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Chemical Identifying Information for Lead
CAS NUMBER: 7439-92-1
ATOMIC FORMULA: Pb
ATOMIC WEIGHT: 207.19
NIOSH Registry Number: OF7525000
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PHYSICAL DESCRIPTION: Silver-bluish white soft solid
SPECIFIC GRAVITY: Not available
DENSITY: 11.3437 g/mL @ 16 C
MELTING POINT: 327.50 C
BOILING POINT: 1740 C
SOLUBILITY: Water: Insoluble DMSO: Insoluble 95% Ethanol: Insoluble Acetone: Insoluble
OTHER SOLVENTS: Not available
OTHER PHYSICAL DATA: Not available
VOLATILITY: Vapor Pressure: 1 mm @ 973 C [703]
FIRE HAZARD: Flash Point: Not available
Flammable in the form of dust when exposed to heat or flame [703]. Metal is a noncombustible solid in bulk form [704].
Autoignition temperature: Not available
LEL: Not available UEL: Not available
REACTIVITY: Mixtures of hydrogen peroxide + trioxane explode on contact with lead. Rubber gloves containing lead may ignite in nitric acid. Violent reaction on ignition with chlorine trifluoride; concentrated hydrogen peroxide; ammonium nitrate (below 200 C with powdered lead); sodium acetylide (with powdered lead). Incompatible with NaN3; Zr; disodium acetylide; oxidants. Can react vigorously with oxidizing materials. [703]
STABILITY: Moderately explosive in the form of dust when exposed to heat or flame. When heated to decomposition it emits highly toxic fumes of Pb. [703]
USES: Lead is very resistant to corrosion and is used in containers for corrosive liquids. Its alloys include solder, type metal, and various antifriction metals. Great quantities of lead and the dioxide are used in storage batteries. Much metal also goes into cable covering, plumbing, ammunition, and lead tetraethyl. The metal is used as a radiation and to absorb vibration. Lead oxide is used in producing fine "crystal glass" and "flint glass". The uses of lead in paints and gasoline, and the use of lead salts as insecticides are being drastically curtailed or eliminated due to health and environmental concerns. [706]
COMMENTS: Care must be used in handling lead as it is a cumulative poison [706].
ACUTE/CHRONIC HAZARDS: Lead powder may be toxic and the effects of exposure are cumulative.
SYMPTOMS: Symptoms of acute exposure may include abdominal pain, diarrhea, shock, muscular weakness and pain, headache, kidney damage, and coma.
Symptoms of chronic exposure may include lead encephalopathy (especially in children), headache, vomiting, delirium/hallucinations, convulsions, coma, death from exhaustion and respiratory failure. Children typically show weight loss, weakness, anemia and exhibit GI and CNS complaints.
Numbers in brackets [ ] are reference numbers in the source of this information.
Source: Instant EPA's Air Toxics, Copyright 1994 by Instant Reference Sources, Inc. and Digital Liaisons, Austin, Texas
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The data below is scanned from Instant Tox-Base. This database contains data on over 1800 chemicals in a highly condensed tabular format. Abbreviations and Definitions used throughout can be viewed here but they are all hyperlinked to the text within Instant Tox-Base for convenience.
Numbers in brackets [ ] are reference numbers in the source of this information.
Source: Instant Tox-Base, Copyright 1994 by Instant Reference Sources, Inc. and Digital Liaisons, Austin, Texas
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EPA's IRIS is the world's most comprehensive toxicology database. Chemical entries often range from 20 to 50 pages of information. The information below represents a small selection of the data involving carcinogenicity in Section II of IRIS. Many of the technical terms are hyperlinked with explanations in Instant EPA's IRIS from which the following exerpts were taken but space limitations preclude that convenience here.
II.A. EVIDENCE FOR CLASSIFICATION AS TO HUMAN CARCINOGENICITY
II.A.1. WEIGHT-OF-EVIDENCE CLASSIFICATION
Classification -- B2; probable human carcinogen
Basis -- Sufficient animal evidence. Ten rat bioassays and one mouse assay have shown statistically 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.
