Gudrun Massmann

The SOLUTIONS project: Challenges and responses for present and future emerging pollutants in land and water resources management

SOLUTIONS (2013 to 2018) is a European Union Seventh Framework Programme Project (EU-FP7). The project aims to deliver a conceptual framework to support the evidence-based development of environmental policies with regard to water quality. SOLUTIONS will develop the tools for the identification, prioritisation and assessment of those water contaminants that may pose a risk to ecosystems and human health. To this end, a new generation of chemical and effect-based monitoring tools is developed and integrated with a full set of exposure, effect and risk assessment models. SOLUTIONS attempts to address legacy, present and future contamination by integrating monitoring and modelling based approaches with scenarios on future developments in society, economy and technology and thus in contamination. The project follows a solutions-oriented approach by addressing major problems of water and chemicals management and by assessing abatement options. SOLUTIONS takes advantage of the access to the infrastructure necessary to investigate the large basins of the Danube and Rhine as well as relevant Mediterranean basins as case studies, and puts major efforts on stakeholder dialogue and support. Particularly, the EU Water Framework Directive (WFD) Common Implementation Strategy (CIS) working groups, International River Commissions, and water works associations are directly supported with consistent guidance for the early detection, identification, prioritisation, and abatement of chemicals in the water cycle. SOLUTIONS will give a specific emphasis on concepts and tools for the impact and risk assessment of complex mixtures of emerging pollutants, their metabolites and transformation products. Analytical and effect-based screening tools will be applied together with ecological assessment tools for the identification of toxicants and their impacts. The SOLUTIONS approach is expected to provide transparent and evidence-based candidates or River Basin Specific Pollutants in the case study basins and to assist future review of priority pollutants under the WFD as well as potential abatement options.

Modeling the fate of organic micropollutants during river bank filtration (Berlin, Germany).

Emerging organic contaminants (EOCs) are frequently detected in urban surface water and the adjacent groundwater and are therefore an increasing problem for potable water quality. River bank filtration (RBF) is a beneficial pretreatment step to improve surface water quality for potable use. Removal is mainly caused by microbial degradation of micropollutants, while sorption retards the transport. The quantification of biodegradation and adsorption parameters for EOCs at field scale is still scarce. In this study, the fate and behavior of a range of organic compounds during RBF were investigated using a two dimensional numerical flow- and transport model. The data base used emanated from a project conducted in Berlin, Germany (NASRI: Natural and Artificial Systems for Recharge and Infiltration). Oxygen isotope signatures and hydraulic head data were used for model calibration. Afterwards, twelve organic micropollutants were simulated with a reactive transport model. Three compounds (primidone, EDTA, and AMDOPH) showed conservative behavior (no biodegradation or sorption). For the nine remaining compounds (1.5 NDSA, AOX, AOI, MTBE, carbamazepine, clindamycin, phenazone, diclofenac and sulfamethoxazole), degradation and/or sorption was observed. 1.5 NDSA and AOX were not sorbed, but slightly degraded with model results for λ=2.25e(-3) 1/d and 2.4e(-3) 1/d. For AOI a λ=0.0106 1/d and R=1 were identified. MTBE could be characterized well assuming R=1 and a low 1st order degradation rate constant (λ=0.0085 1/d). Carbamazepine degraded with a half life time of about 66 days after a threshold value of 0.2-0.3 μg/L was exceeded and retarded slightly (R=1.7). Breakthrough curves of clindamycin, phenazone, diclofenac and sulfamethoxazole could be fitted less well, probably due to the dependency of degradation on temperature and redox conditions, which are highly transient at the RBF site. Conditions range from oxic to anoxic (up to iron-reducing), with the oxic and denitrifying zones moving spatially back and forth over time.

