Indoor Dust Research Articles

Occurrence of radioactive cesium-rich micro-particles (CsMPs) in a school building located 2.8 km south-west of the Fukushima Daiichi Nuclear Power Plant

Radioactive Cs-rich microparticles (CsMPs) released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) are a potential health risk through inhalation. Little has been documented on the occurrence of CsMPs, particularly their occurrence inside buildings. In this study, we quantitatively analyze the distribution and number of CsMPs in indoor dust samples collected from an elementary school located 2.8 km to the southwest of FDNPP. The school had remained deserted until 2016. Then, using a modified version of the autoradiography-based “quantifying CsMPs (mQCP) method,” we collected samples and determined the number of CsMPs and Cs radioactive fraction (RF) values of the microparticles (defined as total Cs activity from CsMPs/bulk Cs activity of the entire sample). The numbers of CsMPs ranged from 653 to 2570 particles/(g dust) and 296–1273 particles/(g dust) on the first and second floors of the school, respectively. The corresponding RFs ranged between 6.85 – 38.9% and 4.48–6.61%, respectively. The number of CsMPs and RF values in additional outdoor samples collected near the school building were 23–63 particles/(g dust or soil) and 1.14–1.61%, respectively. The CsMPs were most abundant on the school's first floor near to the entrance, and the relative abundance was higher near the stairs on the second floor, indicating a likely CsMP dispersion path through the building. Additional wetting of the indoor samples combined with autoradiography revealed that indoor dusts had a distinct absence of intrinsic, soluble Cs species, such as CsOH. These combined observations indicate that a significant amount of poorly soluble CsMPs were likely contained in initial radioactive airmass plumes from the FDNPP and that the microparticles penetrated buildings. CsMPs could still be abundant at the location, with locally high Cs activity in indoor environments near to openings.

Tracing recent outdoor geolocation by analyzing microbiota from shoe soles and shoeprints even after indoor walking

The microbial communities on shoe soles and shoeprints could carry microbial information about where someone walked. This is possible evidence to link a suspect in a crime case to a geographic location. A previous study had shown that the microbiota found on shoe soles depend on the microbiota of the soil on which people walk. However, there is a turnover of microbial communities on shoe soles during walking. The impact of microbial community turnover on tracing recent geolocation from shoe soles has not been adequately studied. In addition, it is still unclear whether the microbiota of shoeprints can be used to determine recent geolocation. In this preliminary study, we investigated whether the microbial characteristics of shoe soles and shoeprints can be used to trace geolocation and whether this information can be destroyed by walking on indoor floors. In this study, participants were asked to walk outdoors on exposed soil, then walk indoors on a hard wood floor. High-throughput sequencing of the 16S rRNA gene was performed to characterize the microbial communities of shoe soles, shoeprints, indoor dust, and outdoor soil. Samples of shoe soles and shoeprints were collected at steps 5, 20, and 50 while walking indoors. The PCoA result showed that the samples were clustered by geographic origin. The shoeprint showed a more rapid turnover of microbial community than the shoe sole during indoor walking. The result of FEAST showed that the microbial communities of shoe sole and shoeprint were mainly (shoe sole, 86.21∼92.34 %; shoeprint, 61.66∼90.41 %) from the soil of the outdoor ground where the individual recently walked, and a small portion (shoe sole, 0.68∼3.33 %; shoeprint, 1.43∼27.14 %) from the indoor dust. Based on the matching of microbial communities between geolocation and shoe sole or shoeprint, we were able to infer the recent geolocation of the individual with relatively high accuracy using the random forest prediction model (shoe sole: 100.00 %, shoeprint: 93.33∼100.00 %). Overall, we are able to accurately infer the geolocation of an individual’s most recent outdoor walk based on the microbiota of shoe sole and shoeprint, even though these microbiotas show a turnover when walking indoor floor. The pilot study was expected to provide a potential method for tracing recent geolocation of suspects.

