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Publications (3 of 3) Show all publications
Gennings, C., Shu, H., Rudén, C., Öberg, M., Lindh, C., Kiviranta, H. & Bornehag, C.-G. (2018). Incorporating regulatory guideline values in analysis of epidemiology data. Environment International, 120, 535-543
Open this publication in new window or tab >>Incorporating regulatory guideline values in analysis of epidemiology data
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2018 (English)In: Environment International, ISSN 0160-4120, E-ISSN 1873-6750, Vol. 120, p. 535-543Article in journal (Refereed) Published
Abstract [en]

Fundamental to regulatory guidelines is to identify chemicals that are implicated with adverse human health effects and inform public health risk assessors about acceptable ranges of such environmental exposures (e.g., from consumer products and pesticides). The process is made more difficult when accounting for complex human exposures to multiple environmental chemicals. Herein we propose a new class of nonlinear statistical models for human data that incorporate and evaluate regulatory guideline values into analyses of health effects of exposure to chemical mixtures using so-called 'desirability functions' (DFs). The DFs are incorporated into nonlinear regression models to allow for the simultaneous estimation of points of departure for risk assessment of combinations of individual substances that are parts of chemical mixtures detected in humans. These are, in contrast to published so-called biomonitoring equivalent (BE) values and human biomonitoring (HBM) values that link regulatory guideline values from in vivo studies of single chemicals to internal concentrations monitored in humans. We illustrate the strategy through the analysis of prenatal concentrations of mixtures of 11 chemicals with suspected endocrine disrupting properties and two health effects: birth weight and language delay at 2.5 years. The strategy allows for the creation of a Mixture Desirability Function i.e., MDF, which is a uni-dimensional construct of the set of single chemical DFs; thus, it focuses the resulting inference to a single dimension for a more powerful one degree-of-freedom test of significance. Based on the application of this new method we conclude that the guideline values need to be lower than those for single chemicals when the chemicals are observed in combination to achieve a similar level of protection as was aimed for the individual chemicals. The proposed modeling may thus suggest data-driven uncertainty factors for single chemical risk assessment that takes environmental mixtures into account.

Keywords
Environmental chemicals, Mixtures, Cumulative risk assessment
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:su:diva-162888 (URN)10.1016/j.envint.2018.08.039 (DOI)000448688500055 ()30170308 (PubMedID)
Available from: 2018-12-21 Created: 2018-12-21 Last updated: 2022-02-26Bibliographically approved
Koponen, J., Winkens, K., Airaksinen, R., Berger, U., Vestergren, R., Cousins, I. T., . . . Kiviranta, H. (2018). Longitudinal trends of per- and polyfluoroalkyl substances in children's serum. Environment International, 121, 591-599
Open this publication in new window or tab >>Longitudinal trends of per- and polyfluoroalkyl substances in children's serum
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2018 (English)In: Environment International, ISSN 0160-4120, E-ISSN 1873-6750, Vol. 121, p. 591-599Article in journal (Refereed) Published
Abstract [en]

Studies suggest negative health impacts from early life exposure to per- and polyfluoroalkyl substances (PFASs). However, information on longitudinal exposure to PFASs during childhood is scarce for background-exposed individuals. This study sought to fill this gap by investigating children's longitudinal exposure trends through measurement of PFAS serum concentrations and calculation of body burdens (mu g, total in body). Blood of 54 Finnish children was sampled 2005-2015 and analyzed for 20 PFASs at 1, 6 and 10.5 years of age. The body burden was calculated by multiplying the serum concentration by the volume of distribution and the bodyweight for each individual. Associations between serum concentrations or body burdens and parameters, such as sex, breastfeeding duration, body mass index as well as indoor dust and air PFAS concentrations, were evaluated. Serum concentrations of perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorohexane sulfonic acid (PFHxS) decreased significantly (p < 0.001) with age. In contrast to serum concentrations, body burdens stayed unchanged or even increased significantly (p < 0.05), except for PFOA in female children. Breastfeeding duration was positively correlated (p < 0.001) with serum concentrations of PFHxS, PFOS, PFOA and PFNA at 1 year of age. Some associations were found at 10.5 years with sex and indoor PFAS concentrations. Observations of longitudinal decreasing trends of serum concentrations can be misleading for understanding exposure levels from external media during childhood, as the serum concentration is influenced by parallel temporal changes and growth dilution. Body burdens account for growth dilution and thus better reflect differences in early-life to adolescence exposure than serum concentrations.

