Occurrence, fate and effects of pharmaceutical substances in the environment--a review.

Medical substances (pharmaceuticals) are a group of substances that until recently have been exposed to the environment with very little attention. The reason why they may be interesting as environmental micropollutants, is that medical substances are developed with the intention of performing a biological effect. Especially antibiotics used as growth promoters, as feed additives in fish farms are anticipated to end up in the environment.

The toxic effect of the antibiotic metronidazole on aquatic organisms.

The acute toxicity of metronidazole was tested on freshwater and marine organisms. The tests showed effect on Chlorella sp. and Selenastrum capricornutum.