In a new paper in Geology Sanei et al. (abstract) address the potential impact of mercury loading from the Siberian Traps during the end-Permian event. Mercury is one of the most toxic elements on our planet, and one that cause much concern from an environmental perspective seing as it is very persistent and has long-ranging impact on biota.
Coupling new mercury data with their previously published carbon-isotope and coal-fly-ash events in the Permian-Triassic boundary succession of the Sverdrup Basin (Grasby et al., 2011) they propose that suppressed organic productivity due to deteriorating environmental conditions in the basin lead to catastrophic build-up of dissolved mercury in the sea.
The excess dissolved mercury could not be removed until conditions turned extreme euxinic and sulfide-mercury drawdown commenced.
It will be interesting to see if mercury-toxicity events are associated with other major volcanic events in Earth’s history!