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31.
绵阳市代表性点位土壤多环芳烃剖面分布特征 总被引:2,自引:0,他引:2
通过挑选绵阳市有代表性的点位土壤柱,应用GC MS分析土壤柱垂直剖面中多环芳烃的含量水平,得出其垂直剖面分布特征。结果表明:5~20 cm深度中的PAHs含量最高,40 cm以下则含量锐减。由于表层(0~5 cm)土壤与大气之间的土气交换频繁,PAHs含量相对较低,而5~20 cm处土壤受到表层土壤的遮盖,PAHs富集较高,含量达到整个土壤柱最高值。多环芳烃总体垂直剖面分布特征表现出随深度增加含量减少的趋势。PAHs总含量以江油市点位(33024 ng/g)最高,其次是三台县点位(29989 ng/g),最低是游仙区点位(11274 ng/g)。研究区主要污染物为Nap、Phe和Chr/y。其中不同的土质、种植物都能影响PAHs的富集和迁移速率,导致含量在不同深度上产生变化。此外,参照有关环境质量标准,发现PAHs总量上江油市点位与三台县点位属于轻微污染、游仙区点位则属于无污染。 相似文献
32.
Gert Jan Reinds Maximilian Posch 《Environmental pollution (Barking, Essex : 1987)》2009,157(4):1258-1269
The dynamic soil chemistry model SMART was applied to 121 intensive forest monitoring plots (mainly located in western and northern Europe) for which both element input (deposition) and element concentrations in the soil solution were available. After calibration of poorly known parameters, the model accurately simulated soil solution concentrations for most plots as indicated by goodness-of-fit measures, although some of the intra-annual variation especially in nitrate and aluminium concentrations could not be reproduced. Model evaluations of two emission-deposition scenarios (current legislation and maximum feasible reductions) for the period 1970-2030 show a strong reduction in sulphate concentrations between 1980 and 2000 in the soil due to the high reductions in sulphur emissions. However, current legislation hardly reduces future nitrogen concentrations, whereas maximum feasible reductions reduces them by more than half. Maximum feasible reductions are also more effective in increasing pH and reducing aluminium concentrations, mostly below ‘critical’ values. 相似文献
33.
Schaefer CE do Amaral EF de Mendonça BA Oliveira H Lani JL Costa LM Fernandes Filho EI 《Environmental monitoring and assessment》2008,140(1-3):279-289
The relationships between soils attributes, soil carbon stocks and vegetation carbon stocks are poorly know in Amazonia, even
at regional scale. In this paper, we used the large and reliable soil database from Western Amazonia obtained from the RADAMBRASIL
project and recent estimates of vegetation biomass to investigate some environmental relationships, quantifying C stocks of
intact ecosystem in Western Amazonia. The results allowed separating the western Amazonia into 6 sectors, called pedo-zones:
Roraima, Rio Negro Basin, Tertiary Plateaux of the Amazon, Javari-Juruá-Purus lowland, Acre Basin and Rondonia uplands. The
highest C stock for the whole soil is observed in the Acre and in the Rio Negro sectors. In the former, this is due to the
high nutrient status and high clay activity, whereas in the latter, it is attributed to a downward carbon movement attributed
to widespread podzolization and arenization, forming spodic horizons. The youthful nature of shallow soils of the Javari-Juruá-Purus
lowlands, associated with high Al, results in a high phytomass C/soil C ratio. A similar trend was observed for the shallow
soils from the Roraima and Rondonia highlands. A consistent east–west decline in biomass carbon in the Rio Negro Basin sector
is associated with increasing rainfall and higher sand amounts. It is related to lesser C protection and greater C loss of
sandy soils, subjected to active chemical leaching and widespread podzolization. Also, these soils possess lower cation exchangeable
capacity and lower water retention capacity. Zones where deeply weathered Latosols dominate have a overall pattern of high
C sequestration, and greater than the shallower soils from the upper Amazon, west of Madeira and Negro rivers. This was attributed
to deeper incorporation of carbon in these clayey and highly pedo-bioturbated soils. The results highlight the urgent need
for refining soil data at an appropriate scale for C stocks calculations purposes in Amazonia. There is a risk of misinterpreting
C stocks in Amazonia when such great pedological variability is not taken into account. 相似文献
34.
Effect of long-term changes in soil chemistry induced by road salt applications on N-transformations in roadside soils 总被引:2,自引:0,他引:2
Of several impacts of road salting on roadside soils, the potential disruption of the nitrogen cycle has been largely ignored. Therefore the fates of low-level ammonium-N and nitrate-N inputs to roadside soils impacted by salting over an extended period (decades) in the field have been studied. The use of road salts disrupts the proportional contributions of nitrate-N and ammonium-N to the mineral inorganic fraction of roadside soils. It is highly probable that the degree of salt exposure of the soil, in the longer term, controls the rates of key microbial N transformation processes, primarily by increasing soil pH. Additional influxes of ammonium-N to salt-impacted soils are rapidly nitrified therefore and, thereafter, increased leaching of nitrate-N to the local waterways occurs, which has particular relevance to the Water Framework Directive. The results reported are important when assessing the fate of inputs of ammonia to soils from atmospheric pollution. 相似文献
35.
