There has been recent concern regarding the possibility of antibiotics entering the aquatic food chain and
impacting human consumers. This work reports experimental results of the bioconcentration of the antibiotic
oxytetracycline (OTC) by the Asian watermeal plant (Wolffia globosa Hartog & Plas) and bioaccumulation
of OTC in watermeal and water by the seven-striped carp (Probarbus jullieni). They show, for the
first time, the extent to which OTC is able to transfer from water to plant to fish and enter the food chain.
The mean bioconcentration factor (dry weight basis) with watermeal was 1.28 103 L kg1. Separate
experiments were undertaken to characterize accumulation of OTC by carp from water and watermeal.
These showed the latter pathway to be dominant under the conditions employed. The bioconcentration
and biomagnification factors for these processes were 1.75 L kg1 and 2 104 kg g1 respectively. Using
an aqueous concentration range of 0.34–3.0 lg L1, hazard quotients for human consumption of contaminated
fish of 1.3 102 to 1.15 101 were derived.