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141.
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
142.
淡水沉积物的生物测试方法研究 总被引:5,自引:0,他引:5
描述了淡水沉积物毒性的生物测试方法。沉积物基质可以通过直接采样法和掺入法制备,储存会影响其生物可利用性。全底泥相,间隙水相和复溶相是目前沉积物毒理学研究常用的试验相,其中,间隙水相被认为是进行沉积物毒理学研究较为理想的试验相。同时推荐采用离心法制备间隙水。此外,为增加试验结果的可比性,文中还讨论了试验生物的选择问题。 相似文献
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146.
Ouchen Cai Yuanxiao Xiong Haijun Yang Jinyong Liu Hui Wang 《Frontiers of Environmental Science & Engineering》2020,14(3):50
147.
Tatiana Semizhon Stefan Röllin Eckehard Klemt 《Journal of environmental radioactivity》2010,101(5):385-402
Discharges from the Krasnoyarsk Mining and Chemical Industrial Complex (KMCIC) near Krasnoyarsk resulted in radioactive contamination of sediments of the River Yenisei. Between 1999 and 2006, 16 sediment cores were collected at different positions 15-1500 km downstream from the discharge point. The concentration of artificial gamma-emitting radionuclides (137Cs, 60Co, 152Eu, and 241Am) was determined with the objective to analyze the migration processes leading to the transport of these radionuclides along the river and to their vertical distribution within the sediment. In cores taken in the vicinity of the reactors, the average activity concentration of 137Cs, 152Eu, and 60Co was about 1000 Bq kg−1, and the activity concentration of 241Am was about 20 Bq kg−1. Contamination levels of artificial radionuclides were decreasing with increasing distance downstream the KMCIC: The fastest decrease of average activity by a factor of 10 over a distance of 300 km was observed for 241Am, whereas for 137Cs this decrease occurred over a distance of 1100 km. Sequential extraction experiments revealed that in all depths and at all distances the studied radionuclides were tightly bound to the sediment.To investigate the mechanisms of transport of the 137Cs and 60Co contamination, mathematical models have been used to describe the contamination in the river water and within the sediments. 相似文献
148.
The importance of physico-chemical parameters on the speciation of natural radionuclides in riverine ecosystems 总被引:1,自引:0,他引:1
External gamma radiation levels were measured in the catchment areas of the Sharavathi River and the dose rates in air were found to be in the range 26.0-61.0 nGy h−1. Soil and sediment samples of the riverine environment were analysed for natural radionuclides such as 226Ra, 232Th and 40K using a NaI(Tl) gamma spectrometer. The activity concentration of 210Pb and 210Po in soil and sediment samples was determined by radiochemical separation techniques. Evaluation of the activity concentration of radionuclides with grain size revealed an increase in the activity of 226Ra, 232Th and 40K towards fine grain size. The activity concentrations for all isotopes in all samples were not significantly correlated with pH. However, the activity of 210Po and 210Pb in sediment showed a moderate positive correlation with organic matter content and a good correlation with clay content of sediment. 相似文献
149.
R.M. Anjos K.D. Macario R. Veiga P.J.F. Fernandes J. Bastos 《Journal of environmental radioactivity》2010,101(1):75-81
Natural gamma radiation measurements of sand deposits were carried out in order to study the chronology of prehistoric colonization of the Brazilian coast during the Holocene. The method employs thorium, uranium and potassium as tracers of the geological provenance of Quaternary deposits, where artificial shellmounds are found. The so-called sambaquis are archaeological settlements, characteristic of fisher-gatherers, specialized in the exploitation of shellfish. Our results show a considerable positive correlation between the formation of coastal deposits, based on cross plots of eTh/eU and eTh/K, and the antiquity of its prehistoric human occupation. 相似文献
150.
Anders Stigebrandt Lars Rahm Lena Viktorsson Malin Ödalen Per O. J. Hall Bengt Liljebladh 《Ambio》2014,43(5):634-643
The external phosphorus (P) loading has been halved, but the P content in the water column and the area of anoxic bottoms in Baltic proper has increased during the last 30 years. This can be explained by a temporary internal source of dissolved inorganic phosphorus (DIP) that is turned on when the water above the bottom sediment becomes anoxic. A load-response model, explaining the evolution from 1980 to 2005, suggests that the average specific DIP flux from anoxic bottoms in the Baltic proper is about 2.3 g P m−2 year−1. This is commensurable with fluxes estimated in situ from anoxic bottoms in the open Baltic proper and from hydrographic data in the deep part of Bornholm Basin. Oxygenation of anoxic bottoms, natural or manmade, may quickly turn off the internal P source from anoxic bottoms. This new P-paradigm should have far-reaching implications for abatement of eutrophication in the Baltic proper.