Cigarette butts may have low toxicity to soil-dwelling invertebrates: Evidence from a land snail.

Cigarette butts are a common form of litter that is often deposited on soil, where toxins from butts may affect soil-dwelling organisms. We examined possible toxicity of cigarette butts to the woodland snail Anguispira alternata using a toxicity study with cigarette butt effluent and a lab-based habitat choice experiment in which snails could feed or rest on areas with different butt densities. No mortality occurred during the 32-day toxicity study, which used six effluent concentrations ranging from 0 to 4butts/l (0 to 0.92butts/kg of soil). Neither food consumption nor snail growth differed among the effluent concentrations. When provided a choice among four habitats with 0 to 4 cigarette butts, snails selected to preferentially rest in the 0-butt habitat and avoided the 4-butt habitat. This distribution pattern was strong during the first wk. but became weaker over time and largely disappeared by the end of the 3-wk experiment. Snails did not discriminate among butt densities when feeding. This is the first toxicity test using cigarette butts on soil-dwelling invertebrates. Declining aversion to cigarette butts over a 3-wk period may indicate declining toxicity of terrestrially deposited butts as they age, but further testing is needed.