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Research Highlights
Fighting Pinhole Leaks In Copper Water LinesPodcastsListen to or download the podcast to learn more about how NRMRL research helps to support the protection of human health and the environment.   Pinhole leaks in copper water lines are a major concern to both homeowners and drinking water utilities because of the high cost of residential line repairs and the waste of water resources from undetected leaks in service lines. Because copper pipe corrosion remains poorly understood, EPA supports ongoing research toward remedying the problem. As part of this effort, scientists at the National Risk Management Research Laboratory (NRMRL) have recently identified certain water chemistry combinations that are potentially involved in the growth of pitting corrosion in copper pipes—and potentially useful to water utilities for predicting the effect of water treatment on pitting corrosion. Background
Corrosion in copper pipe
Copper is the most widely used material for domestic water supply systems because it is relatively inexpensive and easy to use, abundant in nature, and is resistant to permeation by liquids and gasses. Since 1963, over 5.3 million miles of copper plumbing pipe have been installed in about 80 percent of all U.S. buildings. In spite of excellent resistance, copper can be vulnerable to pitting corrosion, and thus, to pinhole leaks. The consequences may be very costly. Pinhole leaks in internal pipes may go undetected for long periods in walls or basements, setting up conditions for mold and mildew to flourish. Leaks may be hard to locate and repair, and may result in higher insurance premiums for homeowners. They are also, of course, a waste of valuable water resources. Researchers have long known that water chemistry plays a key role in the corrosion and pitting of copper pipes, but research results have not been uniform or conclusive. There have been cases of copper pitting in waters having high pH, low alkalinity, and significant levels of sulfate and chloride. In other cases, aluminum, silica, and other materials have been implicated as the cause of pitting corrosion. The objective of the NRMRL water chemistry study was to systematically investigate the effect of pH, sulfate, alkalinity (inorganic carbon), and orthophosphate on the nature of copper corrosion—localized and uniform. Pilot-scale research was conducted using a re-circulating water pipe system located in EPA’s Andrew W. Breidenbach Environmental Research Center in Cincinnati. The system was patterned after previous water chemistry studies for other types of pipe such as asbestos-cement and galvanized iron, with key modifications for the copper pipe research. Water analyses were performed every two or three weeks to ensure consistency in water quality. In all, 43 experimental runs were completed over several years to evaluate the effect of water chemistry on copper solubility and uniform and localized corrosion. At the completion of the exposure period, various analytical techniques were used to evaluate corrosion effects, including X-ray diffraction and scanning electron microscopy. Research Results to Date
Implications for Water UtilitiesThe results of the study provide supporting evidence to suggest that water utilities can construct relatively simple pilot-scale studies to investigate the tendency of their water to induce pitting, and to predict the effect of water treatment. The water quality results of this research show that pitting can be initiated without silica, aluminum, organic carbon, or other variables that have been suggested as being important in pitting or frequently associated with copper plumbing that has failed from pitting corrosion. The paper describing this research recently won the 2009 American Water Works Science & Research Division Best Paper Award. (See Lytle, D.A. and M.R. Schock. (March 2008) “Pitting Corrosion of Copper in High pH and Low Alkalinity Waters.” Journal of the AWWA, 100(3):115–128. For a summary of the paper, see report summary. Continued research on this study supports NRMRL’s Aging Water Infrastructure Research Program. ContactJane Ice, NRMRL Office of Public Affairs (513) 569-7311
