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Occupational exposure to oil fumes, organophosphates, halogenated flame retardants, and other volatile and semi-volatile contaminants is a concern within the aviation industry. There is no current consensus on the risk attributed to exposure to these chemical classes within the aircraft cabin. Contaminant concentrations rarely exceed conventional air quality guidelines, but concerns have been raised about these guidelines' applicability within the aircraft environment. This systematic review, the largest and most comprehensive completed to date on the subject matter, aims to synthesize the existing research related to chemical and other exposures inside the aircraft cabin to determine the occupational risk that may be attributed said exposure, as well as, determine knowledge gaps in source, pathway, and receptor that may exist. The Science Direct, Scopus, and Web of Science databases were queried with five search terms generating 138 manuscripts that met acceptance criteria and screening.. Several potential areas requiring future examination were identified: Potable water on aircraft should be examined as a potential source of pollutant exposure, as should air conditioning expansion turbines. Historical exposure should also be more fully explored, and non-targeted analysis could provide valuable information to comprehend the aircraft cabin exposome. Occupational risk under typical flight scenarios appears to be limited for most healthy individuals. Contaminants of concern were demonstrated to be extant within the cabin, however the concentrations under normal circumstances do not appear to be individually responsible for the symptomologies that are present in impacted individuals. Questions remain regarding those that are more vulnerable or susceptible to exposure. Additionally, establishing the effects of chronic low dose exposure and exposure to contaminant mixtures has not been satisfied. The risk of acute exposure in mitigable fume events is substantial, and technological solutions or the replacement of compounds of concern for safer alternatives should be a priority.

In this study, we introduce a simple three-step workflow for a universally applicable RI system, to be used in GC×GC analysis of ignitable liquid residue (ILR) for arson investigations. The proposed RI system applies a combination of two well-established GC RI systems: non-isothermal Kovats (K) index in the first dimension and Lee (L) index in the second dimension. The proposed KLI RI system showed very good correlations when compared with predicted values and existing RI systems (r2 = 0.97 in first dimension, r2 = 0.99 in second dimension) and was valid for a wide range of analyte concentrations and operational settings (coefficient of variance (CV)

© 2018 Elsevier Ltd Two Guillemot carcases were dissected, each providing 12 discrete tissue samples and 3 samples of partially digested food. One hundred and five PCBs from the 209 PCBs determined by GCxGC-ToFMS were detected. The relative proportions of individual PCBs did not vary greatly within tissue types, although the PCB profile from undigested food could be distinguished. Enantiomer fractions (EFs) were determined for CB-95, CB-136 and CB-149 by GC-HRqToFMS. EFs in the partially digested food were near racemic, with high levels of enrichment for E1 CB-95 in the kidneys and liver (EF of 0.80 and 0.84 respectively). This provides some of the clearest evidence to date that fractionation takes place in the organs where metabolic biotransformation and elimination of PCBs occurs. Our findings also confirm the ability of non-lethal sampling techniques, such as collection of small ( < 1 g) blood samples, to provide PCB signatures that are representative of an individual organism.

The relationship between climate change and wildfires was examined to summarize factors associated with vulnerability to wildfires. The complex and cyclic nature of interaction effects between the two was highlighted and the following conclusions were drawn. Climate change is leading to more frequent wildfires with higher intensity, resulting in release of more gasses and particulate matter that further exacerbates the progression of climate change. Direct and indirect impacts are detailed in the main body. A new fire management policy is deemed necessary, with a more local approach being recommended. Human impacts were found to further complicate the already complex relationship. It is recommended to treat accidental and incendiary fires separately for the purpose of evaluating fire management regimes. This requires successful advances in current fire investigation techniques.

