London Atlas: Materials and methods I: data acquisition

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Ferreira, A, Johnson, C C, Appleton, J D, Flight, D M A, Lister, T R, Knights, K V, Ander, L, Scheib, C, Scheib, A, Cave, M, Wragg, J, Fordyce, F and Lawley, R. 2017. London Region Atlas of Topsoil Geochemistry. British Geological Survey.

The London Region Atlas of Topsoil Geochemistry (LRA) covers a rectangular area of 80 x 62 km (4960 km2), from British National Grid coordinates X, Y: 490000, 153000 to 570000, 215000. The LRA was produced using the London Region Topsoil Dataset (LRD, N=8400), which was created from two BGS geochemical surveys (LOND and SEEN) carried out under the Geochemical Baseline Survey of the Environment (G-BASE[1]) project between 2005 and 2009. LOND is an urban soil survey based on 6801 sampling sites at a sampling density of 1 per 0.25 km2; 6494 (95.5%) of the LOND samples are part of the London Earth[2] project as they are located within the GLA. SEEN is a south-east England rural soil survey carried out at a sampling density of 1 per 2 km2; 1599 (out of the 4089) SEEN sample sites are included in the LRA rectangle area; however, 95% are outwith the GLA limit as these are rural samples (Figure 2).

Field procedures and laboratory methods were undertaken in a standardised way to ensure consistency and enable quality assessment of the analytical results (Johnson et al., 2005[3]). This allowed adequate levelling of geochemical datasets from contiguous areas, sampled and analysed at different times or under different projects. Methods are described in the following sections. Descriptions of the interpolation method (parent material mapping method, Appleton and Adlam, 2012[4]) used to generate maps of the soil geochemical properties and of the exploratory data analysis techniques deployed are outlined in the last section.

Throughout this atlas the LRD dataset, and SEEN and LOND subsets are generally represented by the colours black/white, dark green and dark red respectively, while Quaternary, Palaeogene and Cretaceous geological time periods are represented by soft yellow, orange and lime green colours respectively.

Sampling[edit]

Sampling strategies for geochemical mapping using soil samples in rural (regional) and urban areas are described by Johnson et al. (2005)[3] and Fordyce et al. (2005)[5], respectively. The only major difference between the two is the sampling density. In rural areas soil samples are collected from alternate British National Grid (BNG) kilometre squares, corresponding to a sampling density of 1 sample/2 km2 (or 0.5 samples/km2); sites are ideally located at least 100 m from roads, buildings, railways, electricity pylons etc., on open unforested, and undisturbed ground whenever possible; the site should be generally representative of the land use within the selected kilometre square. In urban areas, the sample density is 1 sample/0.25 km2 (or 4 samples/km2); samples are collected from open ground (preferably gardens, parks, sports fields, road verges, allotments, open spaces, schoolyards, and waste ground) as close as possible to the centre of each 500 m cell (subdivisions of the BNG 1 km cell) (Figure 5). The greater density in urban areas allows the capture of more local-scale element concentration variability caused by human activity. The way of defining an urban area for sample collection purposes is described by Johnson and Ander (2008)[6].

Soil sampling was carried out according to the procedures detailed in the G-BASE[1] field procedures manual (Johnson, 2005[7]). All soil samples were collected and transported in 5”x10” Kraft™ paper bags. Each sample consisted of approximately 250 g of unsieved material and was a composite of five subsamples from auger holes distributed within an area of approximately 20 x 20 m whenever possible. Auger holes were located at the corners and centre of a square (Figure 6). A 1 m stainless steel Dutch auger with a 15 cm auger flight was used to collect soil samples from a fixed depth.

Topsoil samples (sample type code ‘A’) were collected to a depth of 20 cm, after removal of surface vegetation, surface litter and root zone. The bottom depth of the sample was recorded on the field card and the depth of any rootlet zone and surface litter was also noted. The deep soil sample (sample type code ‘S’) was targeted to collect to a depth of 35-50 cm (in rural areas this had the objective of sampling below any ploughed horizon), the actual sampling depth was recorded on the field card. Over terrains where only thin soils were developed e.g. over chalk, then a topsoil sample was collected from the normal surface depth, i.e. 5 to 20 cm and the S sample from as deep as possible down to bedrock. In such instances there may be little difference in the sampling depths between the A and S samples.

