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Fate and exposure assessment of PCDD/Fs at contaminated sites
Umeå University, Faculty of Science and Technology, Chemistry.
Responsible organisation
2008 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzo-furans (PCDFs) belong to the most toxic compounds known to science and they are defined as Persistent Organic Pollutants (POPs) under the Stock-holm Convention. The general human exposure to PCDD/Fs is primarily through dietary intake. The importance of contaminated sites as secondary PCDD/F sources (i.e. sources that once received its contamination from a primary source) are getting increased attention. To be able to assess the risks for human exposure at PCDD/F contaminated sites, the environmen-tal distribution of PCDD/Fs and the potential mobilization between dif-ferent environmental media (e.g. food chain transfer) must be known. The primary aim of the work presented in this thesis was to investigate human exposure pathways associated with PCDD/F contaminated sites by combining field measurements and modeling. Site specific field measurements were made at a PCDD/F contaminated site in Sweden and multimedia modeling scenarios were evaluated against site specific data and national reference data.

The results show that the congener distributions in exposure media affected by contaminated soil may differ significantly from the distribu-tions found in media from reference locations. Higher chlorinated PCDD/Fs may be transferred into food chains where they contribute to a large fraction of the toxic equivalent concentration (TEQ). Ingestion of locally produced animal food may be an important exposure pathway al-ready at low or moderate PCDD/F soil concentrations. However, the con-gener composition of the source is critical for the exposure. The signifi-cance of the individual exposure routes varies depending on e.g. the spatial distribution and magnitude of the soil contamination, the pro-perties of the exposure media and the human behavior. Multimedia mo-deling can be used in risk assessments as long as model algorithms and model parameters are representative for the superhydrophobic properties of PCDD/Fs. However, selection of physical-chemical PCDD/F properties is a challenge due to large variation in reported values. For some proper-ties, data is scattered or completely lacking

Place, publisher, year, edition, pages
Umeå: Kemi , 2008. , 44 p.
Keyword [en]
contaminated sites, dioxins, PCDD/F, exposure, food chain, modeling, risk assessment, physical-chemical properties
Keyword [sv]
förorenade områden, dioxiner, PCDD/F, exponering, födokedja, modellering, riskbedömning, fysikaliska-kemiska egenskaper
National Category
Environmental Sciences
URN: urn:nbn:se:umu:diva-5717ISBN: 978-91-7264-660-5OAI: diva2:145336
Available from: 2009-03-25 Created: 2009-03-25 Last updated: 2009-03-25Bibliographically approved
List of papers
1. Exposure assessment at a PCDD/F contaminated site in Sweden: field measurements of exposure media and serum analysis
Open this publication in new window or tab >>Exposure assessment at a PCDD/F contaminated site in Sweden: field measurements of exposure media and serum analysis
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2010 (English)In: Environmental science and pollution research international, ISSN 0944-1344, E-ISSN 1614-7499, Vol. 17, no 1, 26-39 p.Article in journal (Refereed) Published
Abstract [en]

BACKGROUND, AIM, AND SCOPE: The main pathway for human exposure to the highly toxic polychlorinated-p-dioxins and polychlorinated furans [polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs)] is via dietary intake. Other exposure pathways may, however, be important in close proximity to point sources, such as wood preservation sites, where PCDD/F contaminated chlorophenols (CP) were previously used. In this study, a heavily PCDD/F contaminated CP saw mill site in Sweden was investigated. Human exposure through a broad spectrum of exposure pathways was assessed. Such studies are in demand since the question whether contaminated sites represent a current or future risk can only be answered by detailed site-specific risk assessments. MATERIALS AND METHODS: Sampling of exposure media (soil, air, groundwater, raspberries, carrots, potatoes, grass, milk, eggs, and chicken fodder) was made. Exposure media concentrations and congener distribution patterns were used to investigate the mobilization of PCDD/Fs from soil to the environment and to calculate exposure levels for adults. Blood serum levels from site-exposed and control individuals were also analyzed. RESULTS: Congener distribution patterns at the site were generally dominated by a specific marker congener (1234678-HpCDF), which is highly abundant in the polluted soil. The dioxin toxic equivalents (TEQ) concentrations were notably elevated as compared to national reference samples for most exposure media, and the marker congener was a major contributor to increased TEQ levels. There were also indications of soil-to-air volatilization of tetra- and penta-CDD/Fs. People who participated in the restoration of a contaminated building showed higher levels of 1234678-HpCDF compared to controls, and calculated exposure levels suggest that several site-specific exposure routes may be of importance for the daily intake of PCDD/F. CONCLUSIONS, RECOMMENDATIONS, AND PERSPECTIVES: Despite low mobility of higher chlorinated PCDD/Fs, these contaminants were transferred from the polluted soil to the surroundings and into human tissue. The extent of increased exposure from contaminated sites depends on the PCDD/F source strength of the soil, composition of the pollution, human activities, and dietary patterns of the residents. Impact from the contaminated soil on other exposure media was seen also for areas with low to moderate soil contamination. In the future, not only the levels of PCDD/F soil pollution but also the composition must be considered in risk assessments of contaminated sites.