The abundance and composition of matrix compounds in fire debris samples undergoing ignitable liquid residue analysis frequently leads to inconclusive results, which can be diminished by applying comprehensive two-dimensional gas chromatography (GC × GC). Method development must be undertaken to fully utilize the potential of GC × GC by maximizing separation space and resolution.. The three main areas to consider for method development are column selection, modulator settings and parameter optimization. Seven column combinations with different stationary phase chemistry, column dimensions and orthogonality were assessed for suitability based on target compound selectivity, retention, resolution, and peak shapes, as well as overall peak capacity and area use. Using Box-Behnken design of experimentation (DoE), the effect of modulator settings such as flow ratio and loop fill capacity were evaluated using carbon loading potential, dilution effect, as well as target peak amplitude and skewing effect. The run parameters explored for parameter optimization were oven programming, inlet pressure (column flow rate), and modulation period. Comparing DoE approaches, Box-Behnken and Doehlert designs assessed sensitivity, selectivity, peak capacity, and wraparound; alongside target peak retention, resolution, and shape evaluation. Certified reference standards and simulated wildfire debris were used for method development and verification, and wildfire debris case samples scrutinized for method validation. The final method employed a low polarity column (5% diphenyl) coupled to a semi-polar column (50% diphenyl) and resulted in an average Separation Number (SN) exceeding 1 in both dimensions after optimization. Separation Numbers of 18.16 for first and 1.46 for second dimension without wraparound for compounds with at least four aromatic rings signified successful separation of all target compounds from varied matrix compositions and allowed for easy visual comparison of extracted ion profiles. Mass spectrometry (MS) was required during validation to differentiate ions where no baseline separation between target compounds and extraneous matrix compounds was possible. The resulting method was evaluated against ASTM E1618 and found to be an ideal routine analysis method providing great resolution of target compounds from interferences and excellent potential for ILR classification within a complex sample matrix.

Conifer needles bioaccumulate atmospheric pollutants, including trace metals, and may be used to monitor variations in atmospheric concentration. Needles were analyzed to determine whether a correlation exists between elevations and trace metal concentrations in proximity to roadways and other non-point sources. Composite samples of white spruce (Picea glauca) and balsam fir (Abies balsamea) needles were collected along hillsides in eastern and western Calgary, respectively. A combined total of 11 sites was sampled along two transects of increasing elevation. Qualitative and quantitative analysis of trace metal concentrations was completed using inductively coupled plasma-mass spectrometry (ICP-MS) and synthesized using regression analysis. The concentrations of cobalt, nickel, and calcium in the samples were found to exhibit a significant (P < 0.05) relationship with respect to elevation and proximity to roadways.

Soil salinization impacts millions of hectares of land around the world and threatens many soil ecosystem services. Impacts of soil salinization are long lasting and impact agriculture productivity, reduce plant diversity and cause increase soil erosion due a reduction or loss in surface vegetation. Generally, remediation of saline soil relies on soil washing methods and phytoremediation to translocate salts below the rooting depth of plants. However, standard methods can often be unsuccessful as leached salts are able to return to the rooting zone through subsequent capillary rise in the soil. Surface application of iron (III) ferrocyanide has been used to remediate salt contaminated soil as the ferrocyanide complex induces salts to efflorescence at the soil surface as water evaporates rather than crystallising within the soil matrix. However, surface application of iron (III) ferrocyanide tends to be less successful in clay textured soil and does not work well when subsequent reapplications of water are made for further salt removal. In this study we investigate a biomimetic approach to desalinate soil by mimicking the capillary transport mechanisms employed by vascular plants. Our approach uses evapotranspiration to translocate saline soil water above the soil surface where it is effloresced with ferrocyanides. After 30 days of treatment, the biomimetic approach used 2.1 pore volume equivalents of water and was able to reduce the concentration of salts from 8% (g·NaCl/g·soil) to 0.8% (g·NaCl/g·soil), resulting in a reduction of soil EC from 120 mS/cm to 14 mS/cm. Our findings indicate that the method, with further refinement and expansion to field based trials, could be an effective tool to desalinate soil and reduce global soil salinization.

