Study demonstrates the strength of ht-EDA platform.

Recently Het Waterlaboratorium published a study in cooperation with the Faculty of Science, department Environment and Health of the Free University Amsterdam in which the hr-EDA platform was used for  the  identification of  bioactive compounds in  environmental samples and shed light on the drivers of (anti-)progestogenic and (anti-)androgenic activities in the aquatic environment.

The quality of surface waters is threatened by pollution with low concentrations of bioactive chemicals, among which those interfering with steroid hormone systems. Induced by reports of anti-progestogenic activity in surface waters, a two-year four-weekly survey of (anti-)progestogenic activity was performed at three surface water locations in the Netherlands that serve as abstraction points for the production of drinking water. As certain endogenous and synthetic progestogenic compounds are also potent (anti-)androgens, these activities were also investigated. Anti-progestogenic and anti-androgenic activities were detected in the majority of the monitoring samples, sometimes in concentrations exceeding effect-based trigger values, indicating the need for further research. To characterize the compounds responsible for the activities, a high resolution Effect-Directed Analysis (hr-EDA) panel was combined with PR and AR CALUX bioassays, performed in agonistic and antago-nistic modes. The influent and effluent of a domestic wastewater treatment plant (WWTP) were included as effluent is a possible emission source of active compounds. As drivers for androgenic and progestogenic activities several native and synthetic steroid hormones were identified in the WWTP samples, namely androstenedione, testosterone, DHT, levonorgestrel and cyproterone acetate. The pesticides metolachlor and cyazofamid were identified as contributors to both the anti-progestogenic and anti-androgenic activities in surface water. In addition, epiconazole contributed to the anti-progestogenic activities in the rivers Rhine and Enclosed Meuse. This  study showed the  strength of  hr-EDA for  the  identification of  bioactive compounds in  environmental samples and shed light on the drivers of (anti-)progestogenic and (anti-)androgenic activities in the aquatic environment.

You can download the publication here


Contact our specialist

Corine Houtman

023 517 59 00

Overview of Publications

Our website is full of examples of research we carry out for various clients. We usually publish the results in reports, memos or presentations. Often these publications are only intended for the client, and therefore are not public. However, we also publish studies in public literature and scientific journals. Below, we provide an overview of the scientific publications that we have published in recent years. Also, collaborations with other international research institutions and universities are provided.


  • Rietjens, I. M. C. M., Schriks, M., Houtman, C. J., Dingemans, M. M. L., & van Wezel, A. P. (2022). Letter to the Editor on Bil et al. 2021 “Risk Assessment of Per- and Polyfluoroalkyl Substance Mixtures: A Relative Potency Factor Approach”. Environmental Toxicology and Chemistry41(1), 7-12.
  • Brekelmans, S., Slootweg, T., Houtman, C.J. 2021. Effect Directed Analysis achterhaalt verantwoordelijke stoffen voor bioassayrespons. H2O-online 7 oktober 2021
  • Corine J. Houtman, Kevin Brewster, Rob ten Broek, Bente Duijve, Yvonne van Oorschot, Martine Rosielle, Marja H. Lamoree, Ruud J.C.A. Steen, Characterisation of (anti-)progestogenic and (anti-)androgenic activities in surface and wastewater using high resolution effectdirected analysis, Environment International, Volume 153, 2021, 
  • Been, F., Pronk, T., Louisse, J., Houtman, C., van der Velden-Slootweg, T., van der Oost, R., Dingemans, M. 2021. Development of a framework to derive effect-based trigger values to interpret CALUX data for drinking water quality. Water Research 193
  • E. Pieke, Onderzoek: Vrijwel geen microplastics in drinkwater, H2O-actueel, 2021


  • TJH Jonkers, M Steenhuis, L Schalkwijk, J Luirink, D Bald, CJ Houtman, J Kool, MH Lamoree, T Hamers. 2020. Development of a high-throughput bioassay for screening of antibiotics in aquatic environmental samples. Science of The Total Environment 729.
  • Houtman CJ, ten Broek R, van Oorschot Y, Kloes D, van der Oost R, Rosielle M, et al. High resolution effect-directed analysis of steroid hormone (ant)agonists in surface and wastewater quality monitoring. Environmental Toxicology and Pharmacology. 2020;80:103460. .
  • Kooijman G, de Kreuk M, Houtman C, van Lier J. Perspectives of coagulation/flocculation for the removal of pharmaceuticals from domestic wastewater: A critical view at experimental procedures. Journal of Water Process Engineering. 2020;34:101161.
  • Zwart, N., Jonker, W., Broek, R.t., de Boer, J., Somsen, G., Kool, J., Hamers, T., Lamoree M.H. and Houtman, C.J. (2020) Identification of mutagenic and endocrine disrupting compounds in surface water and wastewater treatment plant effluents using high-resolution effect-directed analysis. Water Research 168, 115204.