An extra surface sample (0–2 cm) was collected in the London Earth[2] GLA area, designated as sample type code ‘X’. The X samples often demanded material from additional auger holes within the 20 m square in order to reach the required sample weight of ca. 250 g. If a root layer was present this was collected as part of the surface sample (Knights and Scheib, 2010[8]).

Field duplicate samples were collected at a rate of 1 duplicate per 100 sampling sites in rural surveys. This rate was doubled (2 per 100 sampling sites) in urban surveys following the higher sampling density implemented in these areas. For quality control purposes, the field duplicates were collected with exactly the same procedure as a regular sample, but in an adjacent auger square (Figure 6).

At each sampling site, information about date of sampling, local details (location, geology, visible contamination, land use, etc.) and observations of the sample, such as soil colour, depth, clast lithology and apparent abundance, and textural classification, were recorded on a field card.

The geochemical results for the topsoil samples type ‘A’ (5-20 cm depth) only are presented in this atlas.


Figure 5 The G-BASE strategy for urban (red X) and rural (green X) soil sampling sites. The grid represents 1 km squares and the urban region is shaded (adapted from Johnson, 2005[7]). (P929861).


Figure 6 Plan of composite auger holes for collecting a soil sample (dashed square represents adjacent duplicate sample) (from Johnson, 2005[7]). (P929862).


Sample preparation and analysis[edit]

Soil samples were prepared and analysed at the BGS laboratories in Keyworth. All samples were dried and sieved but only the topsoils were routinely analysed by XRFS. After air-drying at <35°C (to prevent volatilisation of Se and Hg), each sample was sieved through a nylon sieve to give the <2 mm fraction. The sample was then homogenised, coned and quartered before a 50 g subsample was pulverised in an agate planetary ball mill to create a homogeneous sample (95% under 53 mm), from which a portion (12 g) was taken to prepare a pressed powder pellet for XRFS analysis.

Samples were analysed for total element concentration by XRFS in the BGS laboratories[9] in Keyworth. Analysis is accredited to ISO 17025 and to the Environment Agency's Monitoring Certification Scheme (MCERTS) standard for soils. Several different XRFS instruments were used, namely a PANalytical Axios advanced and a Philips MagiX PRO wavelength dispersive XRF spectrometer (WD-XRFS); and a PANalytical Epsilon-5 polarised energy dispersive XRF spectrometer (ED(P)XRFS), to determine 53 chemical elements. Forty-four of these elements are listed together with their lower limit of detection (LLD[10]) and the number of samples below LLD in Table 3. The remaining nine elements (Table 4) were excluded as six of them (Cl, In, S, Te, Hg and Ta) showed more than 90% of the results below the LLD in at least one of the LRD subsets (SEEN, LOND) and five of them (Sm, Tl, Yb, Hg and Ta) showed a very small between-site variability (less than 35%), due to high within-sample and/or within-site variability mostly as a results of data close to the LLD (Table 5). Of the 44 elements shown in the London Region Atlas of Topsoil Geochemistry, the 10 most abundant elements (Al2O3, CaO, Fe2O3, K2O, MgO, MnO, Na2O, P2O5, SiO2, TiO2) are expressed in terms of weight percent oxide (wt%) as concentration units, while the remaining 34 (Ag, As, Ba, Bi, Br, Cd, Ce, Co, Cr, Cs, Cu, Ga, Ge, Hf, I, La, Mo, Nb, Nd, Ni, Pb, Rb, Sb, Sc, Se, Sn, Sr, Th, U, V, W, Y, Zn and Zr) are shown in mg/kg (equivalent to the non-SI old notation ppm - parts per million).

Two extra parameters, loss on ignition (LOI) and pH were also determined on the topsoil samples from the LOND subset (except one for LOI) and about two thirds (1128 out of 1599) of the SEEN subset, resulting in a total of 7928 (for LOI) and 7929 (for pH) measurements. The loss on ignition, a proxy for the soil’s organic matter content (but can be affected by the loss of structural water in clay soils (Rowell, 1994[11]), was determined on 2 g of <2 mm size material by weighing the sample before and after heating in a furnace at 450°C for 24 hrs. The soil pH was determined with a pH electrode after mixing 10 g of <2 mm size material in 25 ml of 0.01 M CaCl2.2H2O and shaking until a slurry was formed.