Hot Off the Presses—NRMRL PublicationsJournal Articles Baldauf, R.W., T.A. Cahill, C. Bailey, A. Khlystov, K.M. Zang, R. Cook, C. Cowherd, and G.E. Bowker. (2009) “Can Roadway Design be Used to Mitigate Air Quality Impacts From Traffic?” EM: Air and Waste Management Association Magazine. Air & Waste Management Association, Pittsburgh, PA, (8):1–5. Baruwati, B., V. Polshettiwar, and R.S. Varma. (2009) “Magnetically Recoverable Supported Ruthenium Catalyst for Hydrogenation of Alkynes and Transfer Hydrogenation of Carbonyl Compounds.” Tetrahedron Letters. Elsevier Science Ltd, New York, NY, 50(11):1215–1218. Fitzpatrick, F.A., J.C. Knox, and J.P. Schubauer-Berigan. (2009) “Channel, Floodplain, and Wetland Responses to Floods and Overbank Sedimentation, 1846–2006, Halfway Creek Marsh, Upper Mississippi Valley, Wisconsin.” Geological Society of America Special Papers. Geological Society of America, Boulder CO, 451:23–42. Genaidy, A.M., R. Sequeira, T.M. Tolaymat, J. Kohler, and M. Rinder. (2009) “Evidence-Based Integrated Environmental Solutions for Secondary Lead Smelters: Pollution Prevention and Waste Minimization Technologies and Practices.” Science of the Total Environment. Elsevier BV, Amsterdam, Netherlands, 407(10):3239–3268. Hutson, N.D., S.P. Ryan, and A. Touati. (2009) “Assessment of PCDD/F and PBDD/F Emissions from Coal-Fired Power Plants During Injection of Brominated Activated Carbon for Mercury Control.” Atmospheric Environment. Elsevier Science, Ltd, New York, NY, 43(26):3973–3980. Hering, J.G., P.A. O'Day, R.G. Ford, Y.T. He, A. Bilgin, H.J. Reisinger, and R. Burris. (2009) “MNA as a Remedy for Arsenic Mobilized by Anthropogenic Inputs of Organic Carbon.” Ground Water Monitoring and Remediation. National Ground Water Association, Westerville, OH, 29(3):84–92. Kimbrough, E.S., D.A. Vallero, R.C. Shores, A.F. Vette, K. Black, and V. Martinez. (2008) “Multi-Criteria Decision Analysis for the Selection of a Near-Road Ambient Air Monitoring Site for the Measurement of Mobile Source Air Toxics.” Transportation Research Part D. Elsevier Science BV, Amsterdam, Netherlands, 13(8):505–515. Lee, J., K. Cho, L. Cheng, T.C. Keener, G. Jegadeesan, and S.R. Al-Abed. (2009) “Investigation of a Mercury Speciation Technique for Flue Gas Desulfurization Materials.” Journal of Air and Waste Management. Air & Waste Management Association, Pittsburgh, PA, 59(8):972–979. Menetrez, M.Y. (2009) “Antimicrobial Treatments of Indoor Mold and Bacteria. Chapter 6, Fungicides.” Chemistry, Environmental Impact and Health Effects. Nova Science Publishers, Inc., Hauppauge, NY, 167–186. Meyer, D.E., M.A. Curran, and M. Gonzalez. (2009) “An Examination of Existing Data for the Industrial Manufacture and Use of Nanocomponents and Their Role in the Life Cycle Impact of Nanoproducts.” Environmental Science and Technology. John Wiley & Sons, Ltd., Indianapolis, IN, 43(5):1256–1263. Nadagouda, M.N. and R.S. Varma. (2009) “Silver Trees: Chemistry on a TEM Grid” Australian Journal of Chemistry. CSIRO Publishing, Collingwood Victoria, Australia, 62(3):260–264. Polshettiwar, V. and R.S. Varma. (2009) “Nanoparticle-Supported and Magnetically Recoverable Palladium (Pd) Catalyst: A Selective and Sustainable Oxidation Protocol With High Turnover Number.” Organic & Biomolecular Chemistry. RSC Publishing, Cambridge, UK, 7(1):37–40. Polshettiwar, V., B. Baruwati, and R.S. Varma. (2009) “Magnetic Nanoparticle-Supported Glutathione: A Conceptually Sustainable Organocatalyst.” Chemical Communications. Royal Society of Chemistry, Cambridge, UK, (14):1837–1839. Senior, C.L., S. Thornloe, and B. Khan. (2009) “The Fate of Mercury Collected From