  • L.W. Jonker, K. de Vries, N. Althuisius, D. van Iperen, E. Janssen, R. ten Broek, C.J. Houtman, N. Zwart, T. Hamers, M.H. Lamoree, B. Ooms, J. Hidding, J. Kool, G. Samson. Compound Identification Using Liquid Chromatography and High-Resolution Noncontact Fraction Collection with a Solenoid Valve, SLAS Technology 1-13, (2019):
  • C.J. Houtman, J. Kroesbergen, P.K. Baggelaar,J.H.M. van Lieverloo. Statistical analysis of a large set of semi-quantitative GC–MS screening data to evaluate and prioritize organic contaminants in surface and drinking water of the Netherlands. Science of the Total environment 697 (2019).


  • L. Zlatanovic, A. Knezev, J.P. van der Hoek, J.H.G. Vreeburg. Influence of an Extended Domestic Drinking Water System on the Drinking Water Quality. Water 2018, 10.
  • G.L Ya Zhang, E. van der Mark, A. Knezev,  A. Pinto, B. van den Bogert, W. Liu, W. van der Meer, G. Medema. Assessing the origin of bacteria in tap water and distribution system in an unchlorinated drinking water system by SourceTracker using microbial community fingerprints.  Water Research 138 (2018) 86-96.
  • M. Sousi, G. Liu, S.G. Salinas-Rodriquez, A. Knezev, B. blankert, J. Schippers, W. van der Meer, M.D. Kennedy. Further developing the bacterial growth potential method for ultra-pure drinking water produced by remineralization of reverse osmosis permeate. Water Research 145 (2018) 687-696.
  • S.A. Boers, E.I. Prest, M. Tauèer-Kapteijn, A. Knezev, P.G. Schaap, J.P. Hays, R. Jansen. Monitoring of microbial dynamics in a drinking water distribution system using the culture-free, user-friendly, MYcrobiota platform. 2018.
  • N. Zwart, M.H. Lamoree, C.J. Houtman, J. de Boer, J. Kool, T. Hamers. Development of a luminescent mutagenicity test for high-throughput screening of aquatic samples. Toxicology in Vitro 46, (2018) 350-360.
  • N. Zwart, S.L. Nio, C.J. Houtman, J. de Boer, J. Kool, T.Hamers, M.H. Lamoree. High-Throughput Effect-Directed Analysis Using Downscaled in Vitro Reporter Gene Assays To Identify Endocrine Disruptors in Surface Water. Environmental Science & Technology 2018, 52, 4367-4377.
  • C.J. Houtman (HWL), R. ten Broek (HWL), A. Brouwer (BioDetection systems / Faculty of Earth and Life Sciences).  Steroid hormonal bioactivities, culprit natural and synthetic hormones and other emerging contaminants in waste water measured using  bioassays and UPLC-tQ-MS. Science of the Total Environment 630 (2018), 1492-1501.


  • M. Tauèer-Kapteijn, W. Hoogenboezem, G.J. Medema. Source tracking of E. moraviensis and E. haemoperoxidus. Journal of Water and Health 15 (1)  41-49, 2017.
  • N. Zwart, D. Andringa, W.J. de Leeuw, H. Kojima, M. Iida, C. J. Houtman, J. de Boer, J. Kool, M.H. Lamoree, T. Hamers. Improved androgen specificity of AR-EcoScreen by CRISPR based glucocorticoid receptor knockout. Toxicology in vitro 45, p. 1-9, 2017.
  • C.J. Houtman, J. kroesbergen, P. Behnisch, A. Brouwer, E. Felzel. Bioassays als alternatief voor de chemische monitoring van PCB's en PAK's? H2O-online 31 oktober 2017.
  • N. Zwart, M.H. Lamoree, C.J. Houtman, J. de Boer, J. Kool, T. Hamers, Development of a luminescent mutagenicity test for high-throughput screening of aquatic samples, Toxicology in Vitro, 2017.
  • S. van Nevel, S. Koetzsch, C.R. Proctor, M.D. Besmer, E.I. Prest, J.S. Vrouwenvelder, A. Knezev, N. Boon, F. Hammes. Flow cytometric bacterial cell counts challenge conventional heterotrophic plate counts for routine microbiological drinking water monitoring. Elsevier, Water Research 113 191-206, 2017.
  • C.J. Houtman, R. ten Broek, P. Behnisch, J. Kroesbergen. Investigation of chemical compounds in the water cycle with combinations of bioassays and chemical-analytical techniques. 10th BioDetectors Conference, Sorrento Italy, 6-7 April 2017.


