Small Amounts Of Lead Research Articles

Geochemical and mineralogical distinctions between Bonnin and Morris (Philadelphia, 1770–1772) porcelain and some contemporary British phosphatic wares

AbstractThe major element compositions of 15 ceramic sherds from the Bonnin and Morris factory site were determined by electron microprobe. Thirteen samples are phosphatic; the others consist of (a) “soapstone” (magnesian/plombian) and (b) true porcelain, and are interpreted as exotic artifacts, as is one compositionally distinct (relatively SiO2‐poor, P2O5+CaO‐rich) phosphatic sample. Although long considered to be virtually indistinguishable from Bow porcelain (London: ca. 1747–1776), the phosphatic Philadelphia wares have a relatively low mean CaO/P2O5 ratio (3.3 versus 3.8; molecular proportions) and high alumina content (6.6 versus 5.4 wt % Al2O3). Furthermore, unlike Bow, the Bonnin and Morris samples contain calcic plagioclase (bytownite), and in some instances, an orthoclase‐rich ternary feldspar. The preservation of calcic plagioclase indicates that Philadelphia porcelain was fired at (rather than above) the thermal minimum in the An‐SiO2‐C3P system, although the presence of Na (and other fluxes) in these wares precludes the exact determination of the maximum firing temperature from this phase diagram. These wares are also distinctive insofar as the phosphate and melt phases can contain small amounts of lead; they have bulk lead contents of approximately 0.1–1.2 wt % PbO. This component has not been detected in the body of Bow or other contemporary British phosphatic porcelains. Their principal similarity lies in the fact that both wares contain sulfate. In addition, the glazes on Bonnin and Morris porcelain (e.g., PbO ∼ 35–50 wt %; SnO2 ∼ 1–2%) compositionally resemble those used at Bow. If feldspar is formed at all, then Al‐poor phosphatic porcelain (or those with low CaO/P2O5 ratios) will have comparatively low modal calcic plagioclase contents, thereby allowing the rapid depletion of this mineral via resorption by the melt phase during vitrification. Such appears to have been the case for analyzed Bow porcelain, which is therefore interpreted to have been overfired (sensu lato) relative to its Philadelphia counterpart. Conceivably, calcic plagioclase could be preserved in low‐Al wares that were fired only briefly at vitrification temperatures. Given the role of firing history in governing the mineralogy of porcelain, compositional criteria are more reliable for distinguishing these wares. © 2001 John Wiley & Sons, Inc.

Surface morphology and surface chemical states of epitaxial Pb(Zr 0.95 Ti 0.05 )O 3 thin films grown on SrTiO 3 (100) by sputter deposition

Ti0.05)O3 thin films of an orthorhombic perovskite structure were obtained on SrTiO3(100) substrates by radio frequency sputter deposition. The surface morphology of the films was investigated with atomic force microscopy, scanning electron microscopy, and reflection electron microscopy. It is shown that the film surfaces are rather bumpy. There are undulations of about 400 nm in length in an in-plane direction. The mean roughness perpendicular to the surface is 39.6 nm, for the film thickness of 0.45 μm. The surface roughening was probably caused by island-shaped nucleation and growth during the film growth. It has also been found that some gorges and a number of small pits remain at the film surfaces. The surface chemical states of the films were characterized by using X-ray photoelectron spectroscopy. A Pb enrichment layer and a large amount of adsorbed oxygen have been found at the surfaces of the films. Near the film surface Pb and Zr exist mainly in the forms of, besides Pb(Zr,Ti)03, metal Pb, metal Zr, oxygen-chemisorbed Pb, and various lead oxides. In addition, a small amount of lead, whose binding energy of Pb 4f7/2 is much lower than that of metal Pb, was observed at the film surfaces, but its chemical state is unknown up to now.

