Publications by authors named "Thomas Ter Laak"

41 Publications

Changes in drug use in European cities during early COVID-19 lockdowns - A snapshot from wastewater analysis.

Environ Int 2021 Mar 26;153:106540. Epub 2021 Mar 26.

Environmental and Public Health Analytical Chemistry, Research Institute for Pesticides and Water, University Jaume I, Castellón, Spain; Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, the Netherlands. Electronic address:

The COVID-19 outbreak has forced countries to introduce severe restrictive measures to contain its spread. In particular, physical distancing and restriction of movement have had important consequences on human behaviour and potentially also on illicit drug use and supply. These changes can be associated with additional risks for users, in particular due to reduced access to prevention and harm reduction activities. Furthermore, there have been limitations in the amount of data about drug use which can be collected due to restrictions. To goal of this study was to obtain information about potential changes in illicit drug use impacted by COVID-19 restrictions. Wastewater samples were collected in seven cities in the Netherlands, Belgium, Spain and Italy at the beginning of lockdowns (March-May 2020). Using previously established and validated methods, levels of amphetamine (AMP), methamphetamine (METH), MDMA, benzoylecgonine (BE, the main metabolite of cocaine) and 11-nor-9-carboxy-Δ-tetrahydrocannabinol (THC-COOH, main metabolite of tetrahydrocannabinol (THC)) were measured and compared with findings from previous years. Important differences in levels of consumed drugs were observed across the considered countries. Whilst for some substances and locations, marked decreases in consumption could be observed (e.g., 50% decrease in MDMA levels compared to previous years). In some cases, similar or even higher levels compared to previous years could be found. Changes in weekly patterns were also observed, however these were not clearly defined for all locations and/or substances. Findings confirm that the current situation is highly heterogeneous and that it remains very difficult to explain and/or predict the effect that the present pandemic has on illicit drug use and availability. However, given the current difficulty in obtaining data due to restrictions, wastewater analysis can provide relevant information about the situation at the local level, which would be hard to obtain otherwise.
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http://dx.doi.org/10.1016/j.envint.2021.106540DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7997602PMC
March 2021

patRoon: open source software platform for environmental mass spectrometry based non-target screening.

J Cheminform 2021 Jan 6;13(1). Epub 2021 Jan 6.

Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, L-4367, Belvaux, Luxembourg.

Mass spectrometry based non-target analysis is increasingly adopted in environmental sciences to screen and identify numerous chemicals simultaneously in highly complex samples. However, current data processing software either lack functionality for environmental sciences, solve only part of the workflow, are not openly available and/or are restricted in input data formats. In this paper we present patRoon, a new R based open-source software platform, which provides comprehensive, fully tailored and straightforward non-target analysis workflows. This platform makes the use, evaluation and mixing of well-tested algorithms seamless by harmonizing various common (primarily open) software tools under a consistent interface. In addition, patRoon offers various functionality and strategies to simplify and perform automated processing of complex (environmental) data effectively. patRoon implements several effective optimization strategies to significantly reduce computational times. The ability of patRoon to perform time-efficient and automated non-target data annotation of environmental samples is demonstrated with a simple and reproducible workflow using open-access data of spiked samples from a drinking water treatment plant study. In addition, the ability to easily use, combine and evaluate different algorithms was demonstrated for three commonly used feature finding algorithms. This article, combined with already published works, demonstrate that patRoon helps make comprehensive (environmental) non-target analysis readily accessible to a wider community of researchers.
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http://dx.doi.org/10.1186/s13321-020-00477-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7789171PMC
January 2021

Shifting the imbalance: Intentional reuse of Dutch sewage effluent in sub-surface irrigation.

Sci Total Environ 2021 Jan 5;752:142214. Epub 2020 Sep 5.

Copernicus Institute of Sustainable Development, Utrecht University, Utrecht, the Netherlands.

Worldwide, agricultural irrigation currently accounts for 69% of freshwater withdrawal. Countries with a temperate climate, such as the Netherlands, experience periodic freshwater shortages in agriculture. The pressure on available freshwater will increase due to climate change and a growing demand for freshwater by e.g. industrial activities. Possible alternative water resources are considered in order to meet the current and future water demand. In this study we explore where, and how much, sewage treatment plant (STP) effluent can directly be reused in agricultural sub-surface irrigation (SSI) during an average and a dry season scenario, for all active (335) Dutch STPs. SSI systems may have a higher water demand as part of the STP effluent is transported with groundwater flow, although aboveground irrigation has a loss of water due to interception. Furthermore, such aboveground irrigation systems provide direct contact of crops with irrigation water. SSI systems provide a soil barrier which may function as a filter and buffer zone. In the Dutch situation, direct intentional reuse of STP effluent can fulfill up to 25% of croplands SSI water demand present within a five-kilometer transport buffer from the STPs during an average season and 17% during a dry season. Hereto, respectively, 78% and 84% of the total available Dutch STP effluent would be used. Thus, the intentional direct STP effluent reuse in agricultural SSI has the potential to satisfy a significant amount of the agricultural water demand at a national scale, presuming responsible reuse: safe applications for humans and environment and no limiting effects on water availability for other actors.
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http://dx.doi.org/10.1016/j.scitotenv.2020.142214DOI Listing
January 2021

Integration of target analyses, non-target screening and effect-based monitoring to assess OMP related water quality changes in drinking water treatment.

Sci Total Environ 2020 Feb 27;705:135779. Epub 2019 Nov 27.

KWR Water Research Institute, Nieuwegein, the Netherlands; Univerisity of Amsterdam, Amsterdam, the Netherlands.

