Implications for wildlife and humans of dietary exposure to lead from fragments of lead rifle bullets in deer shot in the UK

Abstract

Lead poisoning caused by ingested spent lead shotgun pellets has long been known to be a cause of unnecessary mortality in waterfowl and has led to legislation limiting its use in many countries. Recent evidence has shown that the problem extends to terrestrial ecosystems and to fragmented rifle bullets eaten by scavengers as well as shotgun pellets. Dietary exposure of human consumers to lead from spent ammunition in game meat also poses potential risks to human health. To assess the degree of fragmentation of lead bullets used to kill wild deer, twelve deer were shot in the thorax using copper-jacketed lead-cored bullets, as part of planned deer management operations. The thoracic region of the eviscerated carcasses and the abdominal viscera of each deer were X-rayed. An average of 356 metal fragments was visible on radiographs of the carcass and 180 fragments in the viscera. The weight of fragments was estimated by reference to an X-rayed scale of fragments of known weight. The average total weight of metal fragments, likely to be mostly lead, was estimated to be 1.2g for the carcass and 0.2g for the viscera. The total estimated weight of fragments in the entire carcass was estimated to be 17% of the weight of the bullet. Most fragments were small in size, with those in the viscera being smaller than those in the carcass. Metal fragments in the viscera were sufficiently small that at least 80% of the metallic bullet-derived lead in the viscera would be expected to be ingested by scavenging birds, such as buzzards and eagles, which feed on them.