Comparative 6+studies of environmentally persistent free radicals on nano-sized coal dusts

Coal dust is the major hazardous pollutant in the coal mining environment. Recently environmentally persistent free radicals (EPFRs) were identified as one of the key characteristics which could impart toxicity to the particulates released into the environment. The present study used Electron Paramagnetic Resonance (EPR) spectroscopy to analyze the characteristics of EPFRs present in different types of nano-size coal dust. Further, it analyzed the stability of the free radicals in the respirable nano-size coal dust and compared their characteristics in terms of EPR parameters (spin counts and g-values). It was found that free radicals in coal are remarkably stable (can remain intact for several months). Also, Most of the EPFRs in the coal dust particles are either oxygenated carbon centered or a mixture of carbon and oxygen-centered free radicals. EPFRs concentration in the coal dust was found to be proportional to the carbon content of coal. The characteristic g-values were found to be inversely related to the carbon content of coal dust. The spin concentrations in the lignite coal dust were between 3.819 and 7.089 μmol/g, whereas the g-values ranged from 2.00352 to 2.00363. The spin concentrations in the bituminous coal dust were between 11.614 and 25.562 μmol/g, whereas the g-values ranged from 2.00295 to 2.00319. The characteristics of EPFRs present in coal dust identified by this study are similar to the EPFRs, which were found in other environmental pollutants such as combustion-generated particulates, PM2.5, indoor dust, wildfires, biochar, haze etc., in some of the previous studies. Considering the toxicity analysis of environmental particulates containing EPFRs similar to those identified in the present study, it can be confidently hypothesized that the EPFRs in the coal dust might play a major role in modulating the coal dust toxicity. Hence, it is recommended that future studies should analyze the role of EPFR-loaded coal dust in mediating the inhalation toxicity of coal dust.

PCDD/Fs in indoor environments of residential communities around a municipal solid waste incineration plant in East China: Occurrence, sources, and cancer risks

Prolonged exposure to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) can pose several adverse outcomes on human health. However, there is limited information on public health associated with indoor PCDD/F exposure in residential environments. Here, we examined PCDD/F concentrations in indoor air and indoor dust samples obtained from households near a municipal solid waste incineration (MSWI) plant. Our measurements revealed that the toxic equivalent (TEQ) concentrations of PCDD/Fs in indoor air ranged from 0.01 to 0.05 pg TEQ/m3, which were below intervention thresholds (0.6 pg TEQ/m3). Additionally, the TEQ concentrations of PCDD/Fs in indoor dust ranged from 0.30 to 11.56 ng TEQ/kg. Higher PCDD/F levels were found in household dust in the town of Taopu compared to those in the town of Changzheng. Principal component analysis (PCA) of PCDD/Fs suggested that waste incineration was the primary source of PCDD/Fs in indoor air, whereas PCDD/Fs in indoor dust came from multiple sources. The results of the health risk assessment showed the carcinogenic risk due to indoor PCDD/F exposure was higher for adults than for nursery children and primary school children. The carcinogenic risks of PCDD/Fs for age groups residing near the MSWI plant were all less than the risk threshold (10−5). Our findings will help to better understand the levels of PCDD/F exposure among urban populations living in residential communities around the MSWI plant and to formulate corresponding control measures to reduce probabilistic risk implications.

