166 research outputs found
Concentrations and risks of p âdichlorobenzene in indoor and outdoor air
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/96332/1/ina796.pd
Polycyclic aromatic hydrocarbons bioaccessibility in seafood: Culinary practices effects on dietary exposure
This work aimed to determine the effect of culinary practices on the contamination level and bioaccessibility of polycyclic aromatic hydrocarbons (PAHs) in seafood. The selected farmed seafood species (marine shrimp, clams and seaweed) were commercially available in Portugal. The mean concentrations of PAHs varied between 0.23 and 51.8âŻÂ”gâŻkg-1, with the lowest value being observed in raw shrimp and the highest in dried seaweed. The number of compounds detected in seaweed and clams (naphthalene, acenaphthene, fluorene, phenanthrene, benzo(b)fluoranthene and benzo(j)fluoranthene) were higher than in shrimp (fluorene and pyrene). Among the PAHs measured, fluorene was the predominant one. There was a significant interaction effect between species and culinary treatment (pâŻ<âŻ0.05), thus boiled and dried seaweed samples presented the lowest and the highest levels of fluorene (0.13 and 1.8âŻÂ”gâŻkg-1), respectively. The daily intake of PAHs decreased with bioaccessibility, varying from 22% for benzo(k)fluoranthene (in raw clam) to 84% for phenanthrene (in steamed clam). According to the potency equivalent concentrations, screening values and bioaccessibility of PAHs, the consumption of marine shrimp, clam and seaweed is considered as safe for consumers.This work received financial support from European (FEDER funds through COMPETE) and Portuguese funds (Fundação para a CiĂȘncia e Tecnologia Project UID/QUI/50006/2013). The Portuguese Foundation for Science and Technology supported the Ph.D. Grant of ALM (SFRH/BD/103569/2014) as well as the post-doc Grant of P.A. (SFRH/BPD/100728/2014) and the IF2014 contract of AM.info:eu-repo/semantics/publishedVersio
Comprehensive organic emission profiles, secondary organic aerosol production potential, and OH reactivity of domestic fuel combustion in Delhi, India
Domestic solid fuel combustion is a major source of organic compounds to the atmosphere in gas and aerosol phases; however, large uncertainties exist in the current understanding of the gas-to-particle partitioning and the drivers of the reactivity of these emissions. This study developed comprehensive, model-ready organic emission profiles for domestic solid fuel combustion sources collected from Delhi, India. It also examined the organic species responsible for secondary organic aerosol (SOA) production potential and hydroxyl radical (OH) reactivity of these emissions. The profiles spanned the