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Surface sediments from a 160-km stretch of the River Clyde, Scotland, were analysed for persistent organic pollutants to investigate distribution, source and environmental effect. Glasgow's urban tributaries polyaromatic hydrocarbons (PAH) ranged from 2.3 to 4226mgkg–1, total petroleum hydrocarbons (TPH) 72 to 37879mgkg–1 and polychlorinated biphenyls (PCB) 3 to 809μgkg–1, which were more polluted than the upper River Clyde PAH that ranged from 0.1 to 42mgkg–1, TPH 3 to 260mgkg–1 and PCB 2 to 147μgkg–1. Intermediate values of the inner Clyde estuary PAH ranging from 0.6 to 30mgkg–1, and PCB ranging from 5 to 130μgkg–1, were attributed to point sources and sediment transfer from the urban tributaries. Comparison with sediment quality criteria suggested possible adverse effects on aquatic biota. PAH isomeric ratios confirmed a pyrolytic source throughout the Clyde and benzo[a]pyrene/benzo[g,h,i]perylene ratios >0.6 confirmed that upper, urban and estuarine domains all to a lesser or greater extent accumulated PAH from traffic emissions. The degree of chlorination determined from PCB homologues differed in each of the three domains, suggesting variable source or that the process aerobic/anaerobic degradation varied in each of the three domains. The anthropogenic impact of the city of Glasgow can be quantified in that the urban tributary sediment mean values were 60 (PAH), 33 (TPH) and 11 (PCB) times higher than the rural upper Clyde counterpart.

Concentrations of total organic carbon (TOC), total petroleum hydrocarbons, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) were determined in 84 near-surface soils (5–20 cm depth) taken from a 255 km2 area of Glasgow in the Clyde Basin, UK, during July 2011. Total petroleum hydrocarbon range was 79–2,505 mg kg–1 (mean 388 mg kg–1; median 272 mg kg–1) of which the aromatic fraction was 13–74 % (mean 44 %, median 43 %) and saturates were 28–87 % (mean 56 %, median 57 %). P16 PAH varied from 2–653 mg kg–1 (mean 32.4 mg kg–1; median 12.5mg kg–1) and P31 PAH range was 2.47–852 mg kg–1 (mean 45.4 mg kg–1; median 19.0 mg kg–1). PPCBtri-hepta range was 2.2–1052 mg kg–1 (mean 32.4 mg kg–1; median 12.7 mg kg–1) and the PPCB7 range was 0.3–344 mg kg–1 (mean 9.8 mg kg–1; median 2.7 mg kg–1). The concentration, distribution and source of the persistent organic pollutants were compared with those found in urban soils from other cities and to human health assessment criteria for chronic exposure to chemicals in soil. Total concentrations encountered were generally similar to other urban areas that had a similar industrial history. Benzo[a]pyrene concentrations were assessed against four different land use scenarios (irrespective of current land use) using generic assessment criteria resulting in six of 84 samples exceeding the residential criteria. Isomeric PAH ratios and relative abundance of perylene suggest multiple and environmentally modified pyrogenic PAH sources, inferred to be representative of diffuse pollution. PPCB7 concentrations were exceeded in 10 % of sites using the Dutch target value of 20 mg kg–1. PCB congener profiles were environmentally attenuated and generally dominated by penta-, hexa- and hepta-chlorinated congeners.

