Staten Island, New York. The landfill had been closed for seven years, and featured a very shallow (10 to 30-cm)
soil layer over a 45-cm layer of compacted grey marl (Woodbury series) clay. The test plants had invaded naturally from nearby
forests. All plants examined—including trees as tall as 6 m—had extremely shallow root plates, with deformed tap roots that
grew entirely above and parallel to the clay layer. Only occasional stubby feeder roots were found in the top 1 cm of clay,
and in clay cracks at depths to 6 cm, indicating that the primary impediment to root growth was physical, although both clay
and the overlying soil were highly acidic. These results, if confirmed by experimental research should lead to increased options
for the end use of many closed sanitary landfills. 相似文献
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