Heavy metals contamination status and health risk assessment of indoor and outdoor dust in Ahvaz and Zabol cities, Iran

Dust pollution is a major threat to human health and ecosystems, highly affecting both the outdoor and indoor air quality, while dust particles are an important carrier of potential toxic elements (PTEs) in urban environments. In this study, the concentrations of selected elements in indoor and outdoor dust samples, pollution and ecological risks, along with human health risk are analyzed in the highly dust-polluted cities of Ahvaz and Zabol, Iran during the spring and summer of 2017. The concentrations of elements related to industrial and urban emissions (e.g., Zn, Pb, Cu, Cr) were significantly higher in Ahvaz than Zabol. In general, weak correlations were found between the same heavy metals of indoor and outdoor dust, except for As, suggesting considerable variations in emission sources. The pollution indices revealed moderate contamination from heavy metals like Cd, As, and to some extent Zn and Pb, in the indoor dust samples, and lower contamination in outdoor dust. In both cities, ingestion was the main pathway of health risk exposure to PTEs, followed by dermal contact and inhalation, for both children and adults. The highest non-carcinogenic and cancer risks of indoor and outdoor dust were related to Cr and As, for both children and adults, while Cd and Pb through the respiratory pathway exhibited the lowest non-carcinogenic and cancer risks, respectively. The hazard index (HI) and the total cancer risk (TCR) were found in safe and tolerable levels (HI < 1 and 10−4 < TCR <10−6) in both cities, although higher in Ahvaz, while the health risk was found similar for outdoor and indoor dust in most cases.

Systematic Evidence Mapping of Potential Exposure Pathways for Per- and Polyfluoroalkyl Substances Based on Measured Occurrence in Multiple Media.

Given that human biomonitoring surveys show per- and polyfluoroalkyl substances (PFAS) to be ubiquitous, humans can be exposed to PFAS through various sources, including drinking water, food, and indoor environmental media. Data on the nature and level of PFAS in residential environments are required to identify important pathways for human exposure. This work investigated important pathways of exposure to PFAS by reviewing, curating, and mapping evidence for the measured occurrence of PFAS in exposure media. Real-world occurrence for 20 PFAS was targeted primarily in media commonly related to human exposure (outdoor and indoor air, indoor dust, drinking water, food, food packaging, articles, and products, and soil). A systematic-mapping process was implemented to conduct title-abstract and full-text screening and to extract PECO-relevant primary data into comprehensive evidence databases. Parameters of interest included the following: sampling dates and locations, numbers of collection sites and participants, detection frequencies, and occurrence statistics. Detailed data were extracted on PFAS occurrence in indoor and environmental media from 229 references and on PFAS occurrence in human matrices where available from those references. Studies of PFAS occurrence became numerous after 2005. Studies were most abundant for PFOA (80% of the references) and PFOS (77%). Many studies analyzed additional PFAS, particularly, PFNA and PFHxS (60% of references each). Food (38%) and drinking water (23%) were the commonly studied media. Most studies found detectable levels of PFAS, and detectable levels were reported in a majority of states in the United States. Half or more of the limited studies for indoor air and products detected PFAS in 50% or more of the collected samples. The resulting databases can inform problem formulation for systematic reviews to address specific PFAS exposure queries and questions, support prioritization of PFAS sampling, and inform PFAS exposure measurement studies. The search strategy should be extended and implemented to support living evidence review in this rapidly advancing area.

Co-occurrence of polycyclic aromatic hydrocarbons and their oxygenated derivatives in indoor dust from various microenvironments in Guangzhou, China: levels, sources, and potential human health risk.

For decades, the presence and potential health risk of polycyclic aromatic hydrocarbons (PAHs) in indoor dust have been extensively investigated while with limited attention to oxygenated PAHs (OPAHs). In this study, we collected 45 indoor dust from four microenvironments in Guangzhou City, China, and then focused on the co-occurrence of 16 PAHs and 8 OPAHs and their potential carcinogenic risk to humans. The ΣPAHs concentrations, dominated by 4-6 ring PAHs, ranged from 1761 to 14,290ng/g (mean of 6058ng/g) without significant difference in the different microenvironments (Tukey, p > 0.05). The OPAHs were observed with concentrations from 250 to 5160ng/g (mean of 1646ng/g), and anthraquinone (AQ) was identified as the main OPAHs with significantly high levels in the residential environment than in instrumental rooms. Notably, AQ dominated over the other target analytes in dust in this study. Our results indicated that PAHs and OPAHs in indoor dust were from outdoor environments, which mainly originated from vehicular exhaust and biomass/coal combustion. A potential cancer risk of PAHs and OPAHs to local adults and children was observed via inhalation, ingestion, and dermal absorption, with the main contribution from benzo[a]pyrene and dibenz[a,h]anthracene.

