Michael P. Schlüsener

The fate of selected micropollutants in a single-house MBR

Membrane bioreactor (MBR) technology is an interesting option for single-house wastewater treatment or small communities. Because typically a very high effluent quality is achieved with respect to pathogens, suspended solids, organics and nitrogen, the permeate is well suited for reuse. Little is known about the fate of micropollutants in such small systems. The differences between centralized and decentralized biological wastewater treatment with respect to micropollutants are manifold: besides the operational parameters like hydraulic and sludge retention time, the main difference is in the load variation. While the influent load is expected to be more or less constant in large catchments, it varies strongly in small MBRs due to irregular consumption (e.g. of medication by individuals). Concentrations of micropollutants are higher by a factor 50-1000 than in centralized treatment. It is also unknown how reliable degradation of micropollutants is in case of irregular exposure. In this study, two experiments were conducted in a small MBR treating the wastewater of a three-person household. During normal operation of the treatment plant, 25 pharmaceuticals (antibiotics, antiphlogistics, lipid regulators, iodinated contrast media and hormones) that had not been used by members of the household were added in concentrations typical for municipal wastewater. The removal of most substances was in the same range as for centralized wastewater treatment. It was shown that biological transformation was the main elimination process while adsorption to the activated sludge was negligible for most substances due to the low sludge production at high sludge retention time. No appreciable lag for inducing biological degradation was observed. The high hydraulic and sludge residence time had a positive effect on the elimination of slowly degradable substances, but this was partly compensated by the lower biological activity. An experiment with antibiotics concentrations typical for decentralized treatment (between 500 and 1000 microg l(-1); sulfamethoxazole, sulfapyridine, trimethoprim, clarithromycin, roxithromycin) did not show an inhibitory effect on either nitrification or denitrification.

Determination of antibiotics from soil by pressurized liquid extraction and liquid chromatography–tandem mass spectrometry

A method for the analysis of several macrolide and ionophore antibiotics, as well as tiamulin, from soil was developed using pressurized liquid extraction (PLE), reversed-phase liquid chromatography and atmospheric pressure chemical ionisation (APCI) tandem mass spectrometry (LC-APCI+-MS-MS). The analytes were extracted from soil by PLE in 30 min and the extracts were cleaned up by solid-phase extraction (SPE) on a diol SPE cartridge. Liquid chromatographic (LC) separation of the antibiotics was achieved in 35 min. Recovery experiments were performed using spiked soil and concentrations varying from 1 to 2000 microg/kg. By using a macrolide internal standard the recovery rates for the macrolides erythromycin and roxithromycin ranged from 43 to 94% (RSD 20-23%), for the ionophore salinomycin the recovery rate was 76% (RSD 29%), while the pleuromutilin tiamulin was completely recovered. The limits of detection ranged from 0.2 to 1.6 microg/kg. In soil samples a maximum concentration of 0.7 microg/kg tiamulin was found.

Removal of antibiotics from urban wastewater by constructed wetland optimization

Seven mesocosm-scale constructed wetlands (CWs), differing in their design characteristics, were set up in the open air to assess their efficiency to remove antibiotics from urban raw wastewater. A conventional wastewater treatment plant (WWTP) was simultaneously monitored. The experiment took place in autumn. An analytical methodology including HPLC-MS/MS was developed to measure antibiotic concentrations in the soluble water fraction, in the suspended solids fraction and in the WWTP sludge. Considering the soluble water fraction, the only easily eliminated antibiotics in the WWTP were doxycycline (61±38%) and sulfamethoxazole (60±26%). All the studied types of CWs were efficient for the removal of sulfamethoxazole (59±30-87±41%), as found in the WWTP, and, in addition, they removed trimethoprim (65±21-96±29%). The elimination of other antibiotics in CWs was limited by the specific system-configuration: amoxicillin (45±15%) was only eliminated by a free-water (FW) subsurface flow (SSF) CW planted with Typha angustifolia; doxycycline was removed in FW systems planted with T. angustifolia (65±34-75±40%), in a Phragmites australis-floating macrophytes system (62±31%) and in conventional horizontal SSF-systems (71±39%); clarithromycin was partially eliminated by an unplanted FW-SSF system (50±18%); erythromycin could only be removed by a P. australis-horizontal SSF system (64±30%); and ampicillin was eliminated by a T. angustifolia-floating macrophytes system (29±4%). Lincomycin was not removed by any of the systems (WWTP or CWs). The presence or absence of plants, the vegetal species (T. angustifolia or P. australis), the flow type and the CW design characteristics regulated the specific removal mechanisms. Therefore, CWs are not an overall solution to remove antibiotics from urban wastewater during cold seasons. However, more studies are needed to assess their ability in warmer periods and to determine the behaviour of full-scale systems.

