Ruthenium, Rhodium, Palladium, and Osmium

Abstract

Ruthenium, rhodium, palladium, and osmium are four of the six platinum group metals (the other two are iridium and platinum). These naturally occurring metals are often found in the environment (e.g., airborne) due to their use in vehicle exhaust catalysts and consequent release in car exhaust from catalytic converters. The toxicity, absorption, distribution, and excretion of ruthenium, rhodium, palladium, and osmium and/or their complexes are generally dependent on the route of exposure/administration. These compounds also tend to be skin and eye irritants. Sensitization is often a concern when handling and/or exposed to these metals in the occupational setting as sensitization reactions to each of these metals and/or their complexes (aside from osmium) have been reported. Additionally, cross‐reactions (positive prick tests) in humans have been observed to platinum, palladium, iridium, and rhodium as well as to palladium and nickel. Environmental monitoring studies for several of these metals have found that the (airborne) levels are expected to be below the values thought to cause adverse health effects in humans.