A Method for Detection of Trace Concentrations of Underivatized Amino Acid in Hydrothermal Fluids by Ion-Pairing Reversed-Phase UPLC-ESI-QTOF-MS

Investigation of amino acids in hydrothermal systems is of prime importance for the understanding of geochemistry and microbiology of hydrothermal vents and plumes, for carbon and metals global cycles, for metabolism of some hydrothermal microorganisms and for the origin of life issue. Extensive theoretical and experimental work on amino acids behaviour in hydrothermal fluids has been done, conversely only few data exist on natural samples. Because each hydrothermal vent is unique, the more data we collect the better we will be able to address each of these questions. Usually amino acids in hydrothermal fluids have been measured by HPLC-FLD. The chromatographic separation was at least 26 min and up to 135 min and the required derivatization step may be time consuming, may use harmful chemicals and may be source of contamination. Alternatively, we describe here a method combining quickness (4.5 min), high resolution (10,000), very low LOD (sub-ppb) and without derivatization. Characterisation and separation of 10 relevant proteinogenic underivatized amino acids was achieved by ion-pairing reversed-phase Ultra-high Performance Liquid Chromatography-Electrospray Ionisation-Quadrupole Time of Flight-Mass Spectrometry (UPLC-ESI-QTOF-MS). Excellent linearity in the response was obtained for all amino acids with correlation coefficients > 0.9921. This method was successfully applied to natural hydrothermal fluid samples from ultramafic-hosted vents of the Mid-Atlantic Ridge region. Results are consistent with the only 2 other studies published on ultramafic-hosted vents and complete the few available data.

Mass transfer of an organophosphate flame retardant between product source and dust in direct contact

Organophosphate flame retardants(OPFRs)are a group of semi-volatile organic compounds(SVOCs)and among the most abundant contaminants indoors.Their indoor presence has been associated with potential health risks however there is limited understanding as to how they are released from indoor sources.This study uses an emission micro-chamber to explore one of the currently understudied chemical migration pathways;direct transfer between a source material and settled dust in contact with the source.A tris(2-chloroisopropyl)phosphate(TCIPP)-treated insulation board is used as the source material.Rapid and substantial transfer was observed after only 8 h of source-dust contact,resulting in 80 times higher concentrations in dust compared to pre-experiment levels.Further time points at 24 h and 7 d showed similarly high average dust levels and the TCIPP in the dust and air in the chamber was calculated to be close to thermodynamic equilibrium.It was concluded that TCIPP was effectively transferred from the insulation board to the dust on its surface and the surrounding air via gas-phase diffusion.In a real room,a gradient of TCIPP concentrations in air above the surface of a product could result in higher concentrations in dust sitting on the product than dust in the rest of the room.

Comparisons of indoor active and passive air sampling methods for emerging and legacy halogenated flame retardants in Beijing, China offices

One active and two passive air sampling configurations were deployed simultaneously in three offices in Beijing,China to test their comparability for sampling emerging and legacy halogenated flame retardants spanning a large range of octanoleair partition coefficients(KOA).Sampling in each office was carried out for three consecutive 28-day periods in the spring-summer of 2013.The active sampler was run for 2.5 h at different times every day for 28 days to parallel the passive samplers and sample a total volume comparable to that sampled by the passive samplers(~20 m^3).At the end of each 28-day sampling period,a separate active air sample was taken by running the sampler pump continuously for about 2.5 days.The comparability of measured concentrations varied between the air sampling configurations and for different compounds.The predominant compound measured in nearly all samples was BDE-209,a compound known to have heavy use in China.Several emerging flame retardants were also detected including DBE-DBCH,PBT,HBB,DDC-CO,and DBDPE.Very little of the tetra-hexabrominated BDEs associated with the technical PentaBDE product was observed.

