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951.
Four crop plants were grown in a greenhouse in soils amended with 0, 5, 10, and 20% by weight of coal combustion fly ash to evaluate potential trace element uptake by the vegetation. The leaves and stems from each plant were harvested and analyzed for As, Cd, Co, Cu, Mn, Mo, Pb, Se, Tl, and Zn content during early, middle, and late growth. The trace element data were statistically analyzed using Analysis of Variance (ANOVA) to determine whether the trace element uptake in the four crop plants differed significantly between the soil treatments, and to identify significant differences in trace element uptake through time. The results show that the amount of amended fly ash does not significantly influence the concentration of most trace elements in plant tissue, and that some concentrations actually decrease with time. Although this study did not find a significant increase in trace element uptake, care must be taken in a natural environment where plants may behave differently. 相似文献
952.
R. K. Skogerboe 《毒物与环境化学》2013,95(3):209-218
Several analytical techniques offer the capability of simultaneously determining 5–40 elements. Of those techniques available, two are receiving extensive attention for analysis of water samples. Optical emission spectrometry utilizing plasma excitation has now evolved to a status in which 20–40 elements can be simultaneously determined on a routine basis. Instrumentation which relies on ion exchange chromatography separations is available which allows the routine determination of several cationic and/or anionic species. The present discussion will briefly describe each of the above multielement analysis systems, summarize their respective capabilities and limitations with respect to water analysis, and project areas of future development. 相似文献
953.
运用因子分析法分析了临沂商品城沉积剖面特征微量地球化学元素及其比值,揭示了沂河中游末次冰消期至中全新世的气候演变过程.结果表明,沂河中游末次冰消期至中全新世沂河中游气候演变经历了6个阶段:(1)16866—13630 cal a B.P.末次冰消期气候冷干;(2)13630—10440 cal a B.P.气候回升但在11868—10440 cal a B.P.,气候突然变得冷干,基本上可以与YD气候事件相对应;(3)10440—8672 cal a B.P.进入全新世后气候以冷湿为主;(4)8672—6755 cal a B.P.大暖期气候不稳定波动剧烈,气候干湿交替,以暖湿为主;(5)6755—5850 cal a B.P.气候趋向干旱化;(6)5850—4698 cal a B.P.气候转向暖湿. 相似文献
954.
Neutron activation analysis was used for the determination of the elemental composition of different plants and soils. Variations in concentrations of elements during the day were found. Mean concentrations, standard deviations and relationships between elements in soils and different parts of plants were studied. It was shown that the behaviour of chemical elements in samples from urban and unpolluted areas have significant differences. 相似文献
955.
The major objective of this study was to carry out sequential chemical extraction for the partitioning of particulate trace metals in sediment samples, collected along the eastern Aegean shelf during cruises July‐August 1994, in the framework of a National Marine Measurement and Monitoring Programme for the Aegean Sea. Five metals, Cd, Pb, Cu, Zn and Cr were examined in each of sediment samples. Three chemical fractions of the sediments were separated and concentrations of the trace metals were determined by AAS techniques. The three different leaches used were hydroxylamine hydrochloride‐acetic acid, hydrogen peroxide and nitric‐perchloric acids. Metals were concentrated mainly in the fraction extracted by nitric‐perchloric acids. Lead in the first fraction were found in the sediments of Northern part of Aegean, where the concentration of organic material was high. The total concentrations of Cd, Cu, Zn, Cr were higher in Izmir Bay than the other sampling points. The distribution of Pb concentrations was the highest in Edremit Bay and Izmir Bay. 相似文献
956.
Cd-Cu-Pb复合污染对芥菜吸收Cd、Cu和Pb及矿质元素的影响 总被引:4,自引:2,他引:2
以十字花科的芥菜为材料,通过室内盆栽均匀设计试验,研究了Cd-Cu-Pb复合污染下芥菜对重金属的吸收转运特点以及对矿质元素吸收的影响. 结果表明:3种重金属在芥菜体内积累能力为Cd>Cu>Pb;芥菜对Pb、Cd有较强耐性,对高浓度Cu耐性不强. 土壤中重金属的含量是影响芥菜各部分重金属含量的主要因素之一;Cd可抑制芥菜对Pb的吸收和转移,促进Cu向芥菜地上部转移;Cd-Pb复合效应促进了Cd在芥菜体内累积;Cu抑制芥菜吸收Pb;Cu-Pb可促进Cd抑制Cu在芥菜各部的积累. 与对照相比,复合污染显著降低了芥菜对矿质元素的吸收累积,各处理芥菜对Mg、Fe和K的吸收转移特点显示出相似的规律,即地上部w(Mg)远大于地下部而w(Fe)和w(K)为地下部占优. Cd可极大促进芥菜对K的吸收而抑制对Fe的吸收,Cu则阻碍地下部对K的吸收;Cu与Cd-Pb复合效应可抑制K向地上部转移. 相似文献
957.