Table 3 List of elements determined by XRFS reported in the London Region Atlas of Topsoil Geochemistry. The lower limit of detection (LLD), the number of samples below the LLD (n<LLD) and the n<LLD in percent (%<LLD) are shown for the London Region Dataset (LRD), and the two subsets (SEEN and LOND). Number of samples (N) is as follow: LRD = 8400, SEEN = 1599 and LOND = 6801.

Element
Symbol
Units

-Data-

-LLD-

-n<LLD-

-%<LLD-

.

Element
Symbol
Units

-Data-

-LLD-

-n<LLD-

-%<LLD-

.

Element
Symbol
Units

-Data-

-LLD-

-n<LLD-

-%<LLD-

Aluminium oxide
Al2O3
%

LRD

0.2

0

0.0

Cadmium
Cd
mg/kg

LRD

0.5

2317

27.6

Lead
Pb
mg/kg

LRD

1.3

0

0.0

SEEN

0.2

0

0.0

SEEN

0.5

787

49.2

SEEN

1.3

0

0.0

LOND

0.2

0

0.0

LOND

0.5

1530

22.5

LOND

1.3

0

0.0

Calcium oxide
CaO
%

LRD

0.05

14

0.2

Cerium
Ce
mg/kg

LRD

1

0

0.0

Rubidium
Rb
mg/kg

LRD

1

0

0.0

SEEN

0.05

14

0.9

SEEN

1

0

0.0

SEEN

1

0

0.0

LOND

0.05

0

0.0

LOND

1

0

0.0

LOND

1

0

0.0

Iron (III) oxide
Fe2O3
%

LRD

0.01

0

0.0

Cobalt
Co
mg/kg

LRD

1.5

27

0.3

Antimony
Sb
mg/kg

LRD

0.5

84

1.0

SEEN

0.01

0

0.0

SEEN

1.5

19

1.2

SEEN

0.5

68

4.3

LOND

0.01

0

0.0

LOND

1.5

8

0.1

LOND

0.5

16

0.2

Potassium oxide
K2O
%

LRD

0.01

0

0.0

Chromium
Cr
mg/kg

LRD

3

0

0.0

Scandium
Sc
mg/kg

LRD

3

374

4.5

SEEN

0.01

0

0.0

SEEN

3

0

0.0

SEEN

3

198

12.4

LOND

0.01

0

0.0

LOND

3

0

0.0

LOND

3

176

2.6

Magnesium oxide
MgO
%

LRD

0.3

376

4.5

Caesium
Cs
mg/kg

LRD

1

0

0.0

Selenium
Se
mg/kg

LRD

0.2

140

1.7

SEEN

0.3

83

5.2

SEEN

1

0

0.0

SEEN

0.2

51

3.2

LOND

0.3

293

4.3

LOND

1

0

0.0

LOND

0.2

89

1.3

Element
Symbol
Units

-Data-

-LLD-

-n<LLD-

-%<LLD-

.

Element
Symbol
Units

-Data-

-LLD-

-n<LLD-

-%<LLD-

.

