Concentrations of Pt, Pd and Rh in soil and vegetation: A review

Automotive catalysts play an important role in the work of exhaust systems, reducing emissions of gaseous pollutants such as carbon monoxide (CO), nitrogen oxides (NOx) and hydrocarbons (HC) by more than 75%. However, hot exhaust gases that pass through the automotive catalyst cause platinum (Pt), palladium (Pd) and rhodium (Rh) emissions into the environment. Platinum group elements (PGE) and their complex salts represent a potential risk to human health, causing serious health problems (asthma, allergies). Previous research in the world related to the levels of PGE in the environment shows that these elements can be found in all components of the environment (air, water, soil, plants, road dust, ash, sewage sludge and shellfish). So far there is no data about levels of the mentioned metals in other environmental matrices (vegetation and soil) in our country, except in the air. The results of studies conducted in other countries indicate that Pt, Pd and Rh occur in elevated concentrations in the soil in urban areas (along the road) in relation to their naturally present proportion in the lithosphere. It has also been found that plant species due to emission sources accumulate these elements in their tissue and can translocate them into their upper organs. This review will give an insight into the state of platinum group elements worldwide in soil and vegetation.