Brominated flame retardant migration into indoor dust

Brominated flame retardants (BFRs) are ubiquitous in indoor air and dust, leading to human exposure and resultant concerns about adverse impact on health. Despite elevated concentrations in dust, little is known about how BFRs transfer to dust from treated products. A test chamber was constructed to investigate pathways via which the polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) migrate from source materials to indoor dust. These were: (1) BFRs volatilise and subsequently partition to dust, (2) particles or fibres of the source abrade, transfering to dust directly (3) direct source-dust contact results in transfer. A HBCD treated textile curtain, and a PBDE TV casing were both tested. Partitioning post volatilisation was a less effective mechanism than abrasion. Direct source-dust contact resulted in effective and rapid transfer. A forensic microscopy investigation on ‘real world’ dust of elevated BFR content identified polymer particles containing BDE-209, likely originating from a BFR treated polymeric material indicating abrasion. An $in$ $vitro$ extraction test investigated the bioaccessibility of dust contaminated $via$ pathways (1) and (2). Results indicate bioaccessibility may be less efficient from samples containing elevated concentrations of BFRs, and from dusts contaminated primarily via abrasion. More detailed research is essential to confirm these findings

Does the source migration pathway of HBCDs to household dust influence their bioaccessibility?

A study was conducted to assess the human bioaccessibility of dust contaminated with hexabromocyclododecane (HBCD) via two migration pathways a) volatilisation with subsequent partitioning to dust particles, and b) abrasion of treated textile fibres directly to the dust. This was achieved using previously developed experimental chamber designs to generate dust samples contaminated with HBCDs emit-ted from a HBCD treated textile curtain. The generated dust samples were exposed to an in vitro colon extended physiologically based extraction test (CE-PBET). The bioaccessibility of the HBCDs which were incorporated within dust as a result of volatilisation from the curtain material with subsequent partitioning to dust was higher than in dusts contaminated with HBCDs via abrasion of the curtain (35% and 15% respectively). We propose this occurs due to a stronger binding of HBCDs to treated fabric fibres than that experienced following volatilisation and sorption of HBCDs to dust particles

Mass transfer of PBDEs from plastic TV casing to indoor dust via three migration pathways - A test chamber investigation

Polybrominated diphenyl ethers (PBDEs) are widely detected in humans with substantial exposure thought to occur in indoor environments and particularly via contact with indoor dust. Despite this, knowledge of how PBDEs migrate to indoor dust from products within which they are incorporated is scarce. This study utilises an in-house designed and built test chamber to investigate the relative significance of different mechanisms via which PBDEs transfer from source materials to dust, using a plastic TV casing treated with the Deca-BDE formulation as a model source. Experiments at both room temperature and 60 degrees C revealed no detectable transfer of PBDEs from the TV casing to dust via volatilisation and subsequent partitioning. In contrast, substantial transfer of PBDEs to dust was detected when the TV casing was abraded using a magnetic stirrer bar. Rapid and substantial PBDE transfer to dust was also observed in experiments in which dust was placed in direct contact with the source. Based on these experiments, we suggest that for higher molecular weight PBDEs like BDE-209; direct dust: source contact is the principal pathway via which source-to-dust transfer occurs

Challenges with Quantifying Tire Road Wear Particles: Recognizing the Need for Further Refinement of the ISO Technical Specification

Environmental monitoring data for tire road wear particles are vastly limited compared to those for other microplastics, primarily due to analytical challenges with quantification. Recently, two ISO technical specifications have been released using pyrolysis GC-MS for quantification. However, these methods have major assumptions, including that the content of natural and synthetic rubber in tire tread is constant across formulations and that the pyrolysis products chosen are selective. This study analyzed a wide range of commercially available tires from Australia and Norway, using pyrolysis GC-MS to test these assumptions. The percent mass of synthetic rubber in tires (n = 39) was highly variable, ranging from <0.05 to 28%, when using the ISO-recommended pyrolysis product 4-vinylcyclohexene. The content varied between brands and models, demonstrating that formulations are highly variable and unknown. The styrene butadiene dimer and trimer pyrolysis products were also assessed, and the calculated synthetic rubber content was higher, had an even greater variability, and had no correlation with concentrations calculated using 4-vinylcyclohexene. Using the ISO method has the potential to underreport environmental concentrations of TRWPs by a factor of at least 5, suggesting the specification requires further refinement, and there is an immediate need for large-scale analysis of commercial tire treads and assessments of suitable pyrolysis products.acceptedVersio

Test chamber investigation of the volatilization from source materials of brominated flame retardants and their subsequent deposition to indoor dust

Numerous studies have reported elevated concentrations of brominated flame retardants (BFRs) in dust from indoor micro-environments. Limited information is available, however, on the pathways via which BFRs in source materials transfer to indoor dust. The most likely hypothesized pathways are (a) volatilization from the source with subsequent partitioning to dust, (b) abrasion of the treated product, transferring microscopic fibers or particles to the dust (c) direct uptake to dust via contact between source and dust. This study reports the development and application of an in-house test chamber for investigating BFR volatilization from source materials and subsequent partitioning to dust. The performance of the chamber was evaluated against that of a commercially available chamber, and inherent issues with such chambers were investigated, such as loss due to sorption of BFRs to chamber surfaces (so-called sink effects). The partitioning of polybrominated diphenyl ethers to dust, post-volatilization from an artificial source was demonstrated, while analysis in the test chamber of a fabric curtain treated with the hexabromocyclododecane formulation, resulted in dust concentrations exceeding substantially those detected in the dust pre-experiment. These results provide the first experimental evidence of BFR volatilization followed by deposition to dust

Анализ себестоимости продукции предприятия

Актуальность данной работы обусловлена непосредственным влиянием себестоимости продукции на финансовые результаты деятельности предприятия, его конкурентоспособность и востребованность продукции на рынке. В работе изучены теоретические основы анализа себестоимости продукции, разработаны предложения по снижению себестоимости производства на предприятии АО "АГМК".The relevance of this work is due to the direct influence of the cost of production on the financial results of the enterprise, its competitiveness and the demand for products in the market. The paper studies the theoretical foundations of the analysis of the cost of production, developed proposals to reduce the cost of production at the enterprise of JSC "AGMK"