Testing and comparing bioassays
Broad view of hormone disruptors
The Global Water Research Coalition (GWRC) is a worldwide network of research institutes engaged in collaborative projects in the water sector. KWR researcher Merijn Schriks is working within the GWRC on international research into endocrine disrupting compounds (EDC).
The GWRC has been researching estrogen compounds since 2007. These compounds are able to affect the sex hormones of fish, causing a feminisation of the fish populations. “It’s too simple to say that fish populations die out because of the disappearance of the males,” stresses Schriks. “Because research also shows that populations can recover as well. But the presence of sex hormones in the water is naturally not a desirable situation. They don’t belong there.” The EDC II-Toolbox has been developed for the purpose of better measuring and monitoring endocrine disrupting compounds. “Being able to measure more sensitively and broadly is important, because there is a knowledge gap concerning which hormone-disrupting chemical compounds are in the water and how they influence the environment.”
The EDC II-Toolbox makes use of bioassays, that is, living cell material that reacts to compounds. “Bioassays are biological measurement systems, which constitute a valuable complement to the existing arsenal of analytical chemical techniques,” says Schriks. “With bioassays you don’t look directly at specific compounds, but at what the water, as a whole, does to an organism, such as a water flea, or to cells.” Research – including that conducted within the European DEMEAU project – has already shown that bioassays can lead to completely different conclusions compared to those produced by standard analytical chemical measurements. “For the EDC-Toolbox, we conduct tests using a variety of bioassays alongside each other to determine which is the most sensitive,” says Schriks. But the different bioassays also serve different objectives. “If you want to be able to say something about the water quality for ecosystems, then water fleas work well. If you also want to say something about human health, then you can turn to systems that make use of animal or even human cells.”
“We want to know which hormone-disrupting chemical compounds are in the water and how they influence the environment.”
Within the GWRC project, Schriks and his colleagues are focusing on the presence of chemical compounds that disrupt the functioning of thyroid gland hormones. In 2014, an extensive meta-analysis is being carried out into the practicability of bioassays for androgen and progestagen activity. The researchers will then test ten reference compounds: compounds that resemble the hormone. In phase 2, the field samples will tested to determine which bioassays, based on their level of sensitivity, are the most suitable to monitor the hormone. Lastly, Schriks will be creating a work plan to instruct laboratories from Australia all the way to North America on the use of bioassays. Other partners in the project are WaterRA and WSAA (Australia), TZW (Germany) and VERI/VEOLIA (France).
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Scientific researcher, toxicologist and Project Manager