Analyzing a broader spectrum of endocrine active organic contaminants in sewage sludge with high resolution LC-QTOF-MS suspect screening and QSAR toxicity prediction.
ABSTRACT: Endocrine active contaminants (EACs) in environmental samples can pose a range of toxicological threats to ecosystems, especially through their impacts on reproductive pathways mediated by the estrogen receptor. The physicochemical properties of known organic EACs vary greatly and typically require different sample preparation techniques to identify different classes of compounds. EAC sources are similarly diverse, including both endogenous compounds and anthropogenic chemicals found in personal care products, pharmaceuticals, and their transformation products, which are often disposed of to sewers at their end of use. Looking for EACs in sewage sludge proposes a bottom-up, or end-of-use and treatment approach to discover environmentally relevant EACs, since many EACs accumulate in sludges even after application of robust wastewater treatment processes. This study demonstrates an extraction and analytical method capable of detecting a broad spectrum of known and suspected EACs via High Resolution Liquid Chromatography Quadropole Time-of-Flight Mass Spectrometry (LC-QTOF-MS) suspect screening of fourteen California sewage sludge samples. Spike-recovery experiments were performed using twelve carefully selected surrogates to assess different extraction solvents, sample weights, extraction pH values, procedures for combining extracts with different extraction pH's, and solid phase extraction cartridges. Using LC-QTOF-MS, identifications of several other organic compounds in the samples were made, a goal unachievable with unit resolution mass spectrometry. Suspect screening of California sludge samples discovered 118 compounds including hormones, pharmaceuticals, phosphate flame retardants, recreational drugs, antimicrobials, and pesticides. Additionally, 22 of these identified compounds are predicted to interfere with estrogen receptors or other reproductive/developmental pathways based on the VEGA QSAR toxicity prediction model.
Project description:Efficient strategies are required to implement comprehensive suspect screening methods using high-resolution mass spectrometry within environmental monitoring campaigns. In this study, both liquid and gas chromatography time-of-flight mass spectrometry (LC-QTOF-MS and GC-QTOF-MS) were used to screen for >5000 target and suspect compounds in the Sacramento-San Joaquin River Delta in Northern California. LC-QTOF-MS data were acquired in All-Ions fragmentation mode in both positive and negative electrospray ionization (ESI). LC suspects were identified using two accurate mass LC-QTOF-MS/MS libraries containing pesticides, pharmaceuticals, and other environmental contaminants and a custom exact mass database with predicted transformation products (TPs). The additional fragment information from the All-Ions acquisition improved the confirmation of the compound identity, with a low false positive rate (9%). Overall, 25 targets, 73 suspects, and 5 TPs were detected. GC-QTOF-MS extracts were run in negative chemical ionization (NCI) for 21 targets (mainly pyrethroids) at sub-ng/L levels. For suspect screening, extracts were rerun in electron ionization (EI) mode with a retention time locked method using a GC-QTOF-MS pesticide library (containing exact mass fragments and retention times). Sixteen targets and 42 suspects were detected, of which 12 and 17, respectively, were not identified by LC-ESI-QTOF-MS. The results highlight the importance of analyzing water samples using multiple separation techniques and in multiple ionization modes to obtain a comprehensive chemical contaminant profile. The investigated river delta experiences significant pesticide inputs, leading to environmentally critical concentrations during rain events.
Project description:To simultaneously quantify and profile the complex mixture of short-, median-, and long-chain CPs (SCCPs, MCCPs, and LCCPs) in Australian sewage sludge, we applied and further validated a recently developed novel instrumental technique, using quadrupole time-of-flight high resolution mass spectrometry running in the negative atmospheric pressure chemical ionization mode (APCI-qTOF-HRMS). Without using an analytical column the cleaned extracts were directly injected into the qTOF-HRMS followed by quantification of the CPs by a mathematical algorithm. The recoveries of the four SCCP, MCCP and LCCP-spiked sewage sludge samples ranged from 86 to 123%. This APCI-qTOF-HRMS method is a fast and promising technique for routinely measuring SCCPs, MCCPs, and LCCPs in sewage sludge. Australian sewage sludge was dominated by MCCPs with concentrations ranging from 542 to 3645 ng/g dry weight (dw). Lower SCCPs concentrations (<57-1421 ng/g dw) were detected in the Australian sewage sludge, which were comparable with the LCCPs concentrations (116-960 ng/g dw). This is the first time that CPs were reported in Australian sewage sludge. The results of this study gives a first impression on the distribution of the SCCPs, MCCPs, and LCCPs in Australia wastewater treatment plants (WWTPs).