Excitational, vibrational, and rotational temperatures in Nd:YAG and XeCl Laser-Induced plasmas

Laser-induced plasmas formed on graphite by a Nd:YAG laser at 1064 nm and by a XeCl laser at 308 nm were analyzed spectroscopically to determine vibrational, rotational, and excitation temperatures. For determination of vibrational and rotational temperature, the emission of the CN radical in the region between 385.1 and 388.3 nm was used to construct Boltzmann plots. Relative vibrational transition probabilities were calculated. For determination of excitation temperature, a small amount of lead or iron was added to the graphite target and Boltzmann plots were constructed using transition probabilities found in the literature.

Changes in the heavy metal contents of soil from the Park Grass Experiment at Rothamsted Experimental Station.

The classical Rothamsted Experiments allow to contribute to current research. The heavy metal content of soil and hay samples have been measured with ICP-AES from a control and a fertilized plot of the Park Grass Experiment. Today a difference of 1.2 can be observed in the pH levels of the control and fertilized plots; the pH level of the control plot has decreased about 1.0, that of the fertilized plot about 2.2 as a result of 150 years of acid deposition and fertilization. The changes in the pH levels has caused many changes in the heavy metal content of the top layer of the soil. Using different extraction methods (e.g., ammonium acetate, EDTA, and sequential analysis), the heavy metal content of different fractions have been estimated. In the control plot, the Zn, Cd and Pb content increased. In the fertilized plot, the Pb and Cd contents have also increased because of atmospheric deposition and small amounts of lead in the fertilizer. The available form of Cd and Pb increased in both the control and the fertilized plots.

Effects of small additions of lead, sulphur and oxygen on annealing characteristics of cold-drawn pure copper

Softening of cold-drawn wires of a tough pitch copper containing a small amount of lead as well as oxygen and sulphur is enhanced when hot-rolled rods of the copper are heated at 600 °C before cold-drawing. Enhancement causes were examined using wires of pure Cu, Cu-O, Cu-S, Cu-Pb, Cu-Pb-O, Cu-Pb-S, Cu-Pb-S-O. The softening enhancement appearing in the Cu-Pb-S-O specimen was attributed to the decrease in the amount of dissolved Pb and S in the copper matrix due to precipitation during heating at 600 °C. The addition of lead in the presence of oxygen was shown to decrease the solid solubilities of S in the copper matrix.

Separation of Lead, Cadmium, and Iron in Analyses of Soil Samples

The conditions of sorption of chloride complexes of Pb2+, Cd2+, Fe2+, and Fe3+ ions from media of hydrochloric acid have been studied with a strongly basic anion exchanger - Ostion LG AT. The experiments used an exchanger microcolumn connected with atomic absorption spectrometer as a selective detector of metal ions. From the relation found between retention of the ions studied and hydrochloric acid concentration, conditions of separation have been suggested and used for separations of small amounts of lead and cadmium from many times higher amounts of iron and aluminium in soil extract before determination of both the foreign metals by means of AAS method. The yield of separation exceeded 95%.

The selective solvent extraction of cadmium by mixtures of carboxylic acids and trialkylphosphine sulphides. Part 2. Practical applications in the separation of cadmium from zinc and nickel

The addition of triisobutylphosphine sulphide (TIBPS) to 3,5-diisopropylsalicylic acid (DIPSA) causes a strong synergistic shift in the extraction of cadmium (1.9 pH units for the addition of 0.50 M TIBPS to 0.50 M DIPSA in xylene). The shifts are considerably smaller (up to 0.6 pH units) for other common divalent base metals; such as zinc, lead, manganese, iron, cobalt, nickel, calcium and magnesium, enabling the selective extraction of cadmium to be carried out in most cases. The influence on the separation between cadmium and zinc of variables such as: extractant concentrations, the identity of diluent, the presence of modifiers and the presence of sulphate ion was studied. In batch counter-current experiments using a synthetic solution containing cadmium (5 gl −1) and nickel (24 gl −1) as sulphates and 0.50 M TIBPS plus 0.50 M DIPSA in xylene at an organic to aqueous phase ratio of 2:3 in three extraction stages, quantitative recoveries of 99.8% pure cadmium and > 99.99% pure nickel were obtained. In a continuous counter-current mini-plant trial, a sulphate leach liquor derived from the cadmium cement cake from an electrolytic zinc plant was treated in four extraction stages, two scrubbing stages, and two stripping stages, using 0.40 M TIBPS plus 0.40 M DIPSA in Shellsol 2325. The feed solution, containing up to 16 gl −1 cadmium and 9 gl −1 zinc, as well as small amounts of lead, thallium and other impurities, was processed through to a strip liquor containing up to 110 gl −1 cadmium with a purity of about 99.95% (Zn 0.01, Pb 0.02, Fe 0.01 and Tl 0.005%).