Large volumes of oil sands process-affected water (OSPW) are generated during the extraction of bitumen from oil sands in the Athabasca region of northeastern Alberta, Canada. As part of the development of treatment technologies, molecular characterization of naphthenic acids (NAs) and naphthenic acid fraction compounds (NAFC) in wetlands is a topic of research to better understand their fate and behavior in aquatic environments. Reported here is the application of high-resolution negative-ion electrospray Orbitrap-mass spectrometry for molecular characterization of NAs and NAFCs in a non-aerated constructed treatment wetland. The effectiveness of the wetlands to remove OSPW-NAs and NAFCs was evaluated by monitoring the changes in distributions of NAFC compounds in the untreated sample and non-aerated treatment system. After correction for measured evapotranspiration, the removal rate of the classical NAs followed approximately first-order kinetics, with higher rates observed for structures with relatively higher number of carbon atoms. These findings indicate that constructed wetland treatment is a viable method for removal of classical NAs in OSPW. Work is underway to evaluate the effects of wetland design on water quality improvement, preferential removal of different NAFC species, and reduction in toxicity.

PCB signatures can be used for source identification, exposure studies, age dating and bio-monitoring. This study uses comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GCxGC-ToFMS) to produce a PCB signature comprised of over 80 PCBs for individual Leach's storm petrels (Oceanodroma leucorhoa). The Leach's storm petrel is a relatively small, elusive, understudied pelagic bird, which only returns to remote islands under darkness during the breeding season. Samples were obtained from 25 Leach's storm petrels found dead in Canada and the UK following storm events in 2006 and 2009. Tissue samples were extracted and analysed by GCxGC-ToFMS and results showed that 83 PCB congeners were present in >60% of samples. An assessment of the PCB signature in four different tissue types showed that it did not vary greatly in samples obtained from the gut, heart, liver and stomach. Multivariate statistical analysis identified a distinctive PCB signature in birds from Canada and Europe which was used to identify the regional provenance and transatlantic movement of individual birds. The findings showcase the ability of GCxGC-ToFMS to provide the high quality congener specific analysis that is necessary for PCB fingerprinting, as well as highlighting the potential of PCB signatures for use in ecological studies of movement, foraging and behaviour.

During the bitumen extraction from the oil sands of Alberta, large volumes of process water containing naphthenic acids are stored in tailing ponds. The naphthenic acids along with other components in the processed waters are known to be toxic in aquatic environments. In view of the complex matrix and the toxicity of the processed waters, there is a need for complementary analytical techniques for comprehensive characterization of the naphthenic acid mixtures. This study reports the online gas chromatographic separation of naphthenic acid mixtures prior to ultrahigh resolution mass spectrometry detection, using electron and chemical ionization. Two oil sands processed water samples and two groundwater samples were characterized to evaluate the performance of the instrumental technique. The high mass resolution of the system enabled visualization of the data using Kendrick mass defect plots. The addition of gas chromatographic separations enabled visualization of the data as unique compound class elution fingerprints. The technique is demonstrated to be a valuable tool for chemical fingerprinting of naphthenic acids.

A forensic geo-gas investigation within an urban environment has identified distinct compositional and stable-isotope characteristics related to various reference sources of methane gas by using analytical techniques such as geochemical screening, stable-carbon and stable-hydrogen isotope analysis, and radioactive carbon-isotope analysis. The results of the investigation concluded that the combination of a number of geochemical indicators produced a distinctive geo-gas fingerprint for samples from similar reference sites.

We present an advanced system for on-line position-specific carbon isotope analysis. The main limitation of on-line intramolecular isotope ratio measurements has been that optimal pyrolytic fragments are obtained mostly at temperatures where the analyte has not completely reacted. As a result of undetermined isotopic fractionation, the isotopic signatures of the pyrolysis products are not strictly equal to these of the equivalent moieties in the parent molecule. We designed a pyrolytic unit in which both temperature and reaction time are variable parameters, enabling determination of the enrichment factor of the pyrolysis at optimal temperature by construction of a Rayleigh plot. In the case of methyl tert-butyl ether (MTBE) presented here, a 'pre-pyrolysis' fractionation of MTBE leading to a depletion of 0.9 parts per thousand was discovered and the enrichment factor of the optimal pyrolysis reaction was determined at -1.7 parts per thousand. Absolute delta C-13 values of two functional groups of MTBE - the methoxy group and the 2-methylpropane group - could be determined with 95% confidence intervals of 0.4 parts per thousand and 0.5 parts per thousand, respectively.