Water-to-air transfer of branched and linear PFOA:Influence of pH,concentration and water type

The volatilisation of perfluorooctanoic acid(PFOA)was measured experimentally at a range of pH values using a previously published laboratory method.Water-to-air transfer was studied for five structural isomers,namely:the linear isomer(n-PFOA)and the four most commonly occurring branched isomers(3-,4-,5-and 6-PFOA).The influence of water concentration and water type on the pH-dependent waterto-air transfer was also investigated for n-PFOA.The water-to-air transfer was studied over the course of 48 h at pH values ranging from 0.2 to 5.5.Under all experimental conditions tested,the volatilisation of PFOA was negligible at pH>2.5.In experiments performed with MilliQ water,volatilisation increased with decreasing water pH.In experiments performed with tap water and lake water,maximum volatilisation was observed at pH 1.The concentration of PFOA in water had no influence on the pH value at which water-to-air transfer was observed(i.e.at pH<2.5)for the concentration range tested(0.1e50 mg/L PFOA in deionised water).Although the percentage of PFOA volatilised was significantly different for the four branched isomers at low pH,volatilisation was not observed above pH 2.5 for any branched isomer suggesting that all PFOA isomers have a low pKa.Overall,these laboratory results demonstrate that volatilisation of any structural isomer of PFOA from water is negligible at environmentally-relevant conditions.It is unlikely that PFOA isomers will be fractionated in the environment as a result of volatilisation because it is a process of negligible environmental relevance.

Screening-level exposure-based prioritization to identify potential POPs, vPvBs and planetary boundary threats among Arctic contaminants

A report that reviews Arctic contaminants that are not currently regulated as persistent organic pollutants(POPs)under international treaties was recently published by the Arctic Monitoring and Assessment Programme(AMAP).We evaluated 464 individual chemicals mentioned in the AMAP report according to hazard profiles for POPs,very persistent and very bioaccumulative(vPvB)chemicals,and two novel and distinct hazard profiles we derived from the planetary boundary threat framework.The two planetary boundary threat profiles assign high priority to chemicals that will be mobile and poorly reversible environmental contaminants.Utilizing persistence as a proxy for poor reversibility,we defined two exposure-based hazard profiles;airborne persistent contaminants(APCs)and waterborne persistent contaminants(WPCs)that are potential planetary boundary threats.We used in silico estimates of physicochemical properties and multimedia models to calculate hazard metrics for persistence,bioaccumulation and long-range transport potential,then we synthesized this information into four exposure-based hazard scores of the potential of each AMAP chemical to fit each of the POP,vPvB,APC and WPC exposure-based hazard profiles.As an alternative to adopting a“bright line”score that represented cause for concern,we scored the AMAP chemicals by benchmarking against a reference set of 148 known and relatively well-studied contaminants and expressed their exposure-based hazard scores as percentile ranks against the scores of the reference set chemicals.Our results show that scores in the four exposure-based hazard profiles provide complementary information about the potential environmental exposure-based hazards of the AMAP chemicals.Our POP,vPvB,APC and WPC exposure-based hazard scores identify high priority chemicals for further study from among the AMAP contaminants.

Early life exposure to per-and polyfluoroalkyl substances(PFASs):A critical review

Due to the dynamic developmental processes during pregnancy,infancy,childhood and adolescence,exposure to PFASs is hypothesized to have the most pronounced negative effects during this period.In this review we critically evaluate the current state of the science regarding human early life exposure processes(until 18 years of age)to per-and polyfluoroalkyl substances(PFASs).Efficient placental transfer of perfluoroalkyl acids(PFAAs)results in relatively high prenatal exposure compared with many neutral organic contaminants.The few biomonitoring studies that specifically target infants,toddlers and other children suggest relatively high serum concentrations of perfluorooctane sulfonic acid(PFOS)and perfluorooctanoic acid(PFOA)in early life with peak concentrations occurring sometime before the child reaches 20 months.This peak in serum concentrations is most likely explained by exposure via breastfeeding,ingestion of house dust and/or specific contact events with consumer products leading to high body weight normalized estimated daily intakes(EDIs).Although children have higher EDIs of PFASs than adults,these are not always reflected by higher serum levels of PFASs in children in cross-sectional biomonitoring studies due to the confounding effect of age and birth cohort,and different exposure histories due to production changes.Longitudinal exposure studies measuring internal and external exposure(for multiple pathways and PFASs)at several time points during early life are strongly encouraged to understand temporal changes in exposure of individual children.A better quantitative understanding of early life exposure processes would help to improve the validity of epidemiological studies and allow informed decisions regarding setting of regulatory thresholds and appropriate mitigation actions.