The ever-increasing production and use of chemicals lead to the occurrence of organic micro-pollutants (OMPs) in drinking water sources, and consequently the need for their removal during drinking water treatment. Due to the sheer number of OMPs, monitoring using targeted chemical analyses alone is not sufficient to assess drinking water quality as well as changes thereof during treatment. High-resolution mass spectrometry (HRMS) based non-target screening (NTS) as well as effect-based monitoring using bioassays are promising monitoring tools for a more complete assessment of water quality and treatment performance. Here, we developed a strategy that integrates data from chemical target analyses, NTS and bioassays. We applied it to the assessment of OMP related water quality changes at three drinking water treatment pilot installations. These installations included advanced oxidation processes, ultrafiltration in combination with reverse osmosis, and granular activated carbon filtration. OMPs relevant for the drinking water sector were spiked into the water treated in these installations. Target analyses, NTS and bioassays were performed on samples from all three installations. The NTS data was screened for predicted and known transformation products of the spike-in compounds. In parallel, trend profiles of NTS features were evaluated using multivariate analysis methods. Through integration of the chemical data with the biological effect-based results potential toxicity was accounted for during prioritization. Together, the synergy of the three analytical methods allowed the monitoring of OMPs and transformation products, as well as the integrative biological effects of the mixture of chemicals. Through efficient analysis, visualization and interpretation of complex data, the developed strategy enabled to assess water quality and the impact of water treatment from multiple perspectives. Such information could not be obtained by any of the three methods alone. The developed strategy thereby provides drinking water companies with an integrative tool for comprehensive water quality assessment.
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http://dx.doi.org/10.1016/j.scitotenv.2019.135779DOI Listing
February 2020

Retention soil filters for the treatment of sewage treatment plant effluent and combined sewer overflow.

Sci Total Environ 2020 Jan 12;699:134426. Epub 2019 Sep 12.

Wageningen University and Research, Environmental Technology, P.O. Box 17, 6700 AA Wageningen, the Netherlands.

Retention soil filters (RSFs) are vertical flow constructed wetlands. They are mainly used for the treatment of combined sewer overflow or stormwater, and not operated during dry weather conditions. However, RSFs have been successfully tested as continuous post treatment for sewage treatment plant effluents. In this paper we present a new approach, namely dual usage of the retention soil filter. During dry weather the RSF is used for the polishing treatment of sewage treatment plant effluent and during overflow events, the retention soil filter treats the combined sewer overflow. This study was conducted at two pilot RSFs that were fed with sewage treatment effluent for four years. Removal of TOC, DOC, nutrients and 21 organic micropollutants was determined during six months at different sequences of regular effluent and overflow treatment conditions. TOC, DOC and nutrients, appearing in high concentration in combined sewer overflow, were effectively removed, and metformin and caffeine micropollutants showed >99% removal. Residues from this combined sewer treatment that were sorbed on filter material or stored in pore water were washed out directly after treatment when STP effluent infiltration was initiated. This effect declined within 20 h after combined sewer overflow treatment. Dry periods of 18 h between combined sewer and sewage treatment plant effluent feeding counteracted the wash out effects. The highest removal efficiency was found in the beginning of the feeding time of 28 h, indicating that shorter feeding cycles enhance the overall efficiency of the RSF. Finally, the results show that a single RSF system can successfully reduce emissions of TOC, DOC, nutrients and micropollutants to surface waters from two different emission pathways, i.e. from regular treated effluents and storm related sewer overflows. In conclusion, the dual usage of RSF is a promising approach and ready for upscaling and implementation.
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http://dx.doi.org/10.1016/j.scitotenv.2019.134426DOI Listing
January 2020

In situ removal of four organic micropollutants in a small river determined by monitoring and modelling.

Environ Pollut 2019 Sep 30;252(Pt A):758-766. Epub 2019 May 30.

KWR Watercycle Research Institute, P.O. Box 1072, 3430 BB, Nieuwegein, the Netherlands.

Organic micropollutants (OMPs) are widely detected in surface waters. So far, the removal processes of these compounds in situ in river systems are not yet totally revealed. In this study, a combined monitoring and modelling approach was applied to determine the behaviour of 1-H benzotriazole, carbamazepine, diclofenac and galaxolide in a small river system. Sewage treatment plant effluents and the receiving waters of the river Swist were monitored in 9 dry weather sampling campaigns (precipitation < 1 mm on the sampling day itself and <5 mm total precipitation two days before the sampling) during different seasons over a period of 3 years. With the results gained through monitoring, mass balances have been calculated to assess fate in the river. With the DWA Water Quality Model, OMP concentrations in the river were successfully simulated with OMP characteristics gained through literature studies. No removal was determined for 1-H benzotriazole and carbamazepine, whereas diclofenac showed removal that coincided with light intensity. Moreover, modelling based on light sensitivity of diclofenac also suggested relevant degradation at natural light conditions. These two approaches suggest removal by photodegradation. The highest removal in the river was detected for galaxolide, presumably due to volatilisation, sorption and biodegradation. Furthermore, short-term concentration variability in the river was determined, showing that daily concentration patterns are influenced by dynamics of sewage treatment plant effluent volumes and removal processes in the river.
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http://dx.doi.org/10.1016/j.envpol.2019.05.150DOI Listing
September 2019

Monitoring transformation product formation in the drinking water treatments rapid sand filtration and ozonation.

Chemosphere 2019 Jan 26;214:801-811. Epub 2018 Sep 26.

KWR Watercycle Research Institute, P.O. Box 1072, 3430 BB Nieuwegein, the Netherlands.

Transformation products (TPs) can be formed from organic micropollutants in the water cycle through both biological and technological processes. Despite the TPs' potentially altered toxicity compared to their parent compounds, transformation processes are not routinely monitored, and in particular those induced by drinking water treatment remain elusive. This lack of information is mainly due to the technical challenges in analyzing TPs, which are often unknown compounds occurring in low concentrations. Their analysis requires sophisticated analytical techniques such as non-target screening (NTS) based on high-resolution tandem mass spectrometry (HRMS/MS) methods combined with novel data analysis approaches. Here, we addressed the challenges of TP analysis and the scarcity of TP research concerning studies in drinking water. We performed lab-scale experiments to monitor TP formation of three organic micropollutants prevalent in drinking water sources, i.e. carbamazepine, clofibric acid and metolachlor, during rapid sand filtration and ozonation, two readily applied biotic and abiotic drinking water treatments, respectively. To facilitate TP identification in the NTS data, halogenated and/or isotopically labeled parent compounds were used, revealing potential TPs through their isotopic patterns. The experimental results showed that degradation of the parent compounds and TP formation were treatment and compound specific. In silico TP prediction and literature mining enabled suspect screening of the non-target data and thereby significantly enhanced TP identification. Overall, the developed workflow enables an efficient and more comprehensive assessment of drinking water quality changes during water treatment.
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http://dx.doi.org/10.1016/j.chemosphere.2018.09.140DOI Listing
January 2019

Impact of industrial waste water treatment plants on Dutch surface waters and drinking water sources.

