Finger and toe nails don't seem very interesting at the best of times, but did you know they carry a record of your exposure to metals like lead and arsenic? In this presentation I review how these materials can show if people are being exposed to trace metals and how they can be used to link exposure to possible early health effects. The talk includes work from 3 PhD projects that I have been involved in and show how a project can develop from a humble beginning to cutting edge research.

1. Non-Invasive Methods for
Biomonitoring Human Exposure to
Trace Elements
Dr Chris Harrington
Deputy Director
SAS Trace Element Laboratory,
Royal Surrey County Hospital
RSC TOXICOLOGY GROUP and
SOCIETY FOR BROWNFIELD RISK ASSESSMENT
Current Issues in Contaminated Land Risk Assessment - 2013
1

2. Human Health Effects
2

3. Biomonitoring Model
Two classes of biomarker can be measured:
Biomarkers of exposure and biomarkers of effect.
3

4. Biomarkers of Exposure
4

5. Biomarkers of Exposure
• Random urine: guidance values for occupational
exposure and defined species eg organic Pb.
Requires creatinine correction.
• Venous blood: guidance values for specific elements
(Ag, Cd, Hg, Mn and Pb).
• Hair: reference ranges available for some
populations. Provides a timeline of exposure.
Problems with surface contamination and cosmetic
treatments.
• Nails: similar to hair. Toe-nails better than finger-nails
as less affected by contamination.
• Zinc protoporphyrin in blood: blood drop from fingertip. Screening method for Pb and iron-deficiency
anaemia.
5

6. Study One: Arsenic
Dietary Effects and Ethnicity
6

7. Objectives
Small scale preliminary study looking at:
 Control groups from Leicester.
 As in hair, urine and nails.
 Development of life-style questionnaire.
 Methods for cleaning hair and nails
prior to analysis.
 Total As and As speciation by ICP-MS
and HPLC-ICP-MS.
7

8. Results 1.
Total As concentration in
urine, hair and fingernail of
three ethnic groups:
Asian (n = 21), Somali (n =
22) and White (n = 20).
(A) Total As concentration
(μg/g creatinine) in urine.
(B) Total As concentration
(μg/kg) in hair and
fingernail.
E. I. Brima, P. I. Haris, R.O. Jenkins, A. G. Gault, D. A. Polya, C.
F. Harrington. Understanding arsenic metabolism through a
comparative study of arsenic levels in the urine, hair and
fingernails of healthy volunteers from three unexposed ethnic
groups in the United Kingdom. Toxicology and Applied
Pharmacology, Vol. 216, 122-130, (2006).
8

9. Results 2.
Proportions of As species in the
urine of three ethnic groups.
Differences are predominantly
related to dietary exposure: all
participants refrained from
seafood for 3 days prior to
sampling.
Higher proportion of DMA in
Somali urine could relate to
higher protein intake which
promotes methylation.
9

10. Study Two: Arsenic
Devon Great Consols, Cornwall
10

11. Objectives
Small scale preliminary study looking at:
 Exposure to As from abandoned mine site.
 As in human hair, urine and nails.
 Use of worms as sentinel organisms.
 Use of bioaccessible fraction.
 Used preparation methods and
questionnaire from previous study.
 Total As and As speciation by ICP-MS and
HPLC-ICP-MS.
11

12. Devon Great Consols, Cornwall
Carmarthen
Cheltenham
Swansea
Bristol
Bath
Taunton
Devon Great Consuls
Exeter
Weymouth
Plymouth
Penzance
012.5
25
50
75 100
Kilometers
´
Nottingham garden
used as control site.
Total As (mg/kg)
255 - 289
331- 439
*
913 - 1005
1564 - 2980
5141 - 12466
0
0.25
'
•Total As in soil
determined via ICP-MS
following acid digestion.
•Bioaccessible fraction
0.5 Kilometers by PBET.
•SGV 32 – 640 mg/kg
12