Levels and diverse composition profiles of chlorinated paraffins in indoor dust: possible sources and potential human health related concerns.

Chlorinated paraffins (CPs), a group of mixtures with different carbon chain lengths and chlorine contents, are widely used as plasticizers and flame retardants in various indoor materials. CPs could be released from CP-containing materials into the ambient environment and then enter the human body via inhalation, dust ingestion and dermal absorption, resulting in potential effects on human health. In this study, we collected residential indoor dust in Wuhan, the largest city in central China, and focused on the co-occurrence and composition profiles of CPs as well as the resultant human risk via dust ingestion and dermal absorption. The results indicated that CPs with C9-40 were ubiquity in indoor dust with medium-chain CPs (MCCPs, C14-17) as the main components (6.70-495μg g-1), followed by short-chain CPs (SCCPs, C10-13) (4.23-304μg g-1) and long-chain (LCCPs, C≥18) CPs (3.68-331μg g-1). Low levels (not detected-0.469μg g-1) of very short-chain CPs (vSCCPs, C9) were also found in partial indoor dust. The dominant homolog groups were C9 and Cl6-7 groups for vSCCPs, C13 and Cl6-8 groups for SCCPs, C14 and Cl6-8 groups for MCCPs, and C18 and Cl8-9 groups for LCCPs. Based on the measured concentrations, vSCCPs, SCCPs, MCCPs, and LCCPs posed limited human health risks to local residents via dust ingestion and dermal absorption.

Up in the air: Polyfluoroalkyl phosphate esters (PAPs) in airborne dust captured by air conditioning (AC) filters

Per- and polyfluoroalkyl substances (PFAS) are ubiquitously present in our indoor living environments. Dust is thought to accumulate PFAS released indoors and serve as an exposure pathway for humans. Here, we investigated whether spent air conditioning (AC) filters can be exploited as opportunistic samplers of airborne dust for assessing PFAS burden in indoor environments. Used AC filters from campus facilities (n = 19) and homes (n = 11) were analyzed for 92 PFAS via targeted ultra-high pressure liquid chromatography – tandem mass spectrometry (UHPLC-MS/MS). While 27 PFAS were measured (in at least one filter), the predominant species were polyfluorinated dialkylated phosphate esters (diPAPs), with the sum of 6:2-, 8:2-, and 6:2/8:2diPAPs accounting for approximately 95 and 98 percent of ∑27PFAS in campus and household filters, respectively. Exploratory screening of a subset of the filters revealed the presence of additional species of mono-, di-, and tri-PAPs. Considering the constant human exposure to dust indoors and the potential of PAPs to degrade into terminal species with well-established toxicological risks, assessing dust for these precursor PFAS warrants further investigation with respect to both human health and PFAS loading to landfills from this under studied waste stream.

Distribution of polycyclic aromatic hydrocarbons in indoor/outdoor window films and the indoor film/air partition of northeastern Chinese college dormitories

