Here we present GEM depletion events in dilute and moderately aged (~3-7 hours) volcanic plumes from Piton de La Fournaise on La Réunion Island, observed ~38.5 km away at Maïdo mountain observatory (2160 masl). With the help of a large set of ancillary observations, we thoroughly describe the observed GEM depletions, explore possible drivers, and discuss implications for the atmospheric Hg budget.