No-effect concentrations in algal growth inhibition tests

We propose three simple models for effects of chemical compounds on the growth of batch cultures of algae that allow the estimation of the no-effect concentration. The growth model assumes that the costs for growth is proportional to the concentration that exceeds the no-effect level. The hazard model assumes that the hazard rate is proportional to the concentration that exceeds the no-effect level. The adaptation model is similar to the hazard model, but the effects only occur at the start. The no-effect concentrations of the three models turn out to be very similar.