Trace element concentration in wheat grain: results from the Swedish long-term soil fertility experiments and national monitoring program 总被引:4,自引:1,他引:3
Holger Kirchmann Lennart Mattsson Jan Eriksson 《Environmental geochemistry and health》2009,31(5):561-571
Concentrations of trace elements in wheat grain sampled between 1967 and 2003 from the Swedish long-term soil fertility experiments
were analyzed using ICP-MS. The long-term effect of inorganic and organic fertilization on trace metal concentrations was
investigated including the impact of atmospheric deposition and myccorhiza, whereas other factors such as soil conditions,
crop cultivar, etc. are not discussed in this paper. Mean values derived from 10 experimental sites were reported. Significantly
declining Pb and Cd concentrations in wheat grain could be explained by lower atmospheric deposition. Mean Se contents in
all samples were 0.031 mg kg−1 grain dry weight. No samples had sufficiently high Se concentrations for human (0.05 mg Se kg−1) or animal demand (0.1 mg Se kg−1). Concentrations of Co in wheat grain were extremely low, 0.002–0.005 mg Co kg−1 grain dry weight, and far below the minimum levels required by animals, which applied to all fertilizer treatments. A doubling
of Mo concentrations in grain since 1975 resulted in Cu/Mo ratios often below one, which may cause molybdenosis in ruminants.
The increase in Mo concentrations in crops correlated with the decline in sulfur deposition. Concentrations of Cu and Fe declined
in NPK-fertilized wheat as compared to unfertilized or manure-treated wheat. Very low concentrations of Se and Co and low
concentrations of Fe and Cu require attention to counteract risks for deficiencies. The main characteristic of the study is
that there are few significant changes over time between different fertilizer treatments, but throughout there are low concentrations
of most trace elements in all treatments. In general, good agreement between concentrations in wheat from the long-term fertility
experiments and the national monitoring program indicate that values are representative. 相似文献
958.
Relationships between distributions of longevous population and trace elements in the agricultural ecosystem of Rugao County,Jiangsu, China 总被引:1,自引:0,他引:1
Huang B Zhao Y Sun W Yang R Gong Z Zou Z Ding F Su J 《Environmental geochemistry and health》2009,31(3):379-390
Soil, plant, and water, as well as trace elements they contain, can influence human health through the food chain. A survey
was conducted on distributions of trace elements in soils, plants, and drinking water in Rugao County, Jiangsu Province, China,
an agricultural area with a high level of centenarians and nonagenarians. The ratio of people over 90 years old per 100,000
inhabitants (90-rate) based on village (about 4,000 residents in 4 km2) was correlated with trace elements in soil, drinking water, and rice by means of correlation analysis and/or principal component
analysis. Although the average 90-rate in the whole area was as high as 277, the rates were not uniform across the entire
region. The 90-rate in the area of loamy and strongly-developed Anthrosols and Cambosols was about 330, significantly higher
than the 255 in the areas of sandy and strongly-developed Cambosols and of clayey and weakly-developed Cambosols. The concentrations
of available Se, B, Ni, and Mo in soils of the area with the high 90-rate were markedly greater than those in the area with
the low 90-rate. This was demonstrated by highly positive correlations between the 90-rate and available Se (r = 0.33), B (r = 0.21), Ni (r = 0.17) and Mo (r = 0.17) at the p < 0.01 level and high loadings of available Se (0.851), B (0.535), Ni (0.594) and Mo (0.394) in the longevous factor. Similar
relationships between the available elements in soils and elements in water and rice were found. These results suggest that:
(1) the available forms of elements in soil were more crucial to elemental bio-availability in the ecosystem and human health
than total elements in soil; and (2) the element association above might have affected the 90-rate positively and could be
an important environmental geochemical factor influencing the longevity of humans. 相似文献
959.
Trace elements such as cadmium (Cd) may be inadvertently added to cropland soils through application of fertilizers, irrigation water, and other amendments. These toxic trace elements pose a potentially threat to soil quality and, through the food chain transfer, to human health. A generalized soil trace element mass balance model that accounts for the interactive processes governing the reactions of trace elements in soils, and consequently removed with crop harvest and leaching out of the soil profile with irrigation water was developed in this research. The model conceptually approximates the mechanisms and kinetics of a real field cropland system. The model was used to evaluate the long-term cultivation on distribution of Cd in California croplands. Under typical California cropping practices, Cd added into the soils accumulated primarily in the plow layer while the Cd content below the plow layer was barely affected. After 100 years of continuous cultivation, the soil Cd content of the plow layer increases from the background level 0.22 mg kg−1 to 0.40 mg kg−1. The accumulation of Cd in the plow layer is in proportion to the external inputs and is affected by the soil and plant characteristics, and management practices. The model can be used to evaluate the environmental fates of other toxic element in soils with case specific parameters. 相似文献
960.
土壤酸度对稀土元素在小麦体内的生物可利用性及分馏效应的影响 总被引:2,自引:0,他引:2
采用盆栽实验,研究了土壤酸度对稀土元素在小麦体内的生物可利用性及分馏效应的影响.结果表明:小麦体内稀土含量与pH之间呈二次方程的关系,在实验pH范围内,随pH值升高小麦体内稀土含量逐渐降低,每种稀土含量随pH变化程度表现为:Ce>La>Nd>Sm>Gd>Yb>Tb>Eu,表明Ce对pH值更为敏感,Eu最小.土壤中3种稀土形态的含量顺序为B2(NH2OHHCl提取态)>B3(H2O2-NH4Ac提取态)>B1(HAc提取态),随着酸度的降低,B1有向B2、B3转化的趋势.线性回归和多元逐步回归分析表明不同形态的稀土对小麦吸收的贡献程度因单个稀土元素的不同而不同,但B1态是主要的生物可利用态.小麦体内轻重稀土之间分馏系数与pH值呈负线性相关,土壤酸度越大,分馏系数越大. 相似文献