Greenland snow evidence of large scale atmospheric contamination for platinum, palladium, and rhodium

Since 1976 in the United States, Canada, and Japan; and later in other coun tries, the exhaust: system of gasoline powered cars has been equipped with catalytic converters containing Pt. and/or Pd and/or Rh. This has resulted in a very significant decrease in urban air pollution for various chemical species such as NOx, CO, and hydrocarbons. There has however been concern t hat their ever increasing use might lead to Platinum Group Metals (PGMs) be coming widely dispersed in the environment From the analysis of Pt, Pd, and Rh in central Greenland recent snow and ancientice using the ultrasensitiv e inductively coupled plasma sector field mass spectrometry technique, we s how here that the concentrations of these metals in snow dated from the mid 1990s are indeed similar to 40-120 times higher than in. ice dated from 70 00 years ago. The fact that such an increase is observed far away from popu lated areas at a high altitude location indicates there is now a large scal e contamination of the troposphere of the Northern Hemisphere far PGMs. Pt/ Rh mass ratio in the most recent snow samples, is close to the same ratio d ocumented for catalytic converter exhausts in a recent study; which suggest s that a large fraction of the recent increase. for: Pt and Rh might origin ate from automobile catalytic converters.