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BASIS #   2309TZ 22

Title Toxicity of lead and zinc to wildlife

Project Description

This laboratory study on mallards investigates whether signs of lead poisoning in birds are related to damage from lipid peroxidation. Much of the literature published to date, primarily on mammals, is equivocal. Glutathione, TBARS (a measure of peroxidation), and polyunsaturated fatty acids will be studied in relation to neurologic effects, gross and histopathogical lesions, and indicators of lead poisoning in the blood.      

The annual plan objectives are:

1) To determine sublethal effects of lead poisoning on mallards.
2) To determine whether an antioxidant increases an animal's resistance to lead.        

Relevance and Impact: 

1) The results help us better understand lead poisoning in waterfowl.  This is the first study to relate the clinical signs observed the mallards to biochemical markers.  Lead inhibits antioxidant enzymes and interacts with sulfhydryl groups in proteins, but had only minor effects on lipid peroxidation.  
2) Natural resource damage assessments require the demonstration of injury.  The results allow the association of particular lead residues with specific injuries.  
3) Sometimes poisoned waterfowl are treated for lead poisoning.  The results demonstrate that treatment with vitamin E or other oxidants probably will not be beneficial.       

Strategy and Approach:  Four groups of mallards were fed diets containing high or low levels of vitamin E (20 or 220 UI/kg), an antioxidant, and high or low levels of lead (0 or 2000 mg/kg).  The birds were observed for neurologic impairment, changes in glutathione and related enzymes, and histopathological injury.  

Keywords birds, contaminants, toxicology, waterfowl, wildlife, lead

Principal Investigator Nelson Beyer, USGS Patuxent Wildlife Research Center:

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