Medicine residues can threaten fish

GOTHENBURG, Sweden, April 12 (UPI) -- Swedish scientists say traces of many medicines can be found in fish swimming in treated wastewater, with some of the drugs leading to fish infertility.

Researchers from Umea University and the Sahlgrenska Academy at the University of Gothenburg, Sweden, said one such medicine, the hormone levonorgestrel, was found in higher concentrations in the blood of fish than in women who take the contraceptive pill.

The fish in the study were exposed to treated wastewater from three sewage treatment plants in Stockholm, Umea and Gothenburg. The study showed levonorgestrel can affect the environment and constitutes a risk factor for the ability of fish to reproduce. Levonorgestrel is designed to mimic the female sex hormone progesterone and is produced synthetically.

A previous study from Germany showed less than a billionth of a gram of levonorgestrel per liter inhibited the reproduction of fish in aquarium-based trials.

"If we know how our medicines affect the environment, we will be in a better position to choose environmentally friendly alternatives, though we must always put the health of patients first," said Joakim Larsson at the Sahlgrenska Academy, one of the study's researchers.

The findings appear in the journal Environmental Science and Technology.