Element
Symbol
Units

-Data-

-LLD-

-n<LLD-

-%<LLD-

Manganese oxide
MnO
%

LRD

0.005

20

0.2

Copper
Cu
mg/kg

LRD

1.3

0

0.0

Tin
Sn
mg/kg

LRD

0.5

0

0.0

SEEN

0.005

12

0.8

SEEN

1.3

0

0.0

SEEN

0.5

0

0.0

LOND

0.005

8

0.1

LOND

1.3

0

0.0

LOND

0.5

0

0.0

Sodium oxide
Na2O
%

LRD

0.3

447

5.3

Gallium
Ga
mg/kg

LRD

1

0

0.0

Strontium
Sr
mg/kg

LRD

1

0

0.0

SEEN

0.3

167

10.4

SEEN

1

0

0.0

SEEN

1

0

0.0

LOND

0.3

280

4.1

LOND

1

0

0.0

LOND

1

0

0.0

Phosphorous
pentoxide

P2O5
%

LRD

0.05

16

0.2

Germanium
Ge
mg/kg

LRD

0.5

384

4.6

Thorium
Th
mg/kg

LRD

0.7

3

0.0

SEEN

0.05

15

0.9

SEEN

0.5

109

6.8

SEEN

0.7

1

0.1

LOND

0.05

1

0.0

LOND

0.5

275

4.0

LOND

0.7

2

0.0

Silica
SiO2
%

LRD

0.1

0

0.0

Hafnium
Hf
mg/kg

LRD

1

0

0.0

Uranium
U
mg/kg

LRD

0.5

43

0.5

SEEN

0.1

0

0.0

SEEN

1

0

0.0

SEEN

0.5

1

0.1

LOND

0.1

0

0.0

LOND

1

0

0.0

LOND

0.5

42

0.6

Titanium dioxide
TiO2
%

LRD

0.01

0

0.0

Iodine
I
mg/kg

LRD

0.5

15

0.2

Vanadium
V
mg/kg

LRD

3

0

0.0

SEEN

0.01

0

0.0

SEEN

0.5

3

0.2

SEEN

3

0

0.0

LOND

0.01

0

0.0

LOND

0.5

12

0.2

LOND

3

0

0.0

Element
Symbol
Units

-Data-

-LLD-

-n<LLD-

-%<LLD-

.

Element
Symbol
Units

-Data-

-LLD-

-n<LLD-

-%<LLD-

.

Element
Symbol
Units

-Data-

-LLD-

-n<LLD-

-%<LLD-

Silver
Ag
mg/kg

LRD

0.5

1232

14.7

Lanthanum
La
mg/kg

LRD

1

0

0.0

Tungsten
W
mg/kg

LRD

0.6

219

2.6

SEEN

0.5

175

10.9

SEEN

1

0

0.0

SEEN

0.6

81

5.1

LOND

0.5

1057

15.5

LOND

1

0

0.0

LOND

0.6

138

2.0

Arsenic
As
mg/kg

LRD

2.4

9

0.1

Molybdenum
Mo
mg/kg

LRD

0.2

18

0.2

Yttrium
Y
mg/kg

LRD

1

0

0.0

SEEN

2.4

5

0.3

SEEN

0.2

11

0.7

SEEN

1

0

0.0

LOND

2.4

4

0.1

LOND

0.2

7

0.1

LOND

1

0

0.0

Barium
Ba
mg/kg

LRD

1

0

0.0

Niobium
Nb
mg/kg

LRD

1

0

0.0

Zinc
Zn
mg/kg

LRD

1.3

3

0.0

SEEN

1

0

0.0

SEEN

1

0

0.0

SEEN

1.3

1

0.1

LOND

1

0

0.0

LOND

1

0

0.0

LOND

1.3

2

0.0

Bismuth
Bi
mg/kg

LRD

0.3

4490

53.5

Neodymium
Nd
mg/kg

LRD

4

19

0.2

Zirconium
Zr
mg/kg

LRD

1

0

0.0

SEEN

0.3

918

57.4

SEEN

4

14

0.9

SEEN

1

0

0.0

LOND

0.3

3572

52.5

LOND

4

5

0.1

LOND

1

0

0.0

Bromine
Br
mg/kg

LRD

0.8

0

0.0

Nickel
Ni
mg/kg

LRD

1.3

3

0.0

.

SEEN

0.8

0

0.0

SEEN

1.3

3

0.2

LOND

0.8

0

0.0

LOND

1.3

0

0.0


Table 4 List of elements determined by XRFS not reported in the London Region Atlas of Topsoil Geochemistry. The lower limit of detection (LLD), the number of samples below the LLD (n<LLD) and the n<LLD in percent (%<LLD) are shown for the London Region Dataset (LRD), and the two subsets (SEEN and LOND). Number of samples (N) is as follow: LRD = 8400, SEEN = 1599 and LOND = 6801.

Element
Symbol
Units

Data

LLD

n<LLD

%<LLD

.

Element
Symbol
Units

Data

LLD

n<LLD

%<LLD

.

