Glowing hazards: Toxicological effects of festive glowsticks

The widespread use and improper disposal of glowsticks (GS), especially during coastal festivities and in industrial fishing, raise ecotoxicological concerns for marine ecosystems. These devices contain complex chemical mixtures, including oxalate esters, hydrogen peroxide, phthalates, and polycyclic aromatic hydrocarbons (PAHs), many of which can generate reactive oxygen species (ROS) and cause toxic effects. This study assessed the acute toxicity of four GS colors (green, red, yellow, and blue) using embryo-larval development and mortality assays on three marine invertebrates: the sea urchin Echinometra lucunter, the sand dollar Mellita quinquiesperforata, and the brine shrimp Artemia salina. All colors caused developmental or lethal effects, with green GS consistently showing the highest toxicity. In E. lucunter, green GS fully inhibited larval development at all tested concentrations; EC50 values for yellow, red, and blue were 0.00072, 0.00877, and 0.02156 mL·L^-1, respectively. For M. quinquiesperforata, EC50s were 0.00538 (green), 0.05471 (red), and 0.0000732 mL·L^-1 (blue); yellow GS caused total mortality, precluding EC50 determination. In A. salina, LC50s were 0.00410 (yellow), 0.00583 (blue), and 0.01193 mL·L^-1 (red); green GS had a NOEC of 0.0001 and LOEC of 0.001 mL·L^-1, with no definable LC50. Results revealed species- and color-dependent sensitivity, implicating dye composition as a key toxicity driver. This is the first report of GS-derived toxicity in sand dollars and the first to provide comparative profiles across marine taxa. Findings highlight the need for regulation and environmental oversight of chemiluminescent product disposal.