Project description:The partitioning of pharmaceuticals in the environment can be assessed by measuring their adsorption coefficients (Kd) between aqueous and solid phases. Measuring this coefficient in sewage sludge gives an indication of their partitioning behaviour in a wastewater treatment plant and hence contributes to an understanding of their subsequent fate. The regulatory approved method for measuring Kd in sewage sludge is the US Environmental Protection Agency's Office of Prevention, Pesticides and Toxic Substances (OPPTS) guideline 835.1110, which is labour intensive and time consuming. We describe an alternative method for measuring the Kd of pharmaceuticals in sewage sludge using a modified solid-phase extraction (SPE) technique. SPE cartridges were packed at different sludge/PTFE ratios (0.4, 6.0, 24.0 and 40.0% w/w sludge) and eluted with phosphate buffer at pH 7.4. The approach was tested initially using three pharmaceuticals (clofibric acid, diclofenac and oxytetracycline) that covered a range of Kd values. Subsequently, the sorption behaviour of ten further pharmaceuticals with varying physico-chemical properties was evaluated. Results from the SPE method were comparable to those of the OPPTS test, with a correlation coefficient of 0.93 between the two approaches. SPE cartridges packed with sludge and PTFE were stable for up to one year; use within one month reduced variability in measurements (to a maximum of 0.6 log units). The SPE method is low-cost, easy to use and enables the rapid measurement of Kd values for a large number of chemicals. It can be used as an alternative to the more laborious full OPPTS test in environmental fate studies and risk assessments.
Project description:The use and advantages of high-resolution mass spectrometry (MS) as a discovery tool for environmental chemical monitoring has been demonstrated for environmental samples but not for biological samples. We developed a method using liquid chromatography-quadrupole time-of-flight MS (LC-QTOF/MS) for discovery of previously unmeasured environmental chemicals in human serum. Using non-targeted data acquisition (full scan MS analysis) we were able to screen for environmental organic acids (EOAs) in 20 serum samples from second trimester pregnant women. We define EOAs as environmental organic compounds with at least one dissociable proton which are utilized in commerce. EOAs include environmental phenols, phthalate metabolites, perfluorinated compounds, phenolic metabolites of polybrominated diphenyl ethers and polychlorinated biphenyls, and acidic pesticides and/or predicted acidic pesticide metabolites. Our validated method used solid phase extraction, reversed-phase chromatography in a C18 column with gradient elution, electrospray ionization in negative polarity and automated tandem MS (MS/MS) data acquisition to maximize true positive rates. We identified "suspect EOAs" using Agilent MassHunter Qualitative Analysis software, to match chemical formulas generated from each sample run with molecular formulas in our unique database of 693 EOAs assembled from multiple environmental literature sources. We found potential matches for 282 (41%) of the EOAs in our database. Sixty-five of these suspect EOAs were detected in at least 75% of the samples; only 19 of these compounds are currently biomonitored in National Health and Nutrition Examination Survey. We confirmed two of three suspect EOAs by LC-QTOF/MS using a targeted method developed through LC-MS/MS, reporting the first confirmation of benzophenone-1 and bisphenol S in pregnant women's sera. Our suspect screening workflow provides an approach to comprehensively scan environmental chemical exposures in humans. This can provide a better source of exposure information to help improve exposure and risk evaluation of industrial chemicals.
