PW07 Pesticides and Pharmaceuticals
Exhibit Hall
8:00 AM - Wednesday, 12 November 2003
(PW110) Comparative Toxicity of a Copper Containing Algaecide to Four Algal Species.
Duke, B1, Rodgers, J1, 1 Clemson Institute of Environmental Toxicology, Pendleton, SC, USA
ABSTRACT- The toxicity of copper to vascular and nonvascular aquatic plants is affected by various physiochemical attributes of site water, including hardness, alkalinity and pH. For this study, responses of 4 algal species (Prymnesium parvum, Raphidocelis subcapitata, Nanochloris sp, Anabaena sp.) to exposure of a chelated copper algaecide (Cutrine®-Plus) were observed. Specific objectives of this study were: 1) to compare the toxicity of Cutrine®-Plus, a copper-containing algaecide, to four different species of algae, and 2) to compare the performance of Cutrine®-Plus in waters with different characteristics. The characteristics of interest for this study included pH, alkalinity, hardness and density of algae. Alkalinity and hardness ranged from 32 to 130 mg / L as CaCO3, and 52.7 to 696 mg / L as CaCO3, respectively. The pH of these waters ranged from 7.4 to 8.3. Densities of each algal species, Prymnesium parvum, Raphidocelis subcapitata, Nanochloris sp. and Anabaena sp., were 2.1x 105, 1.1x 106, 2.2x 105 and 1.7x 105 cells / ml, respectively. Algal control (loss of algae from the water column) was obtained at 0.2 mg Cu / L for all algae, except for Nanochloris sp. Control of Nanochloris sp. was obtained at 0.75 mg Cu/ L. Algal toxicity experiments using site-specific waters provide treatments for specific algal species and densities, while minimizing exposures that may be harmful to non-target species. Risk-based decisions to use copper-containing algaecides are facilitated when the target algal species (e.g. Prymnesium parvum), produce a potent toxin.
Key words: Algae, Toxicity, Copper, Algaecide