Short-term toxicity and binding of platinum to freshwater periphyton communities

The release of platinum (Pt) from automobiles equipped with exhaust catalysts has resulted in increasing concentrations of this normally rare metal in the urban and roadside environment. Although concentrations are increasing, little is known about the environmental effects of Pt and its potential toxicity. This study was an investigation of Pt toxicity to naturally grown periphyton communities. Periphyton communities were exposed to Pt(II) and Pt(IV) in reference and stream waters. Uptake increased linearly with Pt concentration for both reference- and stream-water exposure. However, decreased photosynthetic activity was observed only for reference-water exposure. This difference was related to uptake by biotic components in reference water and binding to abiotic components in stream water.