This study examined the range of carbon and hydrogen isotopes within a global set of gasolines to investigate the potential and limitations of isotopic analysis within environmental assessments of gasoline-contaminated sites. Bulk carbon and hydrogen isotope signatures within gasolines from the study had a range greater than 8‰ and 85‰, respectively. The combination of both isotopes produced a highly discriminating two-dimensional (2D) isotope fingerprint, highlighting the potential of 2D fingerprinting to differentiate gasoline sources. Compound-specific carbon isotope analysis was also completed to investigate its application as a method for risk-based management and environmental forensics.

Detailed polychlorinated biphenyl (PCB) signatures and chiral Enantiomer Fractions (EFs) of CB-95, CB-136 and CB-149 were measured for 30 workers at a transformer dismantling plant. This was undertaken to identify sources of exposure and investigate changes to the PCB signature and EFs over different exposure periods. Approximately 1.5 g of serum was extracted and PCB signatures were created through analysis by comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC × GC–TOFMS) and EFs calculated following analysis by gas chromatography with high resolution mass spectrometry (GC–HRMS). A total of 84 PCBs were identified in the serum samples with concentrations of the 7 indicator PCBs ranging from 11–350 ng g−1 of serum (1.2–39 μg g−1 lipid). The PCB signatures were interpreted using principal component analysis (PCA) which was able to distinguish workers with background or recent minimal exposure from those with prolonged occupational exposure. Occupationally exposed individuals had a similar PCB profile to Aroclor A1260. However, individuals with prolonged exposure had depleted proportions of several PCB congeners that are susceptible to metabolism (CB-95, CB-101 and CB-151) and elevated proportions of PCBs that are resistant to metabolism (CB-74, CB-153, CB-138 and CB-180). The results also identified a third group of workers with elevated proportions of CB-28, CB-60, CB-66, CB-74, CB-105 and CB-118 who appeared to have been exposed to an additional source of PCBs. The results show near complete removal of the CB-95 E2 enantiomer in some samples, indicating that bioselective metabolism or preferential excretion of one enantiomer occurs in humans. By considering PCB concentrations along with detailed congener specific signatures it was possible to identify different exposure sources, and gain an insight into both the magnitude and duration of exposure. Keywords: Polychlorinated biphenyls (PCBs), Human exposure, GC × GC–TOFMS, Chemical fingerprinting, PCB atropisomers, Chiral, Enantiomer fractions

Dendroecology and phytoscreening investigations are emerging forensic techniques that have attained scientific maturity in terms of their ability to provide corroborative evidence of contaminant releases in soil and groundwater. In some cases, dendroecology can also provide insight regarding causal relationships between a contaminant release and the presence of the same contaminant in a tree ring. A recent evolution of dendroecology investigations is the development of solid-phase microextraction (SPME) sampling techniques, which allow continuous sampling and provide lower detection limits than traditional head-space analysis of tree core samples.

Polychlorinated biphenyls (PCBs), dioxins (PCDDs) and furans (PCDFs) are frequently detected in grass, soil and farm animals near incineration plants, electric transformers recycling facilities, or after major fires during environmental forensic investigations. The sale of farm animals for food above established PCBs and PCDD/F limits is forbidden, and therefore are slaughtered, or removed from contaminated areas to graze on uncontaminated food, in an attempt to detoxify. If regulated levels are exceeded in one sample, the impacts are rarely limited to one area, or within the sampling period. It is therefore important to establish the extent of the contamination, distinguish the potential source(s) and identify the duration of the contamination event. This manuscript examine potential pitfalls in the analysis of (PCBs), dioxins (PCDDs) and furans (PCDFs) in terms of their regulated levels, sampling challenges, the analysis of samples and statistical interpretation of the test data.

