To Örebro University

Indoor dust contains a complex mixture of chemicals, including endocrine-disrupting chemicals (EDCs), which may pose risks to children's health. As children spend most of their time indoors and have frequent dust contact, their exposure is heightened. This study quantified the endocrine disrupting potential of dust from children's indoor environments in Sweden, and assessed associations with flame retardants and plasticizers in dust, handwipes, and urine.

Fifty dust samples from 18 homes and 11 preschool units were analyzed for estrogen, anti-androgen, and thyroid receptor activities using human osteosarcoma cell-based luciferase reporter assays. Associations were evaluated with 21 legacy and 18 emerging halogenated flame retardants (HFRs) and 11 organophosphate esters (OPEs) in dust and handwipes, as well as nine plasticizers (eight phthalates and di-isononyl cyclohexane 1,2-dicarboxylate (DiNCH)) in dust, and 14 plasticizer metabolites in urine. Samples for biological and chemical analyses were collected from the same designated areas within a limited time frame.

Most dust samples exhibited estrogen receptor agonist (ER) and androgen receptor antagonistic (anti-AR) activity, while thyroid receptor (TR) induction was low. Preschool dust showed significantly higher estrogenic activity than home dust. No seasonal variation was observed. Associations were observed between dust hormonal activities and urinary plasticizer metabolites, as well as HFR and OPE concentrations in dust and handwipes. Relative potency (REP) analyses of 36 HFRs and OPEs revealed notable anti-AR activity for 2,2´,4,4´-tetrabromodiphenyl ether (BDE-47) (REP values 0.85±0.10 (EC25) and 0.93±0.07 (EC50)) and 2,2´,4,4´,6-pentabromo diphenyl ether (BDE-100) (REP values 2.74±0.29 (EC25) and 3.23±0.42 (EC50)). Additionally, BDE-100 showed low ER induction.

Chemicals with plasticizing and flame-retardant properties have widespread usage in materials and products designed and produced for everyday life, therefore present in various indoor environments. Their associations with endocrine-disrupting potentials and related health concerns, particularly for children, motivated exploring children's exposure through their everyday indoor environments, which is the main objective of this thesis. Therefore, a suit of chemicals including 50 halogenated flame retardants (HFRs) and organophosphate esters (OPEs) were measured in preschool and home indoor dust (Paper I) and in children’s handwipes (Paper II), along with 14 urinary plasticizer metabolites (Paper III). In addition, the endocrine activity of home and preschool dust was assessed employing cell-based bioassays (Paper IV) and compared to the results in Paper I-III. HFRs and/or OPEs were detected in all handwipe samples with higher levels related to more electronic devices and plastic toys in the premises. For most compounds the levels differed statistically significantly between municipalities, and several correlated with indoor dust levels. Hand-to-mouth dust ingestion was the predominate exposure route. However, no established reference doses (RfD) were exceeded, except for one OPE in a worst-case scenario. Urinary metabolite levels of strictly regulated plasticizers were higher if attending an older preschool. However, the levels were higher after the weekend than after a preschool day, suggesting higher exposure to banned chemicals in environments other than preschools, with human biomonitoring guidance values (HBM-GV) exceeded in three samples. Endocrine activity was detected in both home and preschool dust, which further emphasizes exposure to EDCs through the indoor environment, promoting a focus on indoor spaces to reduce children’s exposure.

Children are exposed to endocrine disrupting chemicals (EDCs) through inhalation and ingestion, as well as through dermal contact in their everyday indoor environments. The dermal loadings of EDCs may contribute significantly to children's total EDC exposure due to dermal absorption as well as hand-to-mouth behaviors. The aim of this study was to measure potential EDCs, specifically halogenated flame retardants (HFRs) and organophosphate esters (OPEs), on children's hands during preschool attendance and to assess possible determinants of exposure in preschool indoor environments in Sweden. For this, 115 handwipe samples were collected in winter and spring from 60 participating children (arithmetic mean age 4.5 years, standard deviation 1.0) and analyzed for 50 compounds. Out of these, 31 compounds were identified in the majority of samples. Levels were generally several orders of magnitude higher for OPEs than HFRs, and 2-ethylhexyl diphenyl phosphate (EHDPP) and tris(2-butoxyethyl) phosphate (TBOEP) were detected in the highest median masses, 61 and 56 ng/wipe, respectively. Of the HFRs, bis(2-ethyl-1-hexyl)-2,3,4,5-tetrabromobenzoate (BEH-TEBP) and 2,2',3,3',4,4',5,5',6,6'-decabromodiphenyl ether (BDE-209) were detected in the highest median masses, 2.8 and 1.8 ng/wipe, respectively. HFR and/or OPE levels were found to be affected by the number of plastic toys, and electrical and electronic devices, season, municipality, as well as building and/or renovation before/after 2004. Yet, the calculated health risks for single compounds were below available reference dose values for exposure through dermal uptake as well as for ingestion using mean hand-to-mouth contact rate. However, assuming a high hand-to-mouth contact rate, at the 95th percentile, the calculated hazard quotient was above 1 for the maximum handwipe mass of TBOEP found in this study, suggesting a risk of negative health effects. Furthermore, considering additive effects from similar compounds, the results of this study indicate potential concern if additional exposure from other routes is as high.

