Integrated assessment: Chemical characterisation and response of Tisbe biminiensis (Copepoda, Harpacticoida) to toxins from cigarette butts.

The study evaluated lethal, developmental, reproductive and behavioural effects of cigarette butt leachates on the marine copepod Tisbe biminiensisVolkmann-Rocco, 1973. Three experiments were conducted using leachates prepared from cigarette butts collected on beaches: (1) different leachate concentrations (6.25%, 12.5%, 25%, 50% and 100%), (2) four degradation levels (Types I-IV) and (3) four cigarette brands (A-D), in addition to an uncontaminated control. Each treatment comprised five replicates with ten ovigerous females per replicate and lasted 7 days under controlled conditions. Nauplii and copepodites were the most sensitive developmental stages. Significant reductions occurred in nauplii at 50% and 100% leachate and in copepodites at 100%, with EC₅₀-168h values of 1.5 and 2.8 cigarette butts/L, respectively. Type I butts produced the strongest developmental and reproductive effects. Behavioural assays showed alterations in light avoidance and swimming related behaviours, including reduced time in the dark and changes in Swimming Away from the Edge. These changes are ecologically relevant because altered locomotion and stimulus responses may interfere with feeding, reproduction and predator avoidance, potentially modifying the role of benthic copepods in coastal food webs. FTIR spectra showed functional groups associated with oxygenated and aromatic compounds in the analysed butts. Overall, the results indicate that cigarette butt leachates can produce both lethal/sublethal and behavioural effects in T. biminiensis, with potential consequences extending from individual performance to trophic interactions in contaminated coastal environments.