Discarded cigarette butts are the most prevalent litter found in ocean beaches and inland waterways. However, their contribution to environmental damage has not been evaluated. Are the butts just unsightly litter problem? It is well known that cigarette tobacco and cigarette smoke contains numerous toxic chemicals. More than 60 carcinogens were identified in cigarette smoke. It has been widely accepted finally that cigarettes and tobacco are hazardous for human health after decades’ studies. And policy and regulation on cigarette smoking prevented public health.
Cigarette filters are made of non-biodegradable plastic. The filters trap particulates and less volatile chemicals in main stream cigarette smoke. Therefore, it is reasonable to expect that cigarette butts contain harmful chemicals due to the trapped chemicals in filters and chemicals in unburned tobacco. Clearly, a cigarette butt is not just solid waste. It is rather appropriate to label cigarette butts as toxic hazardous waste. Concerns about environmental damage of the hazardous chemicals associated with discarded cigarette butts have been raised. An essential question is whether harmful chemicals found in discarded butts leach into environments such as surface waters, soil, and sand. If so, what are the short- and long term fates of these chemicals? Are they toxic, and if so, in what ways? Moreover, the recalcitrant nature of cigarette filters make them a long-lasting carrier of harmful chemicals in their journey beginning as discarded trash and ending as a source of waterborne contamination. This is particularly relevant in regions such as California with its Mediterranean climate, characterized by periodic and/or seasonal rain events, resulting in stormwater flushing of aggregated cigarette butts initially discarded onto the landscape into streams, urban rivers and stormwater channels, ponds, lakes and other receiving waters.
Thus, identification of the leachable chemicals and assessment of their environmental occurrence and toxicity is critically important for characterizing the ecological and human health risk associated with cigarette butts. We propose to identify leachable chemicals by comprehensive analysis using an innovative analytical instrumentation and evaluate fate of the leachable chemicals by testing various conditions. Toxicity of cigarette butt leachate will be tested by in-vitro bioassays which can provide biological mode of actions at very low concentrations. It is also important whether chemicals can enter food chains, especially in aquatic environments. If so, this will provide a major pathway of human exposure. This will be tested by doing EPA-standard bioaccumulation testing in freshwater fish and saltwater fish. Further evaluation of human exposure to toxic chemicals from cigarette butts will be tested by examination of drinking water supplies, soils in play grounds, and recreational beach sands. The exposure can be more significant to children. Ultimately, we will integrate the results to identify and rank those constituents that may be harmful to humans. Above all, the results of this study will be critically important to determine identity of cigarette butts (solid or hazardous waste).