Preventing Lead Poisoning in Kids: A Win-Win Opportunity

To the Editor.— For many, it is hard to believe that small amounts of lead pose a risk to children. In the February issue of Pediatrics, Dr Edgar Schoen cautioned physicians that the recent national focus on lead is overstated.1 Although Dr Schoen is correct that early lead studies were inadequately designed, he ignores later research which is well-designed and clearly implicates lead. In doing so, he seriously underestimates the hidden cost to our society of this pervasive toxin.

Microstructure and Wear Characteristics of Rheocast Al–Pb Bearing Alloys

A rheocasting unit in which solidifying alloy agitated at a high speed of 53 s−1 was applied to produce aluminium-lead bearing alloys containing up to 20 mass%Pb. It was found by morphological observation of Al–Pb alloys that a continuous lead-rich phase existed between aluminium-rich phases, the thickness and the length of the lead-rich phase increased with increase in lead content, and the aluminium-rich phase was refined with increased lead content. A drastic decrease in bulk wear was observed in Al–Pb alloys even with a small amount of lead. The bulk wear continuously increased with load as a result of propogation of cracks with increasing load. With increase in lead content in these alloys, a minimum in bulk wear with sliding velocity has been observed, but with increase in lead content for a particular sliding velocity, the bulk wear been observed to decrease continuously till about 20 mass% lead, the maximum lead content in Al–Pb alloys in the present investigation.

Spectrophotometric Determination of Lead with Dithizone after Selective Separation on Polyurethane Foam Sorbents

A spectrophotometric method has been developed for determination of small amounts of lead in glass and some ceramic raw materials. The method involves selective separation of lead with 5.85 × 10−5M dithizone and 7.5 × 10−2M KCN at pH∼10 followed by elution of the complex with acetone and making it alkaline with 0.2 ml of 2.5M NH3 in a total volume of 10 ml. The method obeys Beer's law from 0.1 to 2.5 μg Pb.ml−1 at 500 nm. Correlation coefficient calculated from the linearity curve is 0.99. Interferences due tp Cu(II), Co(II), Ni (II), Zn(II), Cd(II), Mn(III) and Fe (II) have been eliminated automatically by using KCN. Effect of Fe(III) could be eliminated by extraction with MIBK prior to the separation of lead. The developed method has been standardized against National Bureau of Standards opal glass sample (NBS 91). Standard deviation of the results has been found to be ±0.0021.

Separation of traces and large amounts of lead from gram amounts of bismuth, tin, cadmium, and indium by cation exchange chromatography in hydrochloric acid-methanol using a macroporous resin

Traces and small amounts of lead can be separated from gram amounts of Bi, Sn, Cd, and In by eluting these elements with 0.5 M HCl in 50% methanol from a column containing only 2.7 mL (1g) of Bio-Rad AG MP-50 macroporous cation exchange resin of 100-200 mesh particle size in the H form. A 5.4 mL (2 g) resin column separates up to 100 mg of lead. Lead can be eluted effectively with 3.0 M aqueous HCl. Separations are sharp and quantitative. In combination with flame atomic absorption spectrometry, the method has been applied for the determination of lead in pure metals or chemicals of the above elements. Relative standard deviations were better than 1% for samples containing 10 ppm of lead or more. The sensitivity is less than 0.1 ppm. Relevant elution curves and results of analyses of binary synthetic mixtures and actual samples are presented. 7 references, 4 figures, 2 tables.

