Bioavailability of Inhaled Or Ingested PFOA Adsorbed To House Dust

Indoor environments may impact human health due to chemical pollutants in the indoor air and house dust. This study aimed at comparing the bioavailability and distribution of PFOA following both an inhalation and an oral exposure to PFOA coated house dust in rats. In addition, extractable organofluorine (EOF) was measured in different tissue samples to assess any potential influence of other organofluorine compounds in the experimental house dust. Blood samples were collected at sequential time points after exposure and at the time of termination; lung, liver and kidney were collected for quantification of PFOA and EOF. The concentration of PFOA in plasma increased rapidly in both exposure groups attaining a Cmax at 3 h post exposure. The Cmax following inhalation was four times higher compared to oral exposures. At 48 h post exposure, the levels of PFOA in plasma, liver and kidney were twice as high from inhalation exposures. This shows that PFOA is readily bioavailable and has a rapid systemic distribution following an inhalation- or oral exposure to house dust coated with PFOA. The proportion of PFOA to EOF corresponded to approximately 54-68% and >80% in plasma and tissues, respectively. The mass balance between EOF and target PFOA indicate that there might be other unknown PFAS precursor and/or fluorinated compounds that co-existed in the house dust sample that might have accumulated in rats.

Characterization of Chemical and Bacterial Concentrations in Floor Dust Samples in Southeast Texas Households

Indoor dust can be a major source of heavy metals, nutrients, and bacterial contamination in residential environments and may cause serious health problems. The goal of this research is to characterize chemical and bacterial contaminants of indoor, settled house dust in the Houston Metropolitan region. To achieve this, a total of 31 indoor dust samples were collected, along with household survey data, which were subsequently analyzed for elemental and bacterial concentrations. Microscopic and geospatial analysis was conducted to characterize and map potential hotspots of contamination. Interestingly Cd, Cr, Cu, Pb, and Zn concentrations of all 31 indoor dust samples were significantly enriched and exceeded soil background concentrations. Furthermore, As, Cd, Pb, and Zn concentrations in the dust samples were significantly correlated to the enteric bacterial load concentrations. Human health assessment revealed that cancer risk values via ingestion for Cd, Cr, and Ni were greater than the acceptable range. Of our 31 dust sample isolates, three Gram-negative and 16 Gram-positive pathogenic bacteria were identified, capable of causing a wide range of diseases. Our results demonstrate that both chemical and bacterial characterization of indoor dust coupled with spatial mapping is essential to assess and monitor human and ecological health risks.

Energy Recovery from Vinery Waste: Dust Explosion Issues

The concern about global warming issues and their consequences is more relevant than ever, and the H2020 objectives promoted by the EU are oriented towards generating climate actions and sustainable development. The energy sector constitutes a difficult challenge as it plays a key role in the global warming impact. Its decarbonization is a crucial factor, and significant efforts are needed to find efficient alternatives to fossil fuels in heating/electricity generation. The biomass energy industry could have a contribution to make in the shift to renewable sources; the quest for a suitable material is basically focused on the energy amount that it stores, its availability, logistical considerations, and safety issues. This work deals with the characterization of a wine-waste dust sample, in terms of its chemical composition, fire behavior, and explosion violence. This material could be efficiently used in energy generation (via direct burning as pellets), but scarce information is present in terms of the fire and explosion hazards when it is pulverized. In the following, the material is analyzed through different techniques in order to clearly understand its ignition sensitivity and fire effects; accelerating aging treatment is also used to simulate the sample storage life and determine the ways in which this affects its flammability and likelihood of explosion.

Bacterial Diversity in House Dust: Characterization of a Core Indoor Microbiome

Our indoor microbiome consists of a wide range of microbial taxa. Whilst many of these microbes are benign, some are beneficial, some harmful, yet our knowledge of the spatial heterogeneity of bacterial assemblages in our residential environment remains limited. To investigate the existence of a common core house dust bacterial microbiome we selected household vacuum dusts, collected through a citizen science approach, from homes across two bioclimatic regions (UK, Oceanic/Maritime and Greece, Mediterranean). Following the extraction of DNA from each dust sample, we targeted the bacterial 16S rRNA gene using Illumina NextSeq sequencing. PERMANOVA analysis of the microbial communities at family level grouped samples within their distinct bioclimatic region and SIMPER analysis at genus level identified the statistically significant taxa responsible for driving diversity between these groups. A “common to all” core house dust microbiome consisted of Acinetobacter, Massalia, Rubellimicrobium, Sphingomonas and Staphylococcus; genera typically associated with human occupancy and common environmental sources. Additionally, a “unique location specific” microbiome was identified, reflective of the bioclimatic region. The Greek dusts indicated a lower average diversity than the UK house dusts, with a high abundance of Rhizobiaceae in the Greek samples. Our study highlights citizen science as a powerful approach to access the indoor residential environment, at scale, and establishes the existence of a “core” house dust microbiome independent of bioclimatic region.

Silica removal from waste of ilmenite concentrate pyrometallurgical processing

The article presents the study results for alkaline leaching of fine ilmenite concentrate dusts from electric smelting. The physical and chemical properties of the dusts were studied using chemical and instrumental analysis methods. The dust composition was determined, X-ray phase analysis showed that the dust sample substance is in the X-ray amorphous state, iron is present in the trivalent state, and silicon is bound to magnesium. The dust sample study using a scanning electron microscope showed that part of the titanium is bound in a hard-to-disclose anasovite encapsulated in amorphous silicon oxide. The leaching study of electric smelting dust with sodium hydroxide solutions included the study of the effect of sodium hydroxide concentration, process duration, temperature, S: L ratio. The optimal conditions for dust leaching from electric smelting of ilmenite concentrate have been established: temperature 80-90 °C, duration 90-120 min, ratio S: L = 1: 5, the concentration of sodium hydroxide solution 110-115 g/dm3. The silicon extraction degree into the solution under these conditions was 77.7%. The behavior of accompanying components of chromium, zinc, iron, and manganese during dust leaching was also studied. X-ray phase analysis of the cake after leaching shows almost complete amorphization of the leached product, the main phase is a solid solution of Fe2O3·TiO2.

