Document gDpRrodLYgk4kZgLKLjLa5eqL

FORMULA: Fb M.W.: 207.19 (Pb); 223.19 (PbO) LEAD METHOO: 7082 ISSUED: 2/15/84 OSHA: 0.05 mg/ma NIOSH: 0.05 mg/ma [1] ACGIH: 0.15 mg/ma; STEL 0.45 mg/ma PROPERTIES: soft metal; d 11.3 g/cma; MP 327.5 C; valences +2, +4 in salts SYNONYMS: vary depending upon the chemical form (elemental lead and lead compounds except alkyl lead); CAS #1317-36-8 (PbO); CAS #7439-92-1 (Pb). SAMPLING SAMPLER: FILTER (0.8-ym cellulose ester menbrane) FLOW RATE: 1 to 4 L/mln VOL-MIN: 200 L 0 0.05 mg/m3 -MAX: 1200 L SHIPMENT: routine SAMPLE STABILITY: stable MEASUREMENT I 'TECHNIQUE: ATONIC ABSORPTION, FLAME ! ANALYTE: lead ASHING: cone. HNO3, 6 mL; 140 C I `FINAL SOLUTION: 10% HNOj, 10 ml i !FLAME: air-acetylene, oxidizing j !WAVELENGTH: 283.3 ran BLANKS: 2 to 10 field blanks per set 1BACKGROUND CORRECTION: 02 or ^ lamp IACCURACY ! !CALIBRATION: Pb++ in 10X HMO3 RANGE STUOIED: 0.13 to 0.4 mg/na [2]; 0.15 to 1.7 mg/ma (fune) [3] !RANGE: 10 to 200 yg per sanple [3,8] ! '.ESTIMATEO LOO: 2.6 yg per sample [9] I BIAS: not significant [2] 'PRECISION (sr): 0.03 [2] I OVERALL PRECISION (sr): 0.072 [2]; 0.068 (fume) [3] ! ! I APPLICABILITY: The working range is 0.025 to 0.5 mg/m* for a 400-L air sanple. The method is applicable to elemental lead, Including Pb fume, and all other aerosols containing lead. This is an elemental analysis, not compound specific. Aliquots of the samples can be analyzed separately for additional elements.________________________________________________ ______________________ INTERFERENCES: Use O2 or H2 continuun background correction to control flame or molecular absorption. High concentrations of calciun, sulfate, carbonate, phosphate, iodide, fluoride, or acetate can be corrected. OTHER METHODS: This method carbines and replaces P&CAM 173 [8] and S341 [7,9] for lead. Method 7300 (ICP-AES) is an alternate analytical method.Method 7505 is specific for lead sulfide. The following have not been revised: the dithizone method, which appears in P&CAM 102 [`1 and the lead criteria document [1]; P6CAM 191 (ASV) [5]; and P6CAM 214 (graphite fumace-AAS) (61. 2/15/84 7082-1 DO 0748D:? CONFTDETNTTAl METHOD: 7062 LEAD CALIBRATION AND QUALITY CONTROL: 11. Prepare a series of working standards covering the range 1 to 20 pg Pb/mL (1 to 200 pg Pb per sample) by adding aliquots of calibration stock solution to 100-mL volunetric flasks. Dilute to volume with 101 HNO3. Store the working standards in polyethylene bottles and prepare fresh weekly. 12. Analyze the working standards together with the blanks and samples (steps 17 and 18). 13. Prepare a calibration graph of absorbance vs. solution concentration (pg/mL). 14. Aspirate a standard for every 10 samples to check for instrunent drift. 15. Check recoveries with at least one spiked media blank per 10 samples. 16. Use method of additions occasionally to check for interferences. MEASUREMENT: 17. Set spectrophotometer as specified by the manufacturer and to conditions on page 7062-1. NOTE: An alternate wavelength is 217.0 nm tlO]. Analyses at 217.0 nm have slightly greater sensitivity, but poorer signal-to-noise ratio compared to 283.3 nm. Also, non-atomic absorption is significantly greater at 217.0 nm, making the use of 03 or H2 continuum background correction mandatory at that wavelength. 18. Aspirate standards, samples, and blanks. Record absorbance readings. NOTE: If the absorbance values for the samples are above the linear range of the standards, dilute with 101 HNO3, reanalyze, and apply the appropriate dilution factor in the calculations. CALCULATIONS: 19. Using the measured absorbances, calculate the corresponding concentrations (pg/mL) of lead in the sample, Cj, and average media blank, C^, from the calibration graph. 20. Using the solution volunes (mL) of the sample, Vs, and media blanks, V^, calculate the concentration, C (mg/ma), of lead in the air volune sampled, V (L): EVALUATION OF METH00: Method S241 [7] was issued on October 24, 1975, and validated over the range 0.13 to 0.4 mg/ma for a 180-L air sample, using generated atmospheres of lead nitrate [2]. Recovery in the range 18 to 72 pg Pb per sample was 961, and collection efficiency of 0.8-pm mixed cellulose ester filters (Millipore Type AA) was 1001 for the aerosols. Subsequent studies on analytical recovery of 200 pg Pb per sanple gave the results [3,9]: Soecies Digestion Method Analytical Recovery. % Pb metal Pb metal PbO PbS Pb2 PbOj Pb in paint* Pb in paint* HNO3 only HNO3 + H2O2 HNO3 only HNO3 only HNO3 only HNO3 + H20? HNO3 only HNO3 + H2O2 92 + 4 103 3 93 + 4 93 + 5 82 + 3 100 + 1 95 + 6 95 + 6 *Standard Reference Material *1579, U.S. National Bureau of Standards. 2/15/84 7062-3 DO 074053 CONFIDENTIAL