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Description
Smoked cigarettes or cigarette butts are one of the most abundant litters found in the ocean today. According to the 2020 International Coastal Cleanup Report published by the Ocean Conservancy, cigarette butts are the second most picked up litter type worldwide behind plastic wrappers. Cigarette filters are made from cellulose acetate, a partially synthetic fiber that can persist in aquatic environments for several years. These filters hold on to toxic constituents associated with tobacco smoke. As smoked cigarette filters persist in the environment, these chemicals leach into ecosystems and expose biota to their harmful effects. The bioaccumulative effects of tobacco chemicals on marine organisms and the possible biomagnification up food chains, has seldom been studied. Bent-nose clams, Macoma nasuta, are a marine species and are common in California natural reserves. California natural reserves are currently being assessed for the impacts of cigarette butts, as many are near heavily urbanized areas, and therefore may be disproportionality impacted by leached cigarette compounds. Using a standard 28-day bioaccumulation bioassay, the bioaccumulation potential of cigarette compounds was assessed in the test species Macoma nasuta. Clams were exposed to 1.0 smoked cigarette/L leachate over the course of 28 days. At the end of the 28 days, the clams entered a depuration period, then promptly shucked and tissue samples were extracted. A nontargeted analysis based on comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC/TOF-MS) was conducted on the tissue. There was no significant evidence that cigarette leachate exposure affected clam mortalities or weights, however, noticeable changes in clam burrowing behavior were noted. A total of 282 unique compounds were identified in the clams exposed to smoked cigarette leachate. 41 compounds were tentatively identified based on their mass spectral similarities, composing 21.1% of the total GC peak area of the 282 unique compounds. Multiple compounds associated with cigarette smoke were identified in the tissue – such as nicotine, 4,4-bipyridine, and cotinine. This study suggests that smoked cigarette leachate chemicals have the propensity to bioaccumulate in the tissue of marine organisms and may result in eventual human exposure up the food chain.
