Fate of Endocrine Disrupting Compounds in the Aqueous Environment and the Associated Effects on Organisms (UBC)
Projektlaufzeit: 2005 - 2008
Prof. Dr. Hans Toni Ratte
Förderung durch EU (Marie Curie Programm Aquabase)
At present, a lot of research has been done concerning the effects of endocrine disrupting compounds after exposure of organisms via the surrounding water. However, there is limited data available on their environmental behaviour and fate. As the most potent xenoestrogens, such as 17a-ethinylestradiol (EE2), nonylphenol (NP) and Bisphenol A (BPA), are hydrophobic organic chemicals, they tend to concentrate in biota and bind to solid phases. Therefore further research should take into account the bioavailability of these substances, the possible exposure of and hazards for benthic biota and the possibility for food web transfer, bioaccumulation and mixture toxicity.
This project intends to examine the distribution pattern of two different test substances in a sediment-water system that functions as a habitat for several organisms related to one another in a food chain.
The chemicals, selected for this research, are p-NP and EE2, because of their known steroid hormone mimicking potencies, industrial relevance and relatively wide distribution in natural waters. In a first phase, larvae of the midge Chironomus riparius, that are sediment-dwelling organisms, will be exposed to the 14C-labelled isotopes of the test compounds, by different routes: through spiking the different compartments of the sediment-water system in all possible combinations and/or by feeding them spiked algae. The possible toxic effects of EE2 and p-NP on C. riparius, associated with the different exposure conditions, will be compared by means of chronic tests, based on the OECD Guidelines 218 and 219. Different endpoints will be considered: among others emergence, sex ratio and fecundity. Afterwards zebrafish (Danio rerio) will be involved to study among others food web transfer and the effectiveness of different exposure routes to stimulate e.g. vitellogenin induction.
The results of the different parts of this research will be coupled and compared to the output of good theoretical models. In this way, a lot of information should be delivered concerning the path of the tested compounds, covered from the external environment, via the water and/or through the food chain, to be metabolised in biota or distributed to the target organ(s) of (an) organism(s) for exhibiting toxic effects or to bind to solid phases like the sediment or organic matter.