Keywords
Perfluoroalkyl, Serum, PFAS, PFAA, Biomonitoring, Child, Body burden, Growth dilution
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:su:diva-162833 (URN)10.1016/j.envint.2018.09.006 (DOI)000449071000063 ()30308470 (PubMedID)
Available from: 2018-12-10 Created: 2018-12-10 Last updated: 2022-03-23Bibliographically approved
Winkens, K., Giovanoulis, G., Koponen, J., Vestergren, R., Berger, U., Karvonen, A. M., . . . Cousins, I. T. (2018). Perfluoroalkyl acids and their precursors in floor dust of children's bedrooms - Implications for indoor exposure. Environment International, 119, 493-502
Open this publication in new window or tab >>Perfluoroalkyl acids and their precursors in floor dust of children's bedrooms - Implications for indoor exposure
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2018 (English)In: Environment International, ISSN 0160-4120, E-ISSN 1873-6750, Vol. 119, p. 493-502Article in journal (Refereed) Published
Abstract [en]

We analysed floor dust samples from 65 children's bedrooms in Finland collected in 2014/2015 for 62 different per- and polyfluoroalkyl substances (PFASs) with a simple and highly efficient method. Validation results from the analysis of standard reference material (SRM) 2585 were in good agreement with literature data, while 24 PFASs were quantified for the first time. In the dust samples from children's bedrooms, five perfluoroalkyl carboxylic acids (PFCAs) and perfluorooctane sulfonic acid (PFOS) were detected in more than half of the samples with the highest median concentration of 5.26 ng/g for perfluorooctanoic acid (PFOA). However, the dust samples were dominated by polyfluoroalkyl phosphoric acid esters (PAPs) and fluorotelomer alcohols (FTOHs) (highest medians: 53.9 ng/g for 6:2 diPAP and 45.7 ng/g for 8:2 FTOH). Several significant and strong correlations (up to p = 0.95) were found among different PFASs in dust as well as between PFASs in dust and air samples (previously published) from the same rooms. The logarithm of dust to air concentrations (log K-dust/air) plotted against the logarithm of the octanol-air partition coefficient (log K-oa) resulted in a significant linear regression line with R-2 > 0.88. Higher dust levels of PFOS were detected in rooms with plastic flooring material in comparison to wood (p < 0.05). Total estimated daily intakes via dust (EDIdust) and air (EDIair) of perfluoroalkyl acids (PFAA), including biotransformation of precursors to PFAAs, were calculated for 10.5-year-old children. The total EDIdust, for PFOA and PFOS were estimated to be 0.007 ng/kg bw/day and 0.006 ng/kg bw/day, respectively, in an intermediate exposure scenario. The sum of the total EDIs for all PFAAs was slightly higher for dust than air (0.027 and 0.019 ng/kg bw/day). Precursor biotransformation was generally important for total PFOS intake, while for the PFCAs, FTOH biotransformation was estimated to be important for air, but not for dust exposure.

Keywords
Per- and polyfluoroalkyl substance (PFAS), Polyfluoroalkyl phosphoric acid ester (PAP), Fluorotelomer alcohol (FTOH), Child exposure, Estimated daily intake (EDI), Standard reference material (SRM 2585)
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:su:diva-161054 (URN)10.1016/j.envint.2018.06.009 (DOI)000444918100054 ()30053737 (PubMedID)
Available from: 2018-10-16 Created: 2018-10-16 Last updated: 2022-03-23Bibliographically approved
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-7168-1611

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