Mountain forest fire ash flushed into the eastern coastal waters of South Korea is known to contain cadmium as one of its significant constituents. To study its impact, two representatives of the micro- and macroalgal communities, Ulva pertusa and Nannochloropsis oculata, were exposed to the concentration range of Cd indicated from the forest fire localities. At low concentrations of 0.224-0.448 mg L-1, a 20% reduction in growth rate of N. oculata was observed. Chlorophyll a pigment concentration was proportionate to the growth reduction while at higher concentrations (1.792 mg L-1) pigments were completely leached. In the macrophyte U. pertusa, a similar trend of pigment leaching was observed. Bioaccumulation factors obtained for these rapidly growing algal species revealed excessive bioconcentration of Cd. Variations in the concentration of Cd among the samples collected along the Korean coast clearly indicated the additional source of metal influx from the forest fires. © 2002 Elsevier Science Ltd. All rights reserved.