Expertise

 

Bioassays; incredible valuable information for water quality research

Using bioassays as a reliable instrument to determine the safety of our drinking water is one of the expertise areas of Het Waterlaboratorium. Bioassays are methods that directly determine the effect of chemicals on living cells. Due to the sensitivity of bioassays, they are suitable for the detection of very low concentrations of chemicals in water that may pose a health risk. They give an indication of harmful substances in water. With this expertise, Het Waterlaboratorium has a leading position in the Netherlands. Also, Het Waterlaboratorium investigates bioassays on how to apply them even more widely..

A closer look at definitions

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Bioassays help to determine whether the drinking water is safe. The safety of the drinking water from the consumers is of high importance which is the reason why Het Waterlaboratorium uses bioassays. Therefore, bioassays are also used in the measurement programs of the drinking water companies. Applying bioassays fits well in the desire to obtain a broader picture in measuring target analytes and their toxicity in water. Besides, bioassays help in additional research to get more insight in the purification steps and therefore support the continuous improvement of water purification processes.

Each bioassay is specifically targeted at measuring one biological effect which is caused by chemicals being a potential risk for humans at a certain concentration. Het Waterlaboratorium has a selection of bioassays that together can trace back the most relevant biological effects for humans by certain groups of chemicals in drinking water. This concerns the following toxicological endpoints:

  1. Breakdown of foreign substances (xenobiotic metabolism) such as the activation of the Ah receptor by PAHs.
  2. Disruption of hormone balance by for example oestrogenic, androgenic, glucocorticoid and progestogenic substances and their antagonists
  3. Unwanted reactivity (reactive modes of action) such as DNA damage
  4. Adaptive stress response
  5. Cell damage (cytotoxicity)

For most of the endpoints, Het Waterlaboratorium uses CALUX® bioassays. These are reporter gene assays that uses genetically modified human cell lines in which specific effects can be measured by means of a light reaction. Besides, Het Waterlaboratorium uses various Salmonella stems originating from the Ames test for measuring DNA damage. Bioassays are not only useful for the drinking water companies but they are also interesting for other companies and institutions which want to gain more insight of their water quality. The amount of bioassays that Het Waterlaboratorium offers, is constantly growing. Besides, if requested by customers, it is possible to use new kinds of bioassays. Het Waterlaboratorium is happy to tell you the most recent developments in the field of bioassays.

 

Effect-directed Analysis

A bioassay measures a particular effect of a chemical but does not identify the chemical itself. If an unexpected or increased bioassay response occurs, the question remains: which chemical is responsible for this effect? To answer this question, Effect Directed Analysis is used. Effect Directed Analysis is a combination of bioassays, liquid chromatography and screening. The extract of a water sample is being separated with a LC-column. The eluate is split in parts and one part of it is sent to a mass spectrometer. The other part is collected in very small fractions and every fraction is then tested in a bioassay with a relevant effect as endpoint such as genotoxicity or hormone disruption. The fractions which showed an effect contain a relevant chemical. The fractions correspond to a certain peak of the same chemical at the same retention time in the mass spectrometer. By using targeted or untargeted screening, the identity of the chemical is being discovered. The availability of this platform at Het Waterlaboratorium is unique in the water sector. More information can be found here:https://pubs.acs.org/doi/pdfplus/10.1021/acs.est.7b06604

Click here to see which bioassays are currently being offered

 

 
 
 
 

Contact our specialist

Corine Houtman

Toxicologist
corine.houtman@hetwaterlaboratorium.nl
023 517 59 00