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291.
Atmospheric phenanthrene pollution modulates carbon allocation in red clover (Trifolium pratense L.)
Desalme D Binet P Epron D Bernard N Gilbert D Toussaint ML Plain C Chiapusio G 《Environmental pollution (Barking, Essex : 1987)》2011,159(10):2759-2765
The influence of atmospheric phenanthrene (PHE) exposure (160 μg m−3) during one month on carbon allocation in clover was investigated by integrative (plant growth analysis) and instantaneous 13CO2 pulse-labelling approaches. PHE exposure diminished plant growth parameters (relative growth rate and net assimilation rate) and disturbed photosynthesis (carbon assimilation rate and chlorophyll content), leading to a 25% decrease in clover biomass. The root-shoot ratio was significantly enhanced (from 0.32 to 0.44). Photosynthates were identically allocated to leaves while less allocated to stems and roots. PHE exposure had a significant overall effect on the 13C partitioning among clover organs as more carbon was retained in leaves at the expense of roots and stems. The findings indicate that PHE decreases root exudation or transfer to symbionts and in leaves, retains carbon in a non-structural form diverting photosynthates away from growth and respiration (emergence of an additional C loss process). 相似文献
292.
Spurgeon DJ Lawlor A Hooper HL Wadsworth R Svendsen C Thomas LD Ellis JK Bundy JG Keun HC Jarup L 《Environmental pollution (Barking, Essex : 1987)》2011,159(12):3425-3432
The relationship of measured or modelled Cd concentrations in soil, house dust and available to plants with human urinary Cd concentrations were assessed in a population living around a Cd/Pb/Zn smelter in the UK. Modelled air concentrations explained 35% of soil Cd variation indicating the smelter contributed to soil Cd loads. Multi-variate analysis confirmed a significant role of biological and life-style factors in determining urinary Cd levels. Significant correlations of urinary Cd with soil, house dust and modelled plant available Cd concentrations were not, however, found. Potential reasons for the absence of clear relationships include limited environmental contact in urban populations; the role of undefined factors in determining exposure; and the limited spatial scope of the survey which did not sample from the full pollution gradient. Further, the absence of any significant relationship indicates that environmental measures provide limited advantage over atmospheric model outputs for first stage human exposure assessment. 相似文献
293.
Rapid increase in industrialization and agricultural activities to meet the population need has led to environmental pollution.
The major revolution in agricultural production is mainly due to increased use of pesticides and fertilizers. Soil act as
a major sink for majority of pesticides applied on agricultural crops. Among the organochlorines, endosulfan is the most commonly
used pesticide, hence this study concentrates on the persistence and distribution behaviour of endosulfan under field conditions.
The result showed that the alpha endosulfan concentrations were very minimum (0.98 mg/kg of soil) in all the four fields under
study (Nazarath, Othikadu, Ekkadu and Ekkadukandigai of Thiruvallur district, Tamil Nadu). Where as beta endosulfan concentration
at the time of application was 6.39 mg/kg and declined to 0.8 mg/kg on soil at 150th day. The endosulfan sulfate concentration
was 11.8 mg/kg in soil at 15th day and then concentration declined to 2.2 mg/kg at 150th day. Field run-off samples showed
maximum residue levels (0.024 mg/l) at the early irrigation period. While plant foliar parts showed maximum concentrations
of α-endosulfan (43.4 mg/kg), β-endosulfan (40.6 mg/kg) and endosulfan sulfate (20.1 mg/kg). At harvest stage, rice grain and husk also had lower concentrations of endosulfan sulfate (2.2 and 0.09 mg/kg), respectively. 相似文献
294.
对四种同脂发热自燃性进行了试验研究,采用回归分析方法,建立了环境温度与油脂发热诱导期之间的定量关系式,即lgT/a/t+b,提出油脂自燃性能可用a和b两参数描述。研究表明,碘值与油脂自燃性能常数a和b存在密切关系,可分别用对数和直线方程表示。 相似文献
295.
The geysers panic grass [Dichanthelium lanuginosum Spellenberg var. thermale (Bol.) Spellenberg or DILA] is exclusively associated with surface geothermal manifestations in Sonoma County, California,
USA (38°46′N, 122°38′W). Steam extraction by power plants could alter the subsurface distribution of heat and water to the
site, potentially impacting subpopulations of this rare plant. The purpose of this study was to use demographic monitoring
to determine: (1) temporal and spatial patterns of soil temperature in relation to the distribution of established DILA individuals
at Little Geysers, (2) in situ response of experimental populations of DILA to spatial variations in soil temperature, and
(3) habitat requirements of DILA as an indicator of its tolerance to variations in surficial geothermal features. Thermocouple
transects and a datalogger provided data for characterizing the spatial and temporal patterns of soil temperature in four
microhabitats (fumarole, DILA stand, Andropogon stand, and cleared). Experimental populations were established by precisely sowing and monitoring DILA seeds in these microhabitats.
The results indicated that spatial and temporal variations in soil temperature had significant effects on the processes of
germination, growth, survivorship, and reproduction, thus producing a readily observed metapopulation patch dynamic in relation
to geothermal activity. Seasonal depressions of soil temperature near the fumaroles by cold air and prolonged rainfall events
also promoted the emergence and survival of DILA seedlings in a microhabitat that was previously too hot to occupy. Over longer
periods of time, DILA metapopulation dynamism reflected climatic and geothermal variation. Drought years inhibited germination
for lack of water, but more importantly for the lack of requisite soil temperature depressions in the fumarole microhabitat.