X-ray Study, Treatment and Conservation of Rameses ii's Stove from the Egyptian Museum, Cairo

Rameses II's stove from the Egyptian Museum was studied by X-ray diffraction and X-ray fluorescence techniques; chemical treatment and conservation processes were then applied. The corrosionproducts covering the surface of the stove were found to be atacamite, paratacamite, calumetite, malachite and, in some patches, azurite. The stove proved toconsist of cast bronze, with a small amount of lead and traces of iron, probably due to impurities in the ores. The upper surface of the stove has four similar circular holes, which lie in a line, as temperature regulators,as well as five old soldering points which were made by ancient Egyptians using cold V-type hammering.

In vivo study on lead and alcohol interaction and the inhibition of erythrocyte delta-aminolevulinic acid dehydratase in man.

The effect on alcohol (EtOH) consumption on the inhibition of erythrocyte delta-amino-levulinic acid dehydratase (ALAD) was investigated in 13 male lead workers and 7 "normal" male subjects. Lead and zinc protoporphyrin in blood and lead, delta-aminolevulinic acid, porphobilinogen and coproporphyrin in 24-h urine specimens were also determined. During 1 h the subjects drank 122.8 (SD 18.65) ml of an almost lead-free brandy, ie, a dose of 11.07 mmol/kg of body weight. This dose resulted in a trend toward a parallel decrease in ALAD activity and an increase in lead in blood (PbB), both of which approached the prealcohol value 24 h after the initial alcohol ingestion. A trend toward increased lead excretion in urine (PbU) was observed on the day of alcohol ingestion, as compared to the preceding and succeeding 24-h urine specimens. However, the observed increase in PbB and PbU cannot be attributed to the small amount of lead ingested through the brandy, ie, 7.09 (SD 1.06) nmol. The characteristic dose-effect relationship between PbB and ALAD (examined prior to and 1, 3, 5, and 24 h after the initial alcohol ingestion) reached the highest correlation coefficient 3 h after the initial alcohol ingestion (p less than 0.001). The data obtained appear to support the hypothesis of a possible role for the body lead pool and the lead-mediated influence of alcohol consumption on ALAD activity in man.

ANACONDA ALLOY 482

Abstract ANACONDA Alloy 482 is a variation of the basic Naval Brass composition; it contains a small amount of lead (nominally 0.70%) to improve its machinability. It has good mechanical properties and high resistance to corrosion by seawater. It is used for marine hardware, valve stems and other machined parts. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Cu-452. Producer or source: Anaconda American Brass Company.

Influence of dietary protein composition on lead absorption in rats.

The relative tissue uptake of lead has been assessed in young adult rats maintained on two different synthetic diets differing only in the type of protein source: casein or soy bean meal. Effects of lead as a function of these diets on the rat hematopoietic system were also determined. Data obtained using the two diets are described in this report. Results show that the use of casein as protein source in the diet of lead-exposed animals clearly enhances both lead assimilation and hematological effects relative to rats ingesting a soybean diet, the difference being 2-3 fold across various tissues in the case of lead concentrations. The sensitivity of diet protein as a factor is seen from the fact that the very small amounts of lead taken in by control animals are lodged in tissues at significantly different amounts in those cases where lead is less mobile. (JMT)

A Study on Distribution of Lead in the Hard Tissue of Rats of Different Age Levels

