Inhalation Toxicity of Cogenerated Graphite Flake and Fog Oil Smoke in the Brown-Headed Cowbird and the Red-Winged Blackbird, Size-Specific Inhalation Surrogates for the Red-Cockaged Woodpecker

摘要

The red-cockaded woodpecker (Picoides borealis) is an endangered species found on many installations where troop readiness training is conducted. Conducting maneuvers under obscurant cover is important for realistic training. Generators that combine fog oil for visual obscuration with graphite flakes for infrared obscuration are being deployed for training scenarios. The effect of this combination on avian species was unknown. Our data indicate that toxicity of inhaled and/or preened graphite flake and cogenerated graphite flake and fog oil is low and similar to controls for adult cowbird and blackbird surrogates for the red-cockaded woodpecker. No mortality, body weight loss, clinical signs of toxicity, or respiratory function deficits were observed in the graphite flake-only, or cogenerated graphite flake/fog oil- treated birds when compared to controls. Hematological response was normal and no toxic effects in erythrocytes or leukocytes were found. White blood cell counts, spleen weights, and incidence of parasitism and disease were indicative of normal immune function in all treatments. Because repeated exposure that may result in particle overload in the lung has the greatest potential for causing harm to birds, it is suggested that exposures to high concentrations of the aerosol-graphite mixture be limited to fewer than eight within any 2-month period.