Using GIS in Exposure assesment to study health effects of Hazardous Waste Sites in Slovakia 1 Trnava University,Faculty of Health and Social Work, Department of Hygiene and Epidemiology,Trnava, Slovakia 2 University of Southern Denmark, Health Promotion Unit, Esbjerg, Denmark Marek Majdan 1, Gabriel Gulis 1,2 ISEE, New Challenges of Environmental Health, 9-11 June, 2005 Budapest

Objectives To show the possibility and relevance of using GIS as a tool to asses the exposure in studies of health effects of hazardous waste sites To show the possibility and relevance of using GIS as a tool to asses the exposure in studies of health effects of hazardous waste sites To discuss the advantages and limitations of this method To discuss the advantages and limitations of this method To demonstrate our methodology on a case of a HWS in Slovakia and its impact on the incidence of low birthweights in the surrounding area To demonstrate our methodology on a case of a HWS in Slovakia and its impact on the incidence of low birthweights in the surrounding area ISEE, New Challenges of Environmental Health, 9-11 June, 2005 Budapest

Background The hazardous waste sites (HWS) are a potential source of hazardous substances and therefore a potential threat for the health of people working on them and living nearby The hazardous waste sites (HWS) are a potential source of hazardous substances and therefore a potential threat for the health of people working on them and living nearby There is a lack of specific research done in this field of environmental health in Slovakia There is a lack of specific research done in this field of environmental health in Slovakia The results of studies conducted in the UK and in the USA confirm that research in this field is of high relevance The results of studies conducted in the UK and in the USA confirm that research in this field is of high relevance We decided to set up a methodology for such research in the environment and conditions of Slovakia We decided to set up a methodology for such research in the environment and conditions of Slovakia ISEE, New Challenges of Environmental Health, 9-11 June, 2005 Budapest

Methods Step 1-to seek for HWS which might pose a threat for the health of Step 1-to seek for HWS which might pose a threat for the health of the people Step 2-health outcome and exposure assesment Step 2-health outcome and exposure assesment Step 3-to analyze the data and to calculate the risk (OR) Step 3-to analyze the data and to calculate the risk (OR) Step 4-to interprete the results properly Step 4-to interprete the results properly ISEE, New Challenges of Environmental Health, 9-11 June, 2005 Budapest

Step 1-to seek There are officially 13 HWS operating in Slovakia There are officially 13 HWS operating in Slovakia Many old, forgotten HWS which were not properly closed up and are not officially in use anymore Many old, forgotten HWS which were not properly closed up and are not officially in use anymore We choosed one of these sites – a HWS near a former nickel refinery to demonstrate the steps of our methodology We choosed one of these sites – a HWS near a former nickel refinery to demonstrate the steps of our methodology ISEE, New Challenges of Environmental Health, 9-11 June, 2005 Budapest

Methods Step 1-to seek for HWS which might pose a threat for the health of the people Step 1-to seek for HWS which might pose a threat for the health of the people Step 2-health outcome and exposure assesment Step 2-health outcome and exposure assesment Step 3-to analyze the data and to calculate the risk (OR) Step 3-to analyze the data and to calculate the risk (OR) Step 4-to interprete the results properly Step 4-to interprete the results properly ISEE, New Challenges of Environmental Health, 9-11 June, 2005 Budapest

Step 2-Health outcome Low birth weight (below 2500g) as a negative health outcome Low birth weight (below 2500g) as a negative health outcome A dataset of birth weights in Slovakia for the period of A dataset of birth weights in Slovakia for the period of One record: One record:  Name of the place of living of the mother  Birth weight of her newborn  Age of the mother  Number of children in the pregnancy ISEE, New Challenges of Environmental Health, 9-11 June, 2005 Budapest

Step 2-exposure assesment The exposure assesment using the GIS as a tool is based on the distance from the HWS The exposure assesment using the GIS as a tool is based on the distance from the HWS Additional Exposure data Additional Exposure data  Individual measurements  Air and water pollution data  Surrogate exposure data (cytogenetic measurements) In our model case we found these additional exposure data: In our model case we found these additional exposure data:  Measurements of ambient air pollution in teh area of the HWS (heavy metals)  Measurements of dust sediments and their analyses on heavy metals  Measurements of ground water pollution in the area of the HWS ISEE, New Challenges of Environmental Health, 9-11 June, 2005 Budapest

