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811.
812.
沉积物中多氯联苯分析的纯化条件优化研究 总被引:5,自引:3,他引:2
比较了各种填料层析柱和洗脱液的差别,并根据有机溶剂使用量较少的样品纯化方案,建立了适用低有机质含量水体表层沉积物中不同极性多氯联苯(PCBs)的分析方法.结果表明,该方法检测限在0.11 ng/g~0.35 ng/g(干重)之间,对主要多氯联苯同族体的回收率是77.9%~112.1%.用该法分析了长江中下游水体表层沉积物中的PCBs,质控结果表明,该纯化方法的效果理想. 相似文献
813.
Application of Eichhornia crassipes and Pistia stratiotes for treatment of urban sewage in Israel 总被引:1,自引:0,他引:1
The effectiveness of sewage purification by aquatic plants, such as water hyacinth (Eichhornia crassipes) and water lettuce (Pistia stratiotes), was tested on laboratory and pilot scales. Cascade and semi-continuous pilot experiments verified that the plants are capable of decreasing all tested indicators of water quality to levels that permit the use of the purified water for irrigation of tree crops. This applies to biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), and turbidity. The laboratory-scale tests confirm the capacity of the plants to reach and hold reasonably low levels of BOD (5-7 mg L(-1)) and COD (40-50 mg L(-1)) and very low levels of TSS (3-5 mg L(-1)) and turbidity (1-2 NTU). In the experimental pilot setup, with circulation, COD decreased from 460 to 100 mg L(-1) after 2.5-4 days of treatment, while 6-7 days were required to this end without circulation. This doubled the active pond area and provided a two-level hydraulic loading (8 and 12 L min(-1)) with circulation that proved to be effective during the summer as well as the winter season. The outflow concentrations were 50-85 mg L(-1) of COD and 4-6 mg L(-1) of BOD. The results show that the use of this free water surface flow system (FWS) and its low maintenance system for treatment of urban and agricultural sewage is a viable option. 相似文献
814.
Determinants of the Willingness-to-Participate in an Environmental Intervention in a Beirut Neighborhood 总被引:1,自引:1,他引:0
Participatory environmental management can empower communities and enhance the sustainability of environmental interventions.
However, existing power structures and inequalities along class, gender, or ethnic lines could prevent part of the community
from accessing the full benefits of the intervention. An analysis of determinants of the willingness-to-participate in an
environmental intervention in a Beirut neighborhood is conducted. Socioeconomic, health-risk distribution, and perception
of community efficacy are used as predictors. A randomly selected sample of residents was surveyed. Respondents were asked
to specify the frequency with which they were willing to be involved in an intervention to address priority environmental
problems in the neighborhood. Bivariate and multivariate ordinal regression analyses were conducted. Tests of significance
were based on the 95% confidence intervals (CI) of the odds ratio (OR). Males versus females (OR = 4.89, P < 0.001), respiratory patients versus nonsufferers (OR = 5.65, P < 0.001), tenants versus house owners (OR = 2.98, P < 0.01), and the less educated versus the more educated (OR = 2.42, P < 0.05) were significantly more likely to be willing to participate. The reluctance of female community members to participate
might be a major hindrance to community-based environmental protection and special strategies must be devised to overcome
it. On the other hand, respondents suffering from an illness perceived to be related to environmental toxins are likely to
be strong participants in environmental conservation efforts. Finally, the study yielded no evidence that belief or lack of
it in the efficacy of community action is a good predictor of the willingness-to-participate in such action. 相似文献
815.
A fuzzy logic approach has been developed to assess the groundwater pollution levels below agricultural fields. The data collected
for Kumluca Plain of Turkey have been utilized to develop the approach. The plain is known with its intensive agricultural
activities, which imply excessive application of fertilizers. The characteristics of the soils and underlying groundwater
for this plain were monitored during the years 1999 and 2000. Additionally, an extensive field survey related to the types
and yields of crops, fertilizer application and irrigation water was carried out. Both the soil and groundwater have exhibited
high levels of nitrogen, phosphorus and salinity with considerable spatial and temporal variations. The pollution level of
groundwater at several established stations within the plain were assessed using Fuzzy Logic. Water Pollution Index (WPI)
values are calculated by Fuzzy Logic utilizing the most significant groundwater pollutants in the area namely nitrite, nitrate
and orthophosphate together with the groundwater vulnerability to pollution. The results of the calculated WPI and the monitoring
study have yielded good agreement. WPI indicated high to moderate water pollution levels at Kumluca plain depending on factors
such as agricultural age, depth to groundwater, soil characteristics and vulnerability of groundwater to pollution. Fuzzy
Logic approach has shown to be a practical, simple and useful tool to assess groundwater pollution levels. 相似文献
816.
Fajer-Avila EJ García-Vásquez A Plascencia-González H Ríos-Sicairos J García-De La Parra LM Betancourt-Lozano M 《Environmental monitoring and assessment》2006,122(1-3):221-237
The relationship between parasites and environmental stress were studied in two tropical coastal lagoons of Northwest Mexico: Urias estuary (highly polluted) and Teacapan estuary (slightly polluted). Metazoan parasites were examined in 292 white mullet (Mugil curema) specimens collected bimonthly during a year from both systems. Haliotrema mugilinus, Metamicrocotyla macracantha, Ergasilus sp., Caligus sp., Holobomolochus sp., and Lernaeopodidae were found in gills, while Contracaecum sp. larvae III was found liver, hepatic portal vein and kidneys. Ecological indices were influenced by the slightly higher number of parasitic species in Urias compared to Teacapan, as well as the clear dominance of two species: Ergasilus sp. and Contracaecum sp. in both systems. In fact, Ergasilus sp. showed considerably higher abundance in Urias, possibly indicating that its success was a result of adverse conditions affecting the host, while Contracaecum sp showed higher abundances in Teacapan, suggesting that the environmental conditions occurring in Urias could have produced negative impacts on the nematode's infective potential. 相似文献
817.
大气环境质量预测模型研究 总被引:9,自引:0,他引:9
为适应青岛和贵阳地区地形和大气流场复杂的特点,吸收高斯烟云模式和烟团模式的优点,建立高斯轨迹烟云模式,模式同时考虑静风条件下的扩散。应用青岛和贵阳的实测数据对模式的性能进行检验,结果证明,该模式可适用于地形和流场复杂的地区。该模式是环境决策支持系统的一部分。 相似文献
818.
819.
820.
通过对近年深圳市区域环境噪声及道路交通噪声的监测数据分析,发现深圳市交通声源是长期影响城市区域环境噪声的主要因素,其根源在于城市机动车辆增加迅速,路网过密,而配套设施跟不上,造成对城区域环境噪声污染相对集中,城区声环境日趋恶化。 相似文献