Comparison of supercritical fluid extraction and thermal desorption methods for analysing organic compounds in house-dust

<p>This study has been focused on the comparison of the application of Thermal Desorption (TD) and Supercritical Fluid Extraction (SFE) methods for the identification and quantification of organic chemicals in house dust samples. To investigate how the results obtained by SFE and TD of house dust compare to one another and whether the SFE has advantages over the TD method, an aliquot of a house dust sample has been subjected to desorption at successively increasing temperatures. The thermal desorption unit used cryo - focusing on capillary tubing and was connected to a GC-MS combination. A quantity of the same house dust sample was extracted, using a method consisting of a two-step SFE with CO2 and CO2 + 5% of methanol, and GC-MS analysis of the eluates. The comparison of the results showed that the SFE method was superior to the TD for analysing indoor dust samples because of the pre-separation and the absence of thermal degradation, particularly for compounds of low volatility. However, TD could be more appropriate for relatively volatile or lower molecular weight range compounds and thermally stable compounds.</p>

Environmental Aspects of Historical Ferromanganese Tailings in the Šibenik Bay, Croatia

The former manganese ferroalloy plant and the remaining tailings are affecting the quality of the environment in Šibenik Bay, Croatia, even though industrial activities ceased more than 25 years ago. This study has revealed that the main manganese mineral phases present in the recently collected tailings, as well as in the dust collected on the roof of the plant during the production period, are bustamite and Mn-oxides. The same type of Mn mineral phases was also found in recently collected sediments from Šibenik Bay. Detailed chemical and phase analyses (XRD, BCR sequential analysis, aqua regia and lithium borate fusion) of the dust sample revealed high manganese values (24.1%), while granulometric analysis showed that 50% of the particles are smaller than PM2.5. The influence of the tailings is visible in the sediment, but the concentrations of the potentially toxic elements determined by the sequential BCR analysis are within the legal limits. Some higher values (20.3 g/kg Mn, 595 mg/kg Pb and 494 mg/kg Zn) are detected in the tailings, which are still exposed to weathering and as such should be additionally monitored. On the other hand, this material contains a considerable number of elements that could be considered lucrative (∑ REE up to 700 mg/kg, Mn up to 23 g/kg, Fe up to 37 g/kg and Al up to 25 g/kg), opening the possibility of reuse and recovery.

Geographic source estimation using airborne plant environmental DNA in dust

Information obtained from the analysis of dust, particularly biological particles such as pollen, plant parts, and fungal spores, has great utility in forensic geolocation. As an alternative to manual microscopic analysis of dust components, we developed a pipeline that utilizes the airborne plant environmental DNA (eDNA) in settled dust to estimate geographic origin. Metabarcoding of settled airborne eDNA was used to identify plant species whose geographic distributions were then derived from occurrence records in the USGS Biodiversity in Service of Our Nation (BISON) database. The distributions for all plant species identified in a sample were used to generate a probabilistic estimate of the sample source. With settled dust collected at four U.S. sites over a 15-month period, we demonstrated positive regional geolocation (within 600 km2 of the collection point) with 47.6% (20 of 42) of the samples analyzed. Attribution accuracy and resolution was dependent on the number of plant species identified in a dust sample, which was greatly affected by the season of collection. In dust samples that yielded a minimum of 20 identified plant species, positive regional attribution was achieved with 66.7% (16 of 24 samples). For broader demonstration, citizen-collected dust samples collected from 31 diverse U.S. sites were analyzed, and trace plant eDNA provided relevant regional attribution information on provenance in 32.2% of samples. This showed that analysis of airborne plant eDNA in settled dust can provide an accurate estimate regional provenance within the U.S., and relevant forensic information, for a substantial fraction of samples analyzed.

Estimation of Geographic Origin from Dust Using Plant DNA Metabarcoding

Information obtained from the analysis of dust, particularly biological particles such as pollen, plant parts, and fungal spores, has great utility in forensic geolocation. As an alternative to manual microscopic analysis, we developed a pipeline that utilizes the environmental DNA (eDNA) from plants in dust samples to estimate previous sample location(s). The species of plant-derived eDNA within dust samples were identified using metabarcoding and their geographic distributions were then derived from occurrence records in the USGS Biodiversity in Service of Our Nation (BISON) database. The distributions for all plant species identified in a sample were used to generate a probabilistic estimate of the sample source. With settled dust collected at four U.S. sites over a 15-month period, we demonstrated positive regional geolocation (within 600 km 2 of the collection point) with 47.6% (20 of 42) of the samples analyzed. Attribution accuracy and resolution was dependent on the number of plant species identified in a dust sample, which was greatly affected by the season of collection. In dust samples that yielded a minimum of 20 identified plant species, positive regional attribution improved to 66.7% (16 of 24 samples). Using dust samples collected from 31 different U.S. sites, trace plant eDNA provided relevant regional attribution information on provenance in 32.2%. This demonstrated that analysis of plant eDNA in dust can provide an accurate estimate regional provenance within the U.S., and relevant forensic information, for a substantial fraction of samples analyzed.