Researcher and media alarms have caused plastic debris to be perceived as a major threat to humans and animals. However, although the waste of plastic in the environment is clearly undesirable for ...aesthetic and economic reasons, the actual environmental risks of different plastics and their associated chemicals remain largely unknown. Here we show how a systematic assessment of adverse outcome pathways based on ecologically relevant metrics for exposure and effect can bring risk assessment within reach. Results of such an assessment will help to respond to the current public worry in a balanced way and allow policy makers to take measures for scientifically sound reasons.
Organic contaminants in shale gas flowback and produced water (FPW) are traditionally expressed as total organic carbon (TOC) or chemical oxygen demand (COD), though these parameters do not provide ...information on the toxicity and environmental fate of individual components. This review addresses identification of individual organic contaminants in FPW, and stresses the gaps in the knowledge on FPW composition that exist so far. Furthermore, the risk quotient approach was applied to predict the toxicity of the quantified organic compounds for fresh water organisms in recipient surface waters. This resulted in an identification of a number of FPW related organic compounds that are potentially harmful namely those compounds originating from shale formations (e.g., polycyclic aromatic hydrocarbons, phthalates), fracturing fluids (e.g., quaternary ammonium biocides, 2-butoxyethanol) and downhole transformations of organic compounds (e.g., carbon disulfide, halogenated organic compounds). Removal of these compounds by FPW treatment processes is reviewed and potential and efficient abatement strategies are defined.
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.
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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•In the suspect screening, data were screened for the presence of a large set of anthropogenic chemicals.•700 detected compounds from LC-HRMS screening data were linked to one or multiple suspects.•From over 5200 chemicals we prioritized 174 suspects for their health relevance for drinking water.•The prioritized suspects are relevant for detailed future risk assessment.•The relatively fast approach shows to be complementary to currently used target-based approaches.
•Overview and evaluation of available literature using WBE to detect illicit drugs .•The WBE approach shows an improvement in quality over the recent years.•High cocaine and methamphetamine ...consumption rates are found in the USA.•Relatively low illicit drug consumption is found in the continent of Asia.
Illicit drug use is complex, hidden and often highly stigmatized behaviour, which brings a vast challenge for drug surveillance systems. Drug consumption can be estimated by measuring human excretion products in untreated wastewater, known as wastewater-based epidemiology (WBE). Over the last decade, the application of wastewater-based epidemiology to monitor illicit drug loads increased and WBE is currently applied on a global scale. Studies from over the globe are evaluated with regard to their sampling method, analytical accuracy and consumption calculation, aiming to further reduce relevant uncertainties in order to make reliable comparisons on a global level. Only a limited number is identified as high-quality studies, so further standardization of the WBE approach for illicit drugs is desired especially with regard to the sampling methodology. Only a fraction of the reviewed papers explicitly reports uncertainty ranges for their consumption data. Studies which had the highest reliability are recently published, indicating an improvement in reporting WBE data. Until now, WBE has not been used in large parts of Africa, nor in the Middle East and Russia. An overview of consumption data across the continents on commonly studied drugs (cocaine, MDMA, amphetamine and methamphetamine) is provided. Overall, high consumption rates are confirmed in the US, especially for cocaine and methamphetamine, while relatively low illicit drug consumption is reported in Asia.
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A wide range of PFAS residues were studied in an aquifer used for drinking water production which was affected by historical PFAS contamination from a landfill and military camp. Samples were taken ...at three monitoring and four pumping wells at different depths ranging from 33 to 147 m below the land surface and analysed for a series of 53 PFAS (C2-C14) and PFAS precursors (C4-C24). A comparison of results to earlier research from 2013, with a more limited range of PFAS, showed decreasing concentrations and migration of PFAS with increasing depth and distance from the contamination source.
The PFAS profile and branched/linear isomer ratio are used as source characterization tools. The landfill was confirmed to contaminate the groundwater in both monitoring wells, while the military camp was indicated as a probable source for PFAS observed in the deep sampling points of one of the monitoring wells. Pumping wells used to produce drinking water are not yet affected by these two PFAS sources. In one of the four sampled pumping wells, a different PFAS profile and isomer pattern was observed, which indicated a different but yet unknown source.
This work shows the necessity of implementing regular screening to identify potential (historical) PFAS sources to be able to prevent future contaminant migration nearby and towards drinking water abstraction wells.
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•Historical PFAS contamination was followed in a drinking water aquifer.•In a decade time PFAS migrated by increase with depth and distance.•PFAS profile and isomer pattern were used as source indicators.•Landfill and military camp were confirmed as contamination sources for groundwater.
We determined pesticide occurrence in groundwater and surface water sources used for drinking water production in The Netherlands, using both routine monitoring data from Dutch drinking water ...companies and by studying the presence of newly authorized pesticides in drinking water sources.
An analytical LC-MS/MS method was developed for 24 recently authorized pesticides, selected based on their mobility and persistence, and applied in a Dutch/Belgian ground- and surface water monitoring campaign. 15 of these pesticides were detected, including seven in concentrations above the water quality standard from the Water Framework Directive. Two neonicotinoids were detected in highest concentrations: acetamiprid (1.1 μg/L) and thiamethoxam (0.4 μg/L).
The routine monitoring data was collected over 2010–2014 in The Netherlands, covering 408 pesticides and 52 metabolites. 63 pesticides and 6 metabolites were prioritized according to their presence in groundwater, surface water and drinking water. The vast majority of the pesticides in routine monitoring has not been detected or only in low concentrations.