Place, publisher, year, edition, pages
Berlin / Heidelberg: Springer, 2010
Ambient air, Biotransfer, Chlorophenol, Contaminated soil, Cow’s milk, Dioxins, Exposure, Food chain, Grass, Groundwater, Human exposure, Indoor air, PCDD/F, Root-crops, Serum, Soil
urn:nbn:se:umu:diva-5718 (URN)10.1007/s11356-009-0223-4 (DOI)000273311100004 ()19641944 (PubMedID)
Available from: 2009-03-25 Created: 2009-03-25 Last updated: 2016-06-03Bibliographically approved
2. Model Selection and Evaluation for Risk Assessment of Dioxin-contaminated Sites
Open this publication in new window or tab >>Model Selection and Evaluation for Risk Assessment of Dioxin-contaminated Sites
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2007 (English)In: AMBIO: A Journal of the Human Environment, Vol. 36, no 6, 458-66 p.Article in journal (Refereed) Published
Abstract [en]

The general European population has a total intake of dioxins and dioxin-like chemicals near the limit recommended by the European Union, making additional exposure above background levels undesirable. For populations living near dioxin-contaminated sites, additional exposure may occur by intake of locally produced food, inhalation of particles, dermal contact with soils, or other exposure pathways. Risk assessment tools are required to estimate risks associated with contaminated sites and to set priorities for site remediation. Here, we review several multimedia models that can be applied as tools to support risk assessment. We then present a strategy to select, apply, evaluate, and adapt a model to address a specific situation. The case study we consider is a risk assessment of generic background dioxin exposure in Sweden, and we compare the predictions with environmental observations and exposure data from Sweden. Arguments are presented for selecting the CalTOX model for this case study. We demonstrate the application, evaluation, and adaptation of the model and discuss the requirements for extending the analysis to conduct risk assessment for subpopulations living near dioxin-contaminated sites.

urn:nbn:se:umu:diva-16879 (URN)doi:10.1579/0044-7447(2007)36[458:MSAEFR]2.0.CO;2 (DOI)
Available from: 2007-10-18 Created: 2007-10-18Bibliographically approved
3. Physical-Chemical Property Data for Dibenzo-p-dioxin (DD), Dibenzofuran (DF), and Chlorinated DD/Fs: A Critical Review and Recommended Values
Open this publication in new window or tab >>Physical-Chemical Property Data for Dibenzo-p-dioxin (DD), Dibenzofuran (DF), and Chlorinated DD/Fs: A Critical Review and Recommended Values
2008 (English)In: Journal of Physical and Chemical Reference Data, ISSN 0047-2689, Vol. 37, no 4, 1997-2008 p.Article in journal (Refereed) Published
Abstract [en]

Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are of global concern due to their persistence, their tendency to bioaccumulate, and their extremely high toxicity. The fate of the PCDD/Fs in the environment is largely determined by their physical-chemical properties, such as solubility in water (SW, mol  m-3), solubility in octanol (SO, mol  m-3), and vapor pressure (P, Pa). It is not unusual that the range of reported values for a given property varies over several orders of magnitude, especially for the highly chlorinated congeners, and consequently, it is a challenge to select physical-chemical property data from the literature for use in chemical fate and risk assessments. In the current study, physical-chemical property data [P, SW, SO, Henry's law constant (H), partitioning coefficients between octanol-water (KOW) and octanol-air (KOA)] for 15 DDs and 17 DFs at 293-299  K are compiled from the literature and evaluated to select literature derived values that are then adjusted to conform to thermodynamic constraints using a least-squares adjustment procedure. We also present an analysis of available data on internal energies of phase change (UA, UW, UO, UOW, UAW, UOA) at 298  K, which describe the temperature dependence of the partitioning properties. The final adjusted values (FAVs) derived from this study are recommended as physical-chemical property data for PCDD/Fs for use in environmental fate modeling. The FAVs for internal energies of phase change can be used as a first approximation for estimating properties at temperatures other than 298  K.

aqueous solubility, Henry's law constant, internal energy of phase change, octanol solubility, octanol-air partition coefficient, octanol-water partition coefficient, PCDD/F, physical-chemical properties, polychlorinated dibenzofurans, polychlorinated dibenzo-p-dioxins, vapor pressure
urn:nbn:se:umu:diva-18994 (URN)10.1063/1.3005673 (DOI)
Available from: 2009-03-03 Created: 2009-03-03 Last updated: 2010-02-09

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