Screening plastic chemicals in birds: insights into environmental exposure of cinereous vultures

Plastic chemicals are a growing concern due to their widespread detection in the environment and their impact on humans and wildlife. Raptors are commonly used as terrestrial bioindicator species for numerous contaminants but remain overlooked regarding their exposure to plastic chemicals. Here, we evaluated the occurrence and concentrations of 8 bisphenols, 17 phthalates, and 9 trace elements in the blood of chicks (n = 51) of an endangered scavenger raptor species, the Cinereous vulture (Aegypius monachus), heavily exposed to plastic in Madrid, Central Spain, by frequently feeding at a landfill. We also investigated the relationships between compound concentrations and biological and phenological factors (i.e., mass and egg laying period), as well as corticosterone concentrations in feathers (CORTf). Ten plastic chemical compounds were quantified in at least one individual, representing for most compounds, the first report in a raptor species. Trace elements (cadmium, copper, lead, selenium, and zinc) were quantified at low concentrations, below toxicity thresholds. Bisphenol A (BPA), mono-isobutyl phthalate (MiBP) and mono-n-butyl phthalate (MnBP) had high quantification frequencies (≥88%), with the highest concentrations observed for MnBP (mean ± SD: 37 ± 15 ng g^-1 ww), followed by BPA and MiBP (36 ± 27 and 31 ± 17 ng g^-1 ww, respectively). However, mono (3-carboxy propyl) phthalate (MCPP) was quantified in very few samples (2%), but at the highest concentration found in this study (2,400.3 ng g^-1 ww). MnBP was negatively related to chick mass (p < 0.05), calling for urgent research into the origin and consequences of plastic chemicals, especially phthalate metabolites, on terrestrial apex predators.