Sci Total Environ 2018 Nov 18;640-641:1489-1499. Epub 2018 Jun 18.

KWR Watercycle Research Institute, Nieuwegein, the Netherlands.

Direct industrial discharges of Chemicals of Emerging Concern (CEC) to surface water via industrial wastewater treatment plants (IWTP) gained relatively little attention compared to discharges via municipal sewage water treatment plants. IWTP effluents may however seriously affect surface water quality. Here we modelled direct industrial emissions of all 182 Dutch IWTP from 19 different industrial classes, and derived their impact on Dutch surface water quality and drinking water production. We selected industrial chemicals relevant for drinking water production, however a lack of systematic information on concentrations in IWTP effluents for many chemicals of interest was found. Therefore, we used data from the European Pollutant Release and Transfer Register and data on Dutch IWTP as surrogate. We coupled these to a detailed hydrological model under two extreme river discharge conditions, and compared the predicted and measured concentrations. We derived relative impact factors for the IWTP based on their contribution to concentrations at surface water locations with a drinking water function. In total, a third of the abstracted water for drinking water production is influenced by the IWTP. From all Dutch 182 IWTP, only a limited number has - based on the model approach using surrogate parameters - a high impact on surface waters with a drinking water function. Mitigation measures can be taken cost-efficiently, by placing extra treatment technologies at the IWTP with high impact. Finally, we propose recommendations for licensing and controlling industrial aqueous emissions and give suggestions to fill the currently existing knowledge gaps and diminish uncertainties in the approach.
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http://dx.doi.org/10.1016/j.scitotenv.2018.05.325DOI Listing
November 2018

Retention soil filter as post-treatment step to remove micropollutants from sewage treatment plant effluent.

Sci Total Environ 2018 Oct 14;637-638:1098-1107. Epub 2018 May 14.

Wageningen University, Sub Department of Environmental Technology, P.O. Box 17, 6700 AA Wageningen, The Netherlands.

Retention soil filters (RSFs) are a specific form of vertical flow constructed wetlands for the treatment of rain water and/or wastewater. We have tested 3 pilot RSFs to investigate removal of dissolved organic carbon (DOC) and 14 different organic micropollutants (OMPs) from the effluent of a large scale sewage treatment plant (STP). Two of them were operated as conventional RSF with material (sand with CaCO and organic matter) from two different full-scale RSFs. The third pilot RSF contained filter material (sand with CaCO) with additional biochar in the upper layer (0-10 cm) and granulated activated carbon (GAC) in the lower layer (60-90 cm). The filters were planted with Phragmites australis. The RSFs were operated and monitored for 3 years, and water samples were taken regularly at inflow, outflows and in 3 depths within the filters. In total 523 samples were taken. In the conventional RSF, best median removal was detected for galaxolide, diclofenac 4-hydroxy, metoprolol and clarithromycin (75-79%). No removal was seen for sulfamethoxazole and carbamazepine. The DOC and OMP removal in the conventional RSFs was best in the upper layer with highest organic matter content, increased in time over the three years of operation and also with extended contact time. In the effluent of the RSF with GAC, 10 out of the 14 OMPs could not be detected; 4 OMPs were detected, but only metformin with removal < 80%, thus showing a more efficient removal than the conventional RSF. A decrease in DOC removal was detected in the GAC layer (>88% to 60%) over the 2.5 years of operation. Biochar was most effective in OMP removal in the first operational year. It can be concluded that the increasing removal efficiency of the conventional RSF material - also present in the RSF with biochar and GAC - might mitigate the reduced efficiency of the sorbent additives biochar and GAC. This enables to extend the operational lifetime of the filters with acceptable removal rates. Finally, our study demonstrates that an RSF with GAC shows an enhanced removal of OMPs, which is a suitable post-treatment step for STPs.
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http://dx.doi.org/10.1016/j.scitotenv.2018.05.063DOI Listing
October 2018

Pharmaceutical concentration variability at sewage treatment plant outlets dominated by hydrology and other factors.

Environ Pollut 2018 Apr 11;235:615-624. Epub 2018 Jan 11.

Erftverband, Department of River Basin Management, Am Erftverband 6, 50126 Bergheim, Germany.

A study was conducted in which the effluent at four small to medium sized sewage treatment plants (STP) in North Rhine-Westphalia, Germany was monitored for three pharmaceutical compounds (carbamazepine, diclofenac, metoprolol) over a period of four years. Grab sampling and auto sampling campaigns were accomplished with respect to various weather conditions in the catchment area. Flow volumes and hydraulic retention times (HRT) from various sampling dates which provide information on processes causing emission changes were additionally taken into account. Monitoring results showed that concentration scattering in the effluent is related to HRT in the sewage treatment plants. Dilution effects following rain events in the catchment area were analysed for the three investigated substances. Short-term emission changes explained by dilution only could be well determined by the mathematical relation between discharge and concentration, and for carbamazepine to be solely determined by the dilution effects at all HRTs. For metoprolol, a clear decrease in concentrations was observed at HRTs above 80 h, and a significant contribution of biodegradation was supported by independent biodegradation tests. For three out of the four STPs, a decrease in concentrations of diclofenac was observed at hydraulic retention times above 80 h, indicating removal, whereas the relationship between concentration and HRT of the other STP could be explained by dilution only. The study shows that emissions can vary with weather conditions, hampering the assessment of emissions and estimation of concentrations in surface waters from generic removal rates only. Furthermore, it illustrates the importance of HRT of rather stable substances in wastewater treatment.
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http://dx.doi.org/10.1016/j.envpol.2017.12.116DOI Listing
April 2018

Projected impact of climate change and chemical emissions on the water quality of the European rivers Rhine and Meuse: A drinking water perspective.

Sci Total Environ 2017 Dec 10;601-602:1682-1694. Epub 2017 Jun 10.