Overall, the study shows that pesticides are of major concern in drinking water sources across the Netherlands. In two third of the abstraction areas pesticides and/or metabolites have been detected. In one third of the abstraction areas pesticide and/or metabolites concentration exceeded water quality standards according to the Water Framework Directive. The results emphasize that monitoring should focus on priority pesticides, since the vast majority of the pesticides has a low priority. The occurrence of recently authorized pesticides in drinking water sources demonstrates the importance to keep routine monitoring methods up to date.
•15 out of 24 recently authorized pesticides were detected, including neonicotinoids.•Of 408 pesticides and 52 metabolites, 63 pesticides and 6 metabolites were prioritized.•In the majority of drinking water sources, pesticides and/or metabolites were detected.•Some prioritized pesticides were not earlier detected in large monitoring studies.
Toxicological risk assessment of contaminants of emerging concern (CEC) in (sources of) drinking water is required to identify potential health risks and prioritize chemicals for abatement or ...monitoring. In such assessments, concentrations of chemicals in drinking water or sources are compared to either (i) health-based (statutory) drinking water guideline values, (ii) provisional guideline values based on recent toxicity data in absence of drinking water guidelines, or (iii) generic drinking water target values in absence of toxicity data. Here, we performed a toxicological risk assessment for 163 CEC that were selected as relevant for drinking water. This relevance was based on their presence in drinking water and/or groundwater and surface water sources in downstream parts of the Rhine and Meuse, in combination with concentration levels and physicochemical properties. Statutory and provisional drinking water guideline values could be derived from publically available toxicological information for 142 of the CEC. Based on measured concentrations it was concluded that the majority of substances do not occur in concentrations which individually pose an appreciable human health risk. A health concern could however not be excluded for vinylchloride, trichloroethene, bromodichloromethane, aniline, phenol, 2-chlorobenzenamine, mevinphos, 1,4-dioxane, and nitrolotriacetic acid. For part of the selected substances, toxicological risk assessment for drinking water could not be performed since either toxicity data (hazard) or drinking water concentrations (exposure) were lacking. In absence of toxicity data, the Threshold of Toxicological Concern (TTC) approach can be applied for screening level risk assessment. The toxicological information on the selected substances was used to evaluate whether drinking water target values based on existing TTC levels are sufficiently protective for drinking water relevant CEC. Generic drinking water target levels of 37 μg/L for Cramer class I substances and 4 μg/L for Cramer class III substances in drinking water were derived based on these CEC. These levels are in line with previously reported generic drinking water target levels based on original TTC values and are shown to be protective for health effects of the majority of contaminants of emerging concern evaluated in the present study. Since the human health impact of many chemicals appearing in the water cycle has been studied insufficiently, generic drinking water target levels are useful for early warning and prioritization of CEC with unknown toxicity in drinking water and its sources for future monitoring.
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•The majority of CEC in drinking water or sources does not pose a human health risk.•Toxicity data (hazard) or concentration (exposure) were lacking for part of the CEC.•TTC-based drinking water target levels were evaluated based on toxicity of 142 CEC.•Such target levels allowing screening level risk assessment and prioritization
Water is a vital resource for natural ecosystems and human life, and assuring a high quality of water and protecting it from chemical contamination is a major societal goal in the European Union. The ...Water Framework Directive (WFD) and its daughter directives are the major body of legislation for the protection and sustainable use of European freshwater resources. The practical implementation of the WFD with regard to chemical pollution has faced some challenges. In support of the upcoming WFD review in 2019 the research project SOLUTIONS and the European monitoring network NORMAN has analyzed these challenges, evaluated the state-of-the-art of the science and suggested possible solutions. We give 10 recommendations to improve monitoring and to strengthen comprehensive prioritization, to foster consistent assessment and to support solution-oriented management of surface waters. The integration of effect-based tools, the application of passive sampling for bioaccumulative chemicals and an integrated strategy for prioritization of contaminants, accounting for knowledge gaps, are seen as important approaches to advance monitoring. Including all relevant chemical contaminants in more holistic “chemical status” assessment, using effect-based trigger values to address priority mixtures of chemicals, to better consider historical burdens accumulated in sediments and to use models to fill data gaps are recommended for a consistent assessment of contamination. Solution-oriented management should apply a tiered approach in investigative monitoring to identify toxicity drivers, strengthen consistent legislative frameworks and apply solutions-oriented approaches that explore risk reduction scenarios before and along with risk assessment.
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•Improve monitoring and strengthen comprehensive prioritization of toxic pollutants•Foster consistent assessment of water pollution•Support solution-oriented management of chemicals in the water cycle
Ozonation, sorption to granular activated carbon and aerobic degradation were compared as potential treatment methods for removal of dissolved organic carbon (DOC) fractions and selected organic ...compounds from shale gas flowback water after pre-treatment in dissolved air flotation unit. Flowback water was characterised by high chemical oxygen demand and DOC. Low molecular weight (LMW) acids and neutral compounds were the most abundant organic fractions, corresponding to 47% and 35% of DOC respectively. Ozonation did not change distribution of organic carbon fractions and concentrations of detected individual organic compounds significantly. Sorption to activated carbon targeted removal of individual organic compounds with molecular weight >115 Da, whereas LMW compounds remained largely unaffected. Aerobic degradation was responsible for removal of LMW compounds and partial ammonium removal, whereas formation of intermediates with molecular weight of 200–350 Da was observed. Combination of aerobic degradation for LMW organics removal with adsorption to activated carbon for removal of non-biodegradable organics is proposed to be implemented between pre-treatment (dissolved air floatation) and desalination (thermal or membrane desalination) steps.
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•Organic matter in flowback water is dominated by low molecular weight fractions.•Low molecular weight organics are effectively removed via biodegradation.•Organics with high molecular weight are targeted by activated carbon.•Biodegradation and activated carbon may complement flowback desalination.
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