Indoor window films can represent short-term air pollution conditions of indoor environment through rapidly capturing organic contaminants as effective passive air samplers. To investigate the temporal variation, influence factors of polycyclic aromatic hydrocarbons (PAHs) in indoor window films, and the exchange behavior with gas phase in college dormitories, 42 pairs window films of interior and exterior window surfaces and corresponding indoor gas phase and dust samples were collected monthly in six selected dormitories, Harbin, China, from August to December 2019 and September 2020. The average concentration of ∑16PAHs in indoor window films (398 ng/m2) was significantly (p < 0.01) lower than that in outdoors (652 ng/m2). In addition, the median indoor/outdoor ∑16PAHs concentration ratio was close to 0.5, showing that outdoor air acted as a major PAH source to indoor environment. The 5-ring PAHs were mostly dominant in window films whereas the 3-ring PAHs contributed mostly in gas phase. 3-ring PAHs and 4-ring PAHs were both important contributors for dormitory dust. Window films showed stable temporal variation, i.e. PAH concentrations in heating months were higher than those in non-heating months. The atmospheric O3 concentration was the main influence factor of PAHs in indoor window films. PAHs with low molecular weight in indoor window films rapidly reached film/air equilibrium phase within in dozens of hours. The large deviation in the slope of the log KF-A versus log KOA regression line from that in reported equilibrium formula might be the difference between the window film composition and octanol.

Presence, source attribution, and human exposure to organophosphate esters in indoor dust from various microenvironments in Nigeria

Very few studies have reported the presence of the organophosphate esters (OPEs) in African indoor microenvironments. We therefore document here, the concentrations, profiles, and human exposure to eight organophosphate esters (OPEs) for the first time in indoor dust from various microenvironments in Nigeria, specifically: cars/buses (n = 10), homes (n = 20), offices (n = 20), and medical centres (n = 14). The concentrations of OPEs in these indoor dust samples were among the lowest reported internationally. Concentrations of ∑8OPEs varied substantially between individual samples and the predominant OPEs were: tris(2-butoxyethyl) phosphate (TBOEP) (detection frequency (DF) = 90–100%), tris(1-chloro-2-propyl) phosphate (TCIPP) (DF = 100%), and 2-ethylhexyl-diphenyl phosphate (EHDPP) (DF = 100%). There were no significant differences (P˃0.05) between ∑8OPEs concentrations in dust samples from cars/buses (average = 295 ng/g), offices (231 ng/g), homes (277 ng/g), and medical centres (127 ng/g). Concentrations of chlorinated OPEs: tris(2-chloroethyl) phosphate (TCEP), TCIPP, and tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) were significantly correlated with those of triphenyl phosphate (TPhP), EHDPP, and TBOEP. Estimated daily intakes (EDI) of target OPEs via indoor dust ingestion and dermal absorption were lower than the corresponding reference dose (RfD) values, indicating that exposure to the studied OPEs in the indoor environment does not pose a significant health risk for the general population in Nigeria, even under a high-end exposure scenario.

Biological effects related to exposure to polychlorinated biphenyl (PCB) and decabromodiphenyl ether (BDE-209) on cats.

As an animal familiar to humans, cats are considered to be sensitive to chemicals; cats may be exposed to polychlorinated biphenyls (PCBs) and decabromodiphenyl ether (BDE-209) from indoor dust, household products, and common pet food, leading to adverse endocrine effects, such as thyroid hormone dysfunction. To elucidate the general biological effects resulting from exposure of cats to PCBs and PBDEs, cats were treated with a single i.p. dose of a principal mixture of 12 PCBs and observed for a short-term period. Results revealed that the testis weight, serum albumin, and total protein of the treated group decrease statistically in comparison with those in the control group. The negative correlations suggested that the decrease in the total protein and albumin levels may be disturbed by 4'OH-CB18, 3'OH-CB28 and 3OH-CB101. Meanwhile, the serum albumin level and relative brain weight decreased significantly for cats subjected to 1-year continuous oral administration of BDE-209 in comparison to those of control cats. In addition, the subcutaneous fat as well as serum high-density lipoprotein (HDL) and triglycerides (TG) levels increased in cats treated with BDE-209 and down-regulation of stearoyl-CoA desaturase mRNA expression in the liver occurred. These results suggested that chronic BDE-209 treatment may restrain lipolysis in the liver, which is associated with lipogenesis in the subcutaneous fat. Evidence of liver and kidney cell damage was not observed as there was no significant difference in the liver enzymes, blood urea nitrogen and creatinine levels between the two groups of both experiments. To the best of our knowledge, this is the first study that provides information on the biochemical effects of organohalogen compounds in cats. Further investigations on risk assessment and other potential health effects of PCBs and PBDEs on the reproductive system, brain, and lipid metabolism in cats are required.

