Cadmium Levels in People Matthew Marah CHEM 4101 Dec. 9 th,

Analyte: Cadmium (Cd) MW= g/mol Most common oxidation state is Cd 2+ Mostly used in Nickel-Cadmium Batteries and electroplating Often a by-product of Zinc & Copper smelting 2

Problem  Long-term and high Cd exposure have a negative impact on health. A Cadmium leak from a plant could cause great damage to people nearby.  Health Effects Include Kidney and liver damage Respiratory troubles Fatal at high exposure 3

Hypothesis  People who live closer to an industrial plant, that uses Cd or produces it as a by-product, will have higher levels of Cd in their blood than people living further away. 4

Sampling & Standards Collect blood from people within 100 miles and between miles of an industrial plant Common levels of Cd range from ppb to ppm – Acceptable daily intake of 1µg of Cd/kg of body weight – Permissible Exposure Limit (PEL) = 0.05mg/m 3 Prepare standards of Cadmium from µg/L for calibration Curve 5

Possible Methods of Analysis MethodProsCons Atomic Absorption Spectroscopy (AAS) Low limit of detection Highly accurate Prior experiments Specialized equipment Time per sample Atomic Emission Spectroscopy (AES) Low limit of detection Highly accurate Specialized equipment Time per sample Ion-Exchange Chromatography (IEC) Separates analyte from most of the matrix Similarly charged ions may interfere. Specialized equipment 6

Possible Methods of Analysis Cont. MethodProsCons Capillary Zone Electrophoresis (CZE) Prior experiments Small sample size needed Specialized equipment Difficult to get good measurement Sample prep Potentiometric Stripping Analysis (PSA) Used in previous experiments with Cd Time per sample Interference from other metals 7

Chosen Method: AAS Select wavelength range and collect data – Cd absorbs at 228.8nm & use PMT to amplify 8 Digest sample with HNO 3 (Nitric Acid) Dilute with 2M ammonium acetate to pH of 5.5 Atomize sample Procedure Possible Interferences Other resonant lines Sample Matrix Combustion Products Low volatility components Dissociation equilibria Ionization equilibria

Atomic Absorption Spectroscopy 9

Equipment Used 10 WFX-210 AAS Spectrometer LOD ≤ 6 µg/L LOQ ≈ 1 µg/L Precision ≤ 3% for Cd Flame & Graphite Furnace atomizer Wavelength Range: nm Photomultiplier Tube (PMT) Autosampler built-in

Conclusion Based on experiments done outside the U.S., the use of AAS for analysis of Cd in the blood appears to be a sound and common choice. Higher levels of Cd are expected to be found in people living closer to the chosen industrial plants. However, the amounts are still expected to be in the µg/L range. A few trial runs could be attempted using pure blood samples to test the necessity of sample preparation for the experiment. 11

References 1.Center for Disease Control: Agency for Toxic Substances & Disease Registry Crouch, Stanley R.; Holler, F. James; Skoog, Douglas A. Principles of Insrumental Analysis, 6th ed.; Brooks/Cole: Belmont, CA, Energy Research Centre of the Netherlands Environmental Protection Agency. Technology Transfer Network: Air Toxics Web Site Qualitest International Inc.: Atomic Absorption Spectrophotometers Weston, Andrea; Brown, Phyllis R.; Jandik, Pter; Jones, william R.; Heckenberg, Allan L. Factors affecting the separation of inorganic metal cations by capillary electrophoresis. Journal of Chromatography 1992, 593, NSF International. NSF International Web Site The Physical and Theoretical Chemistry Laboratory Oxford University. Chemical and Other Safety Information. 12