From carrion-eaters to plastic material plunderers: Toxicological impacts of plastic ingestion on black vultures, Coragyps atratus (Cathartiformes: Cathartidae).

Despite plastic ingestion has already been reported in several bird species, its physiological impacts have been little inspected, especially in representatives of the Cathartidae family. Thus, in this study, we aimed to identify, characterize, and evaluate the effects arising from the ingestion of plastic materials by Coragyps atratus adults, that captured in landfill areas. Herein, a total of 51 individuals were captured, the frequency of plastic intake being higher than 40%. The plastic materials consisted mainly of low-density polyethylene and film-type polystyrene, as well as presenting irregular shapes and diameters between 10 and 30 mm. Biochemically, we observed in animals that contained plastics in the stomach ("plastic" group) high production of reactive oxygen species (ROS), hydrogen peroxide (H2O2) and malondialdehyde (MDA) - especially in the intestine, muscle and brain - whose activity of catalase (CAT) and superoxide dismutase (SOD) was not sufficient to counteract the oxidative stress. Moreover, in the liver of these same animals, we observed high production of nitrite and nitrate, suggesting a hepatic nitrosative stress. Plus, we observed a cholinesterase effect in animals from the "plastic" group, marked by increased activity of butyrylcholinesterase (BChE) (in the brain) and muscle and cerebral acetylcholinesterase (AChE). On the other hand, the biochemical changes perceived were not significantly correlated with the identified plastic material concentrations (2.808 ± 0.598 items/g of stomach content and 0.276 ± 0.070 items/g of stomach - fresh weight), body condition of the animals, size, and shape of the identified plastic materials. Hence, our study sheds the light on the toxicity of plastics deposited in landfills and their ingestion by C. atratus, which reinforces the hypothesis that these materials are harming the health of these birds and, consequently, the dynamics of their populations.

Steel wools microfibers causes iron overload and induces biochemical changes in Gallus gallus domesticus chicks (Galliformes: Phasianidae).

Steel wool (SW) has a broad-spectrum of applicability, particularly as abrasives, cleaning household utensils and surfaces in general. However, when present in the natural environment, they can be ingested by animals, such as birds, and may represent a risk to the survival of individuals. Accordingly, in this study, we attempted the hypothesis that the ingestion of SW microfibers (SWMs) by Gallus gallus domesticus chicks (model system used) alters growth/development, induces redox imbalance and cholinesterasic effect, as well as promotes iron overload in different organs. For this, the animals received SWMs twice (within a 24-h interval) in an amount corresponding to 12% of their total stomach volume. At the end of the experiment, we observed less weight gain and less head growth, increased production of hydrogen peroxide (in the brain, liver, crop, and gizzard), nitrite (liver, crop, proventriculus and gizzard), malondialdehyde (brain, liver, muscle, proventriculus, and gizzard), along with increased superoxide dismutase activity in the liver, muscle and crop of animals exposed to SWMs. Such results were associated with iron overload observed in different organs, especially in liver, crop, and gizzard. Furthermore, we evidenced an anti-cholinesterasic effect in birds that ingested the SWMs, marked by a reduction in the acetylcholinesterase activity (in brain). Thus, our study sheds light on the (eco)toxicological potential of SWMs in avifauna, conceding us to associate their ingestion (despite ephemeral and occasional) with damage to the health of individuals, requiring a greater attention spotted to disposal of these materials in ecosystems.