II.A.2. HUMAN CARCINOGENICITY DATA
Inadequate. There are four epidemiologic studies of occupational cohorts exposed to lead and lead compounds. Two studies (Dingwall-Fordyce and Lane, 1963; Nelson et al., 1982) did not find any association between exposure and cancer mortality. Selevan et al. (1985), in their retrospective cohort mortality study of primary lead smelter workers, found a slight decrease in the total cancer mortality (SMR=95). Apparent excesses were observed for respiratory cancer (SMR=111, obs=41, p>0.05) and kidney cancer (SMR=204, obs=6, p>0.05). Cooper and Gaffey (1975) and Cooper (1985 update) performed a cohort mortality study of battery plant workers and lead smelter workers. They found statistically significant excesses for total cancer mortality (SMR=113, obs=344), stomach cancer (SMR=168, obs=34), and lung cancer (SMR=124, obs=109) in the battery plant workers. Although similar excesses were observed in the smelter workers, they were not statistically significant. Cooper and Gaffey (1975) felt it was possible that individual subjects were monitored primarily on the basis of obvious signs of lead exposure, while others who showed no symptoms of lead poisoning were not monitored.
All of the available studies lacked quantitative exposure information, as well as information on the possible contribution from smoking. All studies also included exposures to other metals such as arsenic, cadmium, and zinc for which no adjustment was done. The cancer excesses observed in the lung and stomach were relatively small (<200). There was no consistency of site among the various studies, and no study showed any dose-response relationship. Thus, the available human evidence is considered to be inadequate to refute or demonstrate any potential carcinogenicity for humans from lead exposure.
II.A.3. ANIMAL CARCINOGENICITY DATA
Sufficient. The carcinogenic potential of lead salts (primarily phosphates and acetates) administered via the oral route or by injection has been demonstrated in rats and mice by more than 10 investigators. The most characteristic cancer response is bilateral renal carcinoma. Rats given lead acetate or subacetate orally have developed gliomas, and lead subacetate also produced lung adenomas in mice after i.p. adminstration. Most of these investigations found a carcinogenic response only at the highest dose. The lead compounds tested in animals are almost all soluble salts. Metallic lead, lead oxide and lead tetralkyls have not been tested adequately. Studies of inhalation exposure have not been located in the literature.
Source: Instant EPA's IRIS, Copyright 1996 by Instant Reference Sources, Inc. and Digital Liaisons, Austin, Texas
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TITLE: Inductively Coupled Plasma-Atomic Emission Spectroscopy
MATRIX: This method is applicable to the determination of trace elements, including metals, in ground water, soils, sludges, sediments, and other solid wastes. All matrices require digestion prior to analysis. The method of standard addition must be used for the analysis of all sample digests unless either serial dilution or matrix spike addition demonstrates it is not required.
METHOD SUMMARY: Method 6010 covers 25 elements using ICP analysis. It measures element-emitted light by optical spectrometry. Samples, following an appropriate acid digestion, are nebulized and the resulting aerosol is transported to the plasma torch. Element-specific atomic line emission spectra are produced by a radio-frequency inductively coupled plasma.
INTERFERENCES: Interferences may be categorized as spectral or non- spectral. Spectral interferences are caused by overlap of a spectral line from another element, unresolved overlap of molecular band spectra, background contribution from continuous or recombination phenomenon, and stray light from the line emission of high concentration elements. Non- spectral interferences include physical and chemical interferences. Physical interferences are effects associated with the sample nebulization and transport processes. Changes in viscosity and surface tension can cause significant inaccuracies. Chemical interferences include molecular compound formation, ionization effects, and solute vaporization effects. Normally these effects are not significant and can be minimized by careful selection of operating conditions. Chemical interferences are highly dependent on matrix type and the specific analyte element.
INSTRUMENTATION: An inductively coupled argon plasma emission spectrometer (ICP) capable of background correction is required.
PRECISION AND ACCURACY: Detection limits, sensitivity, and optimum ranges of the metals will vary with the matrices and model of the spectrometer. In a single laboratory evaluation, seven wastes were analyzed for 22 elements. The mean percent relative standard deviation from triplicate analyses for all elements and wastes was 9 plus or minus 2%. The mean percent recovery of spiked elements for all wastes was 93 plus or minus 6%. Spike levels ranged from 100 ug/L to 100 mg/L. The wastes included sludges and industrial wastewaters.
Estimated Instrument Detection Limit in ug/L is 42.
Spiked Concentration in ug/L is 24.
Mean Reported Value in ug/L is 30.
Precision as RSD % is 32.
SAMPLING METHOD: Samples should be collected in borosilicate glass, linear polyethylene, polypropylene, or Teflon bottles that have been pre-washed with detergent and tap water, and rinsed with 1:1 nitric acid and tap water or 1:1 hydrochloric acid and tap water. Collect at least 2 g of solids and 200 mL of aqueous samples.
SAMPLE PRESERVATION: Add nitric acid to make the samples pH <2.
