Georgia Journal of Science


Metal pollution from anthropogenic sources can pose a threat to aquatic systems. Silver is released into the environment from various industrial processes. In excess, silver can accumulate and cause adverse effects in aquatic organisms, particularly those in lower trophic levels, such as phytoplankton. Water chemistry parameters, such as hardness, have been shown to modify toxicity of metals because divalent cations compete with the metal for binding sites on the biological membrane. The objective of this study was to assess population growth and silver accumulation in the green alga, Raphidocelis subcapitata, after silver exposure in waters of varying hardness for 7 d. Throughout the exposure period, a decrease in algal cell density was observed with increasing silver concentrations. Silver accumulation in the algae decreased and cell density increased with increasing water hardness. Additionally, at least some degree of protection was observed against silver toxicity due to increased water hardness.