Interaction between the regulator and practitioners in the field of environmental investigations An introduction to a multiparameter approach to improve the reliability of environmental crime evidence Environmental litigation issues in Taiwan and the forensics strategies of chlorinated hydrocarbon contaminated sites Forensic investigations in a PCB case: potential pitfalls and tips Use of symmetric tetrachloroethane to age date chlorinated solvent releases A forensic methodology for investigating chlorinated solvent releases from a dry cleaner 13C and delta37Cl on gas-phase TCE for source identification investigation - Innovative solvent-based sampling method Characterisation and modeling of dust in a semi-arid construction environment Assessment of polycyclic aromatic hydrocarbons in an urban soil dataset Statistics of lost historical coal tar PAH contamination in soils and sediments Micro-bubbles oxygen injection in groundwater contaminated by organic biodegradable compounds and metals Heavy metals (lead, cadmium, chromium, nickel and zinc) contamination in selected electronic waste dumpsites in Lagos, Nigeria Evidence for acid mine drainage in an urban stream in the West Midands A Practical Evaluation of Petrogenic and Biogenic Methane Sources in the Context of Redevelopment and Explosive Hazard Management in Los Angeles, California Subject Index

PCBs were first produced in 1929 and were widely used throughout the 20th century for a variety of industrial uses such as dielectric fluids, hydraulic fluids and plasticisers. Production rates decreased steadily throughout the 1970's as the health and environmental risks from PCBs began to be better understood. In the United States this resulted in passing of the Toxic Substances Control Act in 1976, with PCBs phased out from 1979. However, PCBs can still be found in closed systems such as dielectric fluids in electrical equipment. They are highly persistent and still routinely found in environmental and human samples across the globe. All humans have been exposed to background concentrations of PCBs, however, there are also events where individuals are exposed to elevated concentrations. In litigation cases it is important to differentiate specific exposure events from background exposure, as well as identifying the source of contamination and age dating the exposure period. Age dating PCB exposure is complex, but assessments can be made because different PCB congeners have different residence times in the human body.

Environmental forensics is a growing multidisciplinary field which combines traditional applied sciences, in particular analytical chemistry, with socioeconomic factors to identify the source, age, and timing of a contaminant into the environment. Persistent organic pollutants (POPs) are a group of priority pollutants which by their chemical nature are capable of long-range transport and biomagnification in food chains, including bioaccumulation in human and animal tissue. Mounting scientific evidence has suggested that they may be found not only in industrial locations but also in remote regions, such as deep ocean sediments and the Antarctic. They have been found to pose a significant risk to the environment and human health prompting the formation of environmental bodies like the United States Environmental Protection Agency and lead to the implementation of regulations to restrict their use. This chapter highlights significant discoveries of POPs in the environment, development of key analytical techniques and legislative milestones in the control of POPs in the environment. It also includes a brief description of the physical and chemical properties of POPs and finishes with a concise explanation of the main environmental processes that control the environmental behavior of POPs.

Pollution Investigation by Trees (PIT) is an international research program funded by Ademe, the French Agency for Environment and Energy Management. The research program has been established to further test tree-based methods (phytoscreening and dendrochemistry) on well documented sites and new contaminants, and to communicate findings to ensure such methods are readily accessible to potential users. This chapter presents a summary of the science of phytoforensics and dendrochemistry, an introduction to the methodologies used by PIT, and the results of findings from three sites investigated by PIT.

Worldwide there is concern about the continuing release of persistent organic pollutants (POPs) into the environment. To complete an environmental forensic investigation of POPs in the terrestrial environment, an understanding of the source, fate, and behavior of POPs in terrestrial media is required. This chapter examines a variety of terrestrial environments, including soil and sediments, herbage, wildlife, and humans. It includes discussion on the major pathways in which POPs enter each media, the changes which may occur within the media, background concentrations and patterns which may be used to interpret the potential sources of POPs in each media. Two case studies are presented at the end of this chapter to provide context to the discussion and highlight how environmental forensics investigations in the terrestrial environment may be carried out using different tools.