Several plasticizing chemicals induce endocrine disrupting effects in humans, and the indoor environment is suggested to be a source of exposure. As children are particularly vulnerable to the effects from exposure to endocrine disrupting chemicals (EDCs), it is essential to monitor exposure to EDCs such as phthalates and non-phthalate plasticizers in indoor environments intended for use by children. The aim of this study was to assess everyday plasticizer exposure among preschool-aged children in Sweden by measuring urinary plasticizer metabolite concentrations. In addition, it was investigated whether the concentrations would be altered as a result of the children spending part of the day at preschool, in comparison with weekend exposure, when they may spend more time in home environments or engage in various weekend and leisure activities. For this purpose, fourteen metabolites from eight phthalates (di-ethylhexyl phthalate, DEHP; di-n-butyl phthalate, DnBP; di-isobutyl phthalate, DiBP; butyl-benzyl phthalate, BBzP; di-iso-nonyl phthalate, DiNP; di-propylheptyl phthalate, DPHP; di-iso-decyl phthalate, DiDP; and di-ethyl phthalate, DEP) and one non-phthalate plasticizer (di-isononyl cyclohexane 1,2-dicarboxylate, DiNCH) were measured in 206 urine samples collected at four occasions, i.e. twice during the winter and twice during the spring from 54 children (mean 5.1 years, SD 0.94) enrolled at eight preschools in Sweden. A detection frequency (DF) of 99.9% for the 14 metabolites indicates a widespread exposure to plasticizers among children in Sweden. Compared to previous Swedish and international studies performed during approximately the same time period, high urinary concentrations of monobenzyl phthalate (MBzP), a metabolite from the strictly regulated BBzP, were measured in this study (median 17 ng/mL). Overall, high urinary phthalate metabolite concentrations were observed in this study compared to the US CDC-NHANES from the same time period and similar age-group. Compared to European studies, however, similar concentrations were observed for most metabolites and the urinary concentrations from few participating children exceeded the human biomonitoring guidance values (HBM-GV) for children. After days with preschool attendance, lower urinary concentrations of metabolites originating from DEP and phthalates that are strictly regulated within the EU REACH legislation (DEHP, DnBP, and DiBP) and higher concentrations of metabolites originating from DiNP, DPHP, and DiDP, i.e. less or non-regulated phthalates were found compared the urinary concentrations of these metabolites in weekends. This may indicate that factors in the indoor environment itself are important for the extent of the plasticizer exposure. All the analyzed metabolites were measured in lower concentrations in urine collected from children attending preschools built or renovated after the year 2000, while no seasonal differences were observed in this study.