13. Devon Great Consols: Sampling
13

14. Pathways of Exposure to Contaminated Soil
1.
2.
3.
-
-
Inhalation
Dermal uptake
Ingestion
Soil particles adhere to
vegetables
Geophagia
Hand-to-mouth activities
(‘Pica’ Children)
14

15. Unified Bioaccessibility Method
Stomach
Phase
Stomach +
Intestine
Phase
Bioaccessible = Maximum concentration of arsenic available
for gastro-intestinal absorption.
(Bioavailable – Contaminant fraction that reaches the systemic
circulation).
15

16. Results: Stomach vs. Intestine
Sample site
1
2
3
5
6
7
9
10
11
12
13
15
Control
Total As
(mg/kg-1)
3058
1564
996
238
11939
313
272
452
282
5232
2870
876
15.4
Stomach
Only
578
298
308
44.2
340
94.8
60.9
43.8
36.5
1595
848
158
4.6
Stomach +
Intestine
588
303
329
36.8
1603
73.0
72.2
40.5
35.3
1116
690
113
6.7
Bioaccessible
As (%)
19.2
19.4
33.1
18.5
13.4
30.3
26.6
9.68
12.9
30.5
29.6
18.1
43.4
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17. Toe-Nail Levels: DGC
Exposed Group
Control Group
Mean±SD min max
Mean±SD
min
max
Age
46 ± 26
41 ± 13
25
55
Male/Female (n)
5/3
Time outdoors (hr/wk)
11 ± 7
3
2
10
Toenail As (ug/kg)
5406
858 25981 122
73
273
Exogen. TN As (ug/kg)
506
102 3784
2.1
13
11
67
6/3
21
5±2
4.0
Total conc. As in toe-nail as a biomarker of exposure.
Levels much higher in participants living near to DGC.
Small cohort sizes.
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18. Publications From this Project
M.J. Watts, M. Button, T.S Brewer, G.R.T. Jenkin and C. F. Harrington. The speciation of arsenic in two species of
earthworms from a former mine site. Journal of Environmental Monitoring, Vol 10, 753-759, (2008).
M.J. Watts, M. Button, T.S Brewer, C. F. Harrington and G.R.T. Jenkin. Toenails as a biomarker of exposure to
elevated environmental arsenic levels in residents of an abandoned mine site, Devon, UK. Journal of Environmental
Monitoring. Vol. 11, 610-617. (2009).
Mark Button, Mark Cave, Chris F. Harrington, Michael J. Watts. Earthworms and in vitro physiologically based
extraction tests: complimentary tools in a holistic approach towards understanding risk at arsenic contaminated sites.
Environmental Geochemistry and Health, 31, 273-282, (2009).
Button M, Jenkin GRT, Bowman, KJ, Brewer TS, Harrington CF, Jones GDD and Watts MJ (2008). Assessment of
resistance to arsenic in earthworms from genotoxic contaminated soils using the Comet assay. Mutation Research:
Genetic Toxicology and Environmental Mutagenesis, 696, 95-100, (2010).
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19. Study Three: Multielemental
Panasqueira Mine, Portugal
Panasquei
ra Mine
Castelo
dam
19

20. Objectives
Investigate the effects on population health caused by mine
waste contamination
using a multistage approach
integrate different biomarkers
a better characterization of the risk
Three groups: control (n = 35); occup. exp. (n = 34); environ. exp (n = 33).
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21. São Francisco de
Assis village
Geochemical sampling
campaign undertaken
in the vicinity of São
Francisco de Assis
village
Mining
site
Village
Soil samples (when compared to local
background)
As - 36x
Cd - 4x
Stream sediments (when compared to
local background)
As – 117x
Cd – 23x
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22. Biomarkers of Effect
- Genotoxicity:
- T-cell receptor (TCR) mutation assay
- Micronucleus (MN)
- Chromosomal Aberrations (CA)
- Comet Assay
- Immunotoxicity-> Lymphocyte subset frequency
- Susceptibility-> genetic polymorphisms (enzymes
involved in the metabolism of metal(loid)s and
DNA repair)
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23. COLLECTED SAMPLES / METHODS

