FEATHERS AS INDICATORS OF EXPOSURE TO METALS: STUDY IN Anas crecca AND Anser caerulescens IN DURANGO, MEXICO

Abstract

The aim of this study was to evaluate the presence of inorganic elements in feathers of green-winged teals (Anas crecca Linnaeus, 1758) and snow geese (Anser caerulescens Linnaeus, 1758) that hibernate at Laguna de Santiaguillo in Durango. Additionally, the use of feathers as exposure indicators to metallic pollutants was determined. The hypothesis proposed was that the feathers of both bird species contain detectable concentrations of metals, indicating varying levels of exposure to environmental pollutants based on their habits and migration routes. During the 2021–2022 hunting season, a total of 30 green-winged teals and 27 snow geese were collected. The primary P9 and P10 feathers from the left wing of each bird were gathered for analysis. The feathers were cleaned, dehydrated, and analyzed using voltammetry to quantify the concentrations of Zn, Cd, Pb, Cu, Cr, Sn, Al, As, Ni, and Hg. The results revealed significant differences between species. The teals displayed higher concentrations of As, Cr, and Ni, whereas the geese had higher levels of Ni and Cu. Although essential elements like Zn and Cu were present in high concentrations, non-essential elements such as Cd and Pb were also detected. Particularly, Pb levels in some teal individuals were concerning due to their potential toxicity. Significant correlations were identified between certain metals (As-Cr and Pb-Zn), suggesting common exposures to anthropogenic sources, possibly related to agricultural and industrial activities. This study confirms that feathers serve as effective and non-invasive biomarkers to detect the exposure to metallic pollutants, providing a “chemical memory” of accumulation during growth. Consequently, the working hypothesis is accepted, establishing a foundation for future research and environmental conservation efforts focused on priority wetlands, such as Laguna de Santiaguillo.