This study analysed settled dust samples in Sweden to assess children's combined exposure to 39 organohalogenated flame retardants (HFRs) and 11 organophosphate esters (OPEs) from homes and preschools. >94 % of the targeted compounds were present in dust, indicating widespread use of HFRs and OPEs in Swedish homes and preschools. Dust ingestion was the primary exposure pathway for most analytes, except BDE-209 and DBDPE, where dermal contact was predominant. Children's estimated intakes of ∑emerging HFRs and ∑legacy HFRs from homes were 1-4 times higher than from preschools, highlighting higher exposure risk for HFRs in homes compared to preschools. In a worst-case scenario, intakes of tris(2-butoxyethyl) phosphate (TBOEP) were 6 and 94 times lower than the reference dose for children in Sweden, indicating a potential concern if exposure from other routes like inhalation and diet is as high. The study also found significant positive correlations between dust concentrations of some PBDEs and emerging HFRs and the total number of foam mattresses and beds/m2, the number of foam-containing sofas/m2, and the number of TVs/m2 in the microenvironment, indicating these products as the main source of those compounds. Additionally, younger preschool building ages were found to be linked to higher ΣOPE concentrations in preschool dust, suggesting higher ΣOPE exposure. The comparison with earlier Swedish studies indicates decreasing dust concentrations for some banned and restricted legacy HFRs and OPEs but increasing trends for several emerging HFRs and several unrestricted OPEs. Therefore, the study concludes that emerging HFRs and OPEs are replacing legacy HFRs in products and building materials in homes and preschools, possibly leading to increased exposure of children.

Plasticizers are a category of chemicals extensively used in consumer products and, consequently, their presence is ubiquitous in the indoor environment. In the present study, an analytical method has been developed for the quantification of plasticizers (7 legacy phthalate esters (LPEs) and 14 alternative plasticizers (APs)) in indoor floor dust based on ultrasonic and vortex extraction, Florisil fractionation and GC-(EI)-MS analysis. Dust samples (n = 54) were collected from homes, offices, and daycare centers from different EU countries (Belgium, the Netherlands, Ireland and Sweden). Method LOQs ranged from 0.2 to 5 mu g/g. Tri-n-hexyl trimellitate (THTM) was not detected in any sample, whereas dimethyl phthalate (DMP), diphenyl phthalate and acetyl triethyl citrate (ATEC) were detected only in 6, 2 and 1 out of 54 samples, respectively. The highest concentrations of plasticizers were measured in Swedish offices, at a mean concentration of total plasticizers of 1800 mu g/g, followed by Swedish daycare centers at 1200 and 670 mu g/g for winter and spring sampling, respectively. Generally, the contribution of APs was slightly higher than for LPEs for all indoor environments (mean contribution 60% and 40%, respectively based on contributions per indoor environment). For the APs, main contributors were DINP in Belgian homes (28%), Swedish offices (60%), Swedish daycare centers (48%), and Dutch offices (31%) and DEHT in Belgian (28%), Irish (40%) and Dutch homes (37%) of total APs. The predominant LPE was bis-2-ethylhexyl-phthalate (DEHP) with a mean contribution varying from 60% to 85% of total LPEs. Human exposure was evaluated for dust ingestion and dermal absorption using hazard quotients (HQs) of plasticizers (ratio between average daily doses and the reference dose). None of the HQs of plasticizers exceeded 1, meaning that the risk for adverse human health effects from these plasticizers via dust ingestion and dermal absorption is unlikely.

Background: Since we spend most of our time indoors the indoor environment can lead to exposure to substances like metals. Small children are often more exposed than adults, for instance due to their hand-to-mouth behaviour. Since some metals can have adverse health effects in children the aim of this study was to investigate indoor exposure to metals on children’s hands in preschools.

Method: In the study, 60 children at 8 preschools in two cities in Sweden participated. Metals on the hands were sampled at two different periods (winter and spring) giving a total of 109 samples. During sampling, both hands were wiped using hand-wipes soaked in 1 % HNO3, and sampling was done after two hours of indoor activities. The following metals were analyzed using ICP-MS; beryllium, magnesium, aluminium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, arsenic, molybdenum, silver, cadmium, antimony, barium, thallium and lead. Results All samples were above limit of quantification (LOQ) except for beryllium and molybdenum (4 %<LOQ) and silver (100 %<LOQ, LOQ=0.001 µg/sample). The lowest mean level was seen for beryllium (0.0034 µg/sample) and highest for magnesium (140 µg/sample). For cadmium, arsenic and lead the mean levels were 0.023, 0.049 and 0.51 µg/sample, respectively. For about half of the metals statistically significantly higher levels (p<0.05) were seen during spring and in one of the cities.

Conclusion: Metals linked to severe health effects like cadmium, arsenic and lead as well as a range of other metals could be detected on children’s hands. These findings indicate an exposure to metals for children both via dermal uptake and oral intake due to hand-to-mouth transfer, but potential contributions to the body burden are unknown. Higher levels were seen during spring and in one of the cities, possible explanations to these observations needs to be looked into more closely.