Temperature dependent redox zonation and attenuation of wastewater-derived organic micropollutants in the hyporheic zone

The hyporheic zone - a spatially fluctuating ecotone connecting surface water and groundwater - is considered to be highly reactive with regard to the attenuation of organic micropollutants. In the course of the presented study an undisturbed sediment core was taken from the infiltration zone of a bank filtration site in Berlin and operated under controlled laboratory conditions with wastewater-influenced surface water at two different temperatures, simulating winter and summer conditions. The aim was to evaluate the fate of site-relevant micropollutants, namely metoprolol, iopromide, diclofenac, carbamazepine, acesulfame, tolyltriazole, benzotriazole, phenazone and two phenazone type metabolites, within the first meter of infiltration dependent on the prevailing temperature. A change in temperature resulted in a development of significantly distinct redox conditions. Both temperature dependencies and related redox dependencies were identified for all micropollutants except for benzotriazole and carbamazepine, which behaved persistent under all conditions. For the remaining compounds degradation rate constants generally decreased from warm and oxic/penoxic/suboxic over cold and oxic/penoxic to warm and manganese reducing (transition zone). Individual degradation rate constants ranged from 0 (e.g. diclofenac, acesulfame and tolyltriazole in the transition zone) to 1.4×10(-4)s(-1) for metoprolol under warm conditions within the oxic to suboxic zone.

Sorption behavior of 20 wastewater originated micropollutants in groundwater — Column experiments with pharmaceutical residues and industrial agents

Since sorption is an essential process with regard to attenuation of organic pollutants during subsurface flow, information on the sorption properties of each pollutant are essential for assessing their environmental fate and transport behavior. In the present study, the sorption behavior of 20 wastewater originated organic micropollutants was assessed by means of sediment column experiments, since experimentally determined data for these compounds are not or sparsely represented in the literature. Compounds investigated include various psychoactive drugs, phenazone-type pharmaceuticals and β-blockers, as well as phenacetine, N-methylphenacetine, tolyltriazole and para-toluenesulfonamide. While for most of the compounds no or only a low sorption affinity was observed, an elevated tendency to sorb onto aquifer sand was obtained for the β-blockers atenolol, propranolol and metoprolol. A comparison between experimental data and data estimated based on the octanol/water partition coefficient following the QSAR approach demonstrated the limitations of the latter to predict the adsorption behavior in natural systems for the studied compounds.

Redox-dependent removal of 27 organic trace pollutants: compilation of results from tank aeration experiments

The biodegradation of various wastewater-derived organic trace pollutants occurring in different aquatic compartments of the environment was previously reported to be influenced by the prevailing redox conditions. However, comparative studies on the redox-dependent degradation behavior of organic trace pollutants are scarce. The objective of the study presented herein, was to compile and evaluate data from several comparable previous tank experiments, thus, providing an overview on the redox-dependent removal of a total of 27 wastewater-derived trace compounds, including phenazone type compounds, antimicrobials, ß-blockers, psychoactive drugs and sulfonamides. Removal rate constants were fitted assuming first-order degradation kinetics. Six compounds were identified to be removed solely under oxic, three compounds solely under anoxic conditions. Others persisted under all experimental conditions, while some were removed under both oxic and anoxic conditions.

The fate of organic micropollutants during long-term/long-distance river bank filtration

The fate of organic micropollutants during long-term/long-distance river bank filtration (RBF) at a temporal scale of several years was investigated along a row of monitoring wells perpendicular to the Lek River (the Netherlands). Out of 247 compounds, which were irregularly analyzed in the period 1999-2013, only 15 were detected in both the river and river bank observation wells. Out of these, 10 compounds (1,4-dioxan, 1,5-naphthalene disulfonate (1,5-NDS), 2-amino-1,5-NDS, 3-amino-1,5-NDS, AOX, carbamazepine, EDTA, MTBE, toluene and triphenylphosphine oxide) showed fully persistent behavior (showing no concentration decrease at all), even after 3.6 years transit time. The remaining 5 compounds (1,3,5-naphthalene trisulfonate (1,3,5-NTS), 1,3,6-NTS, diglyme, iopamidol, triglyme) were partially removed. Their reactive transport parameters (removal rate constants/half-lives, retardation coefficients) were inferred from numerical modeling. In addition, maximum half-lives for 14 of the fully removed compounds, for which the data availability was sufficient to deduce 100% removal during sub-surface passage, were approximated based on travel times to the nearest well. The study is one of very few reporting on the long-term field-scale behavior of organic micropollutants. It highlights the efficiency of RBF for water quality improvement as a pre-treatment step for drinking water production. However, it also shows the very persistent behavior of various compounds in groundwater.

Modeling the transport behavior of 16 emerging organic contaminants during soil aquifer treatment.

