• Jang, Yong-Chul (Department of Environmental Engineering, Chungnam National University) ;
  • Townsend, Timothy G. (Department of Environmental Engineering, Sciences, University of Florida)
  • Published : 2006.02.28


The proper management of discarded electronic devices (often called electronic-waste) is an emerging issue for solid waste professionals throughout the world because of the large growth of the waste stream, and the content of toxic metals in them, most notably heavy metals such as lead. Notebook computers are becoming one of the major components of discarded computer devices and will continue to increase in the waste stream in the future. While the computers hold great promise for recycling, a substantial amount of this waste is often disposed in municipal solid waste (MSW) landfills. The toxicity characteristic leaching procedure (TCLP) is commonly used to simulate worse case leaching conditions where a potentially hazardous waste is assumed to be disposed along with municipal solid waste in a landfill with actively decomposing materials overlying an aquifer. The objective of this study was to examine leaching potential of lead from discarded notebook computers using the scale-up TCLP, other standard leaching tests such as California waste extraction test (Cal WET), and the synthetic precipitation leaching procedure (SPLP) and actual landfill leachates as leaching solution. The scale-up TCLP is a modified TCLP (where the device was disassembled and leached in or near entirety) to meet the intent of the TCLP. The results showed that the scale-up TCLP resulted in relatively high lead found in the leachate with an average of 23.3 mg/L. The average level was less than those by the standard TCLP and WET (37.0 mg/L and 86.0 mg/L, respectively), but much greater than those by the SPLP and the extractions with the landfill leachates (0.55 mg/L and 1.47 mg/L, respectively). The pH of the leaching solution and the ability of the organic acids in the TCLP and WET to complex with the lead were identified as major factors that controlled the amount of lead leached from notebook computers. Based on the results obtained by a number of leaching tests in this study, notebook computers may present a potential leaching risk to the environment and human health upon land disposal. However, further investigation is still needed to assess the true risk posed by the land disposal of discarded notebook computers.


  1. Macauley, M., Palmer, K., and Shih, J., 'Dealing with electronic waste: modeling the costs and environmental benefits of computer monitor disposal,' J. Env. Man. 68(1), 13-22 (2003)
  2. U.S. EPA. WasteWise Update, EPA530-N-00-007, Solid Waste and Emergency Response, Washington DC (2000)
  3. National Safety Council, Electronic Product Recovery and Recycling Baseline Report, National Safety Council's Environmental Health Center, Washington, DC (1999)
  4. ENVIROSRIS, Options for Recovery of End-of Life IT Equipment Waste in Canada, Final Report submitted to Information Technology Association of Canada, (2001)
  5. Calver, J. The life cycle of a CPU; (2005)
  6. Waldron, H. A. Metals in the environment, Academic Press, Inc. New York, NY (1980)
  7. Gosselin, R. E., Smith, R. P., and Hodge, H. C., Clinical Toxicology of Commercial Products, 5th ed., Williams and Wilkins, Baltimore, MD (1984)
  8. Sittig, M., Handbook of Toxic and Hazardous Chemicals and Carcinogens, 2nd ed. Noyes Data Corporation, Park Ridge, NJ (1985)
  9. Musson, S., Jang, Y., Townsend, T., and Chung, I. 'Characterization of Lead Leachability From Cathode Ray Tubes Using The Toxicity Characteristic Leaching Procedure,' Environ. Sci. Technol. 34(20), 4376-4381 (2000)
  10. U.S. EPA, Federal Register, 40 CFR Part 260. Part IV. Washington DC (2002)
  11. Federal Register, Toxicity Characteristics Leaching Procedure, November 7, 51: 216 (1986)
  12. California Code of Regulations, California Waste Extraction Test, Title 22, Division 30, California Register 85, no 2: 1800, 78-1800.82, (1985)
  13. U.S. EPA. Test Methods for Evaluating Solid Waste, SW-846, 3rd Ed.; Office of Solid Waste: Washington, DC (1996)
  14. Hopper, K., Iskander, M., Sivia, G., Hussein, F., Hsu, J., Deguzman, M., Odion, Z., Ilejay, Z., Sy, F., Petreas, M., and Simmons, B., 'Toxicity Characteristic Leaching Procedure Fails to Extract Oxoanion-Forming Elements that are Extracted by Municipal Solid WasteLeachates ,' Environ. Sci. Technol. 32 (23), 3825-3830 (1998)
