David Megson

A review of the determination of persistent organic pollutants for environmental forensics investigations.

The field of environmental forensics emerged in the 1980s as a consequence of legislative frameworks enacted to enable parties, either states or individuals, to seek compensation with regard to contamination or injury due to damage to the environment. This legal environment requires stringent record keeping and defendable data therefore analysis can sometimes be confined to data to be obtained from certified laboratories using a standard accredited analytical method. Many of these methods were developed to target specific compounds for risk assessment purposes and not for environmental forensics applications such as source identification or age dating which often require larger data sets. The determination of persistent organic pollutants (POPs) for environmental forensic applications requires methods that are selective but also cover a wide range of target analytes which can be identified and quantified without bias. POPs are used in a wide variety of applications such as flame retardants, fire suppressants, heat transfer agents, surfactants and pesticides mainly because of their chemical inertness and stability. They also include compounds such as dioxins that can be unintentionally produced from industrial activities. POPs are persistent in the environment, bioaccumulative and/or toxic and therefore require analytical methods that are sensitive enough to meet the low detection limits needed for the protection of the environment and human health. A variety of techniques, procedures and instruments can be used which are well suited for different scenarios. Optimised methods are important to ensure that analytes are quantitatively extracted, matrix coextractables and interferences are removed and instruments are used most effectively and efficiently. This can require deviation from standard methods which can open the data up to further scrutiny in the courtroom. However, when argued effectively and strict QA/QC procedures are followed the development and optimization of methods based on investigation specific scenarios has the potential to generate better quality and more useful data.

Identifying the provenance of Leach’s storm petrels in the North Atlantic using polychlorinated biphenyl signatures derived from comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry

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 Leachs storm petrels (Oceanodroma leucorhoa). The Leachs 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 Leachs 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.

Can polychlorinated biphenyl (PCB) signatures and enantiomer fractions be used for source identification and to age date occupational exposure

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.

Congener specific determination of polychlorinated naphthalenes in sediment and biota by gas chromatography high resolution mass spectrometry

An isotope dilution congener-specific method for the determination of the most abundant and most toxic polychlorinated naphthalenes (PCNs) was developed using gas chromatography with high resolution mass spectrometry (GC-HRMS). The method was used to determine the concentration of 24 target congeners and total PCN concentrations in fish and sediment samples. Tissue samples were extracted using pressurized liquid extraction (PLE) and sediment samples were extracted using Soxhlet extraction. Sample extracts were cleaned up using either a manual two-stage open column procedure or an automated FMS Power Prep System with multi-analyte and multi-sample capability using a three-column cleanup procedure. Sediment extracts were cleaned up with a dual open column cleanup technique involving the use of both a multi-layered silica (silver nitrate/acid/base/neutral silica) column followed by column containing carbon-activated silica. Fish tissue extracts were cleaned up on the automated system involving the use of a high capacity ABN (acid/base/neutral column), carbon celite column, and a basic alumina column. The method is capable of producing instrument detection limits (IDLs) between 0.06 and 0.13pg for each PCN (on column), with method detection limits (MDLs) for the fish extracts ranging from 1.3 to 3.4pg/g (wet weight) and 0.46 to 1.2pg/g (dry weight) for sediments. The average accuracy of 34 spiked fish samples analysed over a period of several months was 100% with a precision (%RSD) of 12%. Similarly, the average accuracy for 28 spiked sediment samples was 104% with a precision (%RSD) of 12%. The application of the method to environmental samples was demonstrated through the analysis of sediment and fish samples obtained from Lake Ontario, Canada. The method is used both for the determination of 24 PCNs and to perform non-targeted screening for the remaining 51 PCN congeners, which are included in the total PCN quantification result. It is currently one of the most comprehensive and accurate congener-specific methods available and was developed from the existing techniques used for the determination of polychlorinated dioxins and furans to produce high quality data with only minor modifications in the clean-up procedure. It can therefore be readily adopted by other laboratories performing dioxin and POP analyses.

POPs in the Terrestrial Environment

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.

