Lead toxicosis and trace element levels in wild birds and mammals at a firearms training facility

In May 1999, lead poisoning was diagnosed in a yellow-rumped warbler (Dendr oica coronata) and a gray squirrel (Schirus carolinensis) found at the Fede ral Law Enforcement Training Center (FLETC), Glynn County, GA, based on det ection of 6.2 and 90.0 ppm, wet weight (WW) lead in the liver of the warble r and squirrel, respectively. From October 21-26, 1999, 72 wild animals (37 mammals and 35 birds), comprised of 22 different species, were collected f rom a 24-ha area surrounding the FLETC outdoor firearms shooting range comp lex to evaluate exposure to lead and other trace elements. Ten animals were used as controls (five mammals and five birds) and were collected from are as 1.5-3 km outside the shooting range area. Kidney and liver tissues were analyzed for lead, zinc, and other trace elements. Bird gizzards and white- tailed deer abomasums were examined grossly and radiographically to detect metallic objects. Twenty-four (33.3%) animals (I I species) had kidney or l iver tissue lead levels > 1.00 ppm, and 12 of these (6 species) had levels > 2.00 ppm. Carcasses of one brown-thrasher (Toxostoma rufum) and two white -tailed deer (Odocoileus, virginianus) contained lead fragments. Elevated l iver tissue levels of zinc (111.0 ppm) were detected in one brown thrasher that also had elevated kidney and liver tissue lead levels. In February 200 0, seven yellow-rumped warblers and one solitary vireo (Vireo solitarius) f ound dead near the FLETC firearms shooting range also were diagnosed with l ead poisoning, with liver and kidney tissue lead levels from 1.77-11.6 and 4.55-17.8 ppm WW, respectively. This frequency of elevated tissue lead leve ls among the animals examined, in combination with confirmed lead toxicosis in both avian and mammalian species at FLETC, indicates significant lead e xposure of local wild bird and mammal communities via bullets and fragments in and on the soil surface of the four outdoor ranges. Most FLETC firearms training is being shifted to new baffled ranges (four walls with semiopen top) with bullet recovery capabilities to preclude future deposition of lea d in the environment, existing outdoor ranges will be remediated to remove existing lead.