Bioaccessibility of per- and polyfluoroalkyl substances in food and dust: Implication for more accurate risk assessment

Humans are exposed to per- and polyfluoroalkyl substances (PFASs) mainly through oral exposure route, while little is known about their bioaccessibility (BC) in oral matrices. Here, the BC of 13 PFASs in simulated vegetable (VFs) and animal foods (AFs) as well as indoor dust was investigated using a physiology-based extraction test. The BC of PFASs in the AFs (78.5 ± 13.6 %) was distinctly higher than that in the VFs (60.6 ± 13.4 %), because high-saturated and long-chain fatty acids in the animal fat favored formation of more stable micelles. The BC of most long-chain PFASs was positively correlated with the protein content while negatively correlated with the carbohydrate content in the foods. The BC of polyfluoroalkyl phosphate diesters was negatively correlated with the lipid content. The BC of the very long-chain PFASs in the foods was 2.42–6.02 times higher than that in the dust, which might be attributed to their strong sequestration in dust. With the increase in bile salt concentration, the BC of PFASs in food increased and then remained constant, which was related to the changes in fatty acids and stability of the formed micelles. Comparing with the previous results obtained from animal study, the BC obtained in this study has the potential to predict PFAS bioavailability in food.

Pollution Status, Source Apportionment, Ecological and Human Health Risks of Potentially (Eco)toxic Element-Laden Dusts from Urban Roads, Highways and Pedestrian Bridges in Uganda

The occurrence of potentially (eco)toxic elements (PTEs) in street, indoor and roadside dusts have been associated with potential human health risks. For the first time, the pollution levels of PTEs—copper (Cu), nickel (Ni), manganese (Mn), zinc (Zn), lead (Pb), cadmium (Cd) and chromium (Cr)—were investigated in 24 dust samples from eight selected sampling sites on urban roads, highways and pedestrian bridges constructed over River Manafwa, a flood-prone river in Eastern Uganda. Concentration of PTEs in the sample digests were quantified by atomic absorption spectrometry. Multivariate geostatistical (Pearson’s Correlation, Principal Components and Hierarchical Cluster) analyses were used to apportion sources of the contaminants. Contamination, ecological and human health assessment indices and models were employed to establish any potential risks the elements could pose to the environment and humans. The study revealed that there is severe PTE pollution of dusts from roads, highways and pedestrian bridges in Eastern Uganda when compared with their crustal averages, except for Cu, Ni and Cr. The mean concentrations (mg kg−1) of Cu (11.4–23.2), Ni (0.20–23.20), Mn (465.0–2630.0), Zn (26.8–199.0), Pb (185.0–244.0), Cd (0.178–1.994) and Cr (5.40–56.60) were highest in samples obtained near high-traffic areas. Source apportionment studies suggested that Cu, Ni, Mn and Cr are from combustion processes and vehicular traffic, whereas Pb, Zn and Cd came from traffic and geogenic contributions. Assessment using the pollution load index indicated that only dust from Zikoye–Bushika road, the junction of Zikoye–Bushika and Bududa–Manafwa roads and Manafwa town were substantially polluted as the indices were greater than 1. Further assessment of pollution degree of the dust samples using index of geo-accumulation revealed that the dusts were practically uncontaminated to medium-to-strongly contaminated. Health risk assessment showed that there are non-carcinogenic health risks that could emanate from direct ingestion of PTEs in dusts by children. This study therefore opens the lead for investigation of the contamination levels and the health risks of PTEs in dusts from industrial areas as well as busy Ugandan cities such as Kampala, Jinja, Mbarara and Gulu.