Element
Symbol
Units

Data

LLD

n<LLD

%<LLD

Chlorine
Cl
mg/kg

LRD

200

8378

99.7

Tellurium
Te
mg/kg

LRD

0.5

8347

99.4

Samarium
Sm
mg/kg

LRD

3.0

3217

38.3

SEEN

200

1596

99.8

SEEN

0.5

1583

99.0

SEEN

3.0

533

33.3

LOND

200

6782

99.7

LOND

0.5

6764

99.5

LOND

3.0

2684

41.9

Indium
In
mg/kg

LRD

0.5

8348

99.4

Mercury
Hg
mg/kg

LRD

0.5

6921

82.4

Thallium
Tl
mg/kg

LRD

0.5

6054

72.1

SEEN

0.5

1586

99.2

SEEN

0.5

1513

94.6

SEEN

0.5

1049

65.6

LOND

0.5

6762

99.4

LOND

0.5

5408

79.5

LOND

0.5

5005

78.2

Sulphur
S
mg/kg

LRD

2000

8243

98.1

Tantalum
Ta
mg/kg

LRD

1.0

7741

92.9

Ytterbium
Yb
mg/kg

LRD

1.5

2520

30.0

SEEN

2000

1586

99.2

SEEN

1.0

1368

85.6

SEEN

1.5

371

23.2

LOND

2000

6657

97.9

LOND

1.0

6373

93.7

LOND

1.5

2149

33.6


Table 5 Nested ANOVA results for the London Region Data topsoil duplicate and replicate sets. The number of sites indicate the number of locations with duplicate and replicate samples. Results below the lower limit of detection are excluded from the ANOVA analysis (Johnson et al., 2010[12]). Elements are ordered according to their performance in the nested ANOVA test. Shaded elements were excluded from the atlas after this test.

Element

Between-site %

Within-site %

Within-sample %

Number of sites

.

Element

Between-site %

Within-site %

Within-sample %

Number of sites

Nb

94.5

4.2

1.3

171

MnO

84.2

13.1

2.7

171

K2O

93.3

6.4

0.3

171

As

83.8

13.4

2.8

171

Rb

93.1

6.6

0.3

171

P2O5

82.5

16.6

0.9

171

La

92.0

6.0

2.0

171

Ba

82.3

15.3

2.4

171

TiO2

91.6

7.1

1.3

171

Na2O

82.3

10.2

7.5

124

Ce

91.0

7.4

1.6

171

Co

82.1

10.6

7.3

171

Ga

90.7

6.3

2.9

171

Cs

81.7

4.5

13.7

171

MgO

90.7

8.4

0.9

168

W

80.1

5.5

14.4

166

Y

90.6

7.0

2.4

171

Ni

79.9

16.2

3.9

171

Al2O3

90.5

8.7

0.7

171

Cu

79.6

17.8

2.6

171

V

90.5

8.3

1.2

171

Zn

77.0

20.9

2.0

171

Th

89.4

6.2

4.4

171

Sc

76.4

9.3

14.2

165

Zr

88.9

9.4

1.7

171

Sb

75.9

14.9

9.2

170

CaO

88.3

10.3

1.3

171

Sn

75.0

16.4

8.5

171

Fe2O3

88.1

8.8

3.1

171

U

72.1

5.5

22.3

165

Mo

88.1

8.9

3.0

151

Se

66.7

14.9

18.4

171

Sr

88.0

10.5

1.5

171

Cd

62.9

24.7

12.4

108

Nd

86.6

7.5

5.9

170

Ge

62.3

17.8

20.0

168

Br

86.4

11.4

2.2

171

Ag

58.9

30.9

10.2

26

Hf

86.0

7.1

6.9

171

Bi

52.2

28.1

19.7

55

Pb

85.3

10.7

4.0

171

Yb

34.8

5.3

59.8

99

I

85.2

8.8

6.0

171

Hg

29.7

55.2

15.1

39

SiO2

85.0

12.5

2.5

171

Sm

25.7

4.5

69.8

166

Cr

85.0

13.9

1.2

171

Tl

16.6

-8.6

91.9

65

Ta

15.3

3.0

81.7

54


Quality control[edit]

G-BASE[1] analytical results are subjected to rigorous quality control procedures described in detail elsewhere (Lister and Johnson, 2005[13]; Johnson, 2011[14]). The entire process, from field procedures to sample preparation and analysis in the laboratory is designed to minimise errors. Systematic errors are able to be checked because a randomised number is assigned to samples on collection.

