DENITZA VOUTCHKOVAPHD FELLOW

AARHUSUNIVERSITET

7. FEBRUARY 2012

IODINE IN GROUNDWATER IN

DENMARKIMPLICATIONS FOR HUMAN HEALTH

AU

AARHUSUNIVERSITET

IODINE IN GROUNDWATER IN DENMARK

DENITZA VOUTCHKOVA7. FEBRUARY 2012

PROJECT PRESENTATION

› Geo-Center project, financed by GEUS and AU› 2011- 2014› Project title:

“Iodine in the hydrological cycle in Denmark: implications for human health“

› People involved in the project:

› Søren Munch Kristiansen (AU, Department of Geoscience)› Birgitte Hansen, Vibeke Ernstsen, Brian Sørensen & Kim

Esbensen (GEUS)

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AARHUSUNIVERSITET

IODINE IN GROUNDWATER IN DENMARK

DENITZA VOUTCHKOVA7. FEBRUARY 2012

WHY IODINE IS INTERESTING?

Medical aspect

› essential component of the thyroid hormones

› low iodine intake:› variety of IDD – mental retardation, goitre, hypothyroidism, etc;› prevention – fortification of table salt and salt in bread (dk mandatory since 2000/2001)

› high iodine intake:› tolerable upper intake level › associated with the correction of iodine deficiency or/and chronically high intake – iodine induced hyperthyroidism, elevated goitre and subclinical hypothyroidism

Geochemical aspect

› iodine in groundwater (= tap water)

› mapping regional/temporal variations› not included in the monitoring programs of the waterworks;› data mainly from GRUMO wells; some studies

› understanding the involved processes

› source/sources of iodine in the groundwater in Denmark

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AARHUSUNIVERSITET

IODINE IN GROUNDWATER IN DENMARK

DENITZA VOUTCHKOVA7. FEBRUARY 2012

PREVIOUS STUDIES

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Pedersen, Laurberg, Nøhr, Jørgensen, Andersen "Iodine in drinking water varies by more than 100-fold in Denmark. Importance for iodine content of infant formulas" 1999

Andersen, Petersen, Lauberg “Iodine in drinking water is bound in humic substances“ 2002

Rasmussen, Larsen, Ovesen “Iodine content in drinking water and other beverages in Denmark” 2000

AARHUSUNIVERSITET

IODINE IN GROUNDWATER IN DENMARK

DENITZA VOUTCHKOVA7. FEBRUARY 2012

AVAILABLE GROUNDWATER DATA

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Poster Bari

Number of Iodine* samples0 200 400 600 800 1000

1933

19401941

19581959

1975

19861988 1990

1991

1995

2001

20052006

2011Status December 2011: 2562 samples

Data quality assessment

•Different methods•Unit mistakes

Statistical analysis of the dataPicking up interesting areas for case-studies

AARHUSUNIVERSITET

IODINE IN GROUNDWATER IN DENMARK

DENITZA VOUTCHKOVA7. FEBRUARY 2012

MULTIVARIATE DATA ANALYSIS

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Other constituents I

Purpose:1. finding outliers 2. grouping due to date, method,

etc.3. exploring the

relations/correlations between the different data

Hypothesis: there is correlation between iodine and the other constituents or some of them

GeologyDistance to coastline

Distance to major faults

I

Hypotheses:• Iodine originates from

the rock/sediment • sea water intrusion • upward diffusion of old

saltwater SRJODCLBRBA

BORFL

NAMGCABIKMNFEK

REDLEDPH

NO3SO4PO4

NVOCAGGCO2

O2CH4H2S

LI

12692562

16281247

14062131

875987104810261059

161716231614

82216861693

16271621

237901

66765

417430

1200

AARHUSUNIVERSITET

IODINE IN GROUNDWATER IN DENMARK

DENITZA VOUTCHKOVA7. FEBRUARY 2012

2 days 3 days 6 days 10 days 21 days5.006.007.008.009.00

10.0011.0012.0013.0014.0015.00

Storage experimentµg/l

IODINE SPECIATION

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Lab methods development and testing:1. Inorganic Iodine – IC2. Total Iodine – ICP-MS3. Organo-iodine

𝐼𝑂3❑−

Organo-iodine

Inorganic iodine

Total iodine

Storage experiment:How the Iodide concentration in groundwater sample is affected by:1. storage conditions – 5ºC,10ºC,

freezer2. storage period

Statistically significant difference

Freezer – indications that the composition of the water was different; new experiment needed in order to make conclusions

Important for the geochemical understanding of the Iodine cycle

AARHUSUNIVERSITET

IODINE IN GROUNDWATER IN DENMARK

DENITZA VOUTCHKOVA7. FEBRUARY 2012

CASE STUDIES

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Ishøj

Hjelmsølille

Purpose: 1. Source - explanation for the

observed concentrations2. Iodine speciation 3. Geochemical analysis

0 meq/l

Cl

HCO3

SO4Mg

Ca

Na+K

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AARHUSUNIVERSITET

IODINE IN GROUNDWATER IN DENMARK

DENITZA VOUTCHKOVA7. FEBRUARY 2012

FUTURE PLANS AND POSSIBLE COLLABORATION

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Medical aspect Geochemical aspect

In progress:› Case studies› Multivariate

analysis of Jupiter dataNational study on Iodine in drinking water:

› Sampling from waterworks wells› Reflecting the different geology and the size of

the waterworks› Mapping of Iodine concentrations in drinking

water› Estimation of the dietary iodine intake in

Denmark› Combined study with data from medical

registers

Possible collaboration

AARHUSUNIVERSITET

IODINE IN GROUNDWATER IN DENMARK

DENITZA VOUTCHKOVA7. FEBRUARY 2012

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Thank you for the attention