A Systematic Review and Quantitative Synthesis of Metal and Metalloid Contamination in Avian Species in Brazil

Avian species are well-suited as sentinel species concerning metal and metalloid contamination, although knowledge on this subject in Brazil is still scarce and scattered in the literature. In this sense, this review, conducted according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) methodology by means of keyword searches across the Web of Science, Scopus, and PubMed databases, aimed to compile information on this subject in Brazil. In focusing on Brazil, we address the country's unique biodiversity, diverse ecosystems, and specific anthropogenic pressures, while consolidating scattered and regionally published data to support targeted biomonitoring and conservation efforts. Concentrations of key metals (Cd, Cr, Cu, Hg, Pb, Zn) in different bird tissues in Brazil were estimated. Feathers and liver are the most frequently investigated tissues, with the former exhibiting high potential in biomonitoring assessments as a non-invasive sampling method. The most common analytical methods were Inductively Coupled Plasma Mass Spectrometry (ICP-MS), Cold Vapour Atomic Absorption Spectroscopy (CVAAS), and Atomic Absorption Spectroscopy. Ardea alba, Sula leucogaster, Larus dominicanus, and Spheniscus magellanicus are the most studied species. Metal concentrations were varied throughout different studies, indicating the need for standardized protocols and long-term monitoring to track contamination trends and assess mitigation efforts.