The chemical composition of soil from the Glasgow (UK) urban area was used to identify the controls on the availability of potentially harmful elements (PHEs) in soil to humans. Total and bioaccessible concentrations of arsenic (As), chromium (Cr) and lead (Pb) in 27 soil samples, collected from different land uses, were coupled to information on their solid-phase partitioning derived from sequential extraction data. The total element concentrations in the soils were in the range <0.1–135mgkg–1 for As; 65–3680mgkg–1 for Cr and 126–2160mgkg–1 for Pb, with bioaccessible concentrations averaging 27, 5 and 27% of the total values, respectively. Land use does not appear to be a predictor of contamination; however, the history of the contamination is critically important. The Chemometric Identification of Substrates and Element Distribution (CISED) sequential chemical extraction and associated self-modelling mixture resolution analysis identified three sample groupings and 16 geochemically distinct phases (substrates). These were related to iron (n=3), aluminium–silicon (Al–Si; n=2), calcium (n=3), phosphorus (n=1), magnesium (Mg; n=3), manganese (n=1) and easily extractable (n=3), which was predominantly made up of sodium and sulphur. As, Cr and Pb were respectively found in 9, 10 and 12 of the identified phases, with bioaccessible As predominantly associated with easily extractable phases, bioaccessible Cr with the Mg-dominated phases and bioaccessible Pb with both the Mg-dominated and Al–Si phases. Using a combination of the Unified Barge Method to measure the bioaccessibility of PHEs and CISED to identify the geochemical sources has allowed a much better understanding of the complexity of PHE mobility in the Glasgow urban environment. This approach can be applied to other urban environments and cases of soil contamination, and made part of land-use planning.

The collection of drainage samples from active stream channels for geochemical mapping is now a well-established procedure that has readily been adapted for environmental studies. This account details the sampling methods used by the British Geological Survey in order to establish a geochemical baseline for the land area of Great Britain. This involves the collection of stream sediments, waters and panned heavy mineral concentrates for inorganic chemical analysis. The methods have been adapted and used in many different environments around the world. Detailed sampling protocols are given and sampling strategy, equipment and quality control are discussed.

This report is the BGS contribution to Stage 3 of the CRW2012/1 Project ‘A critical review of urban diffuse pollution control: Methodologies to identify sources, pathways and mitigation measures with multiple benefits’. A case study of a typical Scottish urban environment is presented. The report documents work to identify and characterise urban diffuse pollution sources and pathways in a case study stream catchment in Glasgow based on existing information. The findings of this report have been used to support the required research outputs for stages 1, 2 and 3 of the CREW project CRW2012/1.

Selenium (Se) is a naturally occurring metalloid element, which is essential to human and other animal health in trace amounts but is harmful in excess. Of all the elements, selenium has one of the narrowest ranges between dietary deficiency (40 gday1) and toxic levels (400gday1) (WHO, 1996), which makes it necessary to carefully control intakes by humans and other animals, hence, the importance of understanding the relationships between environmental exposure and health. Geology exerts a fundamental control on the concentrations of selenium in the soils on which we grow the crops and animals that form the human food chain. The selenium status of populations, animals, and crops varies markedly around the world as a result of different geological conditions. Because diet is the most important source of selenium in humans, understanding the biogeochemical controls on the distribution and mobility of environmental selenium is key to the assessment of selenium-related health risks. High selenium concentrations are associated with some phosphatic rocks, organic-rich black shales, coals, and sulfide mineralization, whereas most other rock types contain very low concentrations and selenium-deficient environments are far more widespread than seleniferous ones. However, health outcomes are not only dependent on the total selenium content of rocks and soils but also on the amount of selenium taken up into plants and animals—the bioavailable selenium. This chapter demonstrates that even soils containing adequate total amounts of selenium can still produce selenium-deficient crops if the selenium is not in a form ready for plant uptake.