Project description:To investigate the wide range of pollutants occurring in sewage sludge, an analytical method for comprehensive non-target screening is needed. To the best of our knowledge, no procedures currently exist for the full screening of organic contaminants in sewage sludge, which is the ultimate goal of this project. We developed non-discriminating sample preparation methods for gas chromatography-mass spectrometry (GC-MS) analysis. Pressurized liquid extraction (PLE) was used for extraction, with in-line (silica gel selective PLE, SPLE) or off-line clean-up (gel permeation chromatography, GPC). This combination allowed the analysis of non-polar compounds of all sizes and small semi-polar and non-polar compounds. The results show that the combination of SPLE and PLE with GPC is suitable for analysis of established as well as new contaminants. Both methods were validated for 99 compounds with different properties. For all GC suitable analytes, either one of the methods produced acceptable recoveries (64 to 136%). As a test, the two methods were used for non-target screening of Swedish sewage sludge. A tiered approach was used to tentatively identify the sludge contaminants. In total, 1865 and 1593 compounds were found of which 321 and 192 compounds were tentatively identified for the PLE and SPLE method, respectively. For a comprehensive coverage of contaminants, the two methods should be used together, with the PLE method covering a wider polarity range and the SPLE method a wider size range. In addition, polar substances will require liquid chromatography-mass spectrometry analysis, the method for which will be developed soon.
Project description:In this work, two analytical methodologies based on liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) were developed for quantification of emerging pollutants identified in sewage sludge after a previous wide-scope screening. The target list included 13 emerging contaminants (EC): thiabendazole, acesulfame, fenofibric acid, valsartan, irbesartan, salicylic acid, diclofenac, carbamazepine, 4-aminoantipyrine (4-AA), 4-acetyl aminoantipyrine (4-AAA), 4-formyl aminoantipyrine (4-FAA), venlafaxine and benzoylecgonine. The aqueous and solid phases of the sewage sludge were analyzed making use of Solid-Phase Extraction (SPE) and UltraSonic Extraction (USE) for sample treatment, respectively. The methods were validated at three concentration levels: 0.2, 2 and 20 ?g L(-1) for the aqueous phase, and 50, 500 and 2000 ?g kg(-1) for the solid phase of the sludge. In general, the method was satisfactorily validated, showing good recoveries (70-120%) and precision (RSD < 20%). Regarding the limit of quantification (LOQ), it was below 0.1 ?g L(-1) in the aqueous phase and below 50 ?g kg(-1) in the solid phase for the majority of the analytes. The method applicability was tested by analysis of samples from a wider study on degradation of emerging pollutants in sewage sludge under anaerobic digestion. The key benefits of these methodologies are: • SPE and USE are appropriate sample procedures to extract selected emerging contaminants from the aqueous phase of the sewage sludge and the solid residue. • LC-MS/MS is highly suitable for determining emerging contaminants in both sludge phases. • Up to our knowledge, the main metabolites of dipyrone had not been studied before in sewage sludge.
Project description:Five parabens used as preservatives in pharmaceuticals and personal care products (PPCPs) were measured in sewage sludges collected at 14 U.S. wastewater treatment plants (WWTPs) located in nine states. Detected concentration ranges (ng/g, dry weight) and frequencies were as follows: methyl paraben (15.9 to 203.0; 100%), propyl paraben (0.5 to 7.7; 100%), ethyl paraben (<0.6 to 2.6; 63%), butyl paraben (<0.4 to 4.3; 42%) and benzyl paraben (<0.4 to 3.3; 26%). The estrogenicity inherent to the sum of parabens detected in sewage sludge (ranging from 10.1 to 500.1pg/kg 17?-estradiol equivalents) was insignificant when compared to the 106-times higher value calculated for natural estrogens reported in the literature to occur in sewage sludge. Temporal monitoring at one WWTP provided insights into temporal and seasonal variations in paraben concentrations. This is the first report on the occurrence of five parabens in sewage sludges from across the U.S., and internationally, the first on temporal variations of paraben levels in sewage sludge. Study results will help to inform the risk assessment of sewage sludge destined for land application (biosolids).
