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氟与健康的环境流行病学研究 总被引:18,自引:0,他引:18
氟是与机体健康密切相关的微量生命元素,原生环境中氟过量或缺乏均会导致机体产生疾病。氟对人类健康的影响己成为全球性的环境健康问题。综合国内外近年来的相关资料,作者概述了环境生态系物质中氟的含量,分布及化学行为,阐述了氟对机体的健康效应,分析了我国地氟的现状,并指出了今后在氟与健康研究领域中应关注的问题。 相似文献
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由于农产品及饮用水中氟含量升高,会对人体健康产生有害影响,所以对氟随农用化学品进入土壤和植物体内的问题进行研究,具有十分重要的意义。 相似文献
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Cd Pb Cu Zn As复合污染对水稻的影响 总被引:57,自引:3,他引:54
应用田间试验和盆栽试验,研究Cd、Pb,Cu,Zn,As复合污染在草甸棕壤上对水稻产量及元素含量的影响。结果表明,在接近土壤环境标准低浓度水平下,水稻发育正常,减产幅度〈10%,但土壤Cd,Pb临界值下降,籽实中Cd,Pb,Zn吸收系数提高,Cd,Pb含量超标,低剂量对Cd超标37.5%,高剂量时超标100%,增加了对人体健康潜在危险。主要原因在于5元素间存在协同作用Pb,Cu,Zn,As的存在增 相似文献
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金华地区氟污染成因,危害及对策(Ⅲ)——人发氟和若干元素含量?… 总被引:1,自引:0,他引:1
研究结果表明:氟斑牙患者体内氟含量高于正常人体;同年龄组男性发氟含量高于女性;随年龄增加,人发氟含量也不断增加;发中钙含量女性略高于男性;和正常人体相比,氟斑牙患者发Cu,发Fe含量无明显差异。 相似文献
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植物健康营养理论与健康元素 总被引:1,自引:0,他引:1
白由路 《植物营养与肥料学报》2020,26(7):1360-1366
从食物链营养的角度提出植物健康营养理论,即在不影响植物正常生长发育的条件下,通过调节供给植物的营养元素而生产出符合特定需求的产品,提高植物栽培的功能性和经济价值。我们把这种同时注重植物营养和产品功能的人工栽培植物的营养理论称为植物健康营养理论,这里将不具备植物营养功能,但对整个食物链特别是对人和饲养动物有营养作用的元素称为健康元素。根据矿质元素的作用对象,可将健康元素分为营养健康元素和非营养健康元素两类。营养健康元素是指它本身是植物必需营养元素,同时又对食物链上端生物也有重要健康作用。非营养健康元素是指其对植物本身的生长发育没有营养作用,仅对食物链上端的生物有健康作用。把通过植物吸收矿质元素的方式以达到食物链促进健康的栽培管理方式称为健康栽培。本文还定义了植物健康营养理论的学科边界,指出:“奢侈吸收”与动物健康的关系研究,健康元素在植物体内的代谢,健康元素在食物链中的传递形式,植物体内健康元素的含量阈值,健康元素的高效施用与管理都是植物健康营养理论的研究范畴。 相似文献
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叶面喷施锌或硒对生菜吸收镉的拮抗作用研究 总被引:26,自引:0,他引:26
环境污染导致水和土壤中镉等重金属元素超标,是多年来造成农产品质量不合格的重要原因之一。农作物中的重金属元素最终会通过食物链进入人体,对人体造成危害。因此研究如何抑制农作物对镉的吸收在理论上和应用上都有重大意义,前人也做了一些相关的工作。众所周知,硒和锌是对人体有益的微量元素。缺硒会得各种各样的疾病,研究还表明硒具有抗癌作用,近年来人们对富硒食品做了大量的研究;锌是许多金属酶的重要组成部分,并能激活多种酶,因此锌在生物的正常代谢过程中起着重要作用。当镉与锌、硒共存的时候,它们之间有复杂的相互作用。 相似文献
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铜、铅、锌均与硫元素有较强的亲和力,从而使它们具有相似的地球化学性质,并在环境自然体中紧密共生.人们已经认识了铜和锌是人体必需的微量元素,而铅是有害的元素,它们的环境与生物地球化学行为,直接影响到人体的健康.因此,表生环境中的铜、铅、锌始终是研究的热点. 相似文献
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STUDIES IN PEDOGENESIS IN NEW SOUTH WALES 总被引:1,自引:0,他引:1
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Several methods for determination of extractable iron (Fe; or so-called “active Fe”) have been proposed. In this study, three methods of Fe extraction were tested: 1.5% phenanthroline (pH 3) and 1 M hydrochloric acid (HCl) from fresh leaves, and 1 M HCl from oven-dry leaves. A six-year-old avocado orchard (cultivar ‘Hass’), grown on a calcareous soil in the proximity of Cabildo (Valparaíso region, Chile), was selected for the study. Samples of mature (5–7 moths-old) leaves of different degree of chlorosis were collected. Total Fe concentrations in chlorotic leaves were similar or even greater than in green leaves. Regressions between the extractable Fe concentrations and the leaf SPAD-color were statistically significant for phenanthroline method, while non-significant for HCl methods. Thus, phenanthroline method was superior over others for diagnosis of Fe deficiency in avocado. Phenanthroline-extractable Fe concentration of 6 mg kg?1 was considered as a critical value for mature avocado leaves. 相似文献
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Strawberries (Fragaria × ananassa Duch. cv. Nyoho) grown in peat-based substrate often suffer interveinal chlorosis in their immature leaves 10–20 d after planting. Based on our previous results and observations from growing practice, we hypothesized that the cause of this phenomenon could be due to drastic changes in plant nitrogen (N) nutrition in strawberries just after planting into peat bags. To determine optimal sampling time, diurnal variations in foliar ammonium (NH4)-N concentration were evaluated under greenhouse conditions. Results showed a broadly similar pattern of diurnal variation, with the rates increasing to a maximum at midday and decreasing steadily during the second-half of the light period. However, foliar NH4-N concentration was higher under sunny than under cloudy or shaded light conditions. In the second part of this study, changes in foliar NH4-N and in nitrate (NO3)-N in petioles in relation to the occurrence of interveinal chlorosis were investigated. When the plants were supplied with 30 (control) or 50% ‘Ohtsuka A’ nutrient solution for two weeks after planting, foliar NH4-N concentrations increased earlier than petiole NO3-N concentrations, and reached their peak 8 and 10 days after planting in 50% (1.90 μmol g?1 FW) and 30% (1.78 μmol g?1 FW) treatment respectively. Interveinal chlorosis was observed in immature leaves in 50% treatment about 10 days after planting while there was no chlorotic symptom in control treatment. The absence of interveinal chlorosis in immature leaves in control plants, led to the conclusion that a high leaf NH4-N concentration and related accumulation of NH4-N play an important role in triggering interveinal chlorosis. 相似文献