Methods Step 1-to seek for HWS which might pose a threat for the health of the people Step 1-to seek for HWS which might pose a threat for the health of the people Step 2-health outcome and exposure assesment Step 2-health outcome and exposure assesment Step 3-to analyze the data and to calculate the risk (OR) Step 3-to analyze the data and to calculate the risk (OR) Step 4-to interprete the results properly Step 4-to interprete the results properly ISEE, New Challenges of Environmental Health, 9-11 June, 2005 Budapest

Step 3-to analyze We created 3 circle-zones of exposure around the HWS in Sered using the GIS with the diameters of 5, 10 and 15 km We created 3 circle-zones of exposure around the HWS in Sered using the GIS with the diameters of 5, 10 and 15 km We took out the records which refered to one of the places included in these zones from our birthweight dataset We took out the records which refered to one of the places included in these zones from our birthweight dataset We devided this extracted dataset into three datasets which refered to three zones of exposure We devided this extracted dataset into three datasets which refered to three zones of exposure We assumed that in the zone 1 – the closest to the HWS there is the biggest exposure We assumed that in the zone 1 – the closest to the HWS there is the biggest exposure ISEE, New Challenges of Environmental Health, 9-11 June, 2005 Budapest

Step 3-to analyze We conducted a cross-sectional study considering low bithweight newborns (under 2500g) to be our cases and normal birtweight newborns (more than 2500g) to be our controls We conducted a cross-sectional study considering low bithweight newborns (under 2500g) to be our cases and normal birtweight newborns (more than 2500g) to be our controls The records refering to twin-newborns were excluded and settlements which area intersected by one of the zone-borderlines as well The records refering to twin-newborns were excluded and settlements which area intersected by one of the zone-borderlines as well We calculated the Odds Ratio of We calculated the Odds Ratio of  Zone 1 vs zone 2  Zone 1 vs zone 3  Zone 2 vs zone 3 ISEE, New Challenges of Environmental Health, 9-11 June, 2005 Budapest

Table 1: Number of cases and controls in the exposure zones Exposure zone Number of LBW children (cases) Number of NBW children (controls) Sum Zone Zone Zone ISEE, New Challenges of Environmental Health, 9-11 June, 2005 Budapest

Table 2: Odds Ratio of the relationships of cases and controls in the exposure zones Relationship Odds Ratio CI 95% P-value Zone 1:Zone 2 1,220,87-1,700,238 Zone 1:Zone 3 0,920,66-1,270,598 Zone 2:Zone 3 0,760,54-1,060,094 ISEE, New Challenges of Environmental Health, 9-11 June, 2005 Budapest

Methods Step 1-to seek for HWS which might pose a threat for the health of the people Step 1-to seek for HWS which might pose a threat for the health of the people Step 2-health outcome and exposure assesment Step 2-health outcome and exposure assesment Step 3-to analyze the data and to calculate the risk (OR) Step 3-to analyze the data and to calculate the risk (OR) Step 4-to interprete the results properly Step 4-to interprete the results properly ISEE, New Challenges of Environmental Health, 9-11 June, 2005 Budapest

Step 4-Interpretation The results of our model case suggest that the residence near the HWS is a risk factor for developing a low birthweight newborn when comparing to teh areas furtherfrom the HWS The results of our model case suggest that the residence near the HWS is a risk factor for developing a low birthweight newborn when comparing to teh areas furtherfrom the HWS The results are not statistically significant though The results are not statistically significant though We must consider different factors which may confound the result and make the interpretetion complicated and unclear We must consider different factors which may confound the result and make the interpretetion complicated and unclear ISEE, New Challenges of Environmental Health, 9-11 June, 2005 Budapest

Step 4-Interpretation Confounding factors: Confounding factors:  Socio-economical (income, marrital status, education level)  Individual (lifestyle, age, occupational exposure)  Environmental (other sources of pollution in the area) Data quality: Data quality:  The exact address of the mother (street, number,zip code) would make this exposure assesment methodology more appropriate and valid ISEE, New Challenges of Environmental Health, 9-11 June, 2005 Budapest

Conclusions Because of the lack of detailed data for exposure assesment the methodology using the distance of the residence as a basic for exposure may be in the conditions of Slovakia appropriate Because of the lack of detailed data for exposure assesment the methodology using the distance of the residence as a basic for exposure may be in the conditions of Slovakia appropriate In this methodology the GIS are very usefull and can help in the exposure assesment procedure and also can help to calculate and interprete the results In this methodology the GIS are very usefull and can help in the exposure assesment procedure and also can help to calculate and interprete the results Detailed geographical data and additional data which will make the exposure assesment more valid are neccessary Detailed geographical data and additional data which will make the exposure assesment more valid are neccessary ISEE, New Challenges of Environmental Health, 9-11 June, 2005 Budapest