Effects of Ambient Temperature and Humidity on Natural Deposition Characteristics of Airborne Biomass Particles.

In the production process of biomass energy with crop straw as the raw material, the indoor dust environment created by smashed plant fiber can affect the health of workers and lead to the risk of fire and explosions. The physical properties of biomass vary with the ambient air conditions, resulting in different deposition processes for airborne biomass particles. In this study, the deposition of biomass particles in different environments in an experimental chamber was examined by independently controlling the internal temperature and relative humidity. The results show that in the ambient temperature range of 20~40 °C and at a relative humidity of 25~65%, the water absorption rates of the biomass particles were 15.4~24.7%. The deposition rates of the airborne biomass particles with different sizes were 0.9~2.9 h-1, which positively correlated with the particle sizes in the same ambient conditions. The increase in ambient temperature and relative humidity promoted the deposition of biomass particles with diameters over 0.5 μm. For the particles with diameters below 0.5 μm, the deposition rates were nonlinearly related to the ambient temperature and relative humidity and were greater at lower temperatures. The significance levels of the factors influencing the particle deposition were particle size > ambient temperature > ambient relative humidity. For the biomass particles below 0.5 μm, the influence of the relative humidity on the deposition was much weaker than that of the temperature.

Current status of indoor dust PBDE pollution and its physical burden and health effects on children.

Polybrominated diphenyl ethers (PBDEs) are widely detected in indoor dust, which has been identified as a more important route of PBDE exposure for children than food intake. The physical burden and health hazards to children of PBDE exposure in house dust have not been adequately summarized; therefore, this article reviews the current status of PBDE pollution in indoor dust associated with children, highlighting the epidemiological evidence for physical burden and health risks in children. We find that PBDEs remain at high levels in indoor dust, including in homes, schools, and cars, especially in cars showing a significant upward trend. There is a trend towards an increase in the proportion of BDE-209 in household dust, which is indicative of recent PBDE contamination. Conversely, PBDE congeners in car and school indoor dust tended to shift from highly brominated to low brominated, suggesting a shift in current pollution patterns. Indoor dust exposure causes significantly higher PBDE burdens in children, especially infants in early life, than in adults. Exposure to dust also affects breast milk, putting infants at high risk of exposure. Although evidence is limited, available epidemiological studies suggest that exposure to indoor dust PBDEs promotes neurobehavioral problems and cancer development in children.

Predictive modeling of indoor dust lead concentrations: Sources, risks, and benefits of intervention

Lead (Pb) contamination continues to contribute to world-wide morbidity in all countries, particularly low- and middle-income countries. Despite its continued widespread adverse effects on global populations, particularly children, accurate prediction of elevated household dust Pb and the potential implications of simple, low-cost household interventions at national and global scales have been lacking. A global dataset (∼40 countries, n = 1951) of community sourced household dust samples were used to predict whether indoor dust was elevated in Pb, expanding on recent work in the United States (U.S.). Binned housing age category alone was a significant (p < 0.01) predictor of elevated dust Pb, but only generated effective predictive accuracy for England and Australia (sensitivity of ∼80%), similar to previous results in the U.S. This likely reflects comparable Pb pollution legacies between these three countries, particularly with residential Pb paint. The heterogeneity associated with Pb pollution at a global scale complicates the predictive accuracy of our model, which is lower for countries outside England, the U.S., and Australia. This is likely due to differing environmental Pb regulations, sources, and the paucity of dust samples available outside of these three countries. In England, the U.S., and Australia, simple, low-cost household intervention strategies such as vacuuming and wet mopping could conservatively save 70 billion USD within a four-year period based on our model. Globally, up to 1.68 trillion USD could be saved with improved predictive modeling and primary intervention to reduce harmful exposure to Pb dust sources.