  • B. Martijn, A. v. Rompay, E. Penders, Y. Alharbi, P. Baggelaar, J. Kruithof, I. Rietjens. Development of a 4-NQO TEF approach to enable a preliminary risk assessment of unknown genotoxic compounds detected by the Ames II in UV/H2O2 water treatment samples. Elsevier Chemosphere 144 p338-345, 2016.
  • M.M. Bazri (University of British Columbia), B. Martijn (PWN), J. Kroesbergen (HWL), M. Mohseni (University of British Columbia). Impact of anionic ion exchange resins on NOM fractions: Effect on N-DBPs and C-DBPs precursors, Chemosphere 144, 1988-1995, 2016.
  • A. Knezev (HWL), M. Dignum (Waternet). The ATP measurement and flow-cytometry are better parameters for the assessment of general microbial water quality in drinking water treatment than the HPC. IWA Specialist Conference Microbial Ecology and Water Engineering 2016.
  • M. Taucer-Kapteijn et al. 2016.Screening municipal wastewater effluent and surface water used for drinking water production for the presence of ampicillin and vancomycin resistant enterococci. International Journal of Hygiene and Environmental Health 219, 437–442, 2016.
  • M. Tauèer-Kapteijn, W. Hoogenboezem, G.J. Medema. Environmental growth of the faecal indicator Enterococcus moraviensis. Water Science and Technology: Water Supply 16(4), 971-979, 2016.


  • A. Knezev, H. Smidt, D. van der Kooij. Concentration, identity and behaviour of bacteria predominating in Granular Activated Carbon filters in drinking-water treatment. GACF abstract Iwa biofilm 2015.
  • A. Knezev, Microbial Activity in Granular Activated Carbon filters in drinking-water treatment. PhD thesis, WUR,
  • A. Knezev, S. Strating, B. Lohman. Assessment of the integrity of abstraction system with flowcytometry. Abstract, 2015.
  • A. Knezev, L. Zandvliet, W.A. Oorthuizen, E.J. van der Mark. Value of ATP and Total Cell count for the assessment of general microbial water quality after sand filtration. In Progress in slow sand and alternative biofiltration processes. Pp.51-58. 2014.
  • C.J. Houtman, B.J. Pieters, I. Velzeboer, J. Kroesbergen, Organische stoffen in het Drinkwaterbesluit: 1. Hoe geven we invulling aan de eisen voor 'overige' antropogene stoffen, H2O-Online, 12 oktober 2015
  • C.J. Houtman, I. Velzeboer, T. Slootweg, J. Kroesbergen, Organische stoffen in het Drinkwaterbesluit: 2. Monitoring van 'oude' stoffen, H2O-Online, 12 oktober 2015.
  • A.H. Knol, K. Lekkerkerker-Teunissen, C.J. Houtman, J. Scheideler, A. Ried, J.C. Van Dijk. Conversion of organic micropollutants with limited bromate formation during the Peroxone process in drinking water treatment. Drinking Water Engineering and Science, 8 (2015) 25-34.
  • W. Jonker, M.H. Lamoree, C.J. Houtman, T. Hamers, G.W. Somsen, J. Kool. Rapid activity-directed screening of estrogens by parallel coupling of liquid chromatography with a functional gene reporter assay and mass spectrometry.  Journal of Chromatography A, 1406 (2015) 165-174.



