Smoked cigarette butt leachate impacts survival and behaviour of freshwater invertebrates

Abstract

Smoked cigarette filters a.k.a. "butts", composed of plastic (e.g. cellulose acetate) are one of the world's most common litter items. In response to concerns about plastic pollution, biodegradable cellulose filters are being promoted as an environmentally safe alternative, however, once smoked, both contain toxins which can leach once discarded. The impacts of biodegradable butts as littered items on the receiving environment, in comparison with conventional butts has not yet been assessed. A freshwater mesocosm experiment was used to test the effects of leachate from smoked cellulose acetate versus smoked cellulose filters at a range of concentrations (0, 0.2, 1 and 5 butts L -1 ) on the mortality and behaviour of four freshwater invertebrates (Dreissena polymorpha, Polycelis nigra, Planorbis planorbis and Bithynia tentaculata). Leachate derived from 5 butts L -1 of either type of filter caused 60-100% mortality to all species within 5 days. Leachate derived from 1 butt L -1 of either type resulted in adults being less active than those exposed to no or 0.2 butts L -1 leachate. Cigarette butts, therefore, regardless of their perceived degradability can cause mortality and decreased activity of key freshwater invertebrates and should always be disposed of responsibly.

Abundance and Distribution of Cigarette Butts on Coastal Environments: Examples from Southern Spain

“…Toxicity due to the presence of CB in aquatic environments has been demonstrated by numerous investigations including different marine species from unicellular organisms such as foraminifera [25] to larger ones such as invertebrates and fish [22,26]. Environmental groups have expressed concerns for marine creatures that ingest littered filters [8,27].…”

Effects of cigarette butts on marine keystone species (Ulva lactuca L. and Mytilus edulis L.) and sediment microphytobenthos

“…In a closed system, however, such as a rockpool, biodegradable cigarette butts would likely cause similar effects to non-biodegradable cigarette butts due to the retention of leachate in the water (Booth et al 2015). Indeed, a recent experiment in a closed freshwater system showed that biodegradable cellulose butts had similar detrimental effects as plastic cellulose acetate butts; causing mortality and a reduction of movement of four invertebrate species (Green et al 2020). Cigarette butts, regardless of their biodegradability, pose a threat as litter in the environment and need to be disposed of appropriately.…”

“…Alternative cellulose filters have been described as "green", "biodegradable" and "environmentally friendly" implying they would be benign as litter (Amos et al 2017). A recent experiment, however, found that leachate derived from cellulose cigarette butts had the same detrimental effects on freshwater invertebrates as leachate derived from cellulose acetate cigarette butts (Green et al 2020). The comparative effects of cellulose acetate versus cellulose cigarette butts have not yet been tested in a marine system.…”

A Review of Environmental Pollution from the Use and Disposal of Cigarettes and Electronic Cigarettes: Contaminants, Sources, and Impacts

“…Belzagui et al recently showed that microfibers from degraded CBs enhanced the toxicity of CB leachate to freshwater zooplankton (Daphnia magna) in experimental 48 h toxicity tests, suggesting that the microfibers pose an intrinsic risk to small aquatic animals [90]. In another recent study, Green et al compared the toxicity of leachate from conventional plastic cellulose acetate CBs and cellulose CBs, which are being promoted as a biodegradable and environmentally safe alternatives [219]. Both smoked butt types exhibited toxicity to, and decreased activity in, freshwater snails (Bithynia tentaculate).…”