Light-emitting diodes for the illumination of algae in ecotoxicity testing.

Ecotoxic effects of chemicals, preparations, and environmental samples are routinely quantified in standardized algae growth inhibition tests using microalgae like Desmodesmus subspicatus. The intention of this investigation was to prove the suitability of light-emitting diodes (LEDs) as an alternative to tubular discharge lamps in algae growth inhibition tests. This was approached by demonstrating that growth of algae was similar with both illuminating devices. Growth factors of growth controls were determined using LEDs. Growth curves of different light intensities of LEDs were compared with those of tubular discharge lamps. By testing certain chemicals with both illumination methods comparable results for E(r)C50 values were obtained. It could be shown that small-scale construction of incubators using LEDs is possible and could be advantageous, especially for the illumination of algae in 96-well microplate growth inhibition assays.