Bioconcentration of copper and zinc by a laboratory-cultured bryophyte, Hygrohypnum ochraceum, exposed to the metals in a diluter sytem

The aquatic bryophyte Hygrohypnum ochraceum was exposed to copper and zinc in a laboratory diluter system to determine if the bioconcentrations of cop per and zinc would be similar to those investigated in field exposures. The plants were collected from a pristine area in southwestern Colorado, cultu red in the laboratory, and then exposed to binary concentrations of copper and zinc for 21 days. Tissue samples were collected weekly and analyzed for metals. Results showed that tissue-metal bioconcentration factors were nea rly 390,000 (Cu) and nearly 90,000 (Zn) times the metal concentrations in t he test water. These data are similar to the research of others when the pl ants were exposed to ambient metal conditions in field studies. We found co nsiderable variation in the uptake of metals among replicate samples, and f urther analyses suggested one explanation is the differential degrees of me tal absorption by different portions of the plant.