This study is the first investigation of biodegradation of carbon disulphide (CS2) in soil that provides estimates of degradation rates and identifies intermediate degradation products and carbon isotope signatures of degradation. Microcosm studies were undertaken under anaerobic conditions using soil and groundwater recovered from CS2-contaminated sites. Proposed degradation mechanisms were validated using equilibrium speciation modelling of concentrations and carbon isotope ratios. A first-order degradation rate constant of 1.25 × 10-2 h-1 was obtained for biological degradation with soil. Carbonyl sulphide (COS) and hydrogen sulphide (H2S) were found to be intermediates of degradation, but did not accumulate in vials. A 13C/12C enrichment factor of -7.5 ± 0.8 ‰ was obtained for degradation within microcosms with both soil and groundwater whereas a 13C/12C enrichment factor of -23.0 ± 2.1 ‰ was obtained for degradation with site groundwater alone. It can be concluded that biological degradation of both CS2-contaminated soil and groundwater is likely to occur in the field suggesting that natural attenuation may be an appropriate remedial tool at some sites. The presence of biodegradation by-products including COS and H2S indicates that biodegradation of CS2 is occurring and stable carbon isotopes are a promising tool to quantify CS2 degradation.

In human exposure studies involving Polychlorinated Biphenyls (PCBs), it is useful to establish when an individual was potentially exposed. Age dating PCB exposure is complex but assessments can be made because different PCB congeners have different residence times in the human body. The less chlorinated congeners generally tend to have shorter residence times because they are biotransformed and eliminated faster than more chlorinated congeners. Therefore, the presence of high proportions of less chlorinated congeners is often indicative of recent exposure. The 2003-04 National Health and Nutrition Examination Survey (NHANES) dataset contains results for the concentration of 37 PCBs in a sub-sample of the US population. Multivariate statistical analysis of the NHANES data showed that less chlorinated congeners are not always biotransformed faster than higher chlorinated compounds. For example, PCB 28 (a tri-chlorobiphenyl) appears to be more resistant to biotransformation than PCB 101 and 110 (penta-chlorobiphenyls). Using statistical analysis of the NHANES data in conjunction with previously published studies on PCB persistence in humans, it was possible to identify the structural relationships that determine if a PCB is likely to be from a recent exposure (termed 'episodic') or from steady state exposure. Congeners with chlorine atoms in the 2,5- and 2,3,6-positions appear to be more susceptible to biotransformation whereas congeners with chlorine bonds in the 2,3,4- 2,4,5- 3,4,5- and 2,3,4,5-positions appear to be more persistent. This work shows that future investigations to date PCB exposure would benefit from the analysis of a wide range of congeners, including the selection of key congeners based not only on the degree of chlorination but also on the positions of the chlorine atoms on the biphenyl.

Here we propose a 'leap foward' with the application of Position Specific Isotope Analysis to Environmental Forensics, a topic which has a large un-tapped potential for biogeochemical / biodegradation studies. Compound specific isotope analysis (CSIA) is a relatively new methods in Enviornmental Forenscis (figuring out where the contamination in the environment comes from). PSIA could uncover / unlock the questions that CSIA has opened up and leap-frog our understanding of the fate of contaminants in the environment. Isotopic fractionation is limited to reactions at the site or bond in the contaminant molecule associated with the rate-limiting biodegradation step. These fractionation effects are diluted in 'whole molecule' CSIA by the presence of non-reacting carbon atoms. Intramolecular isotope ratios however would be sensitive to such fractionation effects and could be used to determine the pathways and mechanism of degradation. Leveraging the resources of Prof. Kalin's EPSRC funded Platform Grant therefore provides the 'base-line real-world' access to sites and samples for this proposed 'Speculative Engineering' research, thereby allowing the research proposed here to solely focus on solving the question: Is PSIA useful for Environmental Forensics applications?Current convention would say that PSIA is impracticable for the 'real world', however we challenge this and firmly believe in the potential of this approach. There are many other areas of research that may benefit from a concerted speculative research effort on the Environmental Forensic application of PSIA, the results of which are certain to give some insight into the biogeochemical cycling of contaminant organic compounds released to the environment.