KWR Watercycle Research Institute, PO Box 1072, 3430 BB Nieuwegein, The Netherlands; Dunea N.V., Plein van de Verenigde Naties 11, 2719 EG Zoetermeer, PO Box 756, 2700 AT Zoetermeer, The Netherlands. Electronic address:

Low river discharges of the rivers Rhine and Meuse are expected to occur more often and more prolonged in a changing climate. During these dry periods the dilution of point sources such as sewage effluents is reduced leading to a decline in chemical water quality. This study projects chemical water quality of the rivers Rhine and Meuse in the year 2050, based on projections of chemical emissions and two climate scenarios: moderate and fast climate change. It focuses on specific compounds known to be relevant to drinking water production, i.e. four pharmaceuticals, a herbicide and its metabolite and an artificial sweetener. Hydrological variability, climate change, and increased emission show a significant influence on the water quality in the Rhine and Meuse. The combined effect of changing future emissions of these compounds and reduced dilution due to climate change has leaded to increasing (peak) concentrations in the river water by a factor of two to four. Current water treatment efficiencies in the Netherlands are not sufficient to reduce these projected concentrations in drinking water produced from surface water below precautionary water target values. If future emissions are not sufficiently reduced or treatment efficiencies are not improved, these compounds will increasingly be found in drinking water, albeit at levels which pose no threat to human health.
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http://dx.doi.org/10.1016/j.scitotenv.2017.05.250DOI Listing
December 2017

Decision support for water quality management of contaminants of emerging concern.

J Environ Manage 2017 May 23;193:360-372. Epub 2017 Feb 23.

TU Delft, Faculty of Civil Engineering and Geosciences, PO Box 5048, 2600 GA, Delft, The Netherlands; Waternet, Strategic Centre, Amsterdam, The Netherlands.

Water authorities and drinking water companies are challenged with the question if, where and how to abate contaminants of emerging concern in the urban water cycle. The most effective strategy under given conditions is often unclear to these stakeholders as it requires insight into several aspects of the contaminants such as sources, properties, and mitigation options. Furthermore the various parties in the urban water cycle are not always aware of each other's requirements and priorities. Processes to set priorities and come to agreements are lacking, hampering the articulation and implementation of possible solutions. To support decision makers with this task, a decision support system was developed to serve as a point of departure for getting the relevant stakeholders together and finding common ground. The decision support system was iteratively developed in stages. Stakeholders were interviewed and a decision support system prototype developed. Subsequently, this prototype was evaluated by the stakeholders and adjusted accordingly. The iterative process lead to a final system focused on the management of contaminants of emerging concern within the urban water cycle, from wastewater, surface water and groundwater to drinking water, that suggests mitigation methods beyond technical solutions. Possible wastewater and drinking water treatment techniques in combination with decentralised and non-technical methods were taken into account in an integrated way. The system contains background information on contaminants of emerging concern such as physical/chemical characteristics, toxicity and legislative frameworks, water cycle entrance pathways and a database with associated possible mitigation methods. Monitoring data can be uploaded to assess environmental and human health risks in a specific water system. The developed system was received with great interest by potential users, and implemented in an international water cycle network.
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http://dx.doi.org/10.1016/j.jenvman.2017.02.002DOI Listing
May 2017

Data-driven prioritization of chemicals for various water types using suspect screening LC-HRMS.

Water Res 2016 Apr 16;93:254-264. Epub 2016 Feb 16.

KWR Watercycle Research Institute, P.O. Box 1072, 3430 BB, Nieuwegein, The Netherlands; Utrecht University, Copernicus Institute of Sustainable Development, P.O. Box 80.115, 3508 TC, Utrecht, The Netherlands. Electronic address:

For the prioritization of more than 5200 anthropogenic chemicals authorized on the European market, we use a large scale liquid chromatography-high resolution mass spectrometry (LC-HRMS) suspect screening study. The prioritization is based on occurrence in 151 water samples including effluent, surface water, ground water and drinking water. The suspect screening linked over 700 detected compounds with known accurate masses to one or multiple suspects. Using a prioritization threshold and removing false positives reduced this to 113 detected compounds linked to 174 suspects, 24 compounds reflect a confirmed structure by comparison with the pure reference standard. The prioritized compounds and suspects are relevant for detailed risk assessments after confirmation of their identity. Only one of the 174 prioritized compounds and suspects is mentioned in water quality regulations, and only 20% is mentioned on existing lists of potentially relevant chemicals. This shows the complementarity to commonly used target-based methods. The semi-quantitative total concentration, expressed as internal standard equivalents of detected compounds linked to suspects, in effluents is approximately 10 times higher than in surface waters, while ground waters and drinking waters show the lowest response. The average retention time, a measure for hydrophobicity, of the detected compounds per sample decreased from effluent to surface- and groundwater to drinking water, confirming the occurrence of more polar compounds in drinking water. The semi-quantitative total concentrations exceed the conservative and precautionary threshold of toxicological concern. Therefore, adverse effects of mixtures cannot be neglected without a more thorough risk assessment.
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http://dx.doi.org/10.1016/j.watres.2016.02.034DOI Listing
April 2016

Towards spatially smart abatement of human pharmaceuticals in surface waters: Defining impact of sewage treatment plants on susceptible functions.

Water Res 2015 Sep 5;81:356-65. Epub 2015 Jun 5.

KWR Watercycle Research Institute, P.O. Box 1072, 3430 BB, Nieuwegein, The Netherlands; Utrecht University, Copernicus Institute of Sustainable Development, P.O. Box 80.115, 3508 TC, Utrecht, The Netherlands.

For human pharmaceuticals, sewage treatment plants (STPs) are a major point of entry to surface waters. The receiving waters provide vital functions. Modeling the impact of STPs on susceptible functions of the surface water system allows for a spatially smart implementation of abatement options at, or in the service area of, STPs. This study was performed on a nation-wide scale for the Netherlands. Point source emissions included were 345 Dutch STPs and nine rivers from neighboring countries. The Dutch surface waters were represented by 2511 surface water units. Modeling was performed for two extreme discharge conditions. Monitoring data of 7 locations along the rivers Rhine and Meuse fall mostly within the range of modeled concentrations. Half of the abstracted volumes of raw water for drinking water production, and a quarter of the Natura 2000 areas (European Union nature protection areas) hosted by the surface waters, are influenced by STPs at low discharge. The vast majority of the total impact of all Dutch STPs during both discharge conditions can be attributed to only 19% of the STPs with regard to the drinking water function, and to 39% of the STPs with regard to the Natura 2000 function. Attributing water treatment technologies to STPs as one of the possible measures to improve water quality and protect susceptible functions can be done in a spatially smart and cost-effective way, using consumption-based detailed hydrological and water quality modeling.
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http://dx.doi.org/10.1016/j.watres.2015.05.061DOI Listing
September 2015

Different compositions of pharmaceuticals in Dutch and Belgian rivers explained by consumption patterns and treatment efficiency.

