Can sub-lethal effects of plastic ingestion be assessed by phthalates concentration and molecular biomarkers in stranded Manx shearwaters

PEREIRA SERAFINI, PATRICIA; BUGONI, LEANDRO; PICCININ, ISADORA N.L.; GABRIEL DI NASCIMENTO; PEREIRA, ALICE; MARASCHIN, MARCELO; GALLO, LUCIANA; UHART, MARCELA M.; LIMA, DIMAS; ET AL.

Dublin

Congreso; SETAC Europe 33rd Annual Meeting; 2023

SETAC

Seabirds are considered sentinels of marine ecosystems as they reflect environmental changes. Plastic pollution is one of the greatest challenges for marine conservation, and nearly all living seabirds will ingest plastics at some point in their life. Additives (e.g. phthalate esters) can leach from plastics and because seabirds often retain plastic items for extended periods in their digestivetract, they could be vulnerable to the adverse effects of chronic exposure to these compounds. In this study we evaluated molecular biomarkers in stranded Manx shearwaters (Puffinus puffinus) as a tool to assess sub-lethal effects of plastic ingestion. Age class, sex, body mass, and plastic presence were registered for all birds. The transcript levels of genes involved in xenobioticbiotransformation including aryl hydrocarbon receptor (AhR), cytochrome P450 1A5-like (CYP1A5) and UDP-glucuronosyltransferase (UGT1); genes related to endocrine disruption as estrogen receptor alpha (ESR1); and genes responding to metabolic stress as heat shock protein 70 (HSP70) were measured in the liver from 79 fresh carcasses of birds (11% with plastic) strandedalong the coast of southern Brazil from 2016 to 2021. Plastic additives (Dibuthyl phthalate - DBP, Dimethyl phthalate – DMP, and Diethylhexyl phthalate - DEHP) were also quantified by gas chromatography with flame ionization in the uropygial gland from 25 birds (8% with plastic). Overall, 11 of the 104 seabirds sampled had ingested plastic found during necropsy. Of these 11 shearwaters, 55% were males and all were juveniles. The best-fitting generalized additive models (GAM) found associations between the transcript levels of AhR and UGT1 genes responding to bird age class, sex, mass, and plastic presence. Slightly higher transcript levels of both genes in animals with plastic showed a potential positive association. Additives were detected in 10 seabirds for DBP, 2 seabirds for DMP, and 12 for DEHP. GAMs best fitting models showed associations between DEHP concentration and the factors sex and plastic presence. Although preliminary, our findings imply the need to further investigate sublethal effects of plastics, as well as their influence on birds’ metabolism and response to environmental xenobiotics. This study provides baseline data for the conservation of seabirds in an area where plastic pollution is increasing.