degrades it approaches its stable isotope of lead. The lead that is present in the ceramic

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1 Proposal #1 Abstract: Uranium was used as a colorant for ceramic dinnerware up until the 1940 s. As Uranium degrades it approaches its stable isotope of lead. The lead that is present in the ceramic glazes of the dinnerware may be leached out of the glaze into an acidic solution if given enough time. These ceramic dishes may be being used by families on an everyday basis. The FDA has set forth guidelines as to how much lead can be leached into an acidic solution and still be safe. This study is to determine the amount of lead that is leached out of Fiesta Ware bowls which are known to have used uranium glazes. We will let 4% acetic acid sit in the dinnerware for twenty four hours and then test the amount of lead leached using flame atomic absorption spectrometry and comparing it to a known dilution standard. Once the amount of lead in the solution has been determined a conclusion can be made about the safety of the Fiesta Ware dinnerware. Introduction: Lead and uranium have been used in coloring glasses and dinnerware since the 1830 s. Uranium as a colorant was used up until 1943 when the U.S. government restricted its uses and it was no longer available for non military purposes 1. Around this time people also began to understand more of its health risks and dangers. Uranium s most common two isotopes are 235 and 238. The uranium will decompose at a steady rate until it becomes lead 206 or 207. The lead in the glaze of the ceramic dinnerware can be leached into an acidic solution if it is left in there long enough. According to the AOAC s official method of extracting lead from ceramic ware, a 4% acetic acid solution left in a lead

2 containing bowl for twenty four hours can contain toxic amounts of lead. The amount of lead leached into the bowl depends on the amount of lead that was originally in the bowl. The U.S. Food and Drug Administration have set standards as to how much lead can leach out of an item and still be considered safe. Cups and mugs need to leach out less than 0.5 ppm lead while small hallow ware such as bowls need to leach out less than 2.0ppm. Plates have a higher allowance for lead leaching of 3.0ppm. 2 Lead poisoning in humans can become irreversible and sometimes fatal. Children absorb lead at rates much higher than adult. Children can absorb 30 to 75% of the lead they consume while adults will only absorb about 11% 3. The effects of lead poisoning can range from high blood pressure to memory loss and impairment of motor skills. Signs of lead poisoning are usually difficult to detect and do not appear until irreversible damage has already been done. It is believed that the dishes in the chemistry lab in the Natural Sciences building contain lead in their glazes that may be leached out into acidic food. These bowls were produced in the 1930 s by a manufacturer know to use uranium glazes. The objective of this study is to determine the amount of lead that is leached out by these bowls. Once the amount of lead leached has been determined then a conclusion can be drawn about the safety of these bowls. Justification: This experiment should be run because many people may still use this lead leaching dinnerware on a daily basis. It is important to know if families are at risk of lead poisoning. Being able to determine the amount of lead that is being leached out of these

3 ceramics can also cut down on the guesswork of the consumers. Products exist that can determine if lead is present, but the ability to determine the amount of lead present is far more useful. In order to obtain a useful result a proven testing method needs to be used. The AOAC s official method for extracting Lead and Cadmium from ceramicware has been cited by several sources as the procedure used in their experiments. This methodology also states that Flame Atomic Absorption Spectrometry (FAAS) is sufficient for analyzing leach solutions that contain more than 1ppm Lead in Acetic Acid. The FAAS is a common instrument that can provide accurate and reproducible results. The instrument is also easy to use and readily accessible. There is a FAAS located in room 114 of the Natural Sciences building. There will be practically no charge to run the instrument and the entire study can be run in the length of one class period. The solution used to leach the lead from the glaze is simply 4% acetic acid. The acetic acid may easily be prepared by diluting Glacial acetic acid if a prepared solution does not already exist. 4% acetic acid is also white vinegar. The scientists that will be running these tests are well qualified and contain prior experience working with the FAAS. Two previous chemistry classes have already introduced the instrument and explained how to run it. The previous classes have also already explained the delicate process of making standards for calibration curve dilutions. Materials and Methods (AOAC official method Lead and Cadmium Extracted from Ceramicware) 4 Apparatus:

4 Buck Scientific 200A Atomic Absorption Spectrophotometer. Equipped with a light source specific to Lead, instrumental background correction, a 4-in. single slot or boiling burner head, digital concentration readout may be used. Use air-acetylene flame, instrumental background correction, and operating conditions recommended by the manufacturer. Measure Lead at 217 or 283.3nm. Using these conditions, characteristic concentration should be 0.1 and 0.2 ppm of lead measured at and 283.3nm, respectively. Laboratory beakers, flasks, stirring rods should be used. Use chemically resistant plastic, borosilicate glass, quartz or Teflon. Clean by rinsing with dilute nitric acid (1+10) followed by copious amounts of water. Reagents: 4% Acetic Acid- dilute 4mL of glacial acetic acid to 100mL with water. Or use vinegar. Detergent wash: use household dish cleaner. Lead standard solutions: (1) Stock solution (1000ppm): dissolve g Pb(NO3) in 4% acetic acid and dilute to 1L with same solution. (2) Working Solutions: Dilute 0.0, 1.0, 2.0, 3.0, 5.0 and 10.0 ml stock solution to 1L with 4% acetic acid (0, 1, 2, 3, 5, and 10 ppm). (3) Independent check solution- prepare an independent stock solution starting with a different source of Pb(NO3). Prepare it containing 5ppm of Lead. Extraction: Fill the item to be tested with 4% acetic acid until the dinnerware is about 5 to 6 cm from the rim. Let the acetic acid soak in the bowl for twenty four hours at 22±2 C. leave the container covered and do not allow the cover to come in contact with the acetic acid.

5 Testing: Aspirate the blank solution that contains only the acetic acid into the instrument and zero it. Run the known standards three times each making sure to run the blank standard in between every sample. Record the absorbance of each one and plot it on a graph. Run the leach solution three times with the blank standard in between every one. Plot the results on the same graph and determine the amount of lead that has leached from the ceramic glaze. Literature Review: Several Articles were reviewed to find a suitable method for analyzing the lead solutions. Many of them included references to the Association of Official Agricultural Chemists (AOAC) official method. The AOAC s official method fits the situation perfectly. Their method uses an instrument that this laboratory already possesses, and the steps are clearly outlined. Because this method has already been used and positive results have been obtained then the method itself can not be questioned as a source of faulty information. The only thing that may differ in this study is the quality of the available FAAS. If it is not as sensitive as the FAAS used in the other studies then our limit of detection may not be as low. The limit of detection can be easily figured out as the calibration curve is being run. The international lead management center has a handbook about lead glazes for ceramic food ware. It is over two hundred pages long and starts with the history of lead in food ware and covers the different ways of making lead glazes and then provides methods for

6 detecting lead. This handbook is one of the many that suggested using 4% Acetic Acid and FAAS 5. Publications from the FDA were also used to find background information on the effects of lead on people and possible safety precautions. An article written by Donna Strahan was very informative on the background of the Fiesta Ware plates and how they were manufactured. It also included information about the use of uranium in glazes in the time period that the dinnerware was produced. Budget & Timeline: The laboratory already contains the most expensive part of this experiment so the cost to the school will be almost nothing. The acetic acid used in the experiment can either be purchased as a 4% solution or it can be easily diluted using glacial acetic acid. The dilution equation is already set forth in the methods so no time will be needed to make calculations. The amount of time needed to run the experiment should not be more than one class period. The standards will need to be mixed and the dilutions made for the calibration curve, and then ran. That should take the class an hour and a half at most. Then the unknown leach solution will need to be run and then the amount of lead in solution can be determined. Because everyone in the class is familiar with the techniques required to run the instrument and make the appropriate dilutions this experiment should go over very smoothly.

7 References: 1 Strahan, D. (2001). Uranium in Glass, Glazes and Enamels: Histoy, Identification and Handling [Electronic version]. Studies in Conservation, 46(3), Sec Pottery (Ceramics); Imported and Domestic - Lead Contamination (CPG ). (2005). Retrieved January 26, 2008, from vivismo database: 3 Farley, D. (1998, January/February). Dangers of Lead Sill Linger. FDA Consumer. Retrieved from 4 AOAC Offical Method Lead and Cadmium Extracted from Ceramicware. (1996). In Association of Official Agricultural Chemistry (pp. Ch 9 pages 6-6a). 5 Lead Glazes for Ceramic Foodware An ILMC Handbook. (n.d.). 6 Gonzalez-Soto, E., Gonzalaz-Rodriguez, V., Lopez-Suarez, C., Castro-Romero, J., Perez-Iglesias, J., & Fernandez-Solis, J. (2000). Migration of Lead and Cadmium from Ceramic Materials Used in Food Preparation [Electronic version]. Bulletin of Environmental Contamination and Toxicology, 65, Tan, Q., Wu, P., Wu, L., & Hou, X. (2006, March). Sensitive Determination of Lead by Flame Atomic Absorption Spectrometry Improved with Branched Capillary as Hydride Generator and Without Phase Seperation. Microchimica Acta, 155, Tong, S., Von Schirnding, Y. E., & Prapamontol, T. (2000). Environmental Lead Exposure: A Public Health Problem of Global Dimensions [Electronic version]. Bulletin of the World Health Organization, 78(9).