Accuracy, precision and long-term analytical drift is assessed by including BGS XRF laboratory primary and secondary certified reference materials (CRMs) along with every batch of 500 samples in the analytical runs. Secondary CRMs allow any between batch bias to be identified and corrected. Primary CRMs ensure that bias from the 'true' result is minimized. Primary and secondary reference materials have been used routinely to assess the quality of regional geochemical data since the UK national mapping programme commenced in the 1960s (Lister and Johnson, 2005[15]; Johnson et al., 2008[16]). This ensures a ‘seamless’ continuation of geochemical data across large regions for samples collected over many field campaigns and analysed by different analytical instruments. All data in this London Region Geochemical Dataset are levelled using four accredited reference materials (GSD-7, GSS-1, LKSD-1, LKSD-4). Certified values (in red) together with the values reported by the BGS XRF laboratory are shown in Table 6.

A previously unrecognised analytical interference between high topsoil Pb concentration and U measurement in the London Earth[2] results, where high Pb was suppressing the U results, has been corrected in this London Region dataset.

The G-BASE[1] project also inserts field duplicate and laboratory replicate samples in every batch of fifty (urban) or one hundred (rural) samples. The laboratory replicate is a sub-sample of the same sample taken before analysis, whilst a field duplicate is a second sample collected in the field at the same location as a regular sample. These two control samples allow assessment of the analytical and sampling variability respectively and comparison to the total variability. This provides a check that the local (within-site) ‘noise’ is low enough so that the regional patterns (between sites) are distinguishable and reliable. This was achieved by performing a nested unbalanced analysis of variance (ANOVA) using these duplicate and replicate samples (Johnson, 2002[17]). The validity of the nested ANOVA depends on the representativeness of the duplicates and replicates, and it may not be valid if a large number of samples have element concentrations that are near or below the LLD. Nevertheless, results give an indication of the elements for which the natural geochemical variability is significantly higher than the variability related to the sampling and analytical procedures. The higher the percentage of total variability attributed between sites, the higher the confidence in the results (Table 5). For elements with a value above 80% the sampling and analytical methodology is considered suitable, as it does not introduce too much 'background noise'. As between-site variability decreases from 80% down to about 50%, increasing caution must be taken during statistical analysis and/or interpretation. Elements showing a between-site variability below 50% (Yb, Hg, Sm, Tl and Ta) are not considered further in the LRA, as already explained under the Sample preparation and analysis section of this atlas.


Table 6 Summary of primary reference material results for soil samples XRFS analyses in the London Region Atlas of Topsoil Geochemistry. Units for elements shown as oxides are wt% and mg/kg otherwise.

Elements by XRF-ED

CRM ID

.

Ag

Cert Ag

.

Cd

Cert Cd

.

In

Cert In

.

Sn

Cert Sn

.

Sb

Cert Sb

.

I

Cert I

.

Cs

Cert Cs

.

Ba

Cert Ba

.

La

Cert La

.

Ce

Cert Ce

GSD-7

1.4

1.1

0.9

1.1

not detected

no data

4.8

5.4

2.8

2.6

0.9

no data

5

6

740

720

45

45

82

78.0

GSS-1

0.4

0.4

4.4

4.3

not detected

no data

5.9

6.1

1.0

0.9

1.9

1.9

9

9

587

590

34

34

68

70.0

LKSD-1

0.5

0.6

1.1

1.2

0.5

no data

15.2

16.0

0.9

1.2

1.7

no data

1

2

396

430

14

16

25

27.0

LKSD-4

0.1

0.2

1.9

1.9

not detected

no data

4.6

5.0

1.3

1.7

9.5

no data

2

2

262

330

21

26

38

48.0

Elements by XRF-WDT

CRM ID

.

K2O

Cert K2O

.

CaO

Cert CaO

.

TiO2

Cert TiO2

.

MnO

Cert MnO

.

Fe2O3

Cert Fe2O3

.

S

Cert S

.

Cl

Cert Cl

.

