Assessment of selenium toxicity in algae using turbidostat culture

Abstract

The sublethal toxicity of selenium (sodium selenate) was assessed for Chlorella pyrenoidosa using turbidostat culture techniques. In this system the maximum specific growth rate of the population, μ m, was a dependent variable monitored in real-time vs selenium concentration. There was a near linear decrease in steady-state μ m in response to 4 selenium concentrations (control, 0.53, 0.90 and 1.37 μg ml −1) with a μ m IC 50 (toxin concentration which inhibits a growth parameter by 50%) of 0.80 μg selenium ml −1 at a sulfur concentration of 2.70 μg ml −1. Transient changes in μ m between steady states were also quantified using this system. The usefulness of the systems' ability to measure adaptation and recoverability of a population to toxins is discussed.