*Article* **Ecological Impact of End-of-Life-Tire (ELT)-Derived Rubbers: Acute and Chronic Effects at Organism and Population Levels**

**Stefano Magni 1,\*, Erica Tediosi 2,\*, Daniela Maggioni 3, Riccardo Sbarberi 1, Francesca Noé 2, Fabio Rossetti 4, Daniele Fornai 5, Valentina Persici <sup>6</sup> and Maria Chiara Neri <sup>2</sup>**


**Abstract:** Considering the large amount of tires that reach the end of life every year, the aim of this study was the evaluation of both acute and chronic effects of end-of-life-tire (ELT)-derived rubber granules (ELT-dg) and powder (ELT-dp) on a freshwater trophic chain represented by the green alga *Pseudokirchneriella subcapitata*, the crustacean *Daphnia magna* and the teleost *Danio rerio* (zebrafish). Adverse effects were evaluated at the organism and population levels through the classical ecotoxicological tests. Acute tests on *D. magna* and *D. rerio* revealed a 50% effect concentration (EC50) > 100.0 mg/L for both ELT-dg and ELT-dp. Chronic exposures had a lowest observed effect concentration (LOEC) of 100.0 mg/L for both ELT-dg and ELT-dp on *P. subcapitata* grow rate and yield. LOEC decreased in the other model organisms, with a value of 9.8 mg/L for *D. magna*, referring to the number of living offspring, exposed to ELT-dg suspension. Similarly, in *D. rerio*, the main results highlighted a LOEC of 10.0 mg/L regarding the survival and juvenile weight parameters for ELT-dg and a LOEC of 10.0 mg/L concerning the survival and abnormal behavior in specimens exposed to ELT-dp. Tested materials exhibited a threshold of toxicity of 9.8 mg/L, probably a *non*-environmental concentration, although further investigations are needed to clarify the potential ecological impact of these emerging contaminants.

**Keywords:** rubbers; tire particles; acute and chronic effects; freshwater species