Air Pollution Control Devices.” EM: Air and Waste Managemen Association Magazine. Air & Waste Management Association, Pittsburgh, PA, (7):15–21. Taulbee, W.K., C.T. Nietch, D. Brown, B. Ramakrishnan, and M.J. Tompkins. (2009) “Ecosystem Consequences of Contrasting Flow Regimes in an Urban Effects Stream Mesocosm Study.” Journal of the American Water Resources Association. American Water Resources Association, Middleburg, VA, 45(4):907–927. Conference Proceedings Grayman, W.M. (2009) “Environmental and Developmental Risks and Stressors Impacting a 2050 Vision.” In Proceedings World Environmental and Water Resources Congress 2009: Great Rivers, Kansas City, MO, May 17–21, 2009. American Society of Civil Engineers (ASCE), Reston, VA, CD:CD. Kimbrough, E.S., A.F. Vette, R.C. Shores, R.W. Baldauf, D.A. Whitaker, C.W. Croghan, D.A. Vallero, K.N. Black, and V. Martinez. (2009) “The National Near-Road Mobile Source Air Toxics Study.” In Proceedings AWMA's 102nd Annual Conference & Exhibition, Detroit, MI, June 16–19, 2009. AWMA, Pittsburgh, PA. U.S. EPA. (2009) Schenck, K.M. “Proceedings of Japan–United States Joint Conference on Drinking Water Quality Management and Wastewater Control." Las Vegas, NV, March 2–5, 2009. (EPA/600/R-09/047). Meckes, M.C. (2009) “Development of Microbial Assays for Municipal Sludge.” In Proceedings Disinfection 2009 Conference, Atlanta, GA, February 28–March 3, 2009. Water Environment Federation, Alexandria, VA, Session 2. Miller, C.A. (2009) “Environmental Impacts of Biofuel Production and Use.” In Proceedings 238th ACS National Meeting & Exposition, Washington, DC, August 16–20, 2009. American Chemical Society, Washington, DC. Perrault, E.M., L. Pereyra, S. Hiibel, A. Pruden, K.F. Reardon, and D.J. Reisman. (2009) “Response and Recovery of Sulfate-Reducing Biochemical Reactors From Aerobic Stress Event.” In Proceedings 2009 National Meeting of the American Society of Mining and Reclamation, Revitalizing the Environment: Proven Solutions and Innovative Approaches, Billings, MT, May 30–June 5, 2009. American Society of Mining and Reclamation, Lexington, KY, 12 of 16. Smart, P., D.J. Reisman, S. Odell, S. Forrest, K. Ford, and T. Tsukamoto. (2009) “Rotating Cylinder Treatment System Demonstration.” In Proceedings 2009 National Meeting of the American Society of Mining and Reclamation, Revitalizing the Environment: Proven Solutions and Innovative Approaches, Billings, MT, May 30–June 5, 2009. American Society of Mining and Reclamation, Lexington, KY, 76. EPA Published Reports U.S. EPA. (2009) Argus, R., M. Bittens, K. Black, S. Bock, T. DeSantis, U. Ferber, R. Gessler, V.E. Hansen, M. Hauschild, L. Holstenkamp, L. Llan, V. Ketellapper, H. Klein, D. Kooris, M. Lampert, S. McMillen, D. MacCourt, S. Martin, P. Meyer, G. Penn-Bressel, G. Riley, C. Sabedra, R. Schwarze, S. Soler, S. Thiel, A.M. Vega, A, L. Wray, S. Bartke, M. Finkel, A. Rein, and H. Ruegner. “Regional Approach and Tools for Sustainable Revitalization, Documentation of a Workshop of the U.S.-German Bilateral Working Group, May 8 and 9, 2008, New York, New York.” U.S. EPA. (2009) Bless, D.R. and M. Mansfield. “Regional Applied Research Effort Project (RARE) with Region 8 – Beneficial Use of Red and Brown Mud and Phosphogypsum as Alternative Construction Materials.” (EPA/600/R-09/062). U.S. EPA. (2009) Field, R.I., D.J. Murray, M.D. Royer, and A.N. Tafuri. “Innovation and Research for Water Infrastructure for the 21st Century Research Plan.” (EPA/600/X-09/003). U.S. EPA. (2009) “RTI International. Environmental Technology Verification: Test Report of Mobile Source Emission Control Devices – Johnson Matthey PCRT2 1000, Version 2, Filter + Diesel Oxidation Catalyst” (EPA/600/R-09/034). U.S. EPA. (2009) Yang, Y.J. “First National Expert and Stakeholder Workshop on Water Infrastructure Sustainability and Adaptation to Climate Change.” (EPA/600/R-09/010). 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