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DENITZA VOUTCHKOVA PHD FELLOW AARHUS UNIVERSITET 19. JUNE 2012 IODINE IN GROUNDWATER IN DENMARK IMPLICATIONS FOR HUMAN HEALTH AU ATV Jord og Grundvand.

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Presentation on theme: "DENITZA VOUTCHKOVA PHD FELLOW AARHUS UNIVERSITET 19. JUNE 2012 IODINE IN GROUNDWATER IN DENMARK IMPLICATIONS FOR HUMAN HEALTH AU ATV Jord og Grundvand."— Presentation transcript:

1 DENITZA VOUTCHKOVA PHD FELLOW AARHUS UNIVERSITET 19. JUNE 2012 IODINE IN GROUNDWATER IN DENMARK IMPLICATIONS FOR HUMAN HEALTH AU ATV Jord og Grundvand Naturligt forekommende stoffer i jord eller grundvand og deres sundhedseffekter

2 AARHUS UNIVERSITET IODINE IN GROUNDWATER IN DENMARK DENITZA VOUTCHKOVA 19. JUNE 2012 PROJECT PRESENTATION Geo-Center project, financed by GEUS and AU ( ) Project title: Project title: Iodine in the hydrological cycle in Denmark: implications for human health Objective: Objective: to combine both the medical and the geochemical aspect by studying the variations in iodine bioavailability in groundwater and to evaluate the human health effects. 2 Søren Munch Kristiansen Birgitte Hansen Kim Esbensen Vibeke Ernstsen Brian Sørensen

3 AARHUS UNIVERSITET IODINE IN GROUNDWATER IN DENMARK DENITZA VOUTCHKOVA 19. JUNE 2012 PRESENTATION OUTLINE Iodine – essential trace element Iodine in Denmark Geochemical aspect Present work Data Method description Workflow overview Some results Conclusions Future plans and perspectives 3

4 AARHUS UNIVERSITET IODINE IN GROUNDWATER IN DENMARK DENITZA VOUTCHKOVA 19. JUNE IODINE – ESSENTIAL TRACE ELEMENT toxicity deficiency intake function Dose-response of essential trace elements Safe and adequate intake RNI UL groupRNI ug/day (WHO) UL ug/day (European commision) UL ug/day (IOM, US) 0-5yeras years years adults (500)*1100 pregnant * Expert committee on Human Nutrition, France regulates the metabolic processes in cells; plays role in the early development of most organs Recommended daily nutrient intake The highest average daily nutrient intake level unlikely to pose risk of adverse health effects

5 AARHUS UNIVERSITET IODINE IN GROUNDWATER IN DENMARK DENITZA VOUTCHKOVA 19. JUNE 2012 IODINE IN DENMARK 5 Mild iodine deficiency Mild iodine deficiency based on median UI = 50-99ug/l (WHO, 2007) Sub national survey data Sub national survey data (2 cohorts - Aalborg and Copenhagen; west Denmark – moderate; east – mild) Voluntary Voluntary fortification of table salt aiming increase with 50ug/day Program failed Mandatory Mandatory fortification (13mg/kg) of household salt and the salt used for commercial bread production DanThyr ~25% drinking water ~25% of iodine intake in the Danish diet is derived from drinking water, coffee, tea and other beverages (Rasmussen et al., 2000 ) 0,7ug/l to 140ug/l Iodine in drinking water in Denmark varies from 0,7ug/l to 140ug/l ( Pedersen et al., 1999, Andersen et al., 2002)

6 AARHUS UNIVERSITET IODINE IN GROUNDWATER IN DENMARK DENITZA VOUTCHKOVA 19. JUNE 2012 GEOCHEMICAL ASPECT 6 Iodine in groundwater – not studies from geochemical point of view Mapping Regional (and/or temporal) variations Understanding the involved processes Finding the source/sources of iodine in the groundwater in Denmark Available historical data : From groundwater monitoring programs (mainly GRUMO wells); Iodine is not part of the waterworks monitoring; Iodine speciation – important for the geochemical understanding of the Iodine cycle Organo-iodine Inorganic iodine Total iodine

7 AARHUS UNIVERSITET IODINE IN GROUNDWATER IN DENMARK DENITZA VOUTCHKOVA 19. JUNE 2012 PRESENT WORK Multivariate data analysis of historical Danish groundwater data Purpose: Purpose: to elucidate the iodine source(s) in the sediments, the governing processes of its distribution and variations Method: Method: exploring correlations between the different data by using PCA and PLS-R Hypotheses testing: Hypotheses testing: Iodine enrichment: is originating from marine deposits and infiltrating seawater nearby the present coastline; is due to desorption of iodine from old Cretaceous marine deposits; 7 Other constituents Geology Distance to coastline Distance to major faults Other constituents Geology Distance to coastline Distance to major faults I I Is there a correlation? What kind (+/-)? Why?