Environ Sci Pollut Res Int 2014 Nov 29;21(22):12843-55. Epub 2014 Jun 29.

KWR Watercycle Research Institute, P.O. Box 1072, 3430 BB, Nieuwegein, Netherlands,

In the current study, 43 pharmaceuticals and 18 transformation products were studied in the river Meuse at the Belgian-Dutch border and four tributaries of the river Meuse in the southern part of the Netherlands. The tributaries originate from Belgian, Dutch and mixed Dutch and Belgian catchments. In total, 23 pharmaceuticals and 13 transformation products were observed in samples of river water collected from these rivers. Observed summed concentrations of pharmaceuticals and transformation products in river water ranged from 3.5 to 37.8 μg/L. Metformin and its transformation product guanylurea contributed with 53 to 80 % to this concentration, illustrating its importance on a mass basis. Data on the flow rate of different rivers and demographics of the catchments enabled us to calculate daily per capita loads of pharmaceuticals and transformation products. These loads were linked to sales data of pharmaceuticals in the catchment. Simple mass balance modelling accounting for human excretion and removal by sewage treatment plants revealed that sales could predict actual loads within a factor of 3 for most pharmaceuticals. Rivers that originated from Belgian and mixed Dutch and Belgian catchments revealed significantly higher per capita loads of pharmaceuticals (16.0 ± 2.3 and 15.7 ± 2.1 mg/inhabitant/day, respectively) than the Dutch catchment (8.7 ± 1.8 mg/inhabitant/day). Furthermore, the guanylurea/metformin ratio was significantly lower in waters originating from Belgium (and France) than in those from the Netherlands, illustrating that sewage treatment in the Belgian catchment is less efficient in transforming metformin into guanylurea. In summary, the current study shows that consumption-based modelling is suitable to predict environmental loads and concentrations. Furthermore, different consumption patterns and wastewater treatment efficiency are clearly reflected in the occurrence and loads of pharmaceuticals in regional rivers.
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http://dx.doi.org/10.1007/s11356-014-3233-9DOI Listing
November 2014

Hepatic clearance of 6 polycyclic aromatic hydrocarbons by isolated perfused trout livers: prediction from in vitro clearance by liver S9 fractions.

Toxicol Sci 2013 Dec 4;136(2):359-72. Epub 2013 Oct 4.

* U.S. Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, Duluth, Minnesota 55804;

Isolated perfused trout livers were used to evaluate in vitro-in vivo metabolism extrapolation procedures for fish. In vitro depletion rates for 6 polycyclic aromatic hydrocarbons (PAHs) were measured using liver S9 fractions and extrapolated to the intact tissue. Predicted hepatic clearance (CLH) values were then compared with values exhibited by intact livers. Binding in liver perfusates was manipulated using bovine serum albumin (BSA) and was characterized by solid-phase microextraction. Additional studies were conducted to develop binding terms (f U; calculated as the ratio of unbound fractions in liver perfusate [f U,PERF] and the S9 system [f U,S9]) used as inputs to a well-stirred liver model. Hepatic clearance values for pyrene and benzo[a]pyrene, predicted by extrapolating in vitro data to the intact tissue, were in good agreement with measured values (< 2-fold difference). This can be partly attributed to the rapid rate at which both compounds were metabolized by S9 fractions, resulting in perfusion-limited clearance. Predicted levels of CLH for the other PAHs underestimated observed values although these differences were generally small (< 3-fold, except for naphthalene). Setting f U = 1.0 improved clearance predictions at the highest tested BSA concentration (10mg/ml), suggesting that trout S9 fractions exhibit lower levels of intrinsic activity than the intact tissue or that the full binding assumption (ie, f U = f U,PERF/f U,S9) underestimates the availability of hydrophobic substrates to hepatic metabolizing enzymes. These findings provide qualified support for procedures currently being used to predict metabolism impacts on chemical accumulation by fish based on measured rates of in vitro activity.
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http://dx.doi.org/10.1093/toxsci/kft219DOI Listing
December 2013

Analysis of (functionalized) fullerenes in water samples by liquid chromatography coupled to high-resolution mass spectrometry.

Anal Chem 2013 Jun 24;85(12):5867-74. Epub 2013 May 24.

KWR Watercycle Research Institute, P.O. Box 1072, 3430 BB Nieuwegein, The Netherlands.

One of the main challenges in environmental risk assessment of fullerenes is to develop analytical methods that detect and quantify fullerenes at low concentrations. In this paper we report on the development and optimization of a highly specific, robust, and relatively simple method for the quantitative determination of C60, C70, and six functionalized fullerenes, namely, [6,6]-phenyl-C61-butyric acid methyl ester, [6,6]-phenyl-C61-butyric acid butyl ester, [6,6]-phenyl-C61-butyric acid octyl ester, [6,6]-bis(phenyl)-C61-butyric acid methyl ester, [6,6]-thienyl-C61-butyric acid methyl ester, and [6,6]-phenyl-C71-butyric acid methyl ester ([70PCBM], in different aqueous matrixes. For this method fullerenes were extracted from the aqueous phase using solid-phase extraction (SPE), with subsequent analysis on a liquid chromatography-Orbitrap mass spectrometry (LC-Orbitrap MS) system. SPE was optimized by varying different conditions to improve recovery of all fullerenes. Different SPE column materials (C18, C18e, C8, CN) were tested, and recoveries appeared to be the highest for the C18-material. Recoveries were improved by adding NaCl to the water during extraction. Very low limit of detection (LOD) values were obtained for all compounds with this method, ranging from 0.17 ng/L for [70]PCBM to 0.28 ng/L for C60, and subsequent limit of quantitation (LOQ) values of 0.57-0.91 ng/L. Recoveries for the fullerenes were on average 120% in ultrapure and drinking water. Recoveries appeared to be lower, but still acceptable (e.g., >78%), in surface water. The developed approach is promising and will be applied, for example, in (1) environmental monitoring, (2) a more in-depth study of environmental fate and transformation products, and (3) studying water treatment efficiency of C60, C70, and the various functionalized fullerenes.
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http://dx.doi.org/10.1021/ac400619gDOI Listing
June 2013

Prediction of concentration levels of metformin and other high consumption pharmaceuticals in wastewater and regional surface water based on sales data.

