LEAD IN GAME MEAT A Study of Bioaccessibility of Lead Metal Fragments

Author(s): Ulf Qvarfort, Christer Holmgren

The presence of metal lead fragments in the tissue around the wound channel can be observed in animals killed with lead-based bullets. These parts are normally discarded as food but a limited number of fragments may be consumed accidentally. A number of studies are performed to estimate mean lead metal contamination in game meat harvested with rifle and is assumed that all lead metal fragments to its total weight that may accidentally be left in the edible muscle tissue, will be dissolved to an absorbable lead compound which can be taken up by the body severely increasing B-Pb level. When blood lead level, B-Pb, is an important biomarker for dietary exposure from lead several studies have been conducted comparing blood lead levels in hunters with similar population groups who do not eat wild game. Even taking into account environmental and social conditions, eating habits and lead related occupations or hobbies, few conclusions can be drawn concerning risk assessment. This because lead pathways in general as well as the actual bioaccessibility of any metal lead accidently ingested, and the actual absorbable (bioavailable) fraction of this, are not compared or taken into account. The aim of this study was, by mean of in-vitro gastrointestinal simulation (IVG), to experimentally examine what percentage of any metal lead fragments present in tissue from a severely contaminated wound channel is converted to water soluble bioaccessible lead salts in the human gastrointestinal tract. Results obtained show that less than 2 % of all present lead metal fragments in raw meat from wound channel are converted to bioaccessible form in the human GI tract. Using this knowledge of the percentage of bioaccessible lead released, the impact on human blood lead levels from known or estimated contamination of lead metal in food can be easily calculated with use of Carlisle and Wade (1992) empirical equation for dietary exposure adopted by CONTAM panel 2010 using Slope Factor Models and absorption fractions.