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)
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)
来源:Toxin and Toxin Target Database (T3DB)
毒理性
致癌性证据
铅、铅化合物:合理预期为人类致癌物
Lead, lead compounds: Reasonably anticipated to be a human carcinogen
来源:Hazardous Substances Data Bank (HSDB)
毒理性
致癌性证据
A3;已确认对动物有致癌性,但对人类的相关性未知。/铅,元素铅和无机铅化合物,如Pb/
A3; Confirmed animal carcinogen with unknown relevance to humans. /Lead, elemental, and inorganic compounds, as Pb/
来源:Hazardous Substances Data Bank (HSDB)
毒理性
致癌性证据
无法对...碳酸铅...的致癌性进行评估。
No evaluation could be made of the carcinogenicity of ... lead carbonate ... .
Organic lead compounds are not classifiable as to their carcinogenicity to humans (Group 3). To the extent that organic lead compounds are metabolized in part to ionic lead, they are expected to exert the toxicities associated with inorganic lead (Group 2A, probably carcinogenic to humans). (L135)
IVE: This study was designed to evaluate the source of Pb in blood of ... 49 children (48 < 5 years of age) along with 18 adults (> 20 years of age) ... . Mean PbB level of the children was 7.5 ug/dL (range, 1.5-25.7 ug/dL; n = 49; geometric mean, 6.6 ug/dL), with four children whose PbB was > 12 ug/dL. The isotopic data for blood samples lay around two distinct arrays. The blood of all children analyzed for Pb isotopes contained a contribution of Pb from the Magellan mine, which for young children ranged from 27% up to 93% (mean, 64%; median, 71%). Subtraction of the ore component gave a mean background PbB of 2.3 ug/dL. Several children whose PbB was > 9 ug/dL and most of the older subjects have complex sources of Pb. ... The death of the birds acted as a sentinel event; otherwise, the exposure of the community, arising from such a toxic form of Pb, could have been tragic ...
Adult male dogs were given daily doses of 34.1 mg and 68.2 mg basic lead carbonate for 60 days. Ratio of urinary lead excretion to total lead admin was very small, 0.24 & 0.09% respectively. 98.7 & 98.9% respectively of total lead admin was fecally excreted. Urinary and fecal excretions totalled 98.4 & 97.9% respectively. The highest concn was found in teeth and bones, followed by bone marrow, hair, and trachea. /Basic lead carbonate/
Thermal decomposition of carbonates, carboxylates, oxalates, acetates, formates, and hydroxides
作者:Jacob Mu、D.D. Perlmutter
DOI:10.1016/0040-6031(81)80175-x
日期:1981.11
Abstract A study is reported of the controlled decomposition of various metal carbonates, carboxylates, oxalates, acetates, formates and hydroxides and their common hydrates, carried out in a thermogravimetric analyzer, a differential scanning calorimeter, and a differential thermal analyzer. Various sample sizes, heating rates, and ambient atmospheres were used to demonstrate their influence on the
Magnetic structure and properties of Pb8FeIIFe2IIIF24: a 1-D ferrimagnetic chain compound exhibiting a spin-flop transition
作者:A Pierrard、P Gredin、N Dupont、A de Kozak、F Bouree-Vigneron、G Andre、I Rosenman
DOI:10.1016/s0925-8388(99)00296-0
日期:1999.9
The magnetic structure of Pb8FeIIFe2IIIF24 was solved starting from its neutron diffraction powder pattern obtained at 1.4 K and its magnetic properties were characterized using the data recorded on a SQUID magnetometer and on a magneto-susceptometer. Pb8FeIIFe2IIIF24 is triclinic, space group P 1 ; its crystal structure was previously solved on a single crystal. The magnetic structure of this fluoride
摘要 Pb8FeIIFe2IIIF24 的磁结构从其在 1.4 K 下获得的中子衍射粉末图开始求解,并使用 SQUID 磁力计和磁感受计记录的数据表征其磁性能。Pb8FeIIFe2IIIF24是三斜晶系,空间群P 1 ;它的晶体结构以前是在单晶上解决的。这种氟化物的磁性结构是由亚铁磁链构成的,这些链大约沿着细胞的 c 轴反铁磁耦合,构成平行于 (b, c) 平面的层。两个连续的层表现出不同的磁矩取向。Pb8FeIIFe2IIIF24 的净磁矩为零,与反铁磁结构一致。这种磁性结构不会在温度范围内演变:1.4–20 K。因此,
New mixed metal selenites and tellurites containing Pd<sup>2+</sup>ions in a square planar geometry
作者:Su-Yun Zhang、Chun-Li Hu、Jiang-Gao Mao
DOI:10.1039/c1dt11836f
日期:——
Four novel mixed metal selenites or tellurites containing PdO4 squares, namely, BaPd(SeO3)2, Bi2Pd(SeO3)4, and Pb2Pd(QO3)2Cl2 (Q = Se, Te), have been prepared and structurally characterized by single crystal X-ray diffraction analyses. These compounds exhibit three different types of anionic structures. BaPd(SeO3)2 contains one-dimensional (1D) [Pd(SeO3)2]2− anionic chains composed of PdO4 units linked
Thermal decomposition of Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Pb(II) p-toluenesulphonates
作者:Mercedes Bombín、Alejandro Guerrero、Ma Angeles Martinez-Zaporta、Araceli Ramirez、Antonio Jerez
DOI:10.1016/0040-6031(89)87103-5
日期:1989.6
Abstract Thermaldecompositions of Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) hexahydrated p-toluenesulphonates and Pb(II) anhydrous p-toluenesulphonate have been studied in an atmosphere of air and under nitrogen flow. Dehydration enthalpies were measured from the DSC curves and the degradation products of the anhydrous salts were identified by X-ray diffraction.
Convenient Routes for the Preparation of Barium Permanganate and other Permanganate Salts
作者:László Kótai、István E. Sajó、István Gács、Pradeep K. Sharma、Kalyan K. Banerji
DOI:10.1002/zaac.200700142
日期:2007.7
KMnO 4 and sulfuric acid monohydrate in a two-phase (CCl 4 -H 2 SO 4 .H 2 O) system. In the presence of excess barium Introduction Bariumpermanganate has been in use for a long time as auseful starting material (s 75 g/L in water at 18 °C, T dec 170 °C) for the preparation of other permanganate salts [1].It has also been applied as a selective solid phase oxidantin organic chemistry [2]. In spite of the
摘要。开发了两种方便的方法,通过 BaMnO 4 或 Mn 2 O 7 中间体将 KMnO 4 转化为高锰酸钡和其他高锰酸盐。在BaCl 2 和NaOH存在下,KMnO 4 与KI反应制备纯BaMnO 4 。锰酸钡与过量二氧化碳在 100°C 下水热反应 1.5 小时,得到几乎定量收率的高锰酸钡。Mn 2 O 7 是通过KMnO 4 和一水硫酸在两相(CCl 4 -H 2 SO 4 .H 2 O)体系中反应制备的。存在过量钡时 简介 高锰酸钡作为有用的起始材料(s 75 g/L,在 18 °C 下,T dec 170 °C)已用于制备其他高锰酸盐 [1] .它还被用作有机化学中的选择性固相氧化剂[2]。然而,尽管得到了广泛的应用,但尚未实现其方便的合成。高锰酸钾是唯一市售的高锰酸盐化合物,但不能直接将其转化为纯高锰酸钡[3]。然而,两种合成前体,即 BaMnO