1. DENITZA VOUTCHKOVA PHD FELLOW AARHUS UNIVERSITET 7. FEBRUARY 2012 IODINE IN GROUNDWATER IN DENMARK IMPLICATIONS FOR HUMAN HEALTH AU

2. AARHUS UNIVERSITET IODINE IN GROUNDWATER IN DENMARK DENITZA VOUTCHKOVA 7. 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) 2

3. AARHUS UNIVERSITET IODINE IN GROUNDWATER IN DENMARK DENITZA VOUTCHKOVA 7. 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 3

4. AARHUS UNIVERSITET IODINE IN GROUNDWATER IN DENMARK DENITZA VOUTCHKOVA 7. FEBRUARY 2012 PREVIOUS STUDIES 4 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

5. AARHUS UNIVERSITET IODINE IN GROUNDWATER IN DENMARK DENITZA VOUTCHKOVA 7. FEBRUARY 2012 AVAILABLE GROUNDWATER DATA 5 Poster Bari Number of Iodine* samples Status December 2011: 2562 samples Data quality assessment Different methods Unit mistakes Statistical analysis of the data Picking up interesting areas for case-studies

6. AARHUS UNIVERSITET IODINE IN GROUNDWATER IN DENMARK DENITZA VOUTCHKOVA 7. FEBRUARY 2012 MULTIVARIATE DATA ANALYSIS 6 Other constituents I 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 Geology Distance to coastline Distance to major faults Geology Distance to coastline Distance to major faults I I Hypotheses: Iodine originates from the rock/sediment sea water intrusion upward diffusion of old saltwater

7. AARHUS UNIVERSITET IODINE IN GROUNDWATER IN DENMARK DENITZA VOUTCHKOVA 7. FEBRUARY 2012 IODINE SPECIATION 7 Lab methods development and testing: 1. Inorganic Iodine – IC 2. Total Iodine – ICP-MS 3. Organo-iodine Organo-iodine Inorganic iodine Total iodine Storage experiment: How the Iodide concentration in groundwater sample is affected by: 1. storage conditions – 5ºC,10ºC, freezer 2. 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

8. AARHUS UNIVERSITET IODINE IN GROUNDWATER IN DENMARK DENITZA VOUTCHKOVA 7. FEBRUARY 2012 CASE STUDIES 8 Ishøj Hjelmsølille Purpose: 1. Source - explanation for the observed concentrations 2. Iodine speciation 3. Geochemical analysis 0 meq/l Cl HCO3 SO4 Mg Ca Na+K 11

9. AARHUS UNIVERSITET IODINE IN GROUNDWATER IN DENMARK DENITZA VOUTCHKOVA 7. FEBRUARY 2012 FUTURE PLANS AND POSSIBLE COLLABORATION 9 Medical aspectGeochemical aspect In progress: Case studies Multivariate analysis of Jupiter data National 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

10. AARHUS UNIVERSITET IODINE IN GROUNDWATER IN DENMARK DENITZA VOUTCHKOVA 7. FEBRUARY 2012 10