Direct Coupling of Thin-Layer Chromatography with a Bioassay for the Detection of Estrogenic Compounds: Applications for Effect-Directed Analysis

The present study investigated the hypothesis that the coupling of high-performance thin-layer chromatography with the yeast estrogen screen (planar-YES, p-YES) can be used as a screening tool for effect-directed analysis. Therefore, the proposed method was challenged for the first time with several real samples from various origins such as sediment pore water, wastewater, and sunscreens. It was possible to detect and quantify estrogenic effects in all investigated sample types, even in the presence of demanding matrixes. Furthermore, the specific agonistic effect of the estrogen receptor activation could be detected in samples exhibiting cytotoxic effects and at cytotoxic levels of analyzed estrogenic compounds, which is not possible with the classic YES. The analysis of samples by the p-YES results in profiles of estrogenic activity. By means of this profiles samples can be compared qualitatively and quantitatively with respect to different compositions of bioactive compounds in mixtures. In conclusion, the p-YES approach seems to have a high potential to be used as a valuable screening tool for various applications in effect-directed analysis.

Quaternary Triphenylphosphonium Compounds: A New Class of Environmental Pollutants

A nontarget screening using high-resolution mass spectrometry (HRMS) was established to identify industrial emerging contaminants in the Rhine River. With this approach, quaternary triphenylphosphonium compounds (R-Ph3P(+)) were identified as new emerging contaminants in the aquatic environment. The suggested chemical structures were elucidated by MS fragmentation and chemical databank searches and eventually confirmed via authentic standards. R-Ph3P(+) are used worldwide by the chemical industry to synthesize alkenes via the Wittig reaction. In total, five compounds [R = butyl (Bu), R = ethyl (Et), R = methoxymethyl (MeOMe), R = methyl (Me), and R = phenyl (Ph)] were found in German rivers and streams. R-Ph3P(+) were detected only in those rivers and streams that received an appreciable portion of wastewater from the chemical industry. Up to 2.5 μg/L Et-Ph3P(+) was quantified in a small stream from the Hessian Ried, and in the Rhine, up to 0.56 μg/L Me-Ph3P(+) was detected. R-Ph3P(+) were also identified in suspended particulate matter and sediments in the Rhine catchment, with MeOMe-Ph3P(+) concentrations of up to 0.75 mg/kg and up to 0.21 mg/kg, respectively. Because of the lack of ecotoxicological studies, the environmental risks caused by R-Ph3P(+) can be assessed for neither pelagic nor benthic organisms.

Leaching of terbutryn and its photodegradation products from artificial walls under natural weather conditions

Terbutryn is a commonly used biocide in construction materials. Especially polymer-resin-based renders and paints, used in external thermal insulation composite systems, are very susceptible to microbial deterioration. Previous studies have shown that biocides leach out of the material when contacted with rainwater; thus, they reach surface waters where they might have adverse effects on aquatic organisms. The knowledge on the long-term leaching performance and especially the formation and fate of degradation products is rare. In the present study, the leaching of terbutryn from artificial walls equipped with two types of render was observed for 19 months. In addition to concentration and mass load determinations for terbutryn, photodegradation products were identified and studied in the leachate and render. The results show that terbutryn leached mainly within the first 6-12 months. During the exposure, only 3% of the initial terbutryn was emitted to the runoff, while 64-80% remained in the coating. The overall mass balance could be closed by including several degradation products. Contrary to expectations, the major fraction of transformation products remained in the material and was not washed off immediately, which is of high importance for the long-term assessment of biocides in coating materials.