Identifying further chemicals of emerging arctic concern based on‘in silico’screening of chemical inventories

In the past 12 years several studies have screened lists of thousands of chemicals available in the industrial chemical inventories of the European Union,the USA and Canada with the goal of identifying and prioritizing chemicals which are persistent(P),bioaccumulative(B)and toxic(T).Most studies have selected chemicals based on whether their predicted P and B properties and their long-range transport potential exceed guideline thresholds for evaluation of persistent organic pollutants(POPs).A major goal of this study was to review this recent literature on computer-based or‘in silico’screening for POPs.A second goal was to review other approaches for finding previously unidentified chemicals of concern including targeted and non-target analytical approaches that might use lists of suspect chemicals developed from‘in silico’screening studies.Eight studies were reviewed along with several others which examined the screening process and its uncertainties.From these studies we assembled a list of 3421 chemicals,after removing duplicates and substances already on the Stockholm Convention on POPs.About 52%of these were halogenated,while 48%consisted of a broad range of non-halogenated organics.This list was then further analysed by calculating an overall“POPs score”for transport and accumulation in the Arctic for each substance using predicted partition coefficients,overall persistence,transfer efficiency,and bioaccumulation factor.A shorter list of twenty-five substances was developed based on their POPs score ranking.These substances had not been previously analysed in environmental media but were nevertheless on current or recent chemical inventories indicating significant commercial use.

Chemicals of Emerging Arctic Concern:Preface

1.Preface The Arctic Monitoring and Assessment Programme(AMAP)was established as an international program for monitoring and assessing Arctic pollution in 1991,under the Arctic Environmental Protection Strategy[1].AMAP is now aWorking Group of the Arctic Council(http://www.arctic-council.org)responsible for monitoring and assessing a range of pollution-and climate change-related issues in the Arctic in order to“provide reliable and sufficient information on the status of,and threats to,the Arctic environment,and scientific advice on actions to be taken in order to support Arctic governments in their efforts to take remedial and preventive actions relating to contaminants and adverse effects of climate change”(see Ref.[2]).

Sampling strategy for estimating human exposure pathways to consumer chemicals

Human exposure to consumer chemicals has become a worldwide concern.In this work,a comprehensive sampling strategy is presented,to our knowledge being the first to study all relevant exposure pathways in a single cohort using multiple methods for assessment of exposure from each exposure pathway.The selected groups of chemicals to be studied are consumer chemicals whose production and use are currently in a state of transition and are;per-and polyfluorinated alkyl substances(PFASs),traditional and“emerging”brominated flame retardants(BFRs and EBFRs),organophosphate esters(OPEs)and phthalate esters(PEs).Information about human exposure to these contaminants is needed due to existing data gaps on human exposure intakes from multiple exposure pathways and relationships between internal and external exposure.Indoor environment,food and biological samples were collected from 61 participants and their households in the Oslo area(Norway)on two consecutive days,during winter 2013-14.Air,dust,hand wipes,and duplicate diet(food and drink)samples were collected as indicators of external exposure,and blood,urine,blood spots,hair,nails and saliva as indicators of internal exposure.A food diary,food frequency questionnaire(FFQ)and indoor environment questionnaire were also implemented.Approximately 2000 samples were collected in total and participant views on their experiences of this campaign were collected via questionnaire.While 91%of our participants were positive about future participation in a similar project,some tasks were viewed as problematic.Completing the food diary and collection of duplicate food/drink portions were the tasksmost frequent reported as“hard”/“very hard”.Nevertheless,a strong positive correlation between the reported total mass of food/drinks in the food record and the total weight of the food/drinks in the collection bottles was observed,being an indication of accurate performance of the participants despite the challenges of the sampling campaign.

Acknowledgement

The articles in this Special Issue of Emerging Contaminants present the results of AMAP Assessment 2016:Chemicals of Emerging Arctic Concern.The 2016 assessment is the fourth assessment conducted by the Arctic Monitoring and Assessment Programme(AMAP)on Arctic contaminants,and updates previous assessments made in 1998,2002 and 2009.The results of the CEAC component of the 2016 assessment are also summarized for decision-makers in the AMAP report Chemicals of Emerging Arctic Concern:Summary for Policy Makers(for further information,see www.amap.no).