Chemical Education Today
Research Advances: Addressing the Environmental Fates of Everyday Products from Cigarette Butts to Shampoos and Cleaning Agents by Angela G. King Department of Chemistry, Wake Forest University, Winston-Salem, North Carolina 27109, United States
[email protected] Recycling “Tiny Trash”: Cigarette Butts A new study suggests expanding community recycling programs beyond newspapers, beverage containers, and other conventional trash to include an unlikely new potential treasure: cigarette butts (1). Terming this tiny trash “one of the most ubiquitous forms of garbage in the world”, the study describes discovery of a way to reuse the remains of cigarettes to prevent steel corrosion that costs oil producers millions of dollars annually. Jun Zhao and colleagues cite one estimate that 4.5 trillion cigarette butts find their way into the environment each year. Studies show that cigarette butts are more than an eyesore. They contain toxins that can kill fish and harm the environment in other ways. Recycling could solve those problems, but finding practical uses for cigarette butts has been difficult. The scientists showed that extracts of cigarette butts in water, aged for 24 h before being applied to a type of steel (N80) widely used in the oil industry, protected the steel from rusting even under the harsh conditions (90 °C in hydrochloric acid). Inhibition efficiencies were determined by measuring weight loss of the steel and electrochemical techniques such as potentiodynamic polarization and impedance. Through use of LC-MS, the scientists identified nine chemicals in the extracts, including nicotine, which appear to be responsible for this anticorrosion effect. This current research ties in well with a previously published student experiments on corrosion inhibition of metals (2, 3), the design of corrosion inhibitors (4), and application of corrosion science to antique preservation (5, 6). Household Detergents, Shampoos May Form Harmful Substance in Wastewater Scientists at Yale University are reporting evidence that certain ingredients in shampoo, detergents, and other household cleaning agents may be a source of precursor materials for the formation of nitrosamines, suspected cancer-causing contaminants in water supplies that receive water from sewage treatment plants (7). The study sheds new light on possible environmental sources of this poorly understood water contaminant, which is of ongoing concern to health officials. William Mitch and colleagues note that scientists have known that N-nitrosodimethylamine (NDMA) and other nitrosamines can form in small amounts during the disinfection of wastewater and water with chloramine. Although nitrosamines are found in a wide variety of sources, including processed meats and tobacco smoke, scientists
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Journal of Chemical Education
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know little about their precursors in water. Past studies with cosmetics have found that quaternary amines, which are common ingredients in household cleaning agents, may play a role in the formation of nitrosamines. The team used a nitrosamine formation potential test to evaluate the tendency of various quaternary amines to serve as nitrosamine precursors using GC-MS and HPLC-MS in standards methods previously established. In agreement with previous results, they found that the presence of benzyl substituents increased the formation of nitrosamines. Employing the same nitrosamine formation potential test, their laboratory research also showed that, when mixed with chloramine, some household cleaning products, including shampoo, dishwashing detergent, and laundry detergent, formed NDMA. The report notes that sewage treatment plants may remove some of quaternary amines that form NDMA through sedimentation. However, quaternary amines are used in such large quantities that some still may persist and have a potentially harmful effect in the effluents from sewage treatment plants. More information on Mitch's research is available online (8). This Journal has previously published background material on the formation of nitrosamines in the digestive process (9), the transformation of normal cells into cancer cells through exposure to chemical carcinogens (10), and the danger of natural carcinogens such as N-nitrosamines (11). Literature Cited 1. Zhao, J.; Zhang, N.; Qu, C.; Wu, X.; Zhang, J.; Zhang, X. Cigarette Butts and Their Application in Corrosion Inhibition for N80 Steel at 90 °C in a Hydrochloric Acid Solution. Ind. Eng. Chem. Res. 2010, 49, 3986–3991. 2. Onuchukwu, A. J. Chem. Educ. 1989, 66, 681–682. 3. Muller, B. J. Chem. Educ. 1995, 72, 350–351. 4. Walters, F. J. Chem. Educ. 1991, 68, 29–31. 5. Walker, R. J. Chem. Educ. 1982, 59, 943–947. 6. Walker, R. J. Chem. Educ. 1980, 57, 789–791. 7. Kemper, J.; Walse, S.; Mitch, W. Quaternary Amines As Nitrosamine Precursors: A Role for Consumer Products? Environ. Sci. Technol. 2010, 44, 1224–1231. 8. The Mitch Laboratory Home Page: Organic Chemistry at the Nexus. http://www.eng.yale.edu/wmlab/ (accessed Oct 2010). 9. Wishnok, J. J. Chem. Educ. 1977, 54, 440–442. 10. Rademacher, P. J. Chem. Educ. 1976, 53, 757–761. 11. Monroe, D. J. Chem. Educ. 1982, 59, 80.
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Vol. 88 No. 1 January 2011 pubs.acs.org/jchemeduc r 2010 American Chemical Society and Division of Chemical Education, Inc. 10.1021/ed100996k Published on Web 11/02/2010
