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 u sing aquatic flowering plants (Ceratophyllum oryzetorum Kom., Ranuncul us trichophyllus Chaix. and Alisma plantago-aquatica L.) is reported i n this paper. It is based on the effect of simazine on the amount of o xygen produced by photosynthesis which is measured directly using a Cl ark-type oxygen electrode. This method is rapid, sensitive, and capabl e of measuring a simazine concentration of 0.02 mg litre(-1) within 10 min of treatment. The precision of this method was examined with spik ed river water by comparing the results obtained with HPLC. Mean recov eries of simazine measured by bioassay using C. oryzetorum were 96 to 100% which were comparable to those (98 to 100%) obtained with C18 col umn extraction and HPLC measurement. The results obtained by the two m ethods showed excellent agreement. Maintenance of stock cultures of th e plants and the bioassay procedure itself were much simpler and more easily conducted than methods using algae.