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991.
峨嵋山冷杉衰亡与酸性降水关系的初步研究 总被引:3,自引:0,他引:3
本文报道了峨嵋山高海拔地区冷杉衰亡与酸性降水关系的调查和研究,内容包括酸性降水和气态污染物状况的观察,冷杉枝叶生长状况和针叶解剖,树干解剖和根系观察,冷杉冠层对酸性降水的反应及酸性降水在生态系统中的变化,土壤和冷杉的元素分析等方面,并就酸性降水对冷杉衰亡的影响进行了初步评价结果指出,峨嵋山高海拔地区的酸性降水污染严重,雨水的平均pH值为1.37,酸雨频率达85.1:雾水的pH值为1.62,酸雾频率达100 有可能对冷杉产生直接和间接影响。 相似文献
992.
993.
通过采用GDX-502富集,GC-MS分析,对城市河流、湖库中的痕量有机污染物进行分析,共检出58种有机污染物,其中含有多种美国EPA公布的重点污染物,从而为痕量有机污染物的研究建立了灵敏度高,分辨率好的测试方法。 相似文献
994.
Hua Lei Ju Liangliang Xu Hanbing Li Changlian Sun Shu Zhang Qi Cao Jiyu Ding Rui 《Environmental science and pollution research international》2023,30(6):14165-14189
Environmental Science and Pollution Research - According to the “fetal origin of disease” hypothesis, air pollution exposure in pregnancy may play an important role in stimulating the... 相似文献
995.
秸杆燃烧中OCS的排放因子和排放估算 总被引:2,自引:0,他引:2
建立了痕量羰基硫采样及分析方法。利用低温预捕集和被捕集样直接释放进入分离柱技术,对压缩空气进行采样测定。得出了压缩空气中OCS约在2.94×10^-3μg/L,方法精确度以标准误差系数计为±0.72%,利用此采样及分析方法对实验室规模的生物质封闭燃烧系统,稻草、玉米秸、科杆燃烧中排痕量OCS进行了采样分析,得出稻草、玉米秸麦杆燃烧排气中OCS的排放量,以排放因子表示分别是:1.80g/t,2.75 相似文献
996.
997.
论述了环境成本内在化的理论依据,建立了数学模型。环境成本P等于自然资源价值P1与人类劳动产生新价值P2和恢复环境的价值P3之和。总的来看,环境成本内在化有利于环境保护工作,但要防止发达国家利用"环境"问题反对发展中国家的发展。 相似文献
998.
Adsorbent sampling with analysis by thermal desorption, gas chromatography and mass spectrometry (TD/GC/MS) offers many advantages for volatile organic compounds (VOCs) and thus is increasingly used in many applications. For environmental samples and other complex mixtures, the MS detector typically is operated in the scan mode to aid identification of co-eluting compounds. However, scan mode does not achieve the optimal sensitivity, thus compounds occurring at low concentrations may not be detected. This paper develops and evaluates the application of a more sensitive TD/GC/MS method using selective ion monitoring (SIM) that is applicable to VOC mixtures found in ambient and indoor air. Based on toxicity and prevalence, 94 VOCs (including terpenes, aromatic, halogenated and aliphatic compounds) were selected as target compounds. Two analytical methods were developed: a conventional full scan method for ions from 29 to 270 m/z; and a SIM method using 16 time windows and different ions selected for the compounds in each window. Both methods used the same Tenax GR adsorbent sampling tubes, TD and GC parameters, and target and qualifier ions. Laboratory tests determined calibrations, method detection limits (MDLs), precisions, recoveries and storage stability. Field tests compared scan and SIM mode analyses for duplicate samples of indoor air in 51 houses and outdoor air at 41 sites. Statistical analyses included the development of error/precision models. The laboratory tests showed that most compounds demonstrated excellent precision (<10% for concentrations exceeding approximately 0.5 microg m(-3)), good linearity, near identical calibrations for scan and SIM modes, a wide dynamic range (up to 1500 microg m(-3)), and negligible storage losses after 1 month (7 compounds showed moderate losses). SIM mode MDLs ranged from 0.004 to 0.27 microg m(-3), representing a modest (1.1 to 22-fold) improvement compared to scan mode. However, in field tests the SIM method detected significantly more compounds (e.g., styrene and chloroform). Error models fit most compounds and allow quantification of errors at selected percentiles. Overall, while the new SIM method is somewhat time-consuming to develop, it offers greater sensitivity and maintains the high selectivity of traditional scan methods. 相似文献
999.
1000.
Some important naturally occurring α- and β-radionuclides in drinking water samples collected in Italy were determined and the radiological quality evaluated. The mean activity concentrations (mBq L−1) of the radionuclides in the water samples were almost in the order: 26 ± 36 (234U) > 21 ± 30 (238U) > 8.9 ± 15 (226Ra) > 4.8 ± 6.3 (228Ra) > 4.0 ± 4.1 (210Pb) > 3.2 ± 3.7 (210Po) > 2.7 ± 1.2 (212Pb) > 1.4 ± 1.8 (224Ra) > 1.1 ± 1.3 (235U) > 0.26 ± 0.39 (228Th) > 0.0023 ± 0.0009 (230Th) > 0.0013 ± 0.0006 (232Th). The mean estimated dose (μSv yr−1) to an adult from the water intake was in this order: 2.8 ± 3.3 (210Po) > 2.4 ± 3.2 (228Ra) > 2.1 ± 2.1 (210Pb) > 1.8 ± 3.1 (226Ra) > 0.94 ± 1.30 (234U) > 0.70 ± 0.98 (238U) > 0.069 ± 0.087 (224Ra) > 0.036 ± 0.044 (235U) > 0.014 ± 0.021 (228Th) > 0.012 ± 0.005 (212Pb) > 0.00035 ± 0.00029 (230Th) > 0.00022 ± 0.00009 (232Th). It is obvious that 210Po, 228Ra, 210Pb and 226Ra are the most important dose contributors in the drinking water intake. As far as the seventeen brands of analysed drinking water were concerned, the committed effective doses were in the range of 2.81–38.5 μSv yr−1, all well below the reference level of the committed effective dose (100 μSv yr−1) recommended by the WHO. These data throw some light on the scale of the radiological impact on the public from some naturally occurring radionuclides in drinking water, and can also serve as a comparison for the dose contribution from artificial radionuclides released to the environment as a result of human practices. Based on the radionuclide composition in the analysed waters, comment was made on the new screening level for gross α activity in guidelines for drinking-water quality recommended by the WHO, 2004. 相似文献