June 28, 2015
Cigarettes kick butt in mosquito control
What happens to the 6 trillion cigarettes smoked around the world every year? About two-thirds of them end up tossed into the environment. Besides being non-biodegradable, smoked cigarette butts contain 7,000 chemicals, including at least 69 known cancer-causers and many others that are poisonous (American Lung Association). One study reports that a single cigarette butt soaked in 1 liter of water for 96 hours leaches out enough toxins to kill half of the fish exposed to them.
But something else happens when used cigarette butts are soaked in water: They attract egg-laying mosquitoes. Studies show that female mosquitoes actually prefer the tainted ponds to plain water (Mondal et al., 2014). In fact, egg-laying activity increased steadily as cigarette butts steeped in water over 10 days (Dieng et al., 2011). Although hatching rates were the same in both environments, larvae that emerged in the butt-infused habitat did not fare well. They had a much lower survival rate, and those that survived had a shorter lifespan as adults (Dieng et al., 2013).
This is particularly interesting since mosquitoes cause more than 1 million human deaths around the world each year from diseases like dengue fever, malaria, yellow fever, and West Nile virus. Every June, the American Mosquito Control Association designates a National Mosquito Control Awareness Week to call attention to the major public health threat posed by mosquitoes. The World Health Organization estimates that half the world’s population is at risk of dengue fever, a widespread mosquito-borne disease that has increased dramatically across the globe in the past few decades. There is no known treatment for the dengue virus, so prevention and control of this and other mosquito-borne illnesses largely relies on controlling the vector, or source of transmission.
Our recently published module Carlos J. Finlay and Eradicating Yellow Fever profiles the Cuban scientist and medical doctor who in 1865 was the first person to propose that mosquitoes were responsible for transmitting tropical diseases. While attempting to forge a path through Panama to connect the Atlantic and the Pacific Oceans—initially by railway and ultimately via a canal system—34,000 workers died, mostly from tropical diseases. Finlay persevered in spite of being ridiculed for his claim that mosquitoes were vectors of disease, gathering evidence for decades until the scientific community finally accepted his hypothesis. Only then did public health efforts begin to focus to controlling mosquitoes, and the Panama Canal could at last be completed.
Urban birds are already in the know, and have adapted their behavior to take advantage of human carelessness. Wild birds have long been known to line their nests with plants that repel parasites. City birds mimic this behavior, weaving pieces of cellulose acetate from used filters into their nests. Researchers at the Universidad Autónoma de Mexico found that the more smoked filter material there was in the nests, the fewer the parasites. In addition to the insecticide properties of smoked butts, the fluffy plastic in the filters provides structure, warmth, and comfort. But not all cigarette filters are created equal: They must be smoked for optimum pest control; unsmoked filters are less effective in repelling parasites.
In an effort to preserve the environment, humans have found other, non-health-related uses of discarded cigarette butts—as materials for building, art, fashion, and plastics. And last month, a team of South Korean scientists announced success in turning smoked cigarette butts into an efficient energy-storing material that outperformed existing carbon nanotube technology; its supercapacitive performance has potential for use in computers, handheld devices, and electric vehicles.
Discarded butts are a large-scale environmental problem, but on the upside the toxic trash may help solve a serious worldwide public health problem, protect avian species, provide material for art and industry, and advance electronic technology.
Dieng, H. et al. (2013). Turning cigarette butt waste into an alternative control tool against an insecticide-resistant mosquito vector. Acta Tropica, 128(3):584-90. doi: 10.1016/j.actatropica.2013.08.013. http://www.sciencedirect.com/science/article/pii/S0001706X13002180
Dieng, H. et al. (2011). Discarded cigarette butts attract females and kill the progeny of Aedes albopictus. Journal of the American Mosquito Control Association, 27(3):263-71. http://www.ncbi.nlm.nih.gov/pubmed/22017091
Mondal, N. et al. (2015). Cigarette Butt Waste and Its Effective Utilization towards Larvicidal Activity of Mosquito. International Journal of Scientific Research in Environmental Sciences, 3(1):9-15. http://www.ijsrpub.com/uploads/papers/IJSRES/2015/jan/IJSRES-14-88.pdf
Novotny, T. (2014). Time to kick cigarette butts – they’re toxic trash. NewScientist. http://www.newscientist.com/article/mg22229750.200-time-to-kick-cigarette-butts–theyre-toxic-trash.html#.VYyJy7umdMs
ResearchSEA. (2015). Used cigarette butts offer energy storage solution. ScienceDaily. http://www.sciencedaily.com/releases/2015/05/150515144950.htm
Suarez-Rodriguez, M. et al. (2012). Incorporation of cigarette butts into nests reduces nest ectoparasite load in urban birds: new ingredients for an old recipe? Biology Letters, 9 (1). http://rsbl.royalsocietypublishing.org/content/9/1/20120931
Written by Bonnie Denmark
Bonnie Denmark holds an MA in linguistics and teacher certification in English, ESL, and Spanish. She has devoted her professional life to educational and accessibility issues as a computational linguist, multimedia curriculum developer, educator, and writer. She has also worked nationally and internationally as a language instructor, educational technology consultant, and teacher trainer. Bonnie joined the Visionlearning team as a literacy specialist in 2011, assisting the project by developing comprehension aids for science modules and creating other STEM learning materials.