Estrogenic effects along the river saale

Sediments along the river Saale, one of the main tributaries of the river Elbe, were characterized with the yeast estrogen screen to elucidate possible sources of endocrine-disrupting compounds that might contribute to the downstream contamination of the river Elbe. At two sampling sites, elevated levels of estrogenic activity up to 55,000 ng ethinylestradiol equivalents per kilogram sediment dry weight were detected in the respective sediment extracts. Aliquots of the sediment extracts were analyzed for 4-nonylphenols and natural steroidal estrogens as possible candidates with an estrogenic potential. The maximal concentrations of 4-iso-nonylphenol and estrone were 115 mg/kg dry weight and 20 µg/kg dry weight at the sampling site Luppe, which showed in accordance the highest biological activity. Under consideration of compound concentration and compound specific estrogenic activity the 4-iso-nonylphenols contributed most to the observed estrogenic effect. A strong correlation between the measured estrogenic activity and the concentration of the sediment-associated 4-iso-nonylphenol underlines the relevance of this compound class as a xenoestrogen in the catchment area of the river Saale.

Photodegradation of octylisothiazolinone and semi-field emissions from facade coatings

Amongst others, 2-octyl-isothiazol-3(2 H)-one (OIT) is used as film preservative in water-based polymer resin paints and renders to prevent the growth of moulds and bacteria. It is known that biocides leach from facades with rainwater and end up in the environment via stormwater runoff. In the present study the leaching and fate of OIT used in facade coatings was determined under natural conditions. Potential phototransformation products were initially identified in laboratory experiments using UV-light. Afterwards, the leaching of OIT and seven degradation products were studied on artificial walls equipped with organic top coatings formulated with OIT. A mass balance, including the leached and remaining amounts of OIT and its seven transformation products, can explain up to 40% of the initial amount of OIT. The OIT remaining in the material after 1.5 yr is by far the largest fraction. The study shows that in the assessment of biocides in coating material, transformation products need to be taken into account both in leachate and remaining in the material. Furthermore, in case of volatile degradation products, the emissions to air might be relevant.

Quaternary (triphenyl-) phosphonium compounds: Environmental behavior and toxicity

An analytical method based on high resolution mass spectrometry coupled with liquid chromatography (LC-HRMS) for 25 quaternary phosphonium compounds (QPCs) and derived phosphine oxides (POs) was developed and validated. To investigate the occurrence and fate of QPCs in the aquatic environment, water, suspended solids and sediments from the rivers Rhine and Elbe (upper and middle Elbe as well as tidal Elbe) were analyzed, as well as samples from tributaries bearing significant loads of QPCs. For the first time, the quaternary phosphonium compound tetrabutylphosphonium (Bu4P+) was detected. In the river Elbe concentrations were determined of up to 4700 ng/L (surface water) and 1000 μg/kg (sediment), respectively. Analysis of a time series of suspended solids (2005-2015) showed that QPCs have been present in the Elbe and Rhine catchment for at least one decade, with partly rising tendency. A degradation experiment with Rhine sediment revealed that triphenylphosphonium compounds (R-Ph3P+) and Bu4P+ are persistent in contact with sediment and suspended solids and tend to sorb onto sediment particles. Toxicological studies (reactive oxygen species (ROS) after substance exposure, Ames test, Micronucleus test, determination of cytotoxicity) with selected QPCs confirmed that all of them exhibit cytotoxicity and some even genotoxic potential at elevated concentrations, which emphasizes the need for an emission regulation of these compounds.

Occurrence of Glucocorticoids, Mineralocorticoids, and Progestogens in Various Treated Wastewater, Rivers, and Streams

In the current study a high sensitive analytical method was developed for the determination of 60 steroids including glucocorticoids (GC), mineralocorticoids (MC), and progestogens (PG) in WWTP effluents and surface water using liquid chromatography with tandem mass spectrometry detection (LC-MS/MS). The limits of quantification (LOQ) ranged between 0.02 ng/L (cortisone) to 0.5 ng/L (drospirenone) in surface water and from 0.05 ng/L (betamethasone) to 5 ng/L (chlormadinone) in treated wastewater. After optimization, the developed method was applied to WWTP effluents, rivers, and streams around Germany. Numerous steroids have been detected during the sampling campaign and predominant analytes from all steroid types were determined. Moreover, the occurrence of dienogest, mometasone furoate, flumethasone pivalate, and the metabolites 6β-hydroxy dienogest, 6β-hydroxy triamcinolone acetonide, 7α-thiomethyl spironolactone, and 11α-hydroxy canrenone is reported for the first time. In addition, this study revealed the ubiquitous presence of topically applied GC monoesters betamethasone propionate, betamethasone valerate, and 6α-methylprednisolone propionate in WWTP effluents and surface water.