Svein Reid No rsk institutt for jord- og skogkartlegging (NIJOS)
ATV Jord og Grundvand
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ATV Jord ogGrundvand Naturligt forekommende stoffer i jord eller grundvand og deres sundhedseffekterDenitza VoutchkovaPhD fellowAARHUSUNIVERSITET19. June 2012TITEL P PRSENTATIONNavn Navnesen1. september 2011Iodine in Groundwater in DenmarkImplications for human HealthAUAARHUSUNIVERSITETIodine in Groundwater in DenmarkDenitza Voutchkova19. June 20121Project presentationGeo-Center project, financed by GEUS and AU (2011- 2014)
Project title: Iodine in the hydrological cycle in Denmark: implications for human health
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.
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Sren Munch Kristiansen Birgitte HansenKim Esbensen
Vibeke ErnstsenBrian SrensenAARHUSUNIVERSITETIodine in Groundwater in DenmarkDenitza Voutchkova19. June 20122Presentation outlineIodine essential trace element
Iodine in Denmark
Geochemical aspect
Present workData Method descriptionWorkflow overview Some resultsConclusions
Future plans and perspectives
3AARHUSUNIVERSITETIodine in Groundwater in DenmarkDenitza Voutchkova19. June 20124Iodine essential trace elementtoxicitydeficiencyintakefunctionDose-response of essential trace elementsSafe and adequate intakeRNIULgroupRNI ug/day(WHO)UL ug/day(European commision)UL ug/day(IOM, US)0-5yeras90200-250200-3006-12years120250-45030012-17 years150450-500300-900adults150600 (500)*1100pregnant2006001100* Expert committee on Human Nutrition, Franceregulates the metabolic processes in cells; plays role in the early development of most organsRecommended daily nutrient intake The highest average daily nutrient intake level unlikelyto pose risk of adverse health effectsAARHUSUNIVERSITETIodine in Groundwater in DenmarkDenitza Voutchkova19. June 2012Tolerable upper intake level (UL) refers to the highest average daily nutrient intake level unlikelyto pose risk of adverse health effects to almost all (97.5%) apparently healthy individuals inan age- and sex-specifi c population group.Recommended nutrient intake (RNI) refers to the daily intake which meets the nutrient requirementsof almost all (97.5%) apparently healthy individuals in an age- and sex-specific populationgroup. It is set at the estimated average requirement plus 2 standard deviations.4Iodine in Denmark5Mild iodine deficiency based on median UI = 50-99ug/l (WHO, 2007) Subnational survey data (2 cohorts - Aalborg and Copenhagen; west Denmark moderate; east mild)19982000Voluntary fortification of table salt aiming increase with 50ug/dayProgram failed Mandatory fortification (13mg/kg) of household salt and the salt used for commercial bread productionDanThyr~25% of iodine intake in the Danish diet is derived from drinking water, coffee, tea and other beverages (Rasmussen et al., 2000)Iodine in drinking water in Denmark varies from 0,7ug/l to 140ug/l (Pedersen et al., 1999, Andersen et al., 2002) AARHUSUNIVERSITETIodine in Groundwater in DenmarkDenitza Voutchkova19. June 2012Geochemical aspect6Iodine in groundwater not studies from geochemical point of viewMapping Regional (and/or temporal) variationsUnderstanding the involved processesFinding 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 cycleOrgano-iodine Inorganic iodineTotal iodine AARHUSUNIVERSITETIodine in Groundwater in DenmarkDenitza Voutchkova19. June 20126Present WorkMultivariate data analysis of historical Danish groundwater data
Purpose: to elucidate the iodine source(s) in the sediments, the governing processes of its distribution and variations
Method: exploring correlations between the different data by using PCA and PLS-R
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;
7Other constituentsGeologyDistance to coastlineDistance to major faultsIIs there a correlation?What kind (+/-)?Why?AARHUSUNIVERSITETIodine in Groundwater in DenmarkDenitza Voutchkova19. June 2012Iodine in Groundwater8Number of Iodine* samplesStatus December 2011: 2562 samples
Iodine in groundwater (n=2562) for the period 1933-2011
Iodine concentrations:ug/lug/lug/lug/lug/lAARHUSUNIVERSITETIodine in Groundwater in DenmarkDenitza Voutchkova19. June 20128Workflow overview9RMS20 variables505 objects(some missing values)3Data preparation:Variables exclusionDetection limit handlingGross outliers checkObjects exclusionReduced Master Set, prepared for MVDABackground population453 objectsPCA4bMultivariate analysisRMS3 clusters +Background population4aPCAPLS3 clusters52 objects4c5Interpretation of the MVDAMaster set28 variables:IodineLi, H2S, CH4, O2,Agg. CO2, NVOC, PO4, SO4, NO3, pH, K, Fe, Mn, HCO3, Ca, 2562 objects(many missing values)2Mg, Na, Cl, Fl, B, Ba, Br, Srconduct. redox,distance to coastline,distance to major faultsJupiter raw dataExtraction ofdata from the JUPITER----
DGU numberSample numberScreen numberScreen depthX, Ylab methodsdateGeology26 chemical variables1Data preparationAARHUSUNIVERSITETIodine in Groundwater in DenmarkDenitza Voutchkova19. June 2012The purpose of the Multivariate analysis is to investigate what kind of information we can get out of these data.
As first step Im interested if there are any outliers or if there is grouping of the data because of the different analytical method or the year
The second step is to explore the different variables are related:Iodine and the other constituents taken from jupiter databaseThe type of aquifer where the sample is taken (geology) aquifer type present at more than 50% of the length of the screen; grouped together in so called dummy variables;Distance to coast line and the distance to the faults calculated for each well with ArcGISThere might be other factors which play an important role like: the topsoil type, the wind, the rainfall surplus, the landuse: but for now we dont focus on that;
Is it possible to make a model for predicting iodine concentrations
the software The Unscramble is being used for the multivariate analysis. At the present moment Im working on that and Ill be presenting results in the summer.9PLS-R model
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Background population453 objectsPCA4bRMS3 clusters +Background population4aPCAPLS3 clusters52 objects4c5Interpretation of the MVDA
Partial Least Squares Regression ModelR=0,76 (3 PCs, >70% of the variance)AARHUSUNIVERSITETIodine in Groundwater in DenmarkDenitza Voutchkova19. June 2012Results and Interpretation11LocationWater typeInterpretation based on the Loading Weights plot and Score plot (PC1-PC2)
Iodine Ba HCO3 Br Na Fe SO4Ca K Cl cond.B SrLi NO3 Mn pHfaults coast Mg
Snderborg JammerbugtIshjGladsaxeKbenhavn LejreFrederiksbergAARHUSUNIVERSITETIodine in Groundwater in DenmarkDenitza Voutchkova19. June 2012Conclusions12
It is possible to study the groundwater origin and the processes governing its composition by combining MVDA and traditional hydrogeochemical tools,
Data quality - important issue affecting the outcome of the analysis;
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)
A new factor, not included in the working hypothesis was found: distance to major faultsBased 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: AARHUSUNIVERSITETIodine in Groundwater in DenmarkDenitza Voutchkova19. June 2012Future plans and perspectives3 small scale detailed studies
Ishj, 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)
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