Rise and fall of mercury (Hg) pollution in sediment cores of the Thames Estuary, London, UK

Fifty six sediment cores were collected along a 100 km longitudinal transect of the Thames estuary. Total Hg ranged from 0.01 to 12.07 mg/kg, with a mean of 2.10 mg/kg (n=351). Concentrations of the toxic metal decreased downstream from London to the outer estuary and were positively correlated to total organic carbon (TOC) content. Many Hg profiles showed a clear rise, peak and fall, reflecting changing anthropogenic input through time. Surface concentrations averaged 1.27 mg/kg, confirming the effectiveness of recent environmental legislation and improved river management. Sediments at >40 cm depth from London reaches of the river (Waterloo Bridge, Cuckolds Point (Rotherhithe), Butlers Wharf (Tower Bridge), Millwall, Deptford and Millennium Dome) were highly contaminated, with levels of Hg of >7 mg/kg. The outer Thames had lower Hg, with the exception of Rainham, Crossness and Cliffe. Benchmarking against UK guidelines for the disposal of dredged material revealed that 88 samples from 21 sites exceeded the 3 mg/kg criteria (unsuitable for disposal at sea); 173 fell between 0.3 and 3 mg/kg (further assessment required); and 90 were of no concern. Using Hg as a generic pollution marker, the tidal Thames is one of the world's most contaminated river–estuarine sediment systems

Infrared spectroscopy and chemometric modelling of organic carbon measured by Rock-Eval pyrolysis of UK shale rock

Shale rock core from the Bowland Shale Formation, UK was analysed in the laboratory using Rock-Eval(6) pyrolysis and Fourier Transform Infrared Spectroscopy (FTIR). These methods are used to characterise the organic constituents of soil and rock. This research is a proof-of-concept study to investigate whether regression models developed using FTIR and Rock-Eval data for the same length of core can be used to estimate selected Rock-Eval parameters. The accuracy of the regression models was assessed using statistical methods, the results of which were used to choose preferred models for each Rock-Eval parameter. Models produced were shown to have an acceptable level of uncertainty for Total Organic Carbon, S1, S2 and S3 outputs which led us to conclude these are potentially suitable for estimating unknown down-core Rock-Eval parameter values. Conversely, the Tmax model had a higher variability in the cross-validation data above the acceptable level of uncertainty which could lead to erroneous estimates. Down-core interpolations of selected Rock-Eval parameters could be practically achieved by modelling FTIR data by maintaining standard sample frequencies for Rock-Eval while supplementing with higher frequencies for FTIR and chemometric analysis

A typology of different development and testing options for symbolic regression modelling of measured and calculated datasets

AbstractData-driven modelling is used to develop two alternative types of predictive environmental model: a simulator, a model of a real-world process developed from either a conceptual understanding of physical relations and/or using measured records, and an emulator, an imitator of some other model developed on predicted outputs calculated by that source model. A simple four-way typology called Emulation Simulation Typology (EST) is proposed that distinguishes between (i) model type and (ii) different uses of model development period and model test period datasets. To address the question of to what extent simulator and emulator solutions might be considered interchangeable i.e. provide similar levels of output accuracy when tested on data different from that used in their development, a pair of counterpart pan evaporation models was created using symbolic regression. Each model type delivered similar levels of predictive skill to that other of published solutions. Input–output sensitivity analysis of the two different model types likewise confirmed two very similar underlying response functions. This study demonstrates that the type and quality of data on which a model is tested, has a greater influence on model accuracy assessment, than the type and quality of data on which a model is developed, providing that the development record is sufficiently representative of the conceptual underpinnings of the system being examined. Thus, previously reported substantial disparities occurring in goodness-of-fit statistics for pan evaporation models are most likely explained by the use of either measured or calculated data to test particular models, where lower scores do not necessarily represent major deficiencies in the solution itself

A review of the current state of the art of physiologically-based tests for measuring human dermal in vitro bioavailability of polycyclic aromatic hydrocarbons (PAH) in soil