  • M. Tauèer-Kapteijn (HWL), G. Medema (KWR), W. Hoogenboezem (HWL). Comparison between Rapid ID 32 Strep System, MALDI-TOF MS and 16S rRNA gene sequence analysis for the species identification of Enterococcus spp. isolated from water. Water Science & Technology: Water Supply 13 (5), p1383-1389, 2013. 
  • R. Hut, N. van de Giessen, C.J. Houtman. Medicinal Footprint of the population of the Rhine basin. Environmental Research Letters 8(4): 044057 (7p), 2013.
  • M. Schriks, C.J. Houtman, R. van der Oost. The Application of Toxicogenomics for (Drinking) Water Quality Assessment. IWA Publishing. 15 May 2014, ISBN: 9781780406671. 42 pages.
  • W. Jonker, M. Lamoree, C.J. Houtman, J. Kool. Methodologies for Effect-Directed Analysis: Environmental Applications, Food Analysis, and Drug Discovery.  in: Analyzing Biomolecular Interactions by Mass Spectrometry, First Edition, edited by Jeroen Kool and Wilfried M. Niessen. © 2015 Wiley-VCH Verlag GmbH & Co. In press.
  • G. Kooijman, M.L. de Kreuk, C.J. Houtman, J.B. van Lier. The role of colloids in the coagulation/flocculation of pharmaceuticals in domestic wastewater.
  • G. Liu, F.Q. Ling, A. Magic-Knezev, W.T. Liu, J.Q.J.C. Verberk, J.C. van Dijk: Quantification and identification of particle-associated bacteria in unchlorinated drinking water from three treatment plants by cultivation-independent methods. Abstract, Water Research 47, p 3523-3533, 2013.
  • K. Lekkerkerker-Teunissen, A.H. Knol, J.G. Derks, M.B. Heringa, C.J. Houtman, C.H.M. Hofman-Caris, E.F. Beerendonk, A. Reus, J.Q.J.C. Verberk, J.C. van Dijk: Pilot Plant Results with Three Different Types of UV Lamps for Advanced Oxidation. Ozone: Science & Engineering 35:38-48, 2013.


  • Van Lieverloo, Hoogenboezem, Veenendaal en van der Kooij: Variability of invertebrate abundance in drinkingwater distribution systems in the Nethderlands in relation to biostability and sediment volumes. Water Research, 46 p4918-4932, 2012.
  • M. Vital, M. Dignum , A. Magic-Knezev, P. Ross, L. Rietveld,  F. Hammes: Flow cytometry and adenosine tri-phosphate analysis: Alternative possibilities to evaluate major bacteriological changes in drinking water treatment and distribution systems. Water Research 46 p4665-4676, 2012.
  • S.K. Maeng, S.K. Sharma, C.D.T. Abel, A. Magic-Knezev, Kyung-Guen Song, G.L. Amy: Effects of effluent organic matter characteristics on the removal of bulk organic matter and selected pharmaceutically active compounds during managed aquifer recharge: Column study. Journal of Contaminant Hydrology 140–141 p139–149, 2012.
  • R.C.H.M. Hofman-Caris, D.J.H. Harmsen, E.F. Beerendonk, T.H. Knol, C.J. Houtman, D.H. Metz, B.A. Wols: Prediction of advanced oxidation performance in various pilot UV/H2O2 reactor systems with MP- and LP- and DBD-UV lamps. Chemical Engineering Journal 210:520-528, 2012.
  • C.J. Houtman, M. Baneke, T. van der Putten, J. Kroesbergen: Zuiver Water in de Bommelerwaard. In De Snoo GR, Vijver MG, eds, Bestrijdingsmiddelen en waterkwaliteit,  Centrum voor Milieuwetenschappen Leiden; Universiteit Leiden, Leiden, pp 137-149, 2012.
  • K. Lekkerkerker-Teunissen, A.H. Knol, L.P. van Altena, C.J. Houtman, J.Q.J.C. Verberk, J.C. van Dijk: Serial ozone/peroxide/low pressure UV treatment for synergistic and effective organic micropollutant conversion. Separation and Purification Technology 100:22-29, 2012.
  • K. Lekkerkerker-Teunissen, E.T. Chekol, S.K. Maeng, K. Ghebremichael, C.J. Houtman, A.R.D. Verliefde , J.Q.J.C. Verberk, G.L. Amy, R. van Egmond: Pharmaceutical removal during managed aquifer recharge with pretreatment by advanced oxidation. Water Science & Technology: Water Supply 12:755-767, 2012.
  • K. Lekkerkerker-Teunissen, A.H. Knol, P. van 't Hart, G. van Willigen: Ozon en UV-AOP voor effectieve en synergetische omzetting van organische microverontreinigingen. H2O 2012:27-29, 2012.