M.H.T.: The maximum holding time for properly preserved samples is 6 months.
SAMPLE PREPARATION: Preliminary treatment of most matrices is necessary because of the complexity and variability of sample matrices. Water samples which have been prefiltered and acidified will not need acid digestion. Methods for acid digestion of waters for total recoverable or dissolved metals, acid digestions of aqueous samples and extracts for total metals, and acid digestion of sediments, sludges, and soils are summarized below.
Total Recoverable or Dissolved Metals in Water: To prepare surface and ground water samples for determination of total recoverable and dissolved metals, a 100 mL aliquot of well-mixed sample is acidified with concentrated nitric acid and concentrated hydrochloric acid, then heated until the volume is reduced to 15-20 mL. Adjust the final volume to 100 mL with reagent water.
Total Metals in Aqueous Samples, Soil and Sediment Extracts: To prepare aqueous samples, soil and sediment extracts, and wastes that contain suspended solids, a 100 mL aliquot is made acidic with concentrated nitric acid and the solution is evaporated to about 5 mL on a hot plate. Continue heating and adding additional acid until sample digestion is complete, which is usually indicated when the digestate is light in color or does not change in appearance. Evaporate the solution to about 3 mL and cool it and add a small quantity of 1:1 hydrochloric acid (10 mL/100 mL of final solution). Cover the beaker and reflux for 15 minutes. Wash down the beaker walls and filters or centrifuge the sample to remove silicates and other insoluble material. Filter the sample and adjust the final volume to 100 mL with reagent water and the final acid concentration to 10%.
Sediments, Sludges, and Soils: To prepare sediments, sludges and soil samples, transfer 1-2 g to a conical beaker and add 10 mL of 1:1 nitric acid, mix the slurry, and cover it with a watch glass. Heat the sample and reflux for 10 to 15 minutes without boiling. Allow it to cool, then add 5 mL of concentrated nitric acid and reflux for 30 minutes. Repeat last step and then allow the solution to evaporate to 5 mL without boiling. Cool and add 2 mL of water and 3 mL of 30% hydrogen peroxide. Cover and place the beaker on the hot plate. Heat and add 30% hydrogen peroxide in 1 mL aliquots with warming until the effervescence is minimal but do not add more than a total of 10 mL of 30% hydrogen peroxide. If the sample is being prepared for the analysis of Ag, Al, As, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, Os, Pb, Se, Tl, V, and Zn, then add 5 mL of concentrated hydrochloric acid and 10 mL of water and return the covered beaker to a hot plate for 15 minutes of additional refluxing without boiling. Dilute the sample to a 100 mL volume with water after cooling and filter or centrifuge to remove particulates.
QUALITY CONTROL: Laboratory control samples must be analyzed for each analytical method. A method blank should be analyzed with each batch of samples. The effect of the matrix on method performance must be demonstrated: when appropriate, there should be at least one matrix spike and either one matrix duplicate or one matrix spike duplicate per analytical batch. The bias and precision of the method, as well as the method detection limit for each specific matrix type, must be measured.
Dilute and reanalyze samples that are more concentrated than the linear calibration limit. Employ a minimum of one reagent blank per sample batch to determine if contamination or any memory effects are occurring. Whenever a new or unusual sample matrix is encountered, perform either a serial dilution test or a matrix spike addition test to ensure that neither positive or negative interferences are operating on any of the analyte elements. Check the instrument standardization by verifying calibration every 10 samples using a calibration blank and a check standard.
REFERENCE: Test Methods for Evaluating Solid Waste (SW-846). U.S. EPA. 1983. Method 6010, Revision 0, September 1986. Office of Solid Wastes, Washington, D.C.
TITLE: Inductively Coupled Plasma MATRIX: Dissolved, suspended or (ICP) total element in drinking and surface waters and in domestic and industrial wastewaters.
APPLICATION: The method covers the determination of 25 metals. Dissolved elements are determined in filtered and acidified samples after appropriate digestion (which increases dissolved solids). Its primary advantage is that ICP instruments allow simultaneous or rapid sequential determination of many elements in a short time. Samples are first nebulized and the aerosol is transported to a plasma torch in which element specific atomic line emission spectra are produced by a radio frequency inductively coupled plasma. Background correction is required for trace element detection except in the case of line broadning.
INTERFERENCES: There are spectral, physical and chemical interferences. The primary disadvantage of ICP instruments is background radiation from other elements and the plasma gases (spectral interferences). Changes in sample viscosity and surface tension with samples containing high dissolved solids (especially those exceeding 1500 mg/L) or high acid concentrations can cause physical interferences. Ionization effects, solute vaporization and molecular compound formation can cause chemical interferences. Aluminum can cause interference at the 100 mg/L level.