Jörg Luster Manoj Menon Sandra Hermle Rainer Schulin Madeleine S. Günthardt-Goerg Bernd Nowack 《Water, Air, & Soil Pollution: Focus》2008,8(2):163-176
Soil translocation for recultivation of soil removed from construction sites and for the preparation of refilled lysimeters
inevitably involves disturbance of soil structure, and, if intermediate storage is included, also drying and rewetting of
the soil. We report on an experiment with model forest ecosystems, where uncontaminated forest subsoils were covered with
non-contaminated or freshly heavy metal (mainly Zn and Cu) contaminated topsoil in large lysimeters. Monitoring of the chemical
composition of the drainage water revealed two distinct soil conditioning phases. During an initial phase of about a year
strongly elevated nitrate and sulfate concentrations occurred that were attributed to a mineralisation flush caused by the
increased accessability of mineralisable nitrogen and sulfur in destroyed aggregates. These effects were significantly larger
in lysimeters with calcareous subsoil than in those with acidic subsoil. The second phase was characterised by a gradual decrease
in dissolved organic carbon and sulfate concentrations, in particular in the acidic subsoil. This decrease may be attributed
to the depletion of pools made accessible during aggregate destruction or the formation of new aggregates. These chemical
changes had only little effects on the concentrations of copper and zinc in the drainage water. Based on our results, it can
be concluded that large refilled lysimeters can be used for many purposes without risk of compromised results, if a conditioning
phase of about 1 year with sufficiently moist soil conditions is respected. Nevertheless, gradual changes in soil chemical
characteristics still occur after this initial phase. Implications for the recultivation of sites using relocated soils are
discussed. 相似文献
36.
非饱和土土-水特征曲线(SWCC)表示了土中含水量与吸力之间的关系。针对非饱和土干-湿循环过程中的吸力变化特征,开展试验研究。采用体积压力板仪实现非饱和土的脱湿和吸湿过程。试验成果显示:(1)土-水特征曲线是不稳定的,它与土体含水率的变化路径有关;(2)在干湿循环过程中,相同的基质吸力具有不同的含水量。 相似文献
37.
建立了用加速溶剂萃取法(ASE)提取、气相色谱-串联质谱法分析土壤中20种有机氯农药的方法。用正己烷和丙酮(1∶1,V/V)的混合溶剂为提取剂,萃取温度100℃,压力1 500 psi,静态提取10 min,循环提取2次,提取液经石墨化碳黑固相萃取柱净化,浓缩后进行GC-MS/MS测定,外标法定量。试验结果表明,采用串联质谱多反应监测模式,降低了背景干扰,当取5 g土壤时,有机氯农药的检出限在0.1~3.0μg/kg之间,低浓度水平(8μg/kg)的基体加标回收率为70.3%~134%,相对标准偏差〈23%。测定方法背景干扰低,灵敏度高,适合土壤中20种有机氯农药残留的同时测定。 相似文献
38.
通过监测和田地区生态修复项目实施后所取得生态效益的结果表明,生态修复项目实施后,由于项目区风速降低,温度和相对湿度的变化减少,提高了植被盖度,降低了风蚀量,促进了成土作用的进行,从而逐渐改善了土壤的理化性质。 相似文献
39.
Faranak Hadi Amir Mousavi Kambiz Akbari Noghabi Hadi Ghaderi Tabar Ali Hatef Salmanian 《Journal of environmental science and health. Part. B》2013,48(3):208-213
Thirty bacterial strains with various abilities to utilize glyphosate as the sole phosphorus source were isolated from farm soils using the glyphosate enrichment cultivation technique. Among them, a strain showing a remarkable glyphosate-degrading activity was identified by biochemical features and 16S rRNA sequence analysis as Ochrobactrum sp. (GDOS). Herbicide (3 mM) degradation was induced by phosphate starvation, and was completed within 60 h. Aminomethylphosphonic acid was detected in the exhausted medium, suggesting glyphosate oxidoreductase as the enzyme responsible for herbicide breakdown. As it grew even in the presence of glyphosate concentrations as high as 200 mM, Ochrobactrum sp. could be used for bioremediation purposes and treatment of heavily contaminated soils. 相似文献
40.
The effect of the addition of materials on the leaching pattern of As and metals (Cu, Zn, Ni, Pb, and Cd) in two contaminated soils was investigated. The examined materials included bentonites, silicates and industrial wastes, such as sugar foam, fly ashes and a material originated from the zeolitization of fly ash. Soil + material mixtures were prepared at 10% doses. Changes in the acid neutralization capacity, crystalline phases and contaminant leaching over a wide range of pHs were examined by using pHstat leaching tests. Sugar foam, the zeolitic material and MX-80 bentonite produced the greatest decrease in the leaching of pollutants due to an increase in the pH and/or the sorption capacity in the resulting mixture. This finding suggests that soil remediation may be a feasible option for the reuse of non-hazardous wastes. 相似文献