NATURAL IODINE CONTENT IN DRINKING WATER (

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NATURAL IODINE CONTENT IN DRINKING WATER (
GROUNDWATER) IN DENMARK
AU

• DENITZA D. VOUTCHKOVA
• PhD DEFENCE

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PROJECT, FUNDING, PARTICIPANTS
PhD dissertation

• Part of GEOCENTER project Iodine in the
  hydrological cycle in Denmark implications for
  human health
• Funded by the Geological Survey of Denmark and
  Greenland (GEUS) and Aarhus University (AU)
• Financial support also from the International
  Medical Geology Association (IMGA) and the
  International Registry of Pathology (IRP)
  Gardner Research Grant
• Project participants and collaborators Søren M.
  Kristiansen Birgitte Hansen, Vibeke Ernstsen,
  Brian L. Sørensen, Kim H. Esbensen, Chaosheng
  Zhang

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PRESENTATION OUTLINE

• Background
• PhD objectives
• Iodine in groundwater Paper 1, 3 4
• Iodine in drinking water Paper 2 Technical
  Note 1
• General conclusion

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background

• Part 1

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Why Iodine?
WHO region Europe

• Iodine plays an essential role in human
  metabolism and the early development 1
• Iodine deficiency is the single most important
  preventable cause of brain damage 2
• Insufficient iodine intake ? 43.9 (30.5million)
  of 612 years old children AND 44.2 (393.1
  millions) of the general population in WHO Europe
  region 3

1 WHO, Iodine Deficiency in Europe A
continuing public health problem, M. Andersson,
et al., Editors. 2007, World Health Organization,
UNICEF France. p. 1-86. 2 WHO, Assessment of
iodine deficiency disorders and monitoring their
elimination a guide for programme managers.
3rd ed., 2007, World Health Organization
Switzerland p. 97. 3 Zimmermann, M.B. and
Andersson, M., Update on iodine status worldwide.
Current Opinion in Endocrinology, Diabetes and
Obesity, 2012. 19(5) p. 382-387.
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Iodine Status of Danish Population
55 tap water samples

• The last national survey on iodine status of
  Danish population - 1969 2
• Correlation between tap water collected 1999 and
  the UI data from 1969 (r0.68, plt0.01) 1
• USI programme ? 1996 decision, 1998 voluntary,
  2000 mandatory
• DanThyr ? 2 cohorts covering the main difference
  in levels of iodine intake in Denmark caused by
  different levels of iodine in groundwater 3

1 Pedersen, K.M., Laurberg, P., Nøhr, S.,
Jørgensen, A., and Andersen, S., Iodine in
drinking water varies by more than 100-fold in
Denmark. Importance for iodine content of infant
formulas. European Journal of Endocrinology,
1999. 140(5) p. 400-403. 2 Munkner T. Urinary
excretion of 127-iodine in the Danish population.
Scand J Clin Lab Invest 1969110134. 3
Laurberg, P., Jørgensen, T., Perrild, H., Ovesen,
L., Knudsen, N., Pedersen, I.B., Rasmussen, L.B.,
Carlé, A., and Vejbjerg, P., The Danish
investigation on iodine intake and thyroid
disease, DanThyr Status and perspectives.
European Journal of Endocrinology, 2006. 155(2)
p. 219-228.
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Iodine Intake
Recommended daily nutrient intake (RNI) for iodine 1 Recommended daily nutrient intake (RNI) for iodine 1
   
Age group RNI (µg/day)
0-59 months 90
6-12 years 120
12-17 years 150
Adults 150
Pregnancy/lactation 250
?!
Temporal and Spatial Variation Bioavailability Goi
trogens and other factors
1 WHO, Iodine Deficiency in Europe A
continuing public health problem, M. Andersson,
et al., Editors. 2007, World Health Organization,
UNICEF France. p. 1-86. 2 Pedersen, A.N.,
Fagt, S., Groth, M.V., Christensen, T.,
Biltoft-Jensen, A., Matthiessen, J., Andersen,
N.L., Kørup, K., Hartkopp, H., Ygil, K.H.,
Hinsch, H.J., Saxholt, E., and Trolle, E.,
Danskernes kostvaner 2003 - 2008, 2010, DTU
Fødevareinstituttet. p. 1-200
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Drinking Water Supply in Denmark

• Treated groundwater
• Simple treatment mainly
• Decentralised structure

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1 Jupiter database , status December 2012
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Geology Groundwater
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Iodine Cycle
5 µg/L
50-60 µg/L
Total Iodine Iodide Iodate Org. Iodine
No data
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PHD OBJECTIVES

• To map iodine concentration and speciation in DW
  and GW
• To study the spatial patterns and to elucidate
  the governing factors
• To evaluate the importance of the spatial
  variation of DW iodine to the populations
  nutrition

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Iodine in Groundwater

• Part 3

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Paper overview (objectives)

• Paper I Iodine concentrations in Danish
  groundwater historical data assessment 1933-2011
  (published in Environmental Geochemistry and
  Health)
• To give overview on the existing gw iodine data
  with focus on spatial variation, geological
  setting, depth of extraction
• To identify geochemical associations between
  iodine and other variables in order to elucidate
  the governing factors for the spatial variation
• Paper 3 Hydrogeochemical characterisation of
  Danish groundwater in relation to iodine
• Paper 4 High resolution depth profiles of iodine
  concentrations in groundwater at fours
  multiscreen wells in Denmark possibilities for
  future research

