Anthropogenic particles accumulation in sea cucumbers: insights from a transitional environment

Detritivorous organisms, such as sea cucumbers, are key components of marine benthic ecosystems, contributing to sediment bioturbation and nutrient recycling, and thereby playing a pivotal role in ecosystem functioning. However, due to rising plastic production and inadequate waste management, their sediment-ingesting feeding strategy makes them particularly susceptible to anthropogenic particle (AP) contamination, potentially influencing trophic transfer and benthic-pelagic coupling. This study represents the first investigation on AP occurrence in holothuroids, Holothuria sanctori and H. tubulosa , inhabiting the transitional coastal waters of the Capo Peloro Natural Reserve (Mediterranean Sea). Raman and FT-IR analyses identified 12 synthetic polymers, three elastomers, one rubber, one petroleum derivative, and one semisynthetic particle. Additionally, cotton and dyed cellulose were also identified. Overall, our findings reveal a broader spectrum and higher level of complexity of APs than previously reported in sea cucumbers from marine environments, with 18 types identified in H. sanctori and 17 in H. tubulosa . Neoprene and cotton were the most frequently detected APs. The results underscore the suitability of the studied invertebrates as sentinel species for assessing plastic contamination in transitional environments. • First report of anthropogenic particles in H. sanctori and H. tubulosa from transitional waters • A mix of plastics, elastomers, rubbers, semisynthetic and natural particles was found in sea cucumbers. • Neoprene and cotton were the most common anthropogenic particles. • Sea cucumbers are good bioindicator of anthropogenic particle pollution in transitional waters.