Lead is absorbed following inhalation, oral, and dermal exposure. It is then distributed mainly to the bones and red blood cells. In the blood lead may be found bound to serum albumin or the metal-binding protein metallothionein. Organic lead is metabolized by cytochrome P-450 enzymes, whereas inorganic lead forms complexes with delta-aminolevulinic acid dehydratase. Lead is excreted mainly in the urine and faeces. (L136)
IDENTIFICATION AND USE: Lead tungstate is a white or pale yellow powder. It is used as a pigment. HUMAN EXPOSURE AND TOXICITY: There are no data available. ANIMAL STUDIES: There are no data available.
Lead mimics other biologically important metals, such as zinc, calcium, and iron, competing as cofactors for many of their respective enzymatic reactions. For example, lead has been shown to competitively inhibit calcium's binding of calmodulin, interferring with neurotransmitter release. It exhibits similar competitive inhibition at the NMDA receptor and protein kinase C, which impairs brain microvascular formation and function, as well as alters the blood-brain barrier. Lead also affects the nervous system by impairing regulation of dopamine synthesis and blocking evoked release of acetylcholine. However, it's main mechanism of action occurs by inhibiting delta-aminolevulinic acid dehydratase, an enzyme vital in the biosynthesis of heme, which is a necesssary cofactor of hemoglobin. (T4, A20, A22, L136)
There is limited evidence in humans for the carcinogenicity of inorganic lead compounds. ... There is sufficient evidence in experimental animals for the carcinogenicity of inorganic lead compounds. There is sufficient evidence in experimental animals for the carcinogenicity of lead acetate, lead subacetate, lead chromate, and lead phosphate. There is inadequate evidence in experimental animals for the carcinogenicity of lead oxide and lead arsenate. ... There is inadequate evidence in experimental animals for the carcinogenicity of lead powder. Overall evaluation Inorganic lead compounds are probably carcinogenic to humans (Group 2A). /Inorganic lead compounds/
CLASSIFICATION: B2; probable human carcinogen. BASIS FOR CLASSIFICATION: Sufficient animal evidence. Ten rat bioassays and one mouse assay have shown statisticlly significant increases in renal tumors with dietary and subcutaneous exposure to several soluble lead salts. Animal assays provide reproducible results in several laboratories, in multiple rat strains with some evidence of multiple tumor sites. Short term studies show that lead affects gene expression. Human evidence is inadequate. HUMAN CARCINOGENICITY DATA: Inadequate. ANIMAL CARCINOGENICITY DATA: Sufficient. /Lead and Compounds (inorganic), Based on former classification system/
来源:Hazardous Substances Data Bank (HSDB)
毒理性
致癌性证据
A3; 对动物已确认是致癌物,但对人类的相关性未知。/铅和铅的无机化合物,如 Pb/
A3; Confirmed animal carcinogen with unknown relevance to humans. /Lead and and inorganic compounds, as Pb/
WO 3 / BiVO 4异质结被认为是用于光电化学(PEC)水分解的最有希望的光阳极材料之一。为了提高太阳水分解效率,使光电极中的太阳光吸收效率最大化仍然是关键问题。在这里,为了满足上述需求,我们通过溶液加工设计和制造了由卵黄壳结构的纳米颗粒组成的WO 3膜。将带隙较小的BiVO 4薄层涂覆到WO 3的表面和内部外壳,在颗粒和外壳之间提供合理设计的内部空间,以实现更好的电解液可及性。卵黄壳状的PEC光电阳极不仅引起有效的光吸收,而且由于扩大了接触面积,在BiVO 4的电子收集中也起着重要的作用。通过将紫外-可见(UV-vis)吸收光谱与镜面反射和漫反射技术相结合,研究了结构与PEC的性能关系,这表明蛋黄-壳形结构比常规的中空或致密膜结构具有更好的光吸收能力。纯卵黄壳(Y-WO 3 / BiVO 4)光电阳极的光电流密度为2.3 mA cm -2在AM 1.5照度(100 mW cm -2)下以1