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Paper 1 Data Methodology

• Source Jupiter database (November 2011)
• Master dataset (MDS) 2562 x 28
• MDS is characterised by
• missing values
• diversity in the data quality different
• lab methods
• Preparation and pre-treatment
• Detection limits
• Excluding variables and samples
• Missing values
• Centred log-ratio transformation (clr)
• Reduced MDS (r-MDS) 506 x 20
• Principle Component Analysis

Iodine 1933 2011 (n2562)
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Paper 1 Univariate data analysis

• Iodine concentrations
• ltd.l. to 1220 µg/L
• 90 of the samples lt20 µg/L
• 11 samples gt200 µg/L
• Mean 13.83µg/L Median 5.4 µg/L
• Spatial variation
• Large scale trend-gt Capital Region vs. Central
  Denmark (26.81 vs. 7.6 µg/L)
• Small scale heterogeneity
• Depth 40-80 mbt
• Dominating setting at depth of extraction (some
  information about 70 of the samples)

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Paper 1 Multivariate analysis

• Iodine, Li, B, Ba, Br are exhibiting similar
  variability, suggesting common source
• Saline water influence, further studies needed in
  order to specify
• Based on the PC1-PC2 score plot -gt high iodine is
  associated mainly with reduced and alkaline
  groundwater (Ca-HCO3 dominated gw)

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Paper 3

• Despite the same geology at local scale (0.1-0.2
  km and 5-10 km) TI varied
• Speciation -gt reflects the prevailing reduced
  conditions
• The processes governing iodine concentration are
  site and depth specific
• TI at different concentration levels governed by
  different processes

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Paper 4
2,5m depth lacustrine gyttja

• GRUMO iodine included since 2011

2,2-7,1µg/L
1-4,2 µg/L
2,2-25 µg/L
2-48 µg/L
Glacial melt-water aquifers
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Iodine in Drinking water

• Part 2

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Paper overview (objectives)

• Paper 2 Assessment of spatial variation in
  drinking water iodine and its implications for
  dietary intake A new conceptual model (published
  in Science of the Total Environment)
• To identify spatial trends, clusters and/or
  outliers for iodine concentration and speciation
  and factors governing it
• To propose a new conceptual model, while
  illustrating the importance of the chosen
  generalisation for future studies
• To estimate the contribution of drinking water to
  the dietary iodine intake
• Technical Note 1 Design of a nationwide
  drinking-water sampling campaign for assessment
  of dietary iodine intake and human health
  outcomes

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Paper 2 Study design

• Criteria for choosing around 180 sampling
  locations
• Jupiter data on gw abstraction location
• Largest in each municipality
• Largest in each grid cell

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Paper 2 Iodine concentration speciation

• The waterworks were involved in the sampling
• From the updated list (n189)
• Positive 80 (n152)
• Negative 2 (n4)
• No answer n33
• Samples received at the lab (n144)
• 175 mio m3/year

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Paper 2 Governing factors

• Limitations
• Mixing of different water types
• Pumping strategies
• Groundwater treatment
• Treatment
• Advanced treatment n14
• Only aeration n2
• Aeration sand filter(s) the rest
• Possible effects from the treatment
• Organic ? inorganic iodine
• Iodine lost to the atmosphere (I2)
• Iodine removal in the treatment against ferrous
  iron

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Paper 2 Spatial autocorrelation analysis
Local Morans I
a
a Zhang C, Luo L, Xu W, Ledwith V. Use of local
Moran's I and GIS to identify pollution hotspots
of Pb in urban soils of Galway, Ireland. Science
of the Total Environment 2008 398 212-221
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Paper 2 Method of generalisation
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Paper 2 Contribution to dietary intake
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General Conclusion

• Main findings
• Iodine concentration
• GW from lt d.l. up to 14,5 mg/L
• DW from ltd.l. up to 126 µg/L (could be even
  higher)
• Iodine speciation
• GW mainly iodide and DOI (reduced gw)
• DW 6 different combinations
• Spatial pattern
• GW both large scale trends and small (local)
  scale heterogeneity
• DW complex multiple governing factors
• Importance to populations nutrition
• Estimated contribution to dietary intake from 0
  to gt100 of RNI in different parts of the country
• Jutland the biggest variation

• Project Goals
• To map iodine concentration and speciation in DW
  and GW
• To study the spatial patterns and to elucidate
  the governing factors
• To evaluate the importance of the spatial
  variation of DW iodine to the populations
  nutrition

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Thank you for listening! Questions?
Denitza Voutchkova ddv_at_geo.au.dk
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How special is Denmark?

• Iodine intake from drinking water
• Groundwater vs. surface water vs. bottled water
• Registers

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1  Map created by P.Engstrom K.Brauman. Data
BGR UNESCO (2008) Groundwater Resources of the
World 1 25 000 000. Hannover, Paris. Via
http//ensia.com/features/groundwater-wake-up/ 2
WHO 2006 Protecting Groundwater for Health
Managing the Quality of Drinking-water sources.
http//www.who.int/water_sanitation_health/publica
tions/PGWsection1.pdf?ua1
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Is there really a connection between drinking
water iodine and the iodine status of the
population?

• China, Denmark
• Bioavailability?
• How to do it
• Supply area map ?
• Drinking water data
• Exposure from drinking water
• Correlation between IDD distribution and exposure