  • F. Hammes, N. Boon, M. Vital, P. Ross, A. Magic-Knezev, M. Dignum: Bacterial Colonization of Pellet Softening Reactors Used during Drinking Water Treatment. Applied and Environmental Microbiology Feb 2011, p10141-1048, 2011.
  • S.K. Maeng, S.K. Sharma, C.D.T. Abel, A. Magic-Knezev, G.L. Amy: Role of biodegradation in the removal of pharmaceutically active compounds with different bulk organic matter characteristics through managed aquifer recharge: Batch and column studies. water research 45 p4722-4736, 2011.
  • J. Legler, M. van Velzen, P.H. Cenijn, C.J. Houtman, M.H. Lamoree, J.W. Wegener:  Effect-directed analysis of municipal landfill soil reveals novel developmental toxicants in the zebrafish Danio rerio. Environmental Science & Technology 45 p8552-8558, 2011.
  • C.J. Houtman, J. Legler, K.V. Thomas: Effect-Directed Analysis of Endocrine Disruptors in Aquatic Ecosystems. In Brack W, ed, Effect-Directed Analysis of Complex Environmental Contamination, Vol. 15. The Handbook of Environmental Chemistry. Springer Verlag, Berlin-Heidelberg, p237-266, 2011.


  • C.J. Houtman, N.G.F.M. van der Aa, Th. ter Laak: Relatie tussen gebruik geneesmiddelen in Rijnstroomgebied en concentraties in de Rijn. H2O, jaargang 2010, nr. 6, 26 maart 2010.
  • T.L. ter Laak, M. van der Aa, C.J. Houtman, P.G. Stoks, A.P. van Wezel: Relating environmental concentrations of pharmaceuticals to consumption: A mass balance approach for the river Rhine. Environment International 36:403-409, 2010.
  • K. Lekkerkerker-Teunissen , C.J. Houtman, S.K. Maeng, E.  Chekold,  J.Q.J.C.  Verberk, G.  Amy, J. van Dijk: Removal of pharmaceuticals during artificial recharge. Proceedings of the International Symposium on Managed Aquifer Recharge, 2010.
  • M. Tielemans: Zware metalen in drinkwater: balans blijft moeilijk, H2O, 24, 2010.
  • M. Tielemans: Best Practice Guide on the Control of Lead in Drinking Water. Edited bij Colin Hayes, IWA Publising, London, UK, 2010.
  • C.J. Houtman: Emerging contaminants in surface waters and their relevance for the production of drinking water in Europe. Journal of Integrative Environmental Sciences (2010). Vol. 7, issue 4, p. 271-295


  • A. Magic-Knezev: Stand van zaken rond gezondheidsgerelateerde watermicrobiologie. H2O : tijdschrift voor watervoorziening en afvalwaterbehandeling 42 (29). 28-29, 2009.
  • A. Magic-Knezev, B. Wullings, D. van der Kooij: Polaromonas and Hydrogenophaga species are the predominant bacteria cultured from granular activated carbon filters in water treatment. Journal of Applied Microbiology 107 1457–1467, 2009.
  • S. A. Baghoth, M. Dignum, A. Grefte, J. Kroesbergen, G. L. Amy: Characterization of NOM in a drinking water treatment process train with no disinfectant residual. Water Science & Technology: Water Supply—WSTWS | 9.4 | 2009.
  • J. Kroesbergen, K. ten Brinck, T. van der Kaaij: Karakterisering van natuurlijk organisch materiaal,  H2O 30 oktober 2009.
  • A. Magic-Knezev, M.Rosielle, W.Hoogenboezem: The effect of water type on the recovery  of Cryptosporidium oocysts and Gairdia cysts using EnvirochekTM and HemoflowTM pre-concentration techniques. 15th Int. Symposium HRW Microbiology, Greece,2009.


  • C.J. Houtman, S.S. Sterk, M.P.M. van de Heijning, A. Brouwer, R.W. Stephany, B. van der Burg, E. Sonneveld: Detection of anabolic androgenic steroid abuse in doping control using mamalian reporter gene bioassays. Analytica Chimica Acta, 2008.
  • S. K. Maeng, S. K. Sharma, A. Magic-Knezev and G. Amy: Fate of effluent organic matter (EfOM) and natural organic matter (NOM) through riverbank filtration. Water Science & Technology, 2008.