INSTRUMENTATION: Inductively Coupled Argon Plasma Emission Spectroscopy. 220.353 nm Wavelength
RANGE: Not listed
MDL: 42 ug/L.
PRECISION: SD = 16% Mean @ true value 250 ug/L.
ACCURACY: Mean Recovery = 93% +/- 6% of spiked elements for all wastes.
SAMPLING Method: Wash sample container with detergent and tap water, rinse with 1+1 nitric acid and tap water, then rinse with 1+1 hydrochloric acid and tap water, then rinse with deionized, distilled water in that order. Perform any filtration or acid preservation steps when the sample is collected or as soon as possible thereafter.
STABILITY: Cool samples to 4 deg. C. M.H.T. = 24 Hours.
QUALITY CONTROL: Mixed calibration standards, an instrument check standard and an interference check solution are used in addition to a quality control sample. The quality control sample should be prepared in the same acid matrix as the calibration standards at 10 times the instrumental detection limits and in accordance with the instructions provided by the supplier. Furthermore, two types of blanks are required: a calibration blank and a reagent blank.
REFERENCE: Method 200.7, U.S. EPA, EMSL-Cincinnati, OH, Nov. 1980
TITLE: Atomic Absorption, (AA) Direct Aspiration
MATRIX: Drinking, Surface and Saline Waters. Wastewater
APPLICATION: Sample is aspirated and atomized in a flame. A light beam from a Pb hollow cathode lamp is directed through the flame into a monochromator and onto a detector. Since wavelength of light beam is specific for Pb, light energy absorbed by detector is measure of lead.
INTERFERENCES: The most troublesomee type is chemical, caused by lack of absorption of atoms bound in molecular combination in the flame. High dissolved solids in sample may result in nonatomic absorbance interference. Background correction is required.
INSTRUMENTATION: Atomic absorption spectrometer. Lead hollow cathode lamp. [283.3 nm Wavelength(primary)]
RANGE: 1-20 mg/L
MDL: 0.1 mg/L
PRECISION: standard deviation = 128 ug/L @ 367 ug/L (true value) 74 labs
ACCURACY: as bias = +2.9% @ 367 ug/L (true value) 74 labs
SAMPLING Method: Use glass or plastic containers. Collect 200 g of solids and 600 mL of liquid samples.
STABILITY: Cool solid samples to 4 deg. C. and analyze as soon as possible. Add nitric acid to liquid samples to pH < 2; their M.H.T. = 6 months.
QUALITY CONTROL: At least one duplicate and one spike sample should be run every 20 samples or with each matrix type to verify precision of the method. For 20 or more samples per day, verify working standard curve. Run an additional standard at or near mid-range every 10 samples.
REFERENCE: Method 7420, SW-846, 3rd ed., Nov 1986.
TITLE: Atomic Absorption, (AA) Furnace Technique
MATRIX: Drinking, Surface and Saline Waters. Wastewater.
APPLICATION: Pb in solution is readily determined by atomic absorption spectrometer, but detection limits, sensitivity and optimum range vary with the matrices and models of AA spectrophotometers. While drinking water may be analyzed directly, ground water, other aqueous samples, EP extracts, industrial wastes, soils, sludges, and sediments require digestion.
INTERFERENCES: "Chemical" interference is caused by lack of absorption of atoms bound in molecular combination in the flame. High dissolved solids in sample may cause interference from non atomic absorbance. Ionization and spectral interferences can occur.
INSTRUMENTATION: Atomic absorption spectrometer. Lead (Pb) hollow cathode lamp. Graphite furnace. 283 nm Wavelength.
RANGE: 5-100 ug/L
MDL: 1 ug/L
PRECISION: standard deviation = +/- 3.7 @ 100 ug Pb/L.
ACCURACY: Recovery = 95% @ 100 ug Pb/L.
SAMPLING Method: Use glass or plastic containers. Collect 200 g of solids and 600 mL of liquid samples.
STABILITY: Cool solid samples to 4 deg. C. and analyze as soon as possible. Add nitric acid to liquid samples to pH < 2; their M.H.T. = 6 months.
QUALITY CONTROL: At least one duplicate and one spike sample should be run every 20 samples, or with each matrix type to verify method precision. If 20 or more samples are run, run a standard (at or near mid-range) every 10 samples.
REFERENCE: Method 7421, SW-846, 3rd ed., Nov 1986.
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