dr chris harrington - rsc

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RSC TOXICOLOGY GROUP and

SOCIETY FOR BROWNFIELD RISK ASSESSMENT Current Issues in Contaminated Land Risk Assessment - 2013

Dr Chris Harrington

Deputy Director

SAS Trace Element Laboratory,

Royal Surrey County Hospital

Non-Invasive Methods for

Biomonitoring Human Exposure to

Trace Elements

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Human Health Effects

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Biomonitoring Model

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Two classes of biomarker can be measured:

Biomarkers of exposure and biomarkers of effect.

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Biomarkers of Exposure

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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 finger-

tip. Screening method for Pb and iron-deficiency

anaemia.

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Study One: Arsenic Dietary Effects and Ethnicity

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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.

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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.

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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.

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Study Two: Arsenic Devon Great Consols, Cornwall

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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.

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Total As (mg/kg)

255 - 289

331- 439

913 - 1005

1564 - 2980

5141 - 12466 0 0.50.25 Kilometers'

Devon Great Consols, Cornwall

Devon Great Consuls

Bath

Exeter

Taunton

Swansea

Bristol

Weymouth

Plymouth

Penzance

CheltenhamCarmarthen

´0 25 50 75 10012.5Kilometers

Nottingham garden

used as control site.

•Total As in soil

determined via ICP-MS

following acid digestion.

•Bioaccessible fraction

by PBET.

•SGV 32 – 640 mg/kg

*

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Devon Great Consols: Sampling

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Pathways of Exposure to Contaminated Soil

1. Inhalation

2. Dermal uptake

3. Ingestion - Soil particles adhere to

vegetables

- Geophagia

- Hand-to-mouth activities

(‘Pica’ Children)

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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).

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Results: Stomach vs. Intestine

Sample site Total As (mg/kg-1)

Stomach Only

Stomach + Intestine

Bioaccessible As (%)

1 2 3 5 6 7 9

10 11 12 13 15

Control

3058 1564 996 238

11939 313 272 452 282 5232 2870 876 15.4

578 298 308 44.2 340 94.8 60.9 43.8 36.5 1595 848 158 4.6

588 303 329 36.8 1603 73.0 72.2 40.5 35.3 1116 690 113 6.7

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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Toe-Nail Levels: DGC

Exposed Group Control Group

Mean±SD min max Mean±SD min max

Age 46 ± 26 11 67 41 ± 13 25 55

Male/Female (n) 5/3 6/3

Time outdoors (hr/wk) 11 ± 7 3 21 5 ± 2 2 10

Toenail As (ug/kg) 5406 858 25981 122 73 273

Exogen. TN As (ug/kg) 506 102 3784 4.0 2.1 13

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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Study Three: Multielemental Panasqueira Mine, Portugal

Panasquei

ra Mine

Castelo

dam

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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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São Francisco de

Assis village

Geochemical sampling

campaign undertaken

in the vicinity of São

Francisco de Assis

village

Soil samples (when compared to local

background)

As - 36x

Cd - 4x

Stream sediments (when compared to

local background)

As – 117x

Cd – 23x

Mining

site

Village

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- 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)

Biomarkers of Effect

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COLLECTED SAMPLES / METHODS

Blood

Urine

Nails

Hair

Digestion in

microwave

vessels with

HNO3 (conc.)

GFAAS and ICP-MS analysis

ICP-MS analysis

ICP-MS and

ICP-OES

analysis

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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

- Hg in U

- Se in U

- Se in FN - ↑ younger individuals

Smoking Habits

- Cd in WB (↑ in males - E.E.)

↑ older individuals

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

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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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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

Related to the metal(loid) contamination

from Panasqueira mine activities

FURTHER DATA ANALYSIS IS

UNDERWAY

Increased risk of effects on health

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Future Work: Vulnerable populations

Ethically unacceptable to perform wide

scale biomonitoring on children using

invasive methods.

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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