First detection of seven phthalate esters (PAEs) as plastic tracers in superficial neustonic/planktonic samples and cetacean blubber

Ingestion of plastics and microplastics by marine organisms may have physical and toxicological noxious effects creating a serious threat to marine species. There is a need to develop methods to evaluate the plastic exposure in free-ranging marine wildlife particularly related to microplastic ingestion. To this aim, seven phthalate esters (PAEs) were analysed, as plastic tracers, in neustonic/planktonic samples and skin biopsy samples of four cetacean species from the North-Western Mediterranean Sea. Among all phthalates, the highest frequency of detection was obtained from DEHP (78.9%), followed in descending order by MBzP (57.9%), MEHP and BBzP (both 52.6%), DIOIP (47.4%) and MBP and DNHP (both 42.1%). All 19 superficial tows analysed presented microplastic debris, confirming the widespread distribution of microplastics on the seawater surface in the Mediterranean Sea. The abundance of the smallest items (<0.5 mm) found in the samples was significantly correlated with MEHP, MBzP and BBzP, while the abundance of 0.5-1 mm and 2.5-5 mm items were related to BBzP and MBP, respectively. Regarding the PAEs, detected in the neustonic/planktonic samples correlated with microplastics (MEHP, MBzP, BBzP and MBP), appreciable levels of these compounds were found in all the four cetacean species. The present results represent a step forward in the application of a new non-invasive analytical method to evaluate PAEs as tracers of plastic exposure/ingestion in marine wildlife.