Riesgo ambiental marino por pinturas anti‐incrustantes a base de TBT (tributilestaño), sobre el “caracol plomo” Thaisella chocolata (Duclos, 1832) empleando al imposex como un bioindicador, en el puerto de Paita, Perú

Imposex is the development of male sexual organs in female sea snails by the action of TBT (tributyltin) present in antifouling paints. Objective: to evaluate the environmental risk (ERA) by antifouling paints on Thaisella chocolata (Duclos, 1932) "Sea snail" using imposex as a bioindicator in the port of Paita, Peru. Materials and methods: the imposex indicators of two seasons, summer and spring, were analyzed in four sampling locations; two located in Paita and two in coves further south. A total of 30 individuals of T. chocolata were collected per season, which were narcotized with magnesium chloride. The length of the shell was measured with a Vernier and the soft body was removed. Sex was identified and penis length was measured in males and in females with imposex. The vas deferens index (VDSI) stage was determined. Results: the highest VDSI values between 2.11 (coves) and 3.42 (port of Paita), occurred in the summer season, and the specific ERA for T. chocolata was determined. There are significant differences in the occurrence of imposex in T. chocolata depending on the proximity to the port of Paita, which indicates an environmental risk for this species. Conclusions: the ERA standard for antifouling paints, specific for the species under study, indicates that the environmental risk is between levels C (exposure to TBT in concentrations higher than the Environmental Assessment Criterion) and E (populations unable to reproduce, where most or all females are sterile).