  • G.M. Alink, J.T.K. Quik, E.J.M. Penders, A. Spenkelink, S.G.P. Rotteveel, J.L. Maas, W. Hoogenboezem: Genotoxic effects in Eastern Mudminnow (Umbra pygmaea L.) after exposure to Rhine water , as assessed by use of the SCE and Comet assays: a comparison between 1978 and 2005. Elsevier Mutation Research 631 /RIWA-Rijn 2007.
  • C.J. Houtman, P.E.G. Leonards, W. Kapiteijn, J.F. Bakker, A. Brouwer, M.H. Lamoree, J. Legler, H.J.C. Klamer: Sample preparation method for the ER-CALUX bioassay screening of (xeno-)estrogenic activity in sediment extracts. Elsevier Science of the Total Environment, Vol. 386, 2007.
  • C.J. Houtman, K.M. vd Valk, P. v Bodegom, F. vd Ende, A. Gerritsen, M.H. Lamoree, J. Legler, A. Brouwer: Biomonitoring of estrogenic exposure and identification of responsible compounds in bream from Dutch surface waters. Environmental Toxicology and Chemistry, Vol. 26 no.5 p.898-907, 2007.
  • W. Hoogenboezem, F. Ens en E. Gijsbers: Bijzondere bemonsteringstechnieken in drinkwaterleidingen. H2O, nr 13, 2007.


  • D. van Halem, G. Soppe, J. Kroesbergen, H. van der Jagt: Effectiviteit van met zilver geïmpregneerde keramische potfilters voor waterzuivering op kleine schaal. H2O 25/26, 2006.


  • G. van den Berg, R. van der Plaat, B. Putters, A. Bannink, L. Puijker: MTBE in oppervlaktewater problematisch voor de drinkwatervoorziening?. H2O, 12 p.32-34, 2005.


  • A. Magic-Knezev, D. van der Kooij: Optimisation and significance of ATP analysis for measuring active biomass in granular activated carbon filters used in water treatment. Water Research, 38 p.3971-3979, 2004.
  • A. Magic-Knezev, D. van der Kooij: Molecular analysis of microbial communities in water treatment: biological activated carbon filters. Limnological reports, 35 p.215, 2004.
  • R.J.C.A. Steen, F. Ariese, B. van Hattum, J. Jacobsen, A. Jacobson: Monitoring and evaluation of the environmental degradation rate of the marine antifoulant 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT) in a Danish harbour. Chemosphere, 57 p.513-521, 2004.  
  • G.J. Stroomberg, H.Zappey, R.J.C.A. Steen, C.A.M. van Gestel, F. Ariese, N.H. Velthorst, N.M. van Straalen: PAH biotransformation in terrestrial invertebrates - a new phase II metabolite in isopods and springtails. Comparative Biochemistry and Physiology, p.138-137, 2004.
  • P. Diehl, T. Gerke, A. Jeuken, J. Lowis, R. Steen, J. van Steenwijk, P. Stoks, H.G. Willemsen: Early Warning Strategies and Practices Along the River Rhine. Handbook of Environmental Chemistry Vol. 5 The Rhine,Eds. Thomas Knepper, Springer Verlag, Germany, 2004.
  • A. Visser, W. Hijnen, Y. Dullemont, G.J. Medema: Langzame zandfilters als effectieve barriëres voor microorganismen. H2O, 12 p.26-28, 2004.
  • Y. Dullemont, A.Visser, W.Hijnen, G.J. Medema: Eliminatiecapaciteit van langzamezandfiltratie voor micro-organismen bepaald met doseerproeven. H2O, 13 p.22-24, 2004.


  • W.Hoogenboezem, P. Nobel, T. Visser, R. te Welscher: Campylobacter in oppervlaktewater bestemd voor de bereiding van drinkwater. H2O, 19 p.21-23, 2003.
  • H. van Lieverloo, J. Kroesbergen, G. Bakker, W.Hoogenboezem: Systematische beheersing van microbiologische risico's. H2O, 19 p.30-33, 2003.
  • W. Hoogenboezem, E.J.M. Penders: Evaluatie van de genotoxiciteitsgegevens in de Rijn verzameld over de periode 1981 - 2001. RIWA, 2003.
  • J.H.M. Van Lieverloo, D.W. Bosboom, G.L. Bakker, A.J. Brouwer, R. Voogt, J.E.M. de Roos: Sampling and quantifying invertebrates from drinking water distribution mains. Water Research 1 - 12, 2003.
  • E.J.M. Penders, W. Hoogenboezem: Evaluation of the Ames TA98, UMU and Comet assay for quality monitoring of surface water. RIWA, 2003.
  • R. Ghijsen, R. Lindhout, J. Smeenk: De vinger aan de pols. H2O, 25/26 p.30-33, 2003.
  • G.J. Medema, W. Hoogenboezem, A.J. van der Veer: Quantitative risk assessment of Cryptosporidium in surface water treatment. Water Science and Technology, 47  p.241-247, 2003.



