Monday, October 22, 2007 : 11:10 a.m.

Thyroid Hormone Disrupting Activity in the Rhine River

Peter G.M. Stoks, RIWA , Association of River Water Works and Leo M. Puijker, Kiwa Water Research

The Rhine Waterworks Association, RIWA, is an organization in the Netherlands in which the water utilities along the river Rhine have been working together for over 50 years in an attempt to reduce the levels of pollutants in their source water. One of the instruments RIWA employs is a joint monitoring program in which chemical, as well as microbiological water quality variables are being studied. In addition, special surveys are carried out in which effects are determined rather than specific individual substances. During more than one year monthly measurements were conducted for thyroid hormone activity in surface water, both at intake sites for drinking water production and at the Dutch-German border where the Rhine river enters the Netherlands. A competitive binding assay was used in which a derivative of the natural tetraiodothyronine (T4), bound to a sensor, is incubated with several specific binding proteins in the presence of T4 as a standard, or in the presence of water sample extracts. Components present in the water extract showing an affinity for the binding proteins and thus indicate a thyroid activity, will cause a decrease of the binding to the sensor. In over half of the samples investigated a clear activity was observed, well over the detection limit of around 5-6 nM (expressed as T4). Since these are exploratory measurements only, adequate caution is called for in the interpretation of the results. Based on metabolic considerations the activity found in the water samples is most likely due to other substances than the naturally occurring T4. Little is known, however, about the possible nature of such substances. Therefore, no conclusive statements can, as yet, be made about their removal efficiencies during drinking water treatment steps and the potential relevance for the drinking water production.

Peter G.M. Stoks, RIWA , Association of River Water Works Dr Peter G Stoks is the director of RIWA, the Dutch Association of Rhine Water works; an organization founded by those water works using Rhine river water as their drinking water source. RIWA aims to achieve a source water quality allowing simple treatment only, for the production of good quality drinking water. His professional interests are general water management and monitoring, especially effect-oriented monitoring and early warning. His background is in analytical chemistry.


[ Manuscript ] Manuscript

6th International Conference on Pharmaceuticals and Enocrine Disrupting Chemicals in Water