Sc

Cert Sc

GSD-7

3.64

3.54

1.65

1.67

0.707

0.747

0.093

0.089

6.50

6.51

646

190

83

no data

13.7

14.6

GSS-1

2.53

2.59

1.75

1.72

0.766

0.805

0.238

0.227

5.18

5.19

847

310

114

78

10.4

11.2

LKSD-1

1.06

1.10

12.14

10.80

0.448

0.500

0.093

0.100

4.03

4.10

9306

1570

430

no data

6.5

9.0

LKSD-4

0.76

0.80

1.85

1.80

0.299

0.400

0.068

0.100

4.20

4.10

5952

999

215

no data

7.1

7.0

CRM ID

.

V

Cert V

.

Cr

Cert Cr

.

Co

Cert Co

.

Ni

Cert Ni

.

Cu

Cert Cu

.

Zn

Cert Zn

.

Ga

Cert Ga

.

Ge

Cert Ge

GSD-7

93.4

96.0

119.3

122.0

20.6

21.0

55.6

53.0

36.1

38.0

246.2

238.0

16.7

17.7

0.9

1.4

GSS-1

80.7

86.0

60.0

62.0

13.9

14.2

20.7

20.4

19.7

21.0

671.6

680.0

17.6

19.3

0.6

1.3

LKSD-1

47.8

50.0

27.0

31.0

11.0

11.0

16.0

16.0

40.6

44.0

322.4

331.0

9.0

no data

0.1

no data

LKSD-4

45.5

49.0

30.1

33.0

11.7

11.0

34.1

31.0

30.1

31.0

194.3

194.0

7.9

no data

0.5

no data

CRM ID

.

As

Cert As

.

Se

Cert Se

.

Br

Cert Br

.

Rb

Cert Rb

.

Sr

Cert Sr

.

Y

Cert Y

.

Zr

Cert Zr

.

Nb

Cert Nb

GSD-7

83.7

84.0

0.2

0.3

0.6

no data

146.4

147.0

222.4

220.0

24.9

24.0

156.9

162.0

15.1

17.0

GSS-1

35.8

33.5

0.1

0.1

2.5

2.9

137.9

140.0

156.6

155.0

24.9

25.0

250.1

245.0

14.7

16.6

LKSD-1

34.9

40.0

1.0

no data

10.3

11.0

22.7

24.0

259.4

250.0

20.9

19.0

132.8

134.0

4.0

7.0

LKSD-4

16.6

16.0

2.3

no data

50.6

49.0

25.0

28.0

121.0

110.0

22.2

23.0

101.3

105.0

4.3

9.0

CRM ID

.

Mo

Cert Mo

.

Nd

Cert Nd

.

Sm

Cert Sm

.

Yb

Cert Yb

.

Hf

Cert Hf

.

Ta

Cert Ta

.

W

Cert W

.

Hg

Cert Hg

GSD-7

1.3

1.4

34.1

37.0

4.4

6.1

2.2

2.6

5.0

4.9

0.8

1.4

6.5

5.5

-0.3

0.1

GSS-1

1.1

1.4

26.3

28.0

3.9

5.2

2.1

2.7

7.7

6.8

0.5

1.4

4.6

3.1

-0.8

0.0

LKSD-1

9.4

10.0

19.4

16.0

2.9

4.0

1.7

2.0

4.1

3.6

-0.2

0.3

1.7

<4

-0.6

0.0

LKSD-4

1.3

<5

27.1

25.0

4.3

5.0

2.1

2.0

3.1

2.8

-0.1

0.4

1.8

<4

-0.5

no data

CRM ID

.

Tl

Cert Tl

.

Pb

Cert Pb

.

Bi

Cert Bi

.

Th

Cert Th

.

U

Cert U

GSD-7

0.7

0.9

361.1

350.0

0.6

0.7

12.6

12.6

3.4

3.5

GSS-1

0.7

1.0

98.2

98.0

0.7

1.2

11.4

11.6

3.7

3.3

LKSD-1

0.1

no data

83.7

82.0

0.6

no data

2.1

2.2

9.7

9.7

LKSD-4

0.8

no data

97.3

91.0

0.0

no data

5.1

5.1

31.4

31

Elements by XRF-WDM

CRM ID

.

Na2O

Cert Na2O

.

MgO

Cert MgO

.