Internships at Het Waterlaboratorium

Het Waterlaboratorium is a laboratory that checks drinking water from the river to the tap. With approximately 120 colleagues, we carry out routine analyzes as well as research and offer internship positions to approximately 20 students every year. To ensure this, we employ 12 internship supervisors who are specially trained for this. The vast majority of our interns come from laboratory education. However, we also have a interesting subjects for student from a different field of study.

Sustainable entrepreneurship is an important part of the vision of Het Waterlaboratorium. Het Waterlaboratorium strives for good contacts in the educational field, and wants to be an excellent internship company for (laboratory) education. Within Het Waterlaboratorium, we have a lot of knowledge and a very active internship policy. At the moment, various students are working at Het Waterlaboratorium on an internship or graduation assignment at both MBO and HBO level. Het Waterlaboratorium is also open for University students.


At Het Waterlaboratorium, we have 3 types of internships: routine, graduation, and one-day visiting internships.

Routine internships
At the moment, 5 permanent internships for routine internships are offered at the laboratory schools: 3 in biology (micro 2 and hydro 1) and 2 in chemistry (1 organic and 1 inorganic). For internships of 5 to 7 months, these places are filled twice a year. The schools determine which students fill these internships. Routine internships are generally intended for MBO students. An internship should include both learning and independent production. The learning program for the routine internships is determined by the internship coordinator, the school department (supervisor and supervisor(s)), and with the student. Routine internships can also be provided for institutes other than learning institutes. In that case, this is referred as a work experience placement. HWL makes 1 work experience placement of 6 months available per year.

Graduation research and graduation projects
We welcome students from HBO and University to do a research internship or graduation research at BSc or MSc level. Studies consist of innovative experimental research in the laboratory, literature or data evaluating research, or combinations of them. Graduation research and graduation projects are supervised by subject specialists and researchers/advisors. The program is determined in mutual consultation between the University or school, student, supervisor, and group head.

One-day visiting internship
In addition, once a year per laboratory school, a one-day visiting internship (orientation day) is organized to introduce students to this laboratory field.  This will helps students to choose a direction after school. Longer visiting internships are too intensive and/or not sufficiently effective. In addition, there are often requests from others (mainly secondary school students) for an orientation day. There are at least 2 introduction days per year (in September and in February) for starting trainees.

Vision of Het Waterlaboratorium
The basic principle for an internship or graduation assignment is that the assignment must contribute to the development of the students, and must make a direct, valuable contribution to Het Waterlaboratorium.

  • Het Waterlaboratorium wants to work together with educational institutes to improve the quality of the students.
  • Het Waterlaboratorium believes that they should contribute to the eductation of future professionals on the basis of a social responsibility.
  • Interns can, through their input, contribute to an innovative and learning organization.

Are you interested in an internship at Het Waterlaboratorium? Send us an email with your resume (CV) + motivation to

Lead testing

Use our lead analysis to detect lead pipes is an initiative of Het Waterlaboratorium in collaboration with the drinking water companies Dunea, PWN and Waternet. Het Waterlaboratorium is accredited (RvA: L404), operates as an authority in the field of drinking water research, and provides honest advice when analysis is not even necessary. The used method for analysing lead is very sensitive and can detect trace levels. By choosing the lead-in-water test, analysis results and potential further steps that might be required are explained on our website. This approach fits perfectly with the 'Advies monsternamestrategie opsporen loden leidingen', which was established by RIVM, partly based on our experiences.

On our website Loodinwatertesten.nlall information can be found about, for example, pipes containing lead and how to request a test.


Our syllabus provides insight into our standard analyses

In the syllabus you will find information about all our standard analyses. These are arranged in alphabetical order per analysis group. Also, using search filters you can search for an analysis or component. We present, among other things, the measurement principle, the analysis procedure, and the standard method. After selection of the matrix type, we present the performance characteristics for each component in the analysis that apply to this matrix. The Combi-matrix contains the performance characteristics which have been calculated on the basis of the quality checks in varying sample matrices, analyzed in daily practice. We keep the data as current as possible. If you cannot find specific information, you can always contact us, and we are happy to help.