Identifying the Source of Nutrient Contamination in a Lagoon System

Nutrient concentrations within watercourses are often associated with the input of sewage or the runoff of fertilizers. Due to population increases, there has been a dramatic rise in the amount of fertilizer applied to land, as well as in the further development of sewage treatment plants (STPs), both of which can lead to significant discharges with associated eutrophication risks in coastal waters. The implementation of the European Union Water Framework Directive (EU-WFD) should improve the management and quality of European water bodies. The Ria Formosa Lagoon, Portugal, is one such water body monitored under the WFD where two inter-calibration sites have been developed, that of the Ancão Basin, which has a status of “high/good,” and that of the Ramalhete Channel, with a status of “good/moderate.” Spatial nutrient concentrations (NH4 +, NO2 –, NO3 –, PO4 3–) and lipids were measured in two areas that were thought to contribute nutrients into the Ancão Basin; a river that flows through several golf courses and the Ramalhete Channel, which receives discharge from both Faro Airport and a STP. Nutrient analyses showed that waters from the Ramalhete Channel had substantial concentrations, the highest of which was ammonium, which exceeded 180 μ M near the sewage discharge site; however, concentrations diminished towards the sea, reaching 2.7 μ M suggesting the utilization of NH4 + by seagrasses (Zostera noltii). The Atlantic Ocean was also a source of nitrate, contributing 1.8 μ M, whereas sources of phosphate originated in the Ancão Basin catchment and included a commercial horticulture site, several golf courses, and the STP. Principal component analysis (PCA) and cross plots of the 5β-coprostanol/cholesterol and 5β-coprostanol/(5β-coprostanol + 5α-cholestanol) ratios identified areas of fecal contamination, highlighting several sites previously unknown to contain sewage matter. In general, nitrogen sources were associated with agriculture and phosphate originated from the golf complex and sewage discharges. These effects were partly mitigated, however, by eutrophic ponds between the river and the lagoon.

Analytical Methodology of POPs

The analysis of persistent organic pollutants (POPs) for environmental forensic applications requires methods that are very selective to ensure target analytes can be identified and quantified without bias. POPs are used in a wide variety of applications, such as flame retardants, fire suppressants, heat transfer agents, surfactants, and pesticides, mainly because of their chemical inertness and stability. They are persistent in the environment, bioaccumulative and/or toxic and therefore require analytical methods that are sensitive enough to meet the low detection limits needed for the protection of the environment and human health. A variety of techniques, procedures, and instruments can be used. Optimum conditions are important to ensure that analytes are quantitatively extracted, matrix coextractables and interferences are removed and instruments are used most effectively and efficiently.

Brief Overview: Discovery, Regulation, Properties, and Fate of POPs

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.

Environmental forensics : proceedings of the 2014 INEF Conference

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

Limitations of the CLEA model when assessing human health risks from dioxins and furans in soil at an allotments site in Rochdale, NW England

Many allotments in the UK today are situated on urban brownfield areas which creates a potential human health risk from soil borne contamination. This paper looks specifically at the risks to allotment users at a site in Rochdale, UK, from polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo-furans (PCDD and PCDF). A contaminated land investigation was undertaken involving the collection and analysis of 24 soil samples from the top 0.0-0.3 m of the soil profile. Homogenised egg samples were also collected and analysed from plots where poultry were kept. The concentration of PCDD and PCDF in soil at the site varied from 0.69 to 13.62 μg kg(-1); two plots out of a total of eight exceeded the soil guideline value (SGV) of 8 μg kg(-1), however all plots fell below the site specific assessment criteria (SSAC) of 15.9 μg kg(-1). Human health risks were assessed using the Environment Agencys contaminated land exposure assessment (CLEA) model. The assessment using CLEA alone did not provide enough evidence to indicate significant possibility of significant harm (SPOSH) across the entire allotment site. However, when the likely exposure from the soil was combined with potential exposure from consumption of site laid eggs, the results indicated that the potential risks could constitute SPOSH. This paper gives evidence to support the bioconcentration of PCDD and PCDF in eggs and highlights the importance of considering pollutant linkages outside the generic CLEA model.