Blood
GFAAS and ICP-MS analysis

Urine

Nails

Hair
ICP-MS analysis
Digestion in
microwave
vessels with
HNO3 (conc.)
ICP-MS and
ICP-OES
analysis
23

24. RESULTS – ICP-MS

Confounding factors
 Gender
- Cd in WB (↑ in males - E.E.)
- Pb in WB (↑ in males - C. and E.E.)
 Age
- As in U
↑ older individuals
- Hg in U
- Se in U
- Se in FN - ↑ younger individuals
 Smoking Habits
- Cd in WB (↑ in males - E.E.)
24

25. RESULTS – ICP-MS
C. vs. E.E.
E.E. vs. O.E.
C. vs. O.E.
As
↑ WB*, FN* &
TN*
-
↑ FN*
Cd
↑ FN*
↓ FN*,↑ H*
↑ H*
Cr
↑ WB**
↓ WB**
-
Hg
↓ TN** & H*
↑ TN* & H*
↑ H*
Mn
-
↓ U*, ↑ H*
↑ H*
Ni
-
-
-
Pb
-
↑ WB* & H**
↑ WB*
Se
-
↓ FN*
-
* p<0,05
* *p<0,001
C. – Contol Group
E.E. – Environmental Exposed Group
O.E. – Occupational Exposed Group
WB – Whole Blood
FN – Fingernails
TN – Toenails
H – Hair
U – Urine

26. RESULTS – ICP-MS
Correlations between elements & matrices
Significant correlations between:
• different elements / same matrix
• same element / different matrices
• different elements / different matrices were found for
the majority of the elements showing a good synergy
between these biomarkers.
Elements concentrations vs. Reference/Published ranges
Several elements exceed the reference ranges for
WB and U samples, and for FN, TN and H the
published ranges for non-exposed populations.
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27. Initial Conclusions
Preliminary results for the biomarkers of effect:
• Increased MN frequency -> genotoxicity
• Elevated TCR mutation frequency -> mutagenicity
• Alterations in the percentages of lymphocytes subsets ->
immunotoxicity
Increased risk of effects on health
Related to the metal(loid) contamination
from Panasqueira mine activities
FURTHER DATA ANALYSIS IS
UNDERWAY
27

28. Publications From this Project
Patrícia Clara dos Santos Coelho, Solange Costa, Susana Silva, Alan Walter, James Ranville, Ana Sousa, Carla da
Costa, Marta Isabel Correia Coelho, Julia García-Lestón, M. Ramiro Pastorinho, Blanca Laffon, Eduardo Pásaro
Mendez, Chris Harrington, Andrew Taylor and João Paulo Teixeira. Metal(loid) levels in biological matrices from
human populations exposed to mining contamination - Panasqueira Mine (Portugal). Journal of Toxicology and
Environmental Health, Part A. 2012, 75(13-15), 893-908.
P. Coelho, S. Costa, C. Costa, S. Silva, A. Walter, J. Ranville, M.R. Pastorinho, C. Harrington, A. Taylor, V. Dall'Armi,
R. Zoffoli, C. Candeias, E. Ferreira da Silva, S. Bonassi, B. Laffon J.P. Teixeira. Impact of Panasqueira mine
activities on populations environmentally and occupationally exposed – quantification of several metal(loid)s in
different biological matrices. Environmental Geochemistry and Health, published on-line.
All publications relating to this work are available to download from Research Gate :
www.researchgate.net/profile/Chris_Harrington/?ev=hdr_xprf
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29. Future Work:
Vulnerable populations
Ethically unacceptable to perform wide
scale biomonitoring on children using
invasive methods.
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30. Acknowledgements
All colleagues and collaborators who helped with the
different studies:
Study One: De Montfort University Studentship
(Dr Eid Brima).
Study Two:
British Geological Survey, NERC
Award (Dr Mark Button).
Study Three: FCT Portugal (Dr Patricia Coelho).
Current work: NHS for on-going instrument time.
All publications relating to this work are available to
download from Research Gate :
www.researchgate.net/profile/Chris_Harrington/?ev=hdr_xprf
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