MACRO AND MICROPLASTICS REGURGITATED BY SOUTHERN GIANT PETRELS (MACRONECTES GIGANTEUS) AT BREEDING COLONIES FROM PATAGONIA, ARGENTINA

GALLO L; RODRÍGUEZ PIRANI L, PICONE A L, ROMANO R M, DELLA VÉDOVA C OC; GEREZ A; UHART M

Mar del Plata

Congreso; VIII Congreso SETAC Arg 2022; 2022

VIII Congreso SETAC Arg 2022

Plastic debris is widespread, and it has accumulated worldwide in the marine environment. In this study, we analysed regurgitated boluses from Southern Giant Petrels (Macronectes giganteus, SGP) at Gran Robredo and Arce islands, Chubut, Argentina, during late chick rearing of two breeding seasons (2020-2021). Plastic items >1mm (micro and macroplastics) were found in 29.3% (12/41) of boluses (mean abundance ± SD: 0.97 ± 3.33 items, 0.04±0.15 grams; mean intensity ± SD: 3.63 ± 5.81 items, 0.16 ± 0.27 grams). The most common plastic items were foam (52.5%), followed by film (17.5%), rigid fragments (15.0%), other types of plastic (e.g. cigarette filters; 12.5%) and pellets (2.5%). We identified the polymer types of the items recovered by Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Raman Microscopy. Polystyrene was the most abundant polymer (53.8%), followed by polypropylene (12.8%), low density polyethylene (12.8%), cellulose acetate (10.3%), polyamide (7.7%), and high-density polyethylene (2.6%). The frequency of occurrence (FO), intensity, and abundance of plastic items in boluses were lower than those found in stomach content from beach-wrecked carcasses (all age classes: FO= 59.3%, abundance: 4.0 ± 5.9 items, intensity: 6.8 ± 6.4 items; Gallo et al. in prep). This may be due to the retention of plastics in the ventriculus of petrels because of anatomical features of their gastrointestinal tract. However, the type of plastics found in both types of samples was similar; with film, rigid fragments, and foam the most common categories. Thus, our findings confirm that plastic ingestion is a common threat for SGP in the Southwest Atlantic Ocean. In this sense, SPG boluses are valuable as non-invasive samples for the detection of changes in the composition and abundance of marine plastics debris to which they are exposed. In addition, the characterization of ingested plastic polymers provides information on pollution sources as well as potential toxicity derived from plastic additives and leaching.