Phytotoxicity to and uptake of flumequine used in intensive aquaculture onthe aquatic weed, Lythrum salicaria L.

Phytotoxicity of Flumequine on the aquatic weed Lythrum salicaria L. was de termined by two laboratory models: a single concentration test, by which th e effects of 100 mg l(-1) were evaluated after 10, 20, 30 days and a multip le concentration test, by which the effects of 5000-1000-500-100-50 mu g l( -1) were evaluated after 35-day exposure. 100 mg l(-1) are highly toxic and significantly decrease the growth of plants; this effect increases with ti me. Concentrations between 5000 and 50 mu g l(-1) induced hormesis in plant s, by significantly increasing mean number and dimension of leaves and seco ndary roots. The effect is the highest at 50 mu g l(-1) and decreases with increase in concentration. Both toxic effect and hormesis can be related to plant drug uptake, quite high, in the order of mu g g(-1). The ecological implication of Flumequine contamination in aquatic environments and the pos sible use of Lythrum salicaria for bioremediation and/ or monitoring techni que are discussed. (C) 2000 Elsevier Science Ltd. All rights reserved.