The Plastic Signature: Microplastic Ingestion and Phthalate Exposure in Parapenaeus longirostris from Three Tyrrhenian Sites (Mediterranean Sea)

Microplastic pollution is pervasive in marine ecosystems and poses a growing threat to marine organisms and human health. This study simultaneously investigates microplastic ingestion and phthalate exposure in Parapenaeus longirostris, a commercially valuable and ecologically relevant Mediterranean crustacean occupying an intermediate trophic position. Specimens were collected from three coastal areas in the central Tyrrhenian Sea (Western Mediterranean): near the Tiber River mouth, one of the most polluted rivers in Italy, and two additional sites to the north and south. The frequency of individuals with ingested microplastics varied among locations: 78% near the Tiber River, 64% at site S, and 38% at site N, reflecting anthropogenic pressure gradients. Analyses confirmed the lower occurrence at site N, indicating higher ingestion near land-based pollution sources. Ingested microplastic polymer types varied among sites, reflecting location-specific contamination. Phthalates were present in shrimp muscle at all sites (5–1122 ng/g w.w.) with the highest average concentration (68.26 ± 55.74 ng/g) at the site with the highest microplastic ingestion. Although no statistical correlation was found, the similar spatial distribution of microplastics and phthalates suggests a potential link influenced by local pollution and individual variability. These findings provide novel evidence of microplastic and phthalate contamination in P. longirostris, highlighting its role as a trophic connector mediating contaminant transfer through the food web. While current levels suggest no potential risk to human health, continued monitoring and further studies on exposure along trophic pathways are recommended.