Polycyclic Aromatic Hydrocarbons are classed as Persistent Organic Pollutants, a large group of compounds that share similar characteristics. They are lipophilic, resistant to degradation in the environment and harmful to human and environmental health. Soil has been identified as the primary reservoir for Polycyclic Aromatic Hydrocarbons in the United Kingdom. This study reviews the literature associated with, or is relevant to, the measurement and modelling of dermal absorption of Polycyclic Aromatic Hydrocarbons from soils. The literature illustrates the use of in vivo, in vitro and in silico methods from a wide variety of scientific disciplines including occupational and environmental exposure, medical, pharmaceutical and cosmetic research and associated mathematical modelling. The review identifies a number of practical shortcomings which must be addressed if dermal bioavailability tests are to be applied to laboratory analysis of contaminated soils for human health risk assessment

Polycyclic aromatic hydrocarbons (PAH) and polychlorinated biphenyls (PCB) in urban soils of Greater London, UK

Surface soils from a 19 km2 area in east London, UK were analysed for polycyclic aromatic hydrocarbons (PAH) and polychlorinated biphenyls (PCB) (n = 76). ∑16 PAH ranged from 4 to 67 mg/kg (mean, 18 mg/kg) and ∑50 PAH ranged from 6 to 88 mg/kg (mean, 25 mg/kg). ∑7 PCB ranged from 1 to 750 μg/kg (mean, 22 μg/kg) and ∑tri-hepta PCB ranged 9 to 2600 μg/kg (mean, 120 μg/kg). Compared to other international cities concentrations were similar for PAH but higher for PCB. Normal background concentrations (NBC) were calculated and compared to risk-based human health generic assessment criteria (GAC). Benzo[a]pyrene NBC for urban (6.9 mg/kg), semi-urban (4.4 mg/kg) and urban + semi urban (6 mg/kg) domains exceed residential (1 mg/kg) and allotment (2.2 mg/kg) LQM/CIEH GAC (at 6% SOM) and the Indeno[1,2,3-cd]pyrene NBC for urban (6.8 mg/kg) and urban + semi-urban (5.2 mg/kg) domains exceed the residential (4.2 mg/kg) LQM/CIEH GAC (at 6% SOM). Capsule Abstract: Normal background concentrations of polycyclic aromatic hydrocarbons and polychlorinated biphenyls are elevated in east London soils and in some cases exceed regulatory assessment criteria

Soil-sebum partition coefficients for high molecular weight polycyclic aromatic hydrocarbons (HMW-PAH)

In vitro high molecular weight polycyclic aromatic hydrocarbons (HMW-PAH) soil-sebum partition coefficients (KSS) were measured for twelve soils collected from former UK gasworks. Concentrations of ∑16 USEPA PAH in the soils ranged from 51 to 1440 mg/kg. Time series extractions (0.5, 1, 2, 4, 8 and 24 h) at skin temperature (32 °C) of HMW-PAH from sebum to soil for two samples were conducted to determine the maximum release time-step. The maximum HMW-PAH release time-step was determined as 4 h, which was subsequently used as the extraction time for the remaining samples. The 4 h extraction for all samples showed HMW-PAH KSS ranging from 0.06 to 1.4 (median = 0.59; mean = 0.59; standard deviation = 0.27; median absolute deviation = 0.29). Evaluation of KSS data for the 4 h extractions showed that soil type and selected HMW-PAH properties (literature based molecular weight and octanol-carbon partition coefficients) affect the amount of HMW-PAH released from soil into sebum

Digital tools for brownfield redevelopment: Stakeholder perspectives and opportunities