Sci Total Environ 2013 Jan 23;442:380-8. Epub 2012 Nov 23.

Water Board Regge en Dinkel P.O. Box 5006, 7600 GA, Almelo, The Netherlands.

Local consumption data of pharmaceuticals were used to study the emission to wastewater and surface waters in two small Dutch water catchments. For nine high consumption pharmaceuticals: metformin, metoprolol, sotalol, losartan, valsartan, irbesartan, hydrochlorothiazide, diclofenac and carbamazepine, predicted emissions were compared to wastewater concentrations, removal in sewage treatment plants and recovery in regional surface water. The study shows that local consumption data can be very useful to select pharmaceuticals for monitoring and to predict wastewater concentrations. Measured influent concentrations were on average 78% with a range of 31-138% of predicted influent concentrations. Metformin is the pharmaceutical with the highest concentration in wastewater (64-98 μg/L) but it is removed with >98% in sewage treatment plants (STP). Guanylurea, a biodegradation product of metformin, was detected in STP effluents and surface waters at concentrations of 39-56 μg/L and 1.8-3.9 μg/L, respectively. The STP removal of the different pharmaceuticals varied strongly. For carbamazepine, hydrochlorothiazide and sotalol a significant better removal was found at higher temperatures and longer hydraulic retention times while for metoprolol significantly better removal was only observed at higher temperatures. Predicting environmental concentrations from regional consumption data might be an alternative to monitoring of pharmaceuticals in wastewater and surface waters.
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http://dx.doi.org/10.1016/j.scitotenv.2012.10.046DOI Listing
January 2013

Removal of charged micropollutants from water by ion-exchange polymers -- effects of competing electrolytes.

Water Res 2012 Oct 7;46(16):5009-18. Epub 2012 Jul 7.

KWR Watercycle Research Institute, Groningenhaven 7, P.O. Box 1072, 3430 BB Nieuwegein, The Netherlands.

A wide variety of environmental compounds of concern, e.g. pharmaceuticals or illicit drugs, are acids or bases that may predominantly be present as charged species in drinking water sources. These charged micropollutants may prove difficult to remove by currently used water treatment steps (e.g. UV/H(2)O(2), activated carbon (AC) or membranes). We studied the sorption affinity of some ionic organic compounds to both AC and different charged polymeric materials. Ion-exchange polymers may be effective as additional extraction phases in water treatment, because sorption of all charged compounds to oppositely charged polymers was stronger than to AC, especially for the double-charged cation metformin. Tested below 1% of the polymer ion-exchange capacity, the sorption affinity of charged micropollutants is nonlinear and depends on the composition of the aqueous medium. Whereas oppositely charged electrolytes do not impact sorption of organic ions, equally charged electrolytes do influence sorption indicating ion-exchange (IE) to be the main sorption mechanism. For the tested polymers, a tenfold increased salt concentration lowered the IE-sorption affinity by a factor two. Different electrolytes affect IE with organic ions in a similar way as inorganic ions on IE-resins, and no clear differences in this trend were observed between the sulphonated and the carboxylated cation-exchanger. Sorption of organic cations is five fold less in Ca(2+) solutions compared to similar concentrations of Na(+), while that of anionic compounds is three fold weaker in SO(4)(2-) solutions compared to equal concentrations of Cl(-).
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http://dx.doi.org/10.1016/j.watres.2012.06.048DOI Listing
October 2012

Broad target chemical screening approach used as tool for rapid assessment of groundwater quality.

Sci Total Environ 2012 Jun 30;427-428:308-13. Epub 2012 Apr 30.

KWR Watercycle Research Institute, P.O. Box 1072, 3430 BB, Nieuwegein, The Netherlands.

The chemical water quality is often assessed by screening for a limited set of target chemicals. This 'conventional' target analysis approach inevitably misses chemicals present in the samples. In this study a 'broad' target screening approach for water quality assessment using high resolution and accurate mass spectrometry (HR MS) was applied to detect a wide variety of organic chemicals in 42 groundwater samples. In this approach, both known and unidentified chemicals observed in previous samples define the training set for the analysis of future samples and, additionally, new samples can be used to extend the training set. Nearly 400 chemicals were observed in the samples, of which 82 were known and more than 313 are of unknown identity. The obtained results were interpreted in relation to the source characteristics and land use. Groundwater that was affected by landfills showed the highest total MS response (ion counts) and most individual chemicals and was therefore considered most contaminated. Furthermore, river bank filtrated water was generally more contaminated than phreatic groundwater and groundwater from (semi)confined aquifers was most pristine. Additionally, industrial chemicals were more frequently observed in river bank filtrated water and pesticides were more frequently observed in water originating from rural areas. The 'broad' target screening approach for both known and unidentified chemicals does provide more information on the over-all water quality than 'conventional' target analysis.
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http://dx.doi.org/10.1016/j.scitotenv.2012.04.013DOI Listing
June 2012

Screening and human health risk assessment of pharmaceuticals and their transformation products in Dutch surface waters and drinking water.

Sci Total Environ 2012 Jun 1;427-428:70-7. Epub 2012 May 1.

KWR Watercycle Research Institute, P.O. Box 1072, 3430 BB, Nieuwegein, The Netherlands.

Numerous studies describe the presence of pharmaceuticals in the water cycle, while their transformation products are usually not included. In the current study 17 common pharmaceuticals and 9 transformation products were monitored in the Dutch waters, including surface waters, pre-treated surface waters, river bank filtrates, two groundwater samples affected by surface water and drinking waters. In these samples, 12 pharmaceuticals and 7 transformation products were present. Concentrations were generally highest in surface waters, intermediate in treated surface waters and river bank filtrates and lowest or not detected in produced drinking water. However, the concentrations of phenazone and its environmental transformation product AMPH were significantly higher in river bank filtrates, which is likely due to historical contamination. Fairly constant ratios were observed between concentrations of transformation products and parent pharmaceuticals. This might enable prediction of concentrations of transformation products from concentrations of parent pharmaceuticals. The toxicological relevance of the observed pharmaceuticals and transformation products was assessed by deriving (i) a substance specific provisional guideline value (pGLV) and (ii) a group pGLV for groups of related compounds were under the assumption of additivity of effects within each group. A substantial margin exists between the maximum summed concentrations of these compounds present in different water types and the derived (group) pGLVs. Based on the results of this limited screening campaign no adverse health effects of the studied compounds are expected in (sources of) drinking water in the Netherlands. The presence of transformation products with similar pharmacological activities and concentration levels as their parents illustrates the relevance of monitoring transformation products, and including these in risk assessment. More thorough monitoring yielding information on statistical uncertainty and variability in time and space, and research on possible synergistic effects of low concentration mixtures of compounds belonging to similar pharmacological classes require attention.
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http://dx.doi.org/10.1016/j.scitotenv.2012.04.010DOI Listing
June 2012

Sorption behavior of charged and neutral polar organic compounds on solid phase extraction materials: which functional group governs sorption?

