Diploma Thesis Defense by Mrs. Vasiliki Dimitriou
Thesis Title: «TOXICITY OF WATER LEACHATES FROM TOBACCO PRODUCTS»
Thursday 20 February 2020, at: 11:30, Venue: Hall Κ2.Α11
Examination Committee
- Associate Professor Danae Venieri (advisor)
- Professor Elia Psillakis
- Assistant Professor Apostolos Giannis
Abstract
Cigarette butts and other tobacco product wastes are the most common items picked up in environmental trash beach and urban cleanups worldwide.
They are often thrown away on beaches and roads and they are dispersed through sewer systems and streams into the oceans. Up until now, there is minimum awareness regarding the environmental impacts and toxic chemicals that can be removed from the cigarette and become bioavailable to aquatic life, when exposed to water by smokers. Cigarettes butts contain all the toxins, nicotine and carcinogenic ingredients found in tobacco along with the non-biodegradable filter. Toxicity studies have shown that compounds emitted by cigarettes in salt and fresh water are toxic to aquatic organisms. Also, as two-thirds of all smoked cigarettes (numbered in the trillions of cigarettes worldwide) are discharged into the environment each year, it is important to consider the potential toxicity of these wastes. The present work examines the toxicity of water leachates from used and unused tobacco products as well as aqueous nicotine solution. The items which were examined were conventional cigarettes (CC) and non-burned aluminum tobacco sticks in ultra-pure water. The used tobacco products were obtained from an analytical cigarette-smoking machine that operated according to a standardized protocol. In the first stage, bioassays were performed using the bacterial species Vibrio fischeri, which belongs to the trophic level of decomposers. Bioassays took place with used and non-used tobacco products. The results showed that samples of used and unused conventional cigarettes cause a 75-100% reduction of the bacterial population, while used tobacco sticks 50-75% decrease and are considered toxic. On the other hand, unused tobacco sticks allow normal growth of the bacterium as the reduction level reached zero values. In the second stage toxicity was studied with Daphnia magna, which belongs to the trophic level of consumers. The results showed that the most toxic samples were used and unused conventional cigarettes as well as unused tobacco sticks since they caused the death of all organisms. The sample of used tobacco sticks was less toxic as the survival rate at the respective concentrations varied between 50-70%. Finally, the nicotine solution in ultra-pure water had almost no effect on the survival of the organisms. According to the present results D. magna seemed to be highly more sensitive than V. fischeri under the current experimental conditions, especially when conventional cigarettes were tested. Generally, higher organisms are more vulnerable to the toxicity induced by tobacco products, raising many concerns about public health protection.