  15. Halim, C., Amal, R., Natawardaya, H., Beydoun, D., and Scott, J., 'Comparison of Leaching of Pb(II), Cd(II), As(V), and Cr(VI) from Cementitious Wastes Using Acetic Acid and Landfill Leachates, The 18th International Solid Waste Technology Conference, Philadelphia, USA, 23-26 March, pp. 461-470 (2003)
  16. Jang, Y. and Townsend, T., 'Leaching of Lead from Computer Printed Wire Boards and Cathode Ray Tubes by Municipal Solid Waste Landfill Leachates,' Environ. Sci. Technol. 37(20), 4778-4784 (2003)
  17. Yang, G. C., ' Environmental Threats of Discarded Picture Tubes and Printed Circuit Boards,' J. Haz. Mater. 34(2), 235-243 (1993)
  18. Townsend, T., Vann., K., Mutha, S., Pearson, B., Jang, Y., and Musson, S., RCRA toxicity characterization of computer CPUs and other discarded electronic devices, Research Report Submitted to US EPA Region 4 and Region 5 (2004)
  19. Farquhar, G. 'Leachate Production and Characterization,' Can. J Civ. Eng., 16, 317-325 (1989)
  20. Tchobanoglous, G., Theisen, H., and Vigil, S., Integrated Solid Waste Management, 1st Ed., McGraw-Hill Inc., New York. NY (1993)
  21. McBean, E. A., Rovers, F. A., and Farquhar, G. J., Solid Waste Landfill Engineering and Design, Prentice Hall, Englewood Cliffs, NJ. (1995)
  22. Bagchi, A. 'Natural attenuation mechanisms of landfill leachate and effects of various factors on the mechanisms,' Waste Manage. Res. 5, 453-463 (1987)
  23. Lagier, T., Feuillade-Cathalifaud, G., and Matejka, G., 'Fate of heavy metals trapped in landfill under sulphur species: effects of oxidant and complexant macromolecules,' in Proceeding 7th International Waste Management, and Landfill Symposium. S. Margherita di Pula, Cagliari, Italy 4-8 Oct. pp 207-212. (1999)
  24. van der Sloot, H. A. Waste Materials in Construction; Goumans, J., van der Sloot, H., and Aalbers, T. (Eds.); Elsevier, Amsterdam, The Netherlands, pp. 19-36 (1991)
  25. Eighmy, T., Eusden, D., Krzanowski, J., Domingo, D., Stampfli, D., Martine, J., and Erickson, P., 'Comprehensive Approach toward Understanding Element Speciation and Leaching Behavior in Municipal Solid Waste Incineration Electrostatic Precipitator Ash,' Environ. Sci. Technol. 29(3), 629-646 (1995)
  26. Groot, G. and van der Sloot, H., Determination of leaching characteristics of waste materials loading to environmental product certification. Stabilization and solidification of hazardous, radioactive, and mixed wastes, 2nd volume, STP 1123, Gilliam, G. and Wiles, C. eds.; American Society for Testing and Materials, Philadelphia, pp. 149-170 (1992)
  27. van der Sloot, H. A., Heasman, L., and Quevauviller, Ph., Harmonization of Leaching/Extraction Tests, Elsevier, Amsterdam, The Netherlands (1997)
  28. Lee, D. J. 'Performance of pH Static Leaching Test for Evaluating Leachability of Solidified Waste Forms,' Environ. Eng. Res. 9(5), 223-230 (2004)
  29. Lee, D. J. 'pH Effects on Leachability of Pb-doped Solidified Waste Forms using Portland Cement and Calcite,' Environ. Eng. Res. 9(5), 231-237 (2004)
  30. Flyhammar, P. and Hakansson, K., 'The mobilization of heavy metals in partly stabilizedMSW during oxidation, ' In Proceedings Sardinia 99, Seventh International Landfill Symposium S. Margherita di Pula, Caliari, Italy, 4-8 October, pp. 213-218 (1999)
  31. Kjeldsen, P., Barlaz, M., Rooker, A., Baun, A., Ledin, A., and Christensen, T., 'Present and Long-Term Composition of MSW Landfill Leachate: A Review,' Crit. Rew. Environ. Sci. Technol. summer, 32(4) 297-336 (2002)
  32. Gould, J. P., Pohland, F. G., and Cross, W. H., 'Mobilization and retention of mercury and lead from particulates co-disposed with municipal solid wastes,' Particulate Science and Technology, 6, 381-392 (1998)
  33. Clevenger, T. and Rao, D., 'Mobility of lead in mine tailings due to landfill leachate,' Water, Air, and Soil Pollution. 91, 197-207 (1996)
  34. Janusa, M., Bourgeois, J., Heard, G., Kliebert, N., and Landry, A., 'Effects of Particle Size and Contact Time on the Reliability of Toxicity Characteristic Leaching Procedure for Solidified/Stabilized Waste,' Microchem. Jour. 59(2),326-332 (1998)
  35. Stumm, W. and Morgan, J., Aquatic Chemistry, Wiley, New York (1996)
  36. Lackovic, J., Nikolaidis, N., Chheda, P., Carley, R., and Patton, E., 'Evaluation of Batch Leaching Procedures for Estimating Metal Mobility in Glaciated Soils,' Ground Water Monitoring and Remediation 17, 231-240 (1997)