Al2O3

Cert Al2O3

.

SiO2

Cert SiO2

.

P2O5

Cert P2O5

.

SO3

Cert SO3

GSD-7

1.2

1.2

4.3

3.1

14.6

13.4

67.3

64.7

0.21

0.19

not detected

no data

GSS-1

1.4

1.7

2.1

1.8

14.1

14.2

57.4

62.6

0.18

0.17

0.1

0.08

LKSD-1

1.6

2.0

1.8

1.7

5.6

7.8

31.5

40.1

0.16

0.20

2.6

no data

LKSD-4

0.5

0.7

1.0

0.9

5.2

5.9

45.2

41.6

0.36

0.30

2.1

no data

References[edit]

  1. 1.0 1.1 1.2 1.3 Geochemical Baseline Survey of the Environment (G-BASE) http://www.bgs.ac.uk/gbase/home.html
  2. 2.0 2.1 2.2 London Earth http://www.bgs.ac.uk/gbase/londonearth.html
  3. 3.0 3.1 Johnson, C C, Breward, N, Ander, E L, and Ault, L. 2005. GBASE: baseline geochemical mapping of Great Britain and Northern Ireland. Geochemistry: Exploration, Environment, Analysis, Vol. 5 (4), 347–357.
  4. Appleton, J D, and Adlam, K A M. 2012. Geogenic control on soil chemistry in urban areas: a novel method for urban geochemical mapping using parent material classified data. Applied Geochemistry, Vol. 27, 161–170. 10.1016/j.apgeochem.2011.10.001
  5. Fordyce, F M, Brown, S E, Ander, E L, Rawlins, B G, O'Donnell, K E, Lister, T R, Breward, N, and Johnson, C C. 2005. GSUE: urban geochemical mapping in Great Britain. Geochemistry: Exploration, Environment, Analysis, Vol. 5 (4), 325–336. Download from NORA.
  6. Johnson, C C, and Ander, E L. 2008. Urban geochemical mapping studies: how and why we do them. Environmental Geochemistry and Health, Vol. 30, 511–530.
  7. 7.0 7.1 7.2 Johnson, C C. 2005. 2005 G-BASE Field Procedures Manual. British Geological Survey Internal Report, IR/05/097. Download from NORA.
  8. Knights, K V, and Scheib, A J. 2010. London Earth: details of field campaigns across the Greater London area, 2005 to 2009. British Geological Survey Open Report, OR/09/056. Download from NORA.
  9. Laboratory services http://www.bgs.ac.uk/sciencefacilities/laboratories/geochemistry/igf/Services/home.html
  10. Young, M E, and Donald, A W(eds). 2013. A guide to the Tellus data. Geological Survey of Northern Ireland, Belfast, UK. 233 pp.
  11. Rowell, D L. 1994. Soil science: methods and applications. UK: Longman Scientific and Technical
  12. Johnson, C C, Scheib, A, and Lister, T R. 2010 London Earth topsoil chemical results : user guide. British Geological Survey Open Report, OR/11/035.
  13. Lister, T R, and Johnson, C C. 2005. G-BASE data conditioning procedures for stream sediment and soil chemical analyses. British Geological Survey Internal Report, IR/05/150. Download from NORA.
  14. Johnson, C C. 2011 Understanding the quality of chemical data from the urban environment. Part 1, quality control procedures. 61–76 In Johnson, C C et al., (eds.) Mapping the chemical environment of urban areas. Wiley.
  15. Lister, T R, and Johnson, C C. 2005. G-BASE data conditioning procedures for stream sediment and soil chemical analyses. British Geological Survey Internal Report, IR/05/150. Download from NORA.
  16. Johnson, C C, Ander, E L, Lister, T R, and Flight, D M A. 2008. Data conditioning of environmental geochemical data: quality control procedures used in the British Geological Survey's Regional Geochemical Mapping Project. 93–118 in Environmental geochemistry: site characterisation, data analysis and case histories. De Vivo, B, Belkin, H E, and Lima, A (editors). Oxford: Elsevier.
  17. Johnson, C C. 2002. Within-site and between-site nested analysis of variance (ANOVA) for geochemical surveys using MS EXCEL. British Geological Survey Internal Report, IR/02/043. Download from NORA.