Additional information
In addition to the standard offer, we provide cutsom-made solutions in consultation in order to provide the best solution for your analysis problem. For additional information about rates, regulations, and performance characteristics, please contact us at 023-5175900, or at For an up-to-date overview of the analyses that fall under the scope of accreditation, we refer to the website of the RvA ( The scope can be found under number L404.

Sampling standard reference

The syllabus contains standard references for all analyses and components. These are also stated on the analysis report. Accredited sampling only applies to accredited analyses (RvA scope L404).The Sampling tab contains the standard references for sampling activities that cannot always be linked directly to a specific component or analysis.

Note on statistically significant counting areas in microbiological research

Membrane filtration techniques (coli37, E. coli, enterococci, sulfite-reducing clostridia, aeromonas, Clostridium perfringens) have a statistically significant counting range between 10 and 80 colony forming units per plate. For the moulding plate method (colony number 22 °C and 37 °C) and the method for Legionella, a statistically significant counting range between 10 and 300 colony-forming units per plate applies.

  • If 0 colony forming units are reported in the examined volume, this should be interpreted as: “the micro-organism was not found in the examined volume”;
  • If 1 or 2 colony forming units are reported in the examined volume, this should be interpreted as “the micro-organism is present in the examined volume”;
  • If 3 to 9 colony forming units are reported in the examined volume, this should be interpreted as “an estimated number of colony forming units in the examined volume”.
  • The analysis report does not mention these interpretations.

If numbers are reported above the counting areas mentioned, the reported value must be regarded as indicative. However, this is stated on the report. The counting areas are in accordance with NEN-EN-ISO 8199, 2018. If the result is obtained from multiple analysis in microbiological research, the mean is used.

The current syllabus views have incorporated the changes until
April 10, 2024. Current data, as well as historical data, are registered in our LIMS and are always available on request.

Click here for our syllabus in Excel format. 





Plastic in the environment eventually falls apart into ever-smaller pieces. Microplastics are pieces smaller than half a centimeter but can be so small that they are no longer visible to the naked eye. Nanoplastics are barely visible even under the most modern microscopes. Microplastics released through the wear of other plastic materials, such as fibers from synthetic clothing or the abrasion of car tires – these are secondary microplastics. Primary microplastics include microplastics that manufacturers consciously add to personal care products or paints because they fulfill a specific function. These microplastics end up in the ocean easily via drains or through other routes.

For more information, check out the factsheet from RIVM 


Datavisualisation and datascience


Emerging contaminants

Emerging contaminants are substances that may pose a problem for the water quality. However, it is not yet clear whether these substances exceed standards, and whether they are harmful to people or the environment. These substances are not yet listed for WFD or other regulations. Emerging contaminants are not by definition new chemicals, but can be substances that have been on the market for a longer time, and are only now coming to the attention.



Lead is a heavy metal that poses a risk to human health, especially for (unborn) children, where neurological damage can occur.

Lead pipes 

In the Netherlands, the distribution pipes for drinking water are not made of lead. The original lead pipes have been replaced by the drinking water companies. The pipes in the house itself are the responsibility of the owner. Homes built after 1960 do not have lead pipes. It is possible that homes built before 1960 still have lead in the pipe network. In this case, lead may be present in the drinking water.

Recognize lead pipes

  • Search for the water meter. It is usually located in your meter cupboard, or near the central heating boiler. Additional locations are the toilet, bathroom, kitchen or the hatch under your front or back door. The water pipe runs on both sides of the water meter.
  • Don't have a water meter? Find the main valve.

Lead  water pipes (here: on the right of the water meter) can be recognized by the dark, gray color

You can easily recognize a lead water pipe:

  • By the color. Lead pipes are usually dull and gray in color. If you use a sandpaper, the pipe will turn silver. Copper pipes are often green. They will turn yellow or red if you rub them with sandpaper.

  • The sound. A lead pipe makes a dull sound when you tap it with, for example, a spoon.


By sensors, we mean the water quality sensors that are placed in a water system and the waste water chain. They directly measure a physical quantity in the water, such as EGV, turbidity, oxygen or pH. It explicity concerns sensors for measuring water quality.