Wet years promoted subpopulation expansion into transition areas that were once too hot and dry. There have also been shifts
in the underground distribution of steam into areas distant from known geothermal features. The demographic responses of DILA
to spatial and temporal variations in soil temperature indicate that heat is an absolutely essential component of the steam
resource. In its absence, germination, seeding survivorship, growth, and maturation are significantly inhibited even if soil
conditions are favorable and potential competitors are controlled. Ultimately, persistence of the species depends on maintaining
the ecosystem dynamic of colonization and extirpation in response to variations in surficial geothermal features over long
spatial and temporal scales. This should shift management perspective from its narrow focus on individual plants to a wider
focus on monitoring the essential habitat component of steam. 相似文献
296.
《Process Safety and Environmental Protection》2014,92(5):406-411
Management of a plant alarm system has been identified as one of the key safety issues because of disasters caused by alarm floods. When a chemical plant is at abnormal state, an alarm system must provide useful information to operators as the third layer of an independent protection layer (IPL). Therefore, a method of designing a plant alarm system is important for plant safety. Because the plant is maintained in the plant lifecycle, the alarm system for the plant should be properly managed through the plant lifecycle. To manage changes, the design rationales of the alarm system should be explained explicitly. This paper investigates a logical and systematic alarm system design method that explicitly explains the design rationales from know-why information for proper management of changes through the plant lifecycle. In the method, the module structure proposed by Hamaguchi et al. (2011) to assign a fault origin to be distinguished is extended. Using modules to investigate the sets of alarm sensors and the alarm limits setting for first alarm alternative signals to distinguish the fault origin, an alarm system design method is proposed. Also, the completeness of fault propagation for a branch of the cause–effect model as the plant model is explained. Using the modules and the set of fault origins to be distinguished by the alarm system, we try to explicitly explain the design rationales of the alarm system. 相似文献
297.
The effect of textile mill wastewater on germination, delay index, physiological growth parameters, and plant pigments of two cultivars of chickpea was studied. The aim of this study was to evaluate the suitability of textile mill wastewater (treated and untreated) at different concentrations (0, 6.25, 12.5, 25, 50, 75, and 100%) for irrigational purposes. The textile effluent did not show any inhibitory effect on seed germination at a lower concentration (6.25%). The other reported plant parameters (delay index, root length, shoot length, dry weight, chlorophyll, and carotenoid) also followed a similar trend. Seeds germinated in 100% effluents but did not survive for longer periods. It has also been concluded that the effect of the textile effluent is cultivar-specific, and due care should be taken before using the textile mill wastewater for irrigation purposes. 相似文献
298.
Determination of lead, cadmium and copper in roadside soil and plants in Elazig, Turkey 总被引:1,自引:0,他引:1
The concentrations of lead, cadmium and copper in roadside soil and plants in Elazig, Turkey were investigated. Soil samples
were collected at distances of 0, 25 and 50 m from the roadside. The concentrations of lead, cadmium and copper were measured
by Flame Atomic Absorption Spectrophotometry (FAAS). A slotted tube atom trap (STAT) was used to increase the sensitivity
of lead and cadmium in FAAS. Lead concentrations in soil samples varied from 1.3 to 45 mg kg−1 while mean lead levels in plants ranged from120 ng g−1 for grape in point-4 to 866 ng g−1 for apple leaves in point-2. Lead analyses showed that there was a considerable contamination in both soil and plants affected
from traffic intensity. Overall level of Cd in soil samples lies between 78 and 527 ng/g while cadmium concentration in different
vegetations varied in the range of 0.8–98.0 ng g−1. Concentrations of copper in soil and plant samples were found in the range of 11.1–27.9 mg kg−1 for soil and 0.8–5.6 mg kg−1 for plants. Standard reference material (SRM) was used to find the accuracy of the results of soil analyses. 相似文献
299.
首先探讨了特许权经营后政府对城市污水处理厂实行质量管制的必要性;然后,针对当前对污水处理服务进行质量管制存在的普遍问题,通过分析政府管制机构与污水处理厂基于质量的博弈行为,提出了对城市污水处理厂实行有效质量管制的几点建议。 相似文献
300.
This article examines the utilization characteristics and importance of woody biomass resources in the rural-urban fringe
zones of Botswana. In the literature for Africa, attention has been given to the availability and utilization of biomass in
either urban or rural environments, but the rural-urban fringe has been neglected. Within southern Africa, this neglect is
not justified; the rural-urban fringe, not getting the full benefits available in urban environments in Botswana, has developed
problems in woody biomass availability and utilization that require close attention. In this article, socioeconomic data on
the importance of woody biomass in the Batlokwa Tribal Territory, on the rural-urban fringe of Gaborone, Botswana, were collected
together with ecologic data that reveal the utilization characteristics and potential for regrowth of woody biomass. The analysis
of these results show that local woody biomass is very important in the daily lives of communities in the rural-urban fringe
zones and that there is a high level of harvesting. However, there is no effort in planning land use in the tribal territory
to either conserve this resource or provide alternatives to its utilization. The future of woody biomass resources in Botswana’s
rural-urban fringe is uncertain. The investigators recommend that a comprehensive policy for the development of the rural-urban
fringe consider the importance of this resource. The neglect of this resource will have far-reaching implications on the livelihoods
of residents as well as the environment in this zone. 相似文献