8 AARHUS UNIVERSITET IODINE IN GROUNDWATER IN DENMARK DENITZA VOUTCHKOVA 19. JUNE 2012 IODINE IN GROUNDWATER 8 Number of Iodine* samples Status December 2011: 2562 samples Iodine in groundwater (n=2562) for the period Iodine concentrations: ug/l

9 AARHUS UNIVERSITET IODINE IN GROUNDWATER IN DENMARK DENITZA VOUTCHKOVA 19. JUNE 2012 WORKFLOW OVERVIEW 9 RMS 20 variables 505 objects (some missing values) 3 Data preparation: 1. Variables exclusion 2. Detection limit handling 3. Gross outliers check 4. Objects exclusion Reduced Master Set, prepared for MVDA Background population 453 objects PCA 4b Multivariate analysis RMS 3 clusters + Background population 4a PCA PLS 3 clusters 52 objects 4c 5 Interpretation of the MVDA Master set 28 variables: Iodine Li, H 2 S, CH 4, O 2, Agg. CO 2, NVOC, PO 4, SO 4, NO 3, pH, K, Fe, Mn, HCO 3, Ca, 2562 objects (many missing values) 2 Mg, Na, Cl, Fl, B, Ba, Br, Sr conduct. redox, distance to coastline, distance to major faults Jupiter raw data Extraction of data from the JUPITER ---- DGU number Sample number Screen number Screen depth X, Y lab methods date Geology 26 chemical variables 1 Data preparation

10 AARHUS UNIVERSITET IODINE IN GROUNDWATER IN DENMARK DENITZA VOUTCHKOVA 19. JUNE 2012 PLS-R MODEL 10 Background population 453 objects PCA 4b RMS 3 clusters + Background population 4a PCA PLS 3 clusters 52 objects 4c 5 Interpretation of the MVDA P artial L east S quares R egression Model R²=0,76 (3 PCs, >70% of the variance)

11 AARHUS UNIVERSITET IODINE IN GROUNDWATER IN DENMARK DENITZA VOUTCHKOVA 19. JUNE 2012 RESULTS AND INTERPRETATION 11 Location Water type Interpretation based on the Loading Weights plot and Score plot (PC1-PC2) Iodine Ba HCO 3 Br Na Fe SO 4 Ca K Cl cond. B Sr Li NO 3 Mn pH faults coast Mg Sønderborg Jammerbugt Ishøj Gladsaxe København Lejre Frederiksberg

12 AARHUS UNIVERSITET IODINE IN GROUNDWATER IN DENMARK DENITZA VOUTCHKOVA 19. JUNE 2012 CONCLUSIONS 12 It is possible to study It is possible to study the groundwater origin and the processes governing its composition by combining MVDA and traditional hydrogeochemical tools, Data quality Data quality - important issue affecting the outcome of the analysis; It was not possible It was not possible to build satisfactory model explaining iodine concentrations based on all samples and the 20 variables Variables important for explaining the variation in iodine concentration were found (and will be used in next studies) distance to major faults A new factor, not included in the working hypothesis was found: distance to major faults not possible Based on the PLS model (46 samples) it was not possible to reject the two hypotheses. desorption from the sediment and saline water are possible contributors; breakdown of organic might contribute too. Geochemical processes releasing Iodine to groundwater:

13 AARHUS UNIVERSITET IODINE IN GROUNDWATER IN DENMARK DENITZA VOUTCHKOVA 19. JUNE 2012 FUTURE PLANS AND PERSPECTIVES 3 small scale detailed studies Ishøj, Randers, Skagen designing a sampling and experimental campaign Hydrogeochemical aspect: sources and processes on a smaller scale Improved control over data quality Relation to existing epidemiological studies National study on Iodine in drinking water sampling from drinking water wells reflecting different geological regions, the waterworks size, and the administrative division of Denmark; speciation, water composition mapping and MVDA combined study with data from medical registers (spatial correlations with IDD occurrence, specific drug use, or other iodine related health issue) 13


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