It is a well known fact that the influence of age factor is very great in the susceptibility to lead poisoning. However, the reason for this phenomenon has not yet been proven. Further, there has been few studies conducted on the differences in the susceptibility, using experimental animals. The experiments were conducted to determine the relationship between the distribution of lead in the teeth and the femur of rats and their age by using 210-Pb tracer. The animals which were used in the experiments were Wistar male rats of 3 weeks, 3 months, and 22 months of age. A single intraperitoneal injection of lead nitrate solution of 210-Pb 10μCi/kg, and solutions of other densities were administered to the rats and after a lapse of 3 days, the percentages of lead intake in the femur and the teeth were measured, with results as follows.1) Whereas the excretion of lead decreased exponentially when a small amount of lead (210-Pb 10 μCi/kg only) was administered to the control group, the excretion decreased linearly when 1 mg/kg of lead was administered. It was found that 21 days after the administration, the excretion of lead was 39.8% in the former case and 24.3% in the latter. The percetage of excretion in the feces was constantly higher than that in the urine.2) With the increase in the dosage of lead, it was noted that the percentages of lead in the hard tissue decreased. The decrease in the percentage of lead intake was remarkable when 10 mg/kg and 100 mg/kg were administered. This tendency became predominant in the aged rats.3) The average percentage of lead intake measured in the femur, incisor and molar of the 3 weeks old rats in the control group were 6.25%, 0.81% and 0.55%, respectively. Those of the rats of 3 months old were 2.52%, 0.76% and 0.10%, and the rats of 22 months old, 2.28, 0.97 and 0.21%, respectively.4) In the groups of rats to which 1 mg/kg lead were administered, the average intakes of lead in the femur, incisor and molar were 2.50%, 0.37% and 0.19% respectively, in the age group of 3 weeks, 0.80%, 0.17% and 0.05% in the age group of 3 months, 0.22%, 0.07% and 0.02% in the age group of 22 months.5) It was observed that in the suckling rats of the control group, the amount of lead was largest in the femur, but in the adult and aged rats the largest amount of lead was found in the incisor.

X-Ray microanalytical studies of lead-implanted rat brains

Various cytoplasmic and intranuclear inclusions found in macrophages and astrocytes of lead-implanted rat brains were studied with an energy dispersive x-ray microanalytical technique. Cytoplasmic inclusions contained large quantities of lead, calcium and phosphorus. The proportions of these elements were different within each inclusion. Intranuclear inclusions also contained small amounts of lead and, occasionally, calcium.

Biological effects of exposure to lead in ambient air among Tokyo inhabitants.

The purpose of this study was to examine whether the health of Tokyo inhabitants was affected by lead in the ambient air, on the bases of place of residence, age and sex. The study came about as a direct result of public concern over a press report that people living near busy traffic intersections were being poisoned by lead in the air. In 1970 and 1971, the laboratories of the Tokyo Metropolitan Institute of Health and the Occupational Health Service Center performed laboratory tests on inhabitants who were concerned about air pollution and presented themselves to their local health departments. The results were then passed on to the Keio University School of Medicine for evaluation.The average lead levels in blood and urine were slightly higher in those person living in houses which faced a main street (13.3 μg/100ml blood) than in those who living on side streets (12.8 μg/100ml). However, there was no association found to exist according to the distance of the house from the main street. Blood lead levels were higher in males (15.0 μg/100ml) than in females (11.2 μg/100 ml). Lead levels in urine were also higher in males than in females: 13.1 μg/100 ml as opposed to 11.7 μg/100ml. There was no particular association between age and lead levels in blood or urine.The average lead levels in blood and urine differed by district but showed no systematic pattern or relationship to the population density. This seems to be due to technical differences between the two laboratories responsible for the testing as well as to the difficulty in determining such small amounts of lead in blood and urine.In conclusion, according to the available techniques, there was no evidence of an increased level of lead in blood or urine as a result of lead in the ambient air of Tokyo. The results obtained in this study agree with a previous report by the present authors' and with a report by Tepper and Levin2 from the U.S.A.

Rapid determination of lead in used lubricating oils on thin-layer chromatograms

Small amounts of lead can be immediately detected on chromatograms (0.2-0.3 μg on cellulose thin layers and about 0.4 μg on paper) as the fluorescent [PbCl 4] 2− complex (excitation maximum 254 nm; emission maximum 480 nm). Quantitative determinations can be made by diffuse reflectance measurement at 254 nm. This method was utilized for the determination of lead in used lubricating oils. The analytical range could be extended virtually to the detection limits of fluorescence.

The effect of foreign atoms on the properties of electrolytic zinc powders

Kinetic and morphological studies have been made of the deposition of zinc powder on steel substrate, from pure alkaline zincate electrolytes and with small amounts of lead and tin ions in the electrolyte. The rate of co-deposition of hydrogen has been followed volumetrically and the current efficiency of zinc deposition calculated as a function of potential.