METHYLMERCURY ACCUMULATION AND ELIMINATION IN MINK (NEOVISON VISON) HAIR AND BLOOD: RESULTS OF A CONTROLLED FEEDING EXPERIMENT USING STABLE ISOTOPE TRACERS

Concentrations of metals in hair are used often to develop pharmacokinetic models for both animals and humans. Although data on uptake are available, elimination kinetics are less well understood; stable isotope tracers provide an excellent tool for measuring uptake and elimination kinetics. In the present study, methylmercury concentrations through time were measured in the hair and blood of mink (Neovison vison) during a controlled 60-d feeding experiment. Thirty-four mink were fed a standard fish-based diet for 14 d, at the end of which (day 0), 4 mink were sacrificed to determine baseline methylmercury (MeHg) concentrations. From day 0 to day 10, the remaining mink were fed a diet consisting of the base diet supplemented with 0.513 +/- 0.013 mu g (MeHg)-Hg-199/g and 0.163 +/- 0.003 mu g (MeHg)-Hg-201/g. From day 10 to day 60, mink were fed the base diet supplemented with 0.175 +/- 0.024 mu g (MeHg)-Hg-201/g. Animals were sacrificed periodically to determine accumulation of (MeHg)-Hg-201 in blood and hair over the entire 60-d period and the elimination of (MeHg)-Hg-199 over the last 50 d. Hair samples, collected from each mink and cut into 2.0-mm lengths, indicate that both isotopes of MeHg appeared in the hair closest to the skin at approximately day 10, with concentrations in the hair reaching steady state from day 39 onward. The elimination rate of (MeHg)-Hg-199 from the blood was 0.05/d, and the ratio of MeHg in the hair to blood was 119. A large fraction of MeHg (22% to >100%) was stored in the hair, suggesting that in fur-bearing mammals the hair is a major route of elimination of MeHg from the body. Environ Toxicol Chem 2014;33:2873-2880. (c) 2014 SETAC