Evaluation of river model biofilm for assessing pesticide effects: a case study with atrazine

The dose response of the biological parameters of the model river biofilm, consisting of two diatom strains and three bacterial strains on the glass surface, was examined with atrazine. Good correlations (r^2=0.90-0.93) between the atrazine log concentration and the relative increase rates of microbial cell numbers and the amount of chlorophyll a in the model biofilm formation were shown, and similar EC_<50> values for the biological parameters including esterase activity were tentatively obtained as an endpoint. The results suggested that this model biofilm could be used for testing the potential effects of pesticides on natural river biofilms at a community level with high reproducibility.