Environ Sci Technol 2012 Jan 4;46(2):954-61. Epub 2012 Jan 4.

KWR Watercycle Research Institute, Groningenhaven 7, P.O. Box 1072, 3430 BB, Nieuwegein, The Netherlands.

Numerous polar anthropogenic organic chemicals have been found in the aqueous environment. Solid phase extraction (SPE) has been applied for the isolation of these from aqueous matrices, employing various materials. Nevertheless, little is known about the influence of functional groups on the sorption of the solutes onto these materials. Therefore, the sorption interactions of (charged) polar organic solutes to neutral (HLB), cation-exchanging (MCX, WCX), and anion-exchanging (MAX, WAX) OASIS polymers have been studied. For neutral solutes HLB has the highest capacity and affinity. Van der Waals interaction, rather than hydrogen bonding, appears to be the predominant factor determining sorption. For charged molecules, MCX and MAX show by far the highest affinity and capacity. Adsorption is already efficient at low concentrations and the maximum sorption capacity equals the amount of charged functional groups on the material. The results from this study allow semiquantitative predictions if a solute will adsorb on one of the OASIS materials and which functional groups govern adsorption.
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http://dx.doi.org/10.1021/es203404xDOI Listing
January 2012

Quantifying summed fullerene nC60 and related transformation products in water using LC LTQ Orbitrap MS and application to environmental samples.

Environ Int 2011 Aug 6;37(6):1063-7. Epub 2011 May 6.

KWR Watercycle Research Institute, Nieuwegein, The Netherlands.

The application of engineered nanomaterials increases strongly. Development of analytical techniques and their application to environmental samples is essential for human and environmental risk assessment of the nanoparticles. The objective of this study was to develop a sensitive analytical method to quantify nC(60) in water, using accurate mass screening liquid chromatography-hybrid linear ion trap Orbitrap mass spectrometry. nC(60) can be transformed by oxidation, reduction and photochemical reaction. Therefore, the formation of some transformation products of nC(60) was studied as well. Finally, the developed analytical method was applied to surface water samples from several locations in the Netherlands. The developed method enabled to detect and quantify aqueous concentrations of the summed nC(60) and its transformation products as low as 5 ng/L. It was observed that nC(60) transformation products exceed quantities of the parent C(60). Despite the high sensitivity of the developed method, no nC(60) or transformation products were detected in an array of Dutch surface waters. This might be due to low emissions, losses in the aqueous phase by sedimentation, sorption or further transformation processes.
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http://dx.doi.org/10.1016/j.envint.2011.03.020DOI Listing
August 2011

Relating environmental concentrations of pharmaceuticals to consumption: A mass balance approach for the river Rhine.

Environ Int 2010 Jul 15;36(5):403-9. Epub 2010 Apr 15.

KWR Watercycle Research Institute, 3430 BB, Nieuwegein, The Netherlands.

In this study, pharmaceuticals were frequently monitored in the Rhine delta between the year 2002 and 2008. Average concentrations of several X-ray contrast mediums were above 0.1 microg/L, the average concentration of carbamazepine was about 0.1 microg/L, while average concentrations of the other pharmaceuticals generally fell between 0.1 and 0.01 microg/L. Concentrations were used to calculate annual loads transported by the Rhine at Lobith. These loads were compared to the annual sales upstream of Lobith. This mass balance approach shows that substantial fractions (1.1% to 70.4%) of the 20 most frequently observed pharmaceuticals sold in the Rhine catchment area are recovered in the Rhine at Lobith. The observed annual loads were compared to loads predicted from annual sales in the catchment area, excreted fractions by humans and removal by waste water treatment. Observed and predicted annual loads were rather similar. The difference of the loads obtained from monitoring data and estimated from consumption was smaller than a factor of seven and did not exceed a factor of two for 15 out of the 20 pharmaceuticals. This illustrates the potential of using sales data for the prediction of concentrations in the aqueous environment.
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http://dx.doi.org/10.1016/j.envint.2010.02.009DOI Listing
July 2010

Dissolved organic matter enhances transport of PAHs to aquatic organisms.

Environ Sci Technol 2009 Oct;43(19):7212-7

Institute for Risk Assessment Sciences (IRAS), Utrecht University, Yalelaan 2, 3584 CM Utrecht, The Netherlands.

In this study, the uptake of pyrene and benzo[b]fluoranthene by an aquatic worm (Lumbriculus variegatus) and a poly(dimethylsiloxane) coated glass fiber was studied at different humic acid concentrations. The accumulation of pyrene was not affected by the presence of the humic matrix. However, the accumulation rate of benzo[b]fluoranthene increased a factor of 3 for the fiber and a factor of 4 when 55 mg L(-1) dissolved organic carbon was added in the form of humic acid. The difference between the two chemicals can be explained by the higher affinity of benzo[b]fluoranthene for the dissolved humic material. A comparison of modeled transport enhancement of benzo[b]fluoranthene by humic acid and the experimental results suggested that the benzo[b]fluoranthene complexed with the humic phase was not completely labile.
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http://dx.doi.org/10.1021/es803684fDOI Listing
October 2009

Dynamic exposure of organisms and passive samplers to hydrophobic chemicals.

Environ Sci Technol 2009 Apr;43(7):2206-15

CABE, University of Geneva, Sciences II, 30 Quai Ernest Ansermet, CH 1211, Geneva 4, Switzerland.