In this study, four one-dimensional flow and transport models based on the data of a field scale experiment in Greece were constructed to investigate the transport behavior of sixteen organic trace pollutants during soil aquifer treatment. At the site, tap water and treated wastewater were intermittently infiltrated into a porous aquifer via a small pilot pond. Electrical conductivity data was used to calibrate the non-reactive transport models. Transport and attenuation of the organic trace pollutants were simulated assuming 1st order degradation and linear adsorption. Sorption was found to be largely insignificant at this site for the compounds under investigation. In contrast, flow path averaged first order degradation rate constants were mostly higher compared to the literature and lay between 0.036 d(-1) for clofibric acid and 0.9 d(-1) for ibuprofen, presumably owing to the high temperatures and a well adapted microbial community originating from the wastewater treatment process. The study highlights the necessity to obtain intrinsic attenuation parameters at each site, as findings cannot easily be transferred from one site to another.

Detecting Small Groundwater Discharge Springs Using Handheld Thermal Infrared Imagery

Ground-based handheld thermal infrared imagery was used for the detection of small-scale groundwater springs at the northwestern beach of Spiekeroog Island (northwest Germany). The surveys and in situ measurements of electric conductivity were carried out from shortly before to shortly after low tide along the low water line. Several brackish groundwater discharge springs with a diameter of 1-2 cm were observed along the beach at a distance of 2-3 m above the low water line. The high fresh water portion in the discharging water derives from the fresh water lens in the center of the island. During cold weather, the springs were identified by a significantly increased temperature (3-5 °C higher) and a lower electric conductivity (<10 mS/cm) in contrast to the surrounding sea water (1-2 °C, >30 mS/cm). During warmer weather conditions, an inverse temperature contrast was observed. The measurements confirm the applicability of thermal imagery for the detection of small-scale groundwater discharge locations as an extension to the established method of aerial thermal scans and prove the existence of submarine groundwater seeps in porous systems. A ground-based handheld thermal infrared imagery survey enables a precise installation of sampling devices as, for example, seepage meters.

The effect of aeration on the removal of wastewater-derived pharmaceutical residues from groundwater – a laboratory study

Several studies on waste- or drinking water treatment processes as well as on groundwater have recently shown that some pharmaceutical residues (PRs) are redox-sensitive. Hence, their (bio)degradation depends on the redox conditions prevalent in the aquifer. Groundwater, providing raw water for drinking water production, is often anoxic and aeration is a widespread treatment method applied mainly to eliminate unwanted iron and manganese from the water. As a side-effect, aeration may trigger the elimination of PRs. Within the present study the influence of aeration on the fate of a number of wastewater derived analgesics and their residues as well as several antimicrobial compounds was investigated. For this purpose, anoxic groundwater was transferred into stainless steel tanks, some of which were aerated while others were continuously kept anoxic. Results prove that the degradation of six phenazone type compounds is dependent on oxygen availability and compounds are efficiently removed under oxic conditions only. Concerning the antimicrobials, doxycycline and trimethoprim were better removed during aeration, whereas a slightly improved removal under anoxic conditions was observed for clindamycin, roxithromycin and clarithromycin. The study provides first laboratory proof of the redox-sensitivity of several organic trace pollutants. In addition, results demonstrate that aeration is an effective treatment for the elimination of a number of wastewater derived PRs.

Simultaneous determination of psychoactive substances and their metabolites in aqueous matrices by ultrahigh-performance liquid chromatography-tandem mass spectrometry

An analytical method was developed and validated for the simultaneous determination of six psychoactive compounds (meprobamate, primidone, phenobarbital, pyrithyldione, diazepam, and oxazepam) and a metabolite of primidone (phenylethylmalonamide) in environmental water samples. The method involves pre-concentration and clean-up by solid phase extraction (SPE) followed by ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), using electrospray ionization (ESI) in both positive and negative modes. Limits of quantification (LOQs) were between 0.02 and 0.03 µg L−1 in groundwater and between 0.1 and 0.15 µg L−1 in wastewater. With a few exceptions, relative recoveries of the analytes exceeded 80%. The described method was used to analyze the selected psychoactive drugs in groundwater that had been affected by sewage irrigation for several decades ago and treated and untreated wastewater from Berlin (Germany). Highest values were found in groundwater with concentrations reaching up to 1.35 µg L−1 in the case of phenobarbital.