Ammunition Type and Shot Placement Determine Lead Fragmentation in Deer

摘要

Lead remnants from spent ammunition introduce health risks to humans and wildlife that consume game harvested with firearms. Most current research has focused on effects of high-velocity rifle bullets, whereas low-velocity lead ammunition has received little attention. We examined whether fragmentation characteristics differed between 3 common low-velocity ammunition types when shot into the thoracic cavity or shoulder of white-tailed deer (Odocoileus virginianus) culled in Indiana, USA, from May-September of 2009. We shot and subsequently radiographed 43 deer to determine the number of fragments, fragment size, and distance traveled by individual fragments. We also radiographed deer post-evisceration to determine the proportion of fragments available to humans and wildlife scavengers for consumption in muscle and visceral tissue, respectively. All radiographed deer had evidence of fragmentation, with a geometric mean of 13.1 (95% CI = 10.3, 16.8) fragments/deer. Most fragments (89%) were <5 mm from wound channels, and no fragment traveled beyond 205 mm from a wound channel. Fragments were often retained within the muscle tissue of deer with a geometric mean rate of 0.55 (95% CI = 0.48, 0.65). Muzzleloader bullet fragments were larger than those generated by rifled and sabot slugs, and sabot slug fragments had the shortest dispersal from wound channels. Shoulder-shot placement and bone contact for all ammunition resulted in a greater number of fragments (P < 0.01). Shoulder-shots also generated more small fragments and higher fragment retention in muscle tissue. The overall mean number of lead fragments detected across our ammunition treatments was less than previous studies. Our results indicate ammunition type and shot placement may be considerations for hunters wishing to limit their potential exposure to lead from harvested big game. Additionally, when compared to high-velocity rifle bullets, significantly fewer lead fragments are made available to humans and wildlife that consume game harvested with low-velocity ammunition types, such as those tested here. Complete elimination of lead ingestion by humans and wildlife, however, is only possible by using non-toxic ammunition alternatives. (c) 2020 The Wildlife Society.