Impact of platinum group metals on the environment: A toxicological, genotoxic and analytical chemistry study

Recent studies show particles of Platinum Group Metals (PGMs); primarily platinum, palladium and rhodium; released from automobile catalytic converters are being deposited alongside roadways. This deposition is leading to increasing concentrations of PGMs in the environment, raising concerns about the environmental impact and toxicity of these elements in living organisms. The objective of this study was to determine how PGMs alter the patterns of growth, development, and physiology by studying the toxicological and genotoxic effects of these metals. Two vastly different species were used as models: plant - a wild wetland common Sphagnum moss, and animal - 6-week old rats Sprague-Dawley. Both species were exposed, in controlled environments, to different concentrations of the PGMs. Toxicological and genotoxic effects were determined by assessment of plant growth, animal survival and pathology, and influence on DNA in both models. Our results on the uptake of PGMs by Sphagnum showed significant decreases in plant length and biomass as PGM concentration increased. Histological and pathological analysis of the animal model revealed vacuolization, eosinophil inclusion bodies in adrenal glands, shrinkage of glomeruli in the kidney, and enlargement of white pulp in the spleen. In both models, DNA damage was detected. Chemical analysis using ICP-AES atomic absorption demonstrated accumulation of PGMs in plant tissues at all PGM levels, proportional to concentration.