Biomonitoring of Pt and Pd with mosses

Abstract

Platinum (Pt), palladium (Pd), and rhodium (Rh) belong to the rarest element group in the lithosphere and biosphere. Their background values lie in the range of 0.1 ng.g-1 to 1 ng.g-1 (Wedepohl, 1995). However, since the introduction of Pt-containing auto catalyst converters during the 1970s in the USA and later in Japan and Europe, their concentrations in the environment, especially in the roadside environment, have increased rapidly (Lustig, 1997). Retrospective studies on airborne dust samples (Zereini et al. 1997) and ancient ice (Barbante et al. 2001) have facilitated the assessment of the environmental dispersion of these platinum group elements (PGE). Increases in the concentration of PGEs in the environment have been documented in numerous countries and matrixes (Ravindra et al. 2004). As a result, there is now a growing concern on the ecological and human risk of increasing concentrations of PGE in the environment. There have been several passive biomonitoring studies to investigate the bioaccumulation of platinum in animals and plants. An experiment of active biomonitoring of platinum has been performed using grass cultures (Dietl et al. 2000). Palladium bioaccumulation has been less documented as stated by Lustig and Schramel (2000). Moss analyses have been utilized successfully in the environmental biomonitoring of heavy metal atmospheric deposition studies during the past 30 years (e.g. Steinnes, 1995). Both active (using transplanted moss) and passive (using endogenous) monitoring methods have been developed and applied to the monitoring of inorganic and organic pollutants. The fol lowing sections examine the feasibility of using mosses to assess Pt and Pd pollution in the region of Paris, France, and compare the obtained data with those published on PGE biomonitoring using grass.