Synthesis of Tungstate Thin Films and Their Optical Properties
作者:Nobuhiro Saito、Akihiko Kudo、Tadayoshi Sakata
DOI:10.1246/bcsj.69.1241
日期:1996.5
synthetic method of tungstate thin films (CaWO4, MgWO4, PbWO4, ZnWO4) was developed. The absorption and luminescence spectra of tungstate thin films synthesized on quartz substrates were measured; the optical properties were also studied. It was found that CaWO4 has Eg = 5.4 eV of a direct transition nature. Tungstate thin films were strongly luminescent when irradiated with UV-light. Excitation at around
Thermogravimetric investigations on the mechanism of decomposition of Pb compounds on a tungsten surface
作者:Daniele M Santos、Pedro O Luccas、Joaquim A Nóbrega、Éder T.G Cavalheiro
DOI:10.1016/s0040-6031(00)00578-5
日期:2000.11
Abstract Tungstencoils are used as electrothermal atomizers in atomicabsorptionspectrometry (ETA-W), but despite successful applications the atomization mechanism is still obscure. The use of the thermogravimetry (TG) can bring some information on decomposition pathways for atom formation, simulating the drying and pyrolysis steps employed in typical heating program cycles. Thermogravimetric curves
摘要 钨线圈在原子吸收光谱法(ETA-W)中被用作电热雾化器,但尽管应用成功,其雾化机制仍不清楚。热重法 (TG) 的使用可以提供有关原子形成分解途径的一些信息,模拟典型加热程序循环中采用的干燥和热解步骤。使用实验室制造的钨样品架在 90% Ar 和 10% H 2 中使用和不使用化学改性剂(例如抗坏血酸、草酸、酒石酸和葡萄糖)或干扰物(例如 NaNO 3 )获得铅盐的热重曲线ETA-W 中通常使用的气氛。热解步骤的中间体和残留物通过 X 射线衍射表征。这些数据允许更好地建立 ETA-W 的参数,并有助于找到适当的条件来减少干扰。结果表明,一般的分解路线是加热形成 PbO,吹扫气体中的 H 2 将氧化物还原,然后 Pb 挥发。
Efficient <i>Z</i>-scheme charge separation in WO<sub>3</sub>/PbWO<sub>4</sub> for the removal of organic pollutants
作者:Yi Zheng、Yiliang Shao、Xingzhi Jin、Min Shu、Longxiao Zhang、Chunlei Li
DOI:10.1039/d0nj04180g
日期:——
The contact quality of a composite is an important factor for the transfer and separation of photogenerated carriers.
复合材料的接触质量是光生载流子传输和分离的重要因素。
Antimony(III)-Doped PbWO<sub>4</sub> Crystals with Enhanced Photoluminescence via a Shape-Controlled Sonochemical Route
作者:Jun Geng、Dujuan Lu、Jun-Jie Zhu、Hong-Yuan Chen
DOI:10.1021/jp057562v
日期:2006.7.1
Sb(III)-doped leadtungstate single crystals with controlled shapes and enhanced green emission have been synthesized via a facile, Pluronic P123 (EO(20)PO(70)EO(20))-assisted, sonochemical method. The surfactant Pluronic P123 was found to play a crucial role in the morphology control of the final products. The growth process was investigated by carefully following time-dependent experiments, and the
TeO2–WO3 Glasses: Infrared, XPS and XANES Structural Characterizations
作者:P. Charton、L. Gengembre、P. Armand
DOI:10.1006/jssc.2002.9707
日期:2002.10
Transparent (1−x)TeO2–xWO3 glasses with 0≤x≤0.325 mol were synthesized by the fast quenching technique. Several complementary techniques as infrared, X-ray photoelectron and X-ray absorption spectroscopies were used to approach the structure of these tungsten oxide–tellurite glasses. Special attention was paid to the oxidation state and the coordination state of tungsten atoms. The structural results show that
透明(1- X)的TeO 2 - X WO 3眼镜0≤ X ≤0.325摩尔由快速淬火技术合成。几种辅助技术,例如红外,X射线光电子和X射线吸收光谱学,被用于研究这些氧化钨-碲酸盐玻璃的结构。特别注意钨原子的氧化态和配位态。结构结果表明(1- x)TeO 2 - x WO 3玻璃具有特征性的碲环境,其化学成分不同,而钨离子始终采用八面体结构。