The human bioaccessibility of lead (Pb) in Pb-contaminated soils from the Glasgow area was determined by the Unified Bioaccessibility Research Group of Europe (BARGE) Method (UBM), an in vitro physiologically based extraction scheme that mimics the chemical environment of the human gastrointestinal system and contains both stomach and intestine compartments. For 27 soils ranging in total Pb concentration from 126 to 2160 mg kg− 1 (median 539 mg kg− 1), bioaccessibility as determined by the ‘stomach’ simulation (pH ~ 1.5) was 46–1580 mg kg− 1, equivalent to 23–77% (mean 52%) of soil total Pb concentration. The corresponding bioaccessibility data for the ‘stomach + intestine’ simulation (pH ~ 6.3) were 6–623 mg kg− 1 and 2–42% (mean 22%) of soil Pb concentration. The soil 206Pb/207Pb ratios ranged from 1.057 to 1.175. Three-isotope plots of 208Pb/206Pb against 206Pb/207Pb demonstrated that 206Pb/207Pb ratios were intermediate between values for source end-member extremes of imported Australian Pb ore (1.04) – used in the manufacture of alkyl Pb compounds (1.06–1.10) formerly added to petrol – and indigenous Pb ores/coal (1.17–1.19). The 206Pb/207Pb ratios of the UBM ‘stomach’ extracts were similar (< 0.01 difference) to those of the soil for 26 of the 27 samples (r = 0.993, p < 0.001) and lower in 24 of them. A slight preference for lower 206Pb/207Pb ratio was discernible in the UBM. However, the source of Pb appeared to be less important in determining the extent of UBM-bioaccessible Pb than the overall soil total Pb concentration and the soil phases with which the Pb was associated. The significant phases identified in a subset of samples were carbonates, manganese oxides, iron-aluminium oxyhydroxides and clays.

Fluorine (fluoride) is beneficial to human health in low concentration but toxic in excess. One of the main exposure routes is via drinking water. It is unproven whether fluoride is essential for health but numerous studies have demonstrated that low concentrations in drinking water (0-0.5 mg L-1) are associated with increased dental caries (tooth decay) rates whereas contents of 0.5-1.5 mg L-1 are protective against the disease. As a result, fluoride is widely used in dental products and water fluoridation programs have been implemented in many countries. However, exposure to higher concentrations via drinking water (> 1.5 mg L-1), some teas and fluoride-contaminated salt and the burning of high-fluoride fuels can cause deformities of the hard tissues, namely dental and skeletal fluorosis. Dental fluorosis is an irregular calcification disorder of the enamel-forming process during childhood leading to pitted, stained and eroded teeth. In contrast, skeletal fluorosis is a crippling disease caused by over-mineralization of the bones and joints as a result of longer term exposure to high fluoride intakes. It is estimated that these diseases affect over 70 million people globally, limiting their ability to work and support their families. Hence the need for better understanding of environmental exposure to help mitigate these health outcomes.

The Unified Bioaccessibility Method (UBM), which simulates the fluids of the human gastrointestinal tract, was used to assess the oral bioaccessibility of Cr in 27 Glasgow soils. These included several contaminated with Cr(VI), the most toxic form of Cr, from the past disposal of chromite ore processing residue (COPR). The extraction was employed in conjunction with the subsequent determination of the bioaccessible Cr by ICP-OES and Cr(VI) by the diphenylcarbazide complexation colorimetric procedure. In addition, Cr(III)-containing species were determined by (i) HPLC-ICP-MS and (ii) ICP-OES analysis of gel electrophoretically separated components of colloidal and dissolved fractions from centrifugal ultrafiltration of extracts. Similar analytical procedures were applied to the determination of Cr and its species in extracts of the < 10 μm fraction of soils subjected to a simulated lung fluid test to assess the inhalation bioaccessibility of Cr. The oral bioaccessibility of Cr was typically greater by a factor of 1.5 in the ‘stomach’ (pH ~ 1.2) compared with the ‘stomach + intestine’ (pH ~ 6.3) simulation. On average, excluding two COPR-contaminated soil samples, the oral bioaccessibility (‘stomach’) was 5% of total soil Cr and, overall, similar to the soil Cr(VI) concentration. Chromium(VI) was not detected in the extracts, a consequence of pH- and soil organic matter-mediated reduction in the ‘stomach’ to Cr(III)-containing species, identified as predominantly Cr(III)-humic complexes. Insertion of oral bioaccessible fraction data into the SNIFFER human health risk assessment model identified site-specific assessment criteria (for residential land without plant uptake) that were exceeded by the soil total Cr (3680 mg kg-1) and Cr(VI) (1485 mg kg-1) concentration at only the most COPR-Cr(VI)-contaminated location. However, the presence of measurable Cr(VI) in the < 10 μm fraction of the two most highly Cr(VI)-contaminated soils demonstrated that inhalation of Cr(VI)

