Effects of sulphadimethoxine on cosmopolitan weeds (Amaranthus retroflexus L., Plantago major L. and Rumex acetosella L.)

Animal wastes from intensive farming are generally collected for field fertilisation. They may contain drugs that can become soil pollutants. The effect of such contamination on terrestrial biota has been demonstrated in laboratory tests on different plant species, using a common antimicrobial, sulphadimethoxine. In the near future, the monitoring of antimicrobial contamination in arable lands and their crops will be of importance for the protection of natural ecosystems and consumers. A possible tool for this monitoring is the use of weeds that can constitute a 'mesh' from which antimicrobial contamination can be detected. In laboratory tests, some direct effects of sulphadimethoxine contamination were demonstrated on normal development and growth of three cosmopolitan weed species, Amaranthus retroflexus L., Plantago major L. and Rumex acetosella L. These effects depended on the very high accumulation rates in plants (thousand mu g g(-1)). P. major accumulated the highest amount of drug followed by A. retroflexus and R. acetosella. These data further highlight the environmental risk of sludge application on soils and the possible contamination of food nets; but also give a potential tool for the monitoring of antimicrobial soil contamination. (C) 1997 Elsevier Science B.V.