Brownfield redevelopment is a complex process often involving a wide range of stakeholders holding differing priorities and opinions. The use of digital systems and products for decision making, modelling, and supporting discussion has been recognised throughout literature and industry. The inclusion of stakeholder preferences is an important consideration in the design and development of impactful digital tools and decision support systems. In this study, we present findings from stakeholder consultation with professionals from the UK brownfield sector with the aim of informing the design of future digital tools and systems. Our research investigates two broad themes; digitalisation and the use of digital tools across the sector; and perceptions of key brownfield challenge areas where digital tools could help better inform decision-makers. The methodology employed for this study comprises the collection of data and information using a combination of interviews and an online questionnaire. The results from these methods were evaluated both qualitatively and quantitatively. Findings reveal a disparity in levels of digital capability between stakeholder groups including between technical stakeholder types, and that cross-discipline communication of important issues may be aided by the development of carefully designed digital tools. To this end, we present seven core principles to guide the design and implementation of future digital tools for the brownfield sector. These principles are that future digital tools should be: (1) Stakeholder driven, (2) Problem centred, (3) Visual, (4) Intuitive, (5) Interactive, (6) Interoperable, and (7) Geospatial data driven

An overview of research and development themes in the measurement and occurrences of polyaromatic hydrocarbons in dusts and particulates

Polycyclic aromatic hydrocarbons (PAHs) are a group of organic compounds consisting of two or more fused aromatic rings and are probably one of the most studied groups of organic chemicals in environmental research. PAHs originate mainly from anthropogenic processes, particularly from incomplete combustion of organic fuels. PAHs are distributed widely in particulate matter. Due to widespread sources and persistent characteristics, PAHs disperse through atmospheric transport and exist almost everywhere. Human beings are exposed to PAH mixtures in gaseous or particulate phases in ambient air. Long-term exposure to high concentrations of PAHs is associated with adverse health problems. This review identifies the main research and development themes in the measurement and occurrences of PAHs in dusts and particulates using a new approach to carrying out a literature review where many peer-review publications have been produced. The review extracts the most important research themes from a literature search using a combination of text mining and a more detailed review of selected papers from within the identified theme

From data to decisions: empowering brownfield redevelopment with a novel decision support system

This research evaluates a novel decision support system (DSS) for planning brownfield redevelopment. The DSS is implemented within a web-based geographical information system that contains the spatial data informing three modules comprising land use suitability, economic viability, and ground risk. Using multi-criteria decision analysis, an evaluation was conducted on 31,942 ha of post-industrial land and around Liverpool, UK. The representativeness and credibility of the DSS outputs were evaluated through user trials with fifteen land-use planning and development stakeholders from the Liverpool City Region Combined Authority. The DSS was used to explore land use planning scenarios and it could be used to support decision making. Our research reveals that the DSS has the potential to positively inform the identification of brownfield redevelopment opportunities by offering a reliable, carefully curated, and user-driven digital evidence base. This expedites the traditionally manual process of conducting assessments of land suitability and viability. This research has important implications for assessing the impact of current and future planning policy and the potential for the use of digital tools for land use planning and sustainability in the UK and globally.Natural Environment Research Council (NERC): NE/S007350/1 WSP UK Ltd and Groundsure Lt

Arsenic in residential soil and household dust in Cornwall, south west England: potential human exposure and the influence of historical mining

Exposure to arsenic (As) via residential soil and dust is a global concern, in regions affected by mining or with elevated concentrations present in underlying geology. Cornwall in south west England is one such area. Residential soil (n = 127) and household dust (n = 99) samples were collected from across Cornwall as part of a wider study assessing exposure to environmental As. Samples were analysed for total As (soil and dust samples) and human ingestion bioaccessible As (soil samples from properties with home-grown produce). Arsenic concentrations ranged from 12 to 992 mg kg−1 in soil and 3 to 1079 mg kg−1 in dust and were significantly higher in areas affected by metalliferous mineralisation. Sixty-nine percent of soils exceeded the 37 mg kg−1 Category 4 Screening Level (C4SL), a generic assessment criteria for As in residential soils in England, which assumes 100% bioavailability following ingestion. The proportion of exceedance was reduced to 13% when the bioavailability parameter in the CLEA model was changed to generate household specific bioaccessibility adjusted assessment criteria (ACBIO). These criteria were derived using bioaccessibility data for a sub-set of individual household vegetable patch soils (n = 68). Proximity to former As mining locations was found to be a significant predictor of soil As concentration. This study highlights the value of bioaccessibility measurements and their potential for adjusting generic assessment criteria