Epsilon Archive for Student Projects

Abstract

Imagine one drop of food coloring in 70 million liters of water. This low concentration equals one nanogram per liter, which is the level most steroid hormones are effective at. Steroids are produced and excreted by our bodies and are in charge of our hormonal processes, for example the development of sex organs, menstrual cycle and sperm production. But they are also produced synthetically and commonly used as an effective growth stimulator for aquaculture and agriculture or hormonal contraception such as contraceptive pills, IUDs and implants. When excreted by our bodies, these steroids end up in wastewater. Unfortunately, many studies have shown that common wastewater treatment plants fail to fully remove these chemicals, and they are potentially released to rivers and lakes. There, they interfere in hormonal processes of fish, amphibian and mammal species and thus pose a big threat to ecosystems. Worst of all, even unimaginably low concentrations, which are difficult to detect, can lead to these effects.

This study developed a sensitive measurement technique, which can detect and quantify such low concentrations. With this method, levels of eleven natural and synthetic steroids were measured in the inlet and outlet of a Swedish wastewater treatment plant. All out of the tested steroids were found in the inlet water, while five steroids were found in the outlet water. This study indicates an insufficient removal of most tested steroid hormones and stresses the need of steroid screening in Swedish freshwaters.