Understanding Lead Levels and Potential Effects in the Andes Through a River-Specialized Waterfowl, Merganetta Armata, Must Consider Hematological Processes

Mining and mineral extraction in modern-day Peru has existed for centuries, even before Spanish influence.  However, mineral extraction today continues at a highly elevated pace in Peru, partially because new technologies have opened previously unprofitable deposits for extraction.  Mercury, cadmium, lead and other elements are released into the environment through natural erosive forces and through human activities such as mining and other development.  This is evident in the Andes, since potentially toxic levels of lead have been detected in the blood of human populations in the Andes, close to highly developed areas and mining activities (Cooke 2008, Krause et al. 2003a, Krause et al. 2003b, Fraser 2009). Lead is toxic to a number of organ systems, especially the nervous and the circulatory systems, based on the level of exposure.  Torrent ducks (Merganetta armata) are found throughout the South American Andes, including in close proximity to mining activity. Monitoring lead levels in torrent ducks may provide a way to identify areas that pose a potential human health risk, as well as identifying health risks to the torrent ducks and other ducks that reside in the rivers.  In September and October of 2010, 49 torrent ducks were sampled in the Peruvian Andes.  Blood and feather samples were collected, hematological analyses (hemoglobin concentration, packed cell volume, red blood cell concentration) were completed, and morphometrics (such as mass, wing chord length, etc.) were taken.  At the Wildlife Toxicology Laboratory at UAF, feather samples were analyzed for lead using a Perkin-Elmer Atomic Absorption Spectrometer.  Lead in feather samples was highly variable, depending on the age of the feather after last molt, and on placement on the body.  Worn tail feather (n=1) was found to have the highest level of lead, whereas dorsal feathers were mostly below detection. Although the lead levels found in many feathers were below those considered toxic in waterfowl, we have shown that lead levels may be highly variable, depending on sample collection.