A bioassay for determining simazine in water using aquatic flowering plants (Ceratophyllum oryzetorum,Ranunculus trichophyllus and Alisma plantago-aquatica)

A simple and rapid bioassay for the measurement of simazine in water using aquatic flowering plants (Ceratophyllum oryzetorum Kom., Ranunculus trichophyllus Chaix. and Alisma plantago-aquatica L.) is reported in this paper. It is based on the effect of simazine on the amount of oxygen produced by photosynthesis which is measured directly using a Clark-type oxygen electrode. This method is rapid, sensitive, and capable of measuring a simazine concentration of 0.02 mg litre^?1 within 10 min of treatment. The precision of this method was examined with spiked river water by comparing the results obtained with HPLC. Mean recoveries of simazine measured by bioassay using C. oryzetorum were 96 to 100% which were comparable to those (98 to 100%) obtained with C18 column extraction and HPLC measurement. The results obtained by the two methods showed excellent agreement. Maintenance of stock cultures of the plants and the bioassay procedure itself were much simpler and more easily conducted than methods using algae.