Urban planners and developers in some parts of the United Kingdom can now access geodata in an easy-to-retrieve and understandable format. 3D attributed geological framework models and associated GIS outputs, developed by the British Geological Survey (BGS), provide a predictive tool for planning site investigations for some of the UK's largest regeneration projects in the Thames and Clyde River catchments. Using the 3D models, planners can get a 3D preview of properties of the subsurface using virtual cross-section and borehole tools in visualisation software, allowing critical decisions to be made before any expensive site investigation takes place, and potentially saving time and money. 3D models can integrate artificial and superficial deposits and bedrock geology, and can be used for recognition of major resources (such as water, thermal and sand and gravel), for example in buried valleys, groundwater modelling and assessing impacts of underground mining. A preliminary groundwater recharge and flow model for a pilot area in Glasgow has been developed using the 3D geological models as a framework. This paper focuses on the River Clyde and the Glasgow conurbation, and the BGS's Clyde Urban Super-Project (CUSP) in particular, which supports major regeneration projects in and around the City of Glasgow in the West of Scotland.

Urban regeneration in the UK tackles deprivation stemming from industrial decline. These long-term projects (up to 25 years) are some of Europe’s largest. They implement land recycling, sustainable development and effective management of land and water resources. Those engaged in regeneration and large-scale construction (e.g. Olympic Games 2012 in London) need accessible and readily understood environmental geoscience information. The British Geological Survey (BGS) increasingly meets these needs with interactive, bespoke, 3D attributed geologic models, constructed with GSI3D and other software, and related GIS datasets. Close partnerships with decision-makers, including environmental regulators, help ensure effective data use. For example, in the Clyde Corridor, Scotland’s national regeneration priority, BGS works with Glasgow City Council, delivering 3D models of surficial deposits and bedrock in an urban area undermined for coal and ironstone, and masked by variably contaminated anthropogenic deposits. Comprehensive geochemical datasets are also produced. The models incorporate engineering data, and provide a platform for groundwater recharge and flow models, developed using ZOOM object-oriented software, which will be parameterized with data from a groundwater monitoring network under development. This will facilitate monitoring of groundwater quality and levels during regeneration, and aid assessment of: large-scale remediation of chromium waste; point-source groundwater recharge associated with sustainable urban drainage, a growing part of metropolitan drainage strategy; and the potential for and sustainability of ground source heat from extensive minewaters and aquifers beneath Glasgow.

The British Geological Survey's Geochemical Baseline Survey of the Environment (G-BASE) project is responsible for the systematic geochemical mapping of the land surface of Great Britain. Samples of soils, stream sediments and stream waters collected at an average density of 1 sample per 1.5 km2 are determined for up to 46 elements/parameters. Concerns over land quality in population centres have raised interest in the concentrations and behaviour of chemical substances within the urban environment. This prompted the G-BASE project to expand the geochemical survey into urban areas. The sampling strategy of urban areas differs to that of the regional survey as only soil samples are collected, but at a much higher density of 4 samples per km2. Top (5 - 20 cm) and deeper (35 - 50 cm) samples are collected at each site. 22 urban centres from different parts of the UK have been surveyed so far, giving an extensive dataset of over 16000 samples. This provides a unique picture of the status of UK urban soil chemistry.

There are currently few reliable data available for the concentrations of trace elements in Scottish groundwaters. A new project Baseline Scotland, jointly funded by the British Geological Survey (BGS) and the Scottish Environment Protection Agency (SEPA), seeks to improve the data availability and general understanding of the chemistry of Scotland’s groundwater. However, this is a major undertaking and these new data will take several years to collect and interpret across the whole of Scotland. In the interim, SEPA have asked BGS to use their existing knowledge and data to give a rough estimate of where certain elements are more likely to be elevated in groundwater. This information will be used to help focus future monitoring and give background for Baseline Scotland. Predicting trace element concentrations is difficult, in part due to lack of knowledge on the distribution of mineral phases, the reactivity of different minerals and the geochemical environment, particularly the redox status. This report scopes the potential scale of naturally elevated trace elements in Scottish groundwater, in particular those elements that are potentially harmful to health: e.g. aluminium, arsenic, barium, cadmium, chromium, lead, manganese, nickel, uranium and zinc. The problems and limitations of prediction are discussed in the report and this work does not replace a proper assessment based on actual chemical analyses of groundwater. The method uses information on the geochemistry of the Scottish environment derived from the most comprehensive geochemical data set for Scotland, the BGS Geochemical Baseline Survey of the Environment (G-BASE), combined with the limited data available on the chemistry of Scottish groundwaters. The conditions under which each of the elements can become elevated in groundwater are discussed and the geological and geochemical information interpreted to produce a series of maps highlighting areas where each trace element may be elevated in groundwater

Iodine is an essential element for human and other animal health and forms an important constituent of the thyroid hormones thyroxine (T4, also known as tetraiodothyronine) and triiodothyronine (T3). These hormones play a fundamental biological role controlling growth and development (Hetzel and Maberly, 1986). If the amount of utilisable iodine reaching the thyroid gland is inadequate, or if thyroid function is impaired, hormone production can be reduced resulting in a group of conditions collectively referred to as Iodine Deficiency Disorders (IDD) (Fernando et al., 1987; Hetzel, 1989). The World Health Organisation (WHO, 1993) estimate that in excess of one billion people world-wide are at risk from IDD, the most common manifestation of which is goitre (Figure 1). Iodine deficiency is the world’s most common cause of preventable mental retardation and brain damage, and has a significant negative impact on the social and economic development of communities.

On a global scale, trace elements occur at very low concentrations (Wedephol 1978). At a regional scale, elevated trace element concentrations can be associated with natural and/or anthropogenic sources and are of concern because of their potential detrimental health effects on natural life forms, including humans, The term ‘trace elements’ used throughout this chapter encompasses heavy metals (also known as trace metals) such as chromium, copper, cobalt, nickel, manganese, lead, cadmium and zinc, and other trace elements (metals, metalloids and non-metals) which are also known to cause potentially detrimental health effects in high doses. The ecological role, toxicity and dual-toxicity of trace elements has been the subject of much scientific research (WHO 1996).

Endemic goitre has been reported in the climatic wet zone of south-west Sri Lanka for the past 50 years, but rarely occurs in the northern dry zone. Despite government-sponsored iodised salt programmes, endemic goitre is still prevalent. In recent years, it has been suggested that Se deficiency may be an important factor in the onset of goitre and other iodine deficiency disorders (IDD). Prior to the present study, environmental concentrations of Se in Sri Lanka and the possible relationships between Se deficiency and endemic goitre had not been investigated. During the present study, chemical differences in the environment (measured in soil, rice and drinking water) and the Se-status of the human population (demonstrated by hair samples from women) were determined for 15 villages. The villages were characterised by low (<10%), moderate (10–25%) and high (>25%) goitre incidence (NIDD, MIDD and HIDD, respectively). Results show that concentrations of soil total Se and iodine are highest in the HIDD villages, however, the soil clay and organic matter content appear to inhibit the bioavailability of these elements. Concentrations of iodine in rice are low (≤58 ng/g) and rice does not provide a significant source of iodine in the Sri Lankan diet. High concentrations of iodine (up to 84 μg/l) in drinking water in the dry zone may, in part, explain why goitre is uncommon in this area. This study has shown for the first time that significant proportions of the Sri Lankan female population may be Se deficient (24, 24 and 40% in the NIDD, MIDD and HIDD villages, respectively). Although Se deficiency is not restricted to areas where goitre is prevalent, a combination of iodine and Se deficiency could be involved in the pathogenesis of goitre in Sri Lanka. The distribution of red rice cultivation in Sri Lanka is coincident with the HIDD villages. Varieties of red rice grown in other countries contain anthocyanins and procyanidins, compounds which in other foodstuffs are known

In the light of recent UK and European legislation there is a need to identify and quantify the potential hazard of contaminated land.