An insight into the dynamic aspects of the accumulation process is essential for understanding bioaccumulation as well as effect studies of hydrophobic organic chemicals. This review presents an overview of kinetic studies with organisms (fish, bivalve, crustacean, insect, worm, algae, and protozoan) as well as passive samplers (solid and liquid phase microextraction, semipermeable membrane device, polymer sheet, solid-phase extraction, Chemcatcher, etc.) for the uptake of neutral nonpolar chemicals from the aqueous phase. Information about uptake rates, elimination rates, and 95% equilibration times was collected and analyzed with diffusion based models. The present literature review suggests that the surface to volume ratio appears to be a critical parameter for the uptake rate of the more hydrophobic chemicals both for samplers and organisms. In addition, as a very first approximation, the combination of the first-order kinetic model with the assumption that diffusion through the aqueous boundary layers is rate limiting, gives a reasonable description of the experimental kinetic data. In this way, the presented model might be used to estimate uptake and elimination rate constants of chemicals by organisms or passive samplers.
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http://dx.doi.org/10.1021/es8029895DOI Listing
April 2009

Facilitated transport of polychlorinated biphenyls and polybrominated diphenyl ethers by dissolved organic matter.

Environ Sci Technol 2009 Mar;43(5):1379-85

Institute for Risk Assessment Sciences, Utrecht University, Yalelaan 2, 3584 CM Utrecht, The Netherlands.

The exchange rate of hydrophobic organic chemicals between the aqueous phase and a sorbent (e.g., soil, organism, passive sampler) is relevant for distribution processes between environmental compartments, including organisms. Dissolved phases such as humic acids, proteins, and surfactants can affect the transfer of such chemicals between the aqueous and sorbent phases by sorption and desorption processes. In this study, the desorption of polychlorinated biphenyls and polybrominated diphenyl ethers from a polymer phase to an aqueous medium was monitored at different humic acid concentrations. The rate of release of the chemical by the polymer phase demonstrates thatthe chemical sorbed to dissolved humic acid contributed significantly to the total mass transfer when the affinity for the humic acid was sufficiently high. This illustrates that environmentally relevant humic acid concentrations can facilitate transport of hydrophobic organic chemicals. The consequences of these facilitated transport mechanisms for uptake into passive samplers are discussed, in particular in situations where equilibration is very slow or when exposure varies in time or space.
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http://dx.doi.org/10.1021/es802403vDOI Listing
March 2009

Chronic exposure of the oligochaete Lumbriculus variegatus to polycyclic aromatic compounds (PACs): bioavailability and effects on reproduction.

Environ Sci Technol 2008 May;42(9):3434-40

Aquatic Ecology and Ecotoxicology, University of Amsterdam, Kruislaan 320, Amsterdam, Noord Holland 1098SM, The Netherlands.

This study aimed to monitor PAC availability to the oligochaete Lumbriculus variegatus during 28 days of exposure to spiked sediments, in order to obtain reliable chronic effect concentrations for reproduction. Sediment toxicity tests were performed using three pairs of PAC isomers: two homocyclic compounds (anthracene and phenanthrene), two azaarenes (acridine and phenanthridine), and the two main transformation products of the azaarenes (acridone and phenanthridone). During the experiment, available PAC concentrations in pore water (estimated using solid phase microextraction) decreased more than total PAC concentrations in the sediment. Relating effect concentrations to PAC concentrations in pore water and in organisms showed that the two homocyclic compounds caused narcotic effects during chronic exposure, but only one of the four tested heterocyclic PACs caused narcotic effects. The transformation product phenanthridone was not toxic at the tested concentrations (up to 4000 micromol/kg dry sediment), whereas EC50 values for the parent compound phenanthridine and the isomer acridone were below the estimated limit for narcosis, suggesting a specific mode of action. These results demonstrated the unpredictable (isomer) specific toxicity of azaarenes and their transformation products, emphasizing the need of chronic toxicity testing to gain insight into the long-term effects of heterocyclic PACs, which have been overlooked in risk assessment.
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http://dx.doi.org/10.1021/es702500tDOI Listing
May 2008

Poly(dimethylsiloxane) as passive sampler material for hydrophobic chemicals: effect of chemical properties and sampler characteristics on partitioning and equilibration times.

Anal Chem 2008 May 19;80(10):3859-66. Epub 2008 Apr 19.

IRASInstitute for Risk Assessment Sciences, Utrecht University, Yalelaan 2, 3584 CM Utrecht, The Netherlands.

Information about sampling rates and equilibration times of passive samplers is essential in their calibration in field monitoring studies as well as sorption studies. The kinetics of a sampler depends on the distribution coefficient between the sampler material and aqueous phase and the exchange rates of chemicals between these phases. In this study, the elimination kinetics of four poly(dimethylsiloxane) (PDMS) passive samplers with different surface-volume ratios are compared. The samplers were loaded with polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) that cover a broad range of hydrophobicities. The surface-volume ratios of the samplers could largely explain the observed kinetics. Furthermore, a simple diffusion-based model illustrates that the exchange of chemicals was limited by diffusion through the aqueous diffusion layer surrounding the sampler. On the basis of this simple diffusion model, equilibration times are predicted for organic chemicals that vary in hydrophobicity and samplers with different dimensions and polymeric phases. This information is of importance in the selection of a passive sampler for a specific purpose.
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http://dx.doi.org/10.1021/ac800258jDOI Listing
May 2008

Steady-state diffusion regime in solid-phase microextraction kinetics.

Anal Chim Acta 2008 Feb 16;609(1):113-9. Epub 2008 Jan 16.

Institute for Risk Assessment Sciences (IRAS), Utrecht University, Yalelaan 2, P.O. Box 80176, 3508 TD Utrecht, The Netherlands.

The temporal evolution of diffusion-controlled analyte accumulation in solid-phase microextraction (SPME) is critically discussed in terms of the various aspects of steady-state diffusion in the two phases under conditions of fast exchange of the analyte at the solid phase film/water interface. For partition coefficients (K(sw)) much larger than unity and a sufficiently thin polymer film, the concentration gradient of the analyte in the polymer phase is largely insignificant. The growth of the accumulated amount of analyte is then adequately described by the well-known exponential expression for steady-state diffusion under non-depletive conditions, provided the initial transient stage is properly taken into account. In case of fiber-type solid phases, the cylindrical nature of the diffusion complicates the nature of the transient stage as well as the magnitude of the steady-state flux.
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http://dx.doi.org/10.1016/j.aca.2007.11.053DOI Listing
February 2008