Project description:Although sewage sludge is a rich source of nutrients for arable farming and soil improvement, it can also be a source of pollutants. The effects of the land application of sludge on the PCB and nutrient content of leachate were investigated using cylindrical 650 mm length columns filled with poor quality soil. Treatments included no fertilization (control), fertilization using a 62.5 t/ha dose (O50) of sewage sludge from the largest Polish Wastewater Treatment Plant, in Lodz, and a 62.5 t/ha dose of sewage sludge mixed with CaO (O50Ca). The leaching of sludge-borne PCBs and nutrients was simulated by the application of distilled water in a quantity reflecting the annual rainfall of 562.5 mm. The obtained results demonstrate that application of sewage sludge and water simulated leaching of the most mobile chemical compounds, nitrate for example, whereas the addition of CaO decreased the average PCB and phosphorus concentrations in comparison to the control and O50 samples.
Project description:In this study, we analyzed 27 pharmaceuticals in liquid and solid phase samples collected from the unit processes of four different sewage treatment plants (STPs) to evaluate their distribution and behavior of the pharmaceuticals. The examination of the relative distributions of various categories of pharmaceuticals in the influent showed that non-steroidal anti-inflammatory drugs (NSAIDs) were the most dominant. While the relative distribution of antibiotics in the influent was not high (i.e., 3%-5%), it increased to 14%-30% in the effluent. In the four STPs, the mass load of the target pharmaceuticals was reduced by 88%-95% mainly in the biological treatment process, whereas the ratio of pharmaceuticals in waste sludge to those in the influent (w/w) was only 2%. In all the STPs, the removal efficiencies for the stimulant caffeine, NSAIDs (acetaminophen, naproxen, and acetylsalicylic acid), and the antibiotic cefradine were high; they were removed mainly by biological processes. Certain compounds, such as the NSAID ketoprofen, contrast agent iopromide, lipid regulator gemfibrozil, and antibiotic sulfamethoxazole, showed varying removal efficiencies depending on the contribution of biodegradation and sludge sorption. In addition, a quantitative meta-analysis was performed to compare the pharmaceutical removal efficiencies of the biological treatment processes in the four STPs, which were a membrane bioreactor (MBR) process, sequencing batch reactor (SBR) process, anaerobic-anoxic-oxic (A2O) process, and moving-bed biofilm reactor (MBBR) process. Among the biological processes, the removal efficiency was in the order of MBR > SBR > A2O > MBBR. Among the tertiary treatment processes investigated, powdered activated carbon showed the highest removal efficiency of 18%-63% for gemfibrozil, ibuprofen, ketoprofen, atenolol, cimetidine, and trimethoprim.
Project description:The identification and determination of transformation products (TPs) of pharmaceuticals is essential nowadays, in order to track their fate in the aqueous environment and, thus, to estimate the actual pollution. However, this is a challenging task due to the necessity to apply high-resolution instruments enable to detect known and unknown compounds. This work presents the use of liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) as a powerful tool for the identification of three selected pharmaceuticals, furosemide (FUR), ibuprofen (IBP), and ketoprofen (KET), and their TPs in various water samples. Laboratory degradation experiments were performed using xenon lamp as a source of the irradiation in order to simulate phototransformation processes which may occur in the environment. Furthermore, the photodegradation kinetics of three selected compounds were assessed in a reactor equipped with xenon lamp in river water samples. Five TPs of IBP, seven of KET, and five of FUR were identified; some of them are presented here for the first time. Accurate mass measurements and fragmentation pattern obtained during an LC-QTOF-MS analysis allowed for structure elucidation of TPs followed by the creation of transformation pathway of selected pharmaceuticals. Finally, different water samples (wastewater influent and effluent, river water, untreated and treated water) were analyzed in order to estimate the presence of parent and transformed compounds. Only KET was detected in untransformed form in considered samples. Most of the TPs of selected drugs were found at least once in all water samples. Although IBP and FUR were not present in water samples as parent compounds, their different TPs occur. A great potential of LC-QTOF-MS in the identification and structural elucidation of TPs in the environment, allowing the recognition of the fate of pharmaceuticals in the environment through the determination of transformation pathway, has been presented.