Concentrations of organophosphate esters in drinking water from the United Kingdom: Implications for human exposure

Data on the presence of organophosphate esters (OPEs) in drinking water and its significance as a pathway of exposure are limited. In this study, we measure for the first time, concentrations of eight OPEs in 50 UK drinking water samples. Arithmetic mean concentrations of ∑8OPEs were: 6.4 and 11 ng/L in bottled (n = 25) and tap water samples (n = 25), respectively. Concentrations of ∑8OPEs in tap water (mean: 11 ng/L) exceed significantly those in bottled water (mean: 6.4 ng/L) (p ˂ 0.01). Moreover, UK tap water is more contaminated with chlorinated, aryl-, and alkyl-OPEs than bottled water. The predominant OPEs detected were: tris (butoxyethyl) phosphate (TBOEP), tris (2-chloroethyl) phosphate (TCEP), and tris(2-chloroisopropyl) phosphate (TCIPP) with arithmetic mean concentrations in the two water sample types ranging between (3.5–3.8 ng/L), (0.60–3.0 ng/L), and (1.02–2.9 ng/L), respectively. Estimated daily intakes (EDIs) (mean and high-end exposure) via drinking water for different sectors of the UK population were: infants (0.93 and 6.4 ng/kg bw/day) ˃ toddlers (0.46 and 3.1 ng/kg bw/day) ˃ children (0.35 and 2.3 ng/kg bw/day) ˃ adults (0.28 and 2.1 ng/kg bw/day). Based on these data, exposure to Σ8OPEs via drinking water is much lower than via: food, indoor dust ingestion, inhalation, and dermal uptake for adults and toddlers. Reassuringly, our EDIs were lower than relevant reference dose (RfD) values. However, combining our drinking water ingestion data with exposure via other pathways revealed overall exposure to 2-ethylhexyl diphenyl phosphate (EHDPP) and TCIPP to approach health-based limit values for UK toddlers under a high-end exposure scenario.

Association of indoor dust microbiota with cognitive function and behavior in preschool-aged children

BackgroundChildhood cognitive development depends on neuroimmune interactions. Immunomodulation by early-life microbial exposure may influence neuropsychological function. In this study, we investigate the association between residential indoor microbiota and cognition and behavior among preschoolers.ResultsIndoor-settled dust bacterial and fungal characteristics were assessed using 16S and ITS amplicon sequencing (microbial diversity) and qPCR measurements (microbial loads). Child behavior was assessed using four scales: peer relationship, emotional, conduct, and hyperactivity was assessed by the Strengths and Difficulties Questionnaire (SDQ). Cognitive function was assessed using four tasks of the Cambridge Neuropsychological Test Automated Battery (CANTAB) software. The first two tasks were designed to assess attention and psychomotor speed (Motor Screening (MOT) and Big/Little Circle (BLC)) and the last two to evaluate the child’s visual recognition/working memory (Spatial Span (SSP) and Delayed Matching to Sample (DMS)). Among the 172 included children (age 4–6 years), we observed a 51% (95%CI;75%;9%) lower odds of children scoring not normal for hyperactivity and a decrease of 3.20% (95%CI, −6.01%; −0.30%) in BLC response time, for every IQR increase in fungal Shannon diversity. Contrarily, microbial loads were directly associated with SDQ scales and response time. For example, a 2-fold increase in Gram-positive bacterial load was associated with 70% (95%CI 18%; 156%) higher odds of scoring not normal for hyperactivity and an increase of 5.17% (95%CI 0.87%; 9.65%) in DMS response time.ConclusionsOur findings show that early-life exposure to diverse indoor fungal communities is associated with better behavioral and cognitive outcomes, whereas higher indoor microbial load was associated with worse outcomes.-hh8RCLyRPCU1iX3VFx5YbVideo

An International Investigation of Chlorinated Paraffin Concentrations and Homologue Distributions in Indoor Dust

An International Investigation of Chlorinated Paraffin Concentrations and Homologue Distributions in Indoor Dust