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491.
沉积物中多环芳烃和有机氯农药定量分析的质量保证和质量控制 总被引:118,自引:8,他引:118
以美国EPA为方法为基础,进行了沉积物中多环芳烃和有机氯农药分析的质量保证和质量控制实验,采用回收率指示物控制回收率,用内标法定量。结果表明多环芳烃的指示物回收率为50.67-97.33%,目标化合物的回收率为58.67-96.33%,方法检测限为3.30-9.26μg.kg^-1。 相似文献
492.
493.
Geostatistical analyses and hazard assessment on soil lead in Silvermines area, Ireland 总被引:42,自引:0,他引:42
Spatial distribution and hazard assessment of soil lead in the mining site of Silvermines, Ireland, were investigated using statistics, geostatistics and geographic information system (GIS) techniques. Positively skewed distribution and possible outlying values of Pb and other heavy metals were observed. Box-Cox transformation was applied in order to achieve normality in the data set and to reduce the effect of outliers. Geostatistical analyses were carried out, including calculation of experimental variograms and model fitting. The ordinary point kriging estimates of Pb concentration were mapped. Kriging standard deviations were regarded as the standard deviations of the interpolated pixel values, and a second map was produced, that quantified the probability of Pb concentration higher than a threshold value of 1000 mg/kg. These maps provide valuable information for hazard assessment and for decision support. 相似文献
494.
新型混凝剂在废水处理中的应用研究 总被引:2,自引:0,他引:2
自行研发出一种新型混凝剂,它能广泛应用于印染废水、生活污水和餐饮废水等的处理。经过一步强化混凝处理后,各种废水的COD、色度和浊度等均有良好的去除效果。混凝污泥可以再生重复利用。 相似文献
495.
Nitrogen balance and groundwater nitrate contamination: comparison among three intensive cropping systems on the North China Plain 总被引:72,自引:0,他引:72
Ju XT Kou CL Zhang FS Christie P 《Environmental pollution (Barking, Essex : 1987)》2006,143(1):117-125
The annual nitrogen (N) budget and groundwater nitrate-N concentrations were studied in the field in three major intensive cropping systems in Shandong province, north China. In the greenhouse vegetable systems the annual N inputs from fertilizers, manures and irrigation water were 1358, 1881 and 402 kg N ha(-1) on average, representing 2.5, 37.5 and 83.8 times the corresponding values in wheat (Triticum aestivum L.)-maize (Zea mays L.) rotations and 2.1, 10.4 and 68.2 times the values in apple (Malus pumila Mill.) orchards. The N surplus values were 349, 3327 and 746 kg N ha(-1), with residual soil nitrate-N after harvest amounting to 221-275, 1173 and 613 kg N ha(-1) in the top 90 cm of the soil profile and 213-242, 1032 and 976 kg N ha(-1) at 90-180 cm depth in wheat-maize, greenhouse vegetable and orchard systems, respectively. Nitrate leaching was evident in all three cropping systems and the groundwater in shallow wells (<15 m depth) was heavily contaminated in the greenhouse vegetable production area, where total N inputs were much higher than crop requirements and the excessive fertilizer N inputs were only about 40% of total N inputs. 相似文献
496.
曝气强度对膜污染的影响 总被引:1,自引:1,他引:1
混合液浓度的高低及其粒度分布特性是影响膜生物反应器膜污染的重要因素。在一定污泥浓度下,主要考察了曝气强度对污泥絮体粒度分布的影响,以及不同粒度下的膜污染特性。试验结果表明,曝气强度提高,可以起到减缓污泥颗粒在膜表面的沉积作用,但高的错流流速产生的剪切效应使得污泥颗粒变得琐碎,导致细小胶体粒子和溶解性部分增多,增加了膜孔吸附和堵塞的机会,加剧了膜污染的进程。膜污染速率在曝气强度提高初期阶段迅速降低,接着又随曝气强度增加而缓慢升高,在污泥质量浓度为8 g/L的试验条件下,对应的最适曝气强度为84 m3/(m2.h)。 相似文献
497.
采用热脱附-气相色谱/质谱联用法对4辆处于静止状态下的车辆内部空气中挥发性有机物(VOCs)进行了研究,共定性检出了48种有机物,其中C6~C9之间的组分较多;并对VOCs的总浓度进行了定量,1#~4#车分别为1846、2289、1104和3146 μg/m^3;其中BTEX占VOCs总量的20%~30%;车内VOCs浓度与温度及车辆使用年限密切相关. 相似文献
498.
Pollution sources identification of polycyclic aromatic hydrocarbons of soils in Tianjin area, China 总被引:7,自引:0,他引:7
A total of 188 surface soil samples were collected from different types of utilization soils in Tianjin area. Factor analysis and scatter point surface tension spine function interpolation were used to analyze types and spatial distributions of PAH sources of surface soils in Tianjin area. The results showed that most pollution sources were mixed sources including coal burning and petroleum spill. Mixed sources occupied 56.12%, 58.96%, 46.45% and 59.50% in farmland of wastewater irrigation, common farmland, wild land and city greenbelt, respectively. Other pollution sources such as vehicle emission, biogenic conversion, wood burning and natural gas combustion were also significant. The spatial distributions of pollution sources were closely related to geographic location, geographic condition and living habit of indigenes. 相似文献
499.
以自制Ti基RuO2-IrO2镀层形稳电极为阳极,采用电催化氧化处理偶氮染料甲基橙模拟废水。以硫酸钠为支持电解质,在自然pH条件下分别考察了电解时间、电极间距、电流密度和电解质浓度等因素对甲基橙去除率的影响,并分析其原因。实验结果表明,在自然pH、电极间距为1.0 cm、电流密度为30.0 mA/cm2、电解质硫酸钠浓度为20.0 g/L、电解1.0 h,甲基橙去除率高达90.0%以上。 因此,电催化氧化法作为一种高效、简便的染料废水处理技术,具有一定的应用潜力。 相似文献
500.