Comparison of spatial Cu stream water concentrations with intra- and inter- annual monitoring data

The Geochemical Baseline Survey of the Environment (G-BASE) is the long established high resolution geochemical baseline mapping project of the British Geological Survey. The geochemical mapping is based on the systematic sampling and analysis of soils, stream sediments, and stream waters, and this study concerns the latter. The central aim of this study is to establish whether the spatial variation, caused by geology, topography etc, predominates over temporal variations; and establish whether such temporal variations in trace element concentrations limit the representativeness of spatial distribution maps. Water concentrations are known to vary on a diurnal basis, and in response to external factors such as rainfall. This report addresses an assumption that stream water chemistry significantly varies over prolonged sampling periods. This report describes the temporal stream water Cu data from samples collected during the summer field seasons in central and eastern England between 1997 and 2007. These temporal samples were collected in parallel with the primary samples used for mapping. The temporal data are obtained from sampling “monitor sites”: a carefully selected site sampled each day from each temporary fieldbase used by the field teams. Comparison of these data showed that the variations of Cu concentrations sampled over time at monitor sites, were less than spatial variations determined by factors such as geology, topography and landuse. The concentration of Cu in the monitor site samples varied by as much as 13 mg/L at one site, so the relevance of outliers, and their effect on the interpretation and mapping of spatial data were examined. In comparison to the spatial variations, temporal variations were limited

Normal background concentrations (NBCs) of contaminants in English soils : final project report

The British Geological Survey (BGS) has been commissioned by the Department for Environment, Food and Rural Affairs (Defra) to give guidance on what are normal levels of contaminants in English soils in support of the Part 2A Contaminated Land Statutory Guidance. This has initially been done by studying the distribution of four contaminants – arsenic, lead, benzo[a]pyrene (BaP) and asbestos – in topsoils from England. This work was extended to a further four contaminants (cadmium, copper, nickel and mercury) which enabled methodologies developed to be tested on a larger range of contaminants. The first phase of the Project gathered data sets that were: nationally extensive; systematically collected so a broad range of land uses were represented; and collected and analysed to demonstrably and acceptable levels of quality. Information on the soil contaminant concentrations in urban areas was of particular importance as the normal background is considered to be a combination of both natural and diffuse anthropogenic contributions to the soil. Issues of soil quality are most important in areas where these affect most people, namely, the urban environment. The two principal data sets used in this work are the BGS Geochemical Baseline Survey of the Environment (G-BASE) rural and urban topsoils (37,269 samples) and the English NSI (National Soil Inventory) topsoils (4,864 samples) reanalysed at the BGS laboratories by X-ray fluorescence spectrometry (XRFS) so both data sets were highly compatible. These two data sets provide results for most inorganic element contaminants, though results explored for mercury and BaP are drawn from a variety of different and much less extensive data sets

How does temporal variation affect the value of stream water as a medium for regional geochemical survey?

Stream water is a key medium for regional geochemical survey for mineral exploration and environmental protection. However, stream waters are transient, and measurements are susceptible to various sources of temporal variation. In a regional geochemical survey stream water data comprise ‘snapshots’ of the state of the medium at a sample time. For this reason the British Geological Survey (BGS) has included monitoring streams in its regional geochemical baseline surveys (G-BASE) at which daily stream water samples are collected, over variable time intervals, to supplement the spatial data collected in once-off sampling events. In this study we present results from spatio-temporal analysis of spatial stream water surveys and the associated monitoring stream data. We show that the variability of monitoring stream data from the G-BASE surveys has a temporally correlated component which can be treated as independent between streams, and therefore as a component of the nugget (spatially uncorrelated variance) of the spatial variograms of stream water survey data. For the variables examined this component was small relative to the spatial variability, which indicates that the value of stream water data to provide spatial geochemical information is not compromised by temporal variability. However, these conclusions are conditioned on the particular data set which was collected only in the summer months, specifically to limit temporal variability. Temporal variation in stream water analyses may be less tractable in wetter conditions. We show how the spatial data from stream water surveys can be mapped by ordinary kriging, with the predictions interpreted as an estimate of the temporal (summer months) mean, and the kriging variance reflecting the partition of the nugget variance of the spatial variogram between spatial and temporal components

Soil Reference Material Data Sheets : BGS110 to BGS119

The British Geological Survey (BGS) has produced a suite of 10 new soil Reference Materials, BGS110 to BGS119. They are intended for use as quality control samples for the determination of total elemental concentrations in soils. The Reference Materials contain a wide range of concentrations to cater for different analytical needs, interests and industries, e.g. agriculture, geochemical exploration, contaminated land. Data sheets for each of these materials are available on the BGS website https://www.bgs.ac.uk/sciencefacilities/laboratories/geochemistry/igf/Services/referenceMaterials.html

Quality control of 2012 and 2013 southern England G-BASE stream water sample data

This report describes the quality control of the laboratory analyses of stream water samples collected in south west England during the summer of 2012 and some of those collected in 2013. The samples are part of the Geochemical Baseline Survey of the Environment (G-BASE) project. The analytical work was undertaken in the laboratories at the British Geological Survey (BGS) in Keyworth. The sample collection and field office methods followed the procedures described in Johnson (2005a), and with updates reported by Johnson (2005b). Stream water sampling methods were unchanged from 2010, the previous field season in which water samples were taken (Ander, 2014; Bearcock et al., 2016; Bearcock and Strutt, 2012). As the G-BASE project was due for completion by 2014 there were strict time and budget restraints. This meant that stream sediment samples taken by the BGS’s Mineral Reconnaissance Program (MRP) in the 1980s, and archived in BGS, could be reanalysed. Where MRP samples had been taken in close proximity to a planned G-BASE sample, only water samples were taken from that site. At all other sites stream sediments, panned concentrates, and water samples were collected as standard. Laboratory analysis for the 2013 samples was restricted due to financial constraints. The samples which were analysed are described more fully in Section 2

GSUE: urban geochemical mapping in Great Britain

The British Geological Survey is responsible for the national strategic geochemical survey of Great Britain. As part of this programme, the Geochemical Surveys of Urban Environments (GSUE) project was initiated in 1992 and to date, 21 cities have been mapped. Urban sampling is based upon the collection of top (0.05 to 0.20 m) and deeper (0.35 to 0.50 m) soil samples on a 500 m grid across the built environment (1 sample per 0.25 km2). Samples are analysed for c. 46 total element concentrations by X-ray Fluorescence Spectrometry (XRFS), pH and loss on ignition (LOI) as an indicator of organic matter content. The data provide an overview of the urban geochemical signature and because they are collected as part of a national baseline programme, can be readily compared with soils in the rural hinterland to assess the extent of urban contamination. The data are of direct relevance to current UK land use planning, urban regeneration and contaminated land legislative regimes. An overview of the project and applications of the data to human health risk assessment, water quality protection and contaminant source identification are presented

Sources, mobility and bioaccessibility of potentially harmful elements in UK soils

Potentially harmful elements (PHE) occur both naturally from geogenic sources and from anthropogenic derived pollution. Anthropogenic sources can be further categorised into those derived from point sources. A point source is a single identifiable source which is confined to a very small area such as that arising from disposal of waste material or from an industrial plant. Diffuse pollution arises where substances are widely used and dispersed over an area as a result of land use activities, often associated with urban development. Examples of diffuse pollution include atmospheric deposition of contaminants arising from industry, domestic coal fires and traffic exhaust, and disposal of domestic coal ash. The total concentration and the chemical form and hence the mobility of the PHE in a soil is highly dependent on the source

Validation for the transition of SPSS QI Analyst to the SPC for Excel program for quality control charting

The statistical process control charting software utilised by the Inorganic Geochemistry team, SPSS QI Analyst version 3.5, (1998, (QIA)), was no longer viable because it was incompatible with operating system requirements for networked computers. Therefore, an alternative program, SPC for Excel version 5, (2017, (SPC)), has been validated to replace the legacy version of QIA. The benefits of using SPC include but are not limited to the following: Conformity with accredited QC processes according to the Inorganic Geochemistry Analytical Quality Control Operating Procedure (AGN 1.7) Ease of transferring results from the analytical software Program is accessible to computers connected to the network Control charting and recording QC checks are all accomplished using Excel alone User friendly with moderate Excel skills Lower cost per licence than the latest version of the existing software The following document provides evidence to satisfy the requirements of UKAS accredited Standard ISO17025 by validating the new software system against the existing QIA software according to a validation plan using two complementary approaches. Specifically, this validation document comprises: Tests with a synthetic dataset, which confirms that QIA and SPC for Excel produce the same result against the criteria specified by Analytical Quality Control procedures (AGN 1.7) Tests with standards run during a recent large stream water analysis programme, which confirms that QIA and SPC for Excel control charts are able to perform the same quality control checks for analytes in “real” control sample data A comparative table of terminology differences between QIA and SPC for Excel A companion document “SPC for Excel Instruction manual v2_WORKING VERSION”, provides working guidance on the operation of SPC for Excel version 5 2017, located in Appendix 5

Soil Reference Material Data Sheets : BGS120 to BGS126

There is a paucity of appropriately characterised Reference Materials to inform quality assessments for agronomic chemical analysis of soil. These analyses are used to provide data for systematic regional geochemical/agricultural soil surveys and underpin on-farm decision making for soil fertility and crop yield management. This partially unmet need for reference materials is further exacerbated in low-income/resource settings and limits the frequency with which quality control samples can be routinely analysed: this gap has been specifically identified by the FAO Global Soil Laboratory Network (GLOSOLAN https://www.fao.org/global-soil-partnership/glosolan/en/) capacity strengthening activities. The insufficient supply of appropriately characterised reference materials, particularly soils from tropical sources, has been identified as a limiting factor in the global adoption of effective, harmonised analytical methods. The customer base for new reference materials is potentially broad. In addition to any of the ~1000-strong GLOSOLAN global community of laboratories, other commercial and research laboratories providing agricultural soil sample analyses, in the UK and internationally, as well as academic researchers and PhD students in environmental geochemistry. Existing soil reference materials on the market may present a matrix-matching problem as they are generally milled to <75 μm, as required for total elemental concentration methods. Routine/survey agricultural soil testing is usually undertaken on a more coarse, un-milled sieved fraction, such as <2 mm or <4 mm. This difference in size fraction (especially the changes to particle surfaces caused by additional mineral breakdown during milling) may cause unintended changes to soil texture and, together with an unrepresentative reduction in sample heterogeneity, lead to systematically biased analysis in relation to conventional soil analysis. The use of un-milled soil material for these Reference Materials has avoided such adverse effects that might influence parameter measurement (e.g., pH) or provide enhanced nutrient availability that is itself unrealistic (e.g., available P). Furthermore, extractable (not total) concentrations are used in agriculture to assess the fertility status of soil and make nutrient input decisions appropriate to the next crop. BGS has experience of creating reference materials across a range of rock, sediment, and soil matrices. Ten soil Reference Materials are available (BGS110-BGS119) which are optimised for major, minor and trace element variation from nine contrasting soil parent materials, and one anthropogenically contaminated soil (Kalra et al., 2020). BGS therefore set out to create suite of new reference materials that will help to support high-quality analysis for agriculturally relevant parameters, to augment the soil Reference Materials already offered for sale. This suite comprises a range of sample matrices from temperate silt-rich to peat-rich (BGS120 to BGS124), and equatorial agricultural soils (BGS125 to BGS126). OR/23

A spatial analysis of lime resources and their potential for improving soil magnesium concentrations and pH in grassland areas of England and Wales

Magnesium (Mg) is essential for animal health. Low Mg status (hypomagnesaemia) can be potentially fatal in ruminants, like cattle and sheep, and is widespread in Europe with economic impacts on farming. The application of Mg-rich agricultural lime products can help to ensure pasture forage consumed by animals contains sufficient Mg and, in areas of low pH, has the dual benefit of reducing soil acidity to levels best suited for grass production. This aim of this study was to determine if Mg-rich lime products could be used in a more effective manner in agricultural production systems. Potential resources of carbonate rocks (limestone, dolostone and chalk) in the UK, and their Mg:Ca status were identified, using datasets from the British Geological Survey (BGS). These data were combined with the locations of agricultural lime quarries, and areas where soils are likely to be deficient in Mg and/or require liming. Areas of potential demand for Mg-rich agricultural lime include areas in south east Wales, the Midlands and North East England. Although, areas where this may be an effective solution to low soil Mg values are restricted by the availability of suitable products. Conversely, areas of low soil pH in England and Wales are often found close to quarries with the ability to supply high Ca limes, suggesting that the low rates of lime use and liming is not due to supply factors. This study provides information that can help to guide on-farm decision making for use of Mg-rich and other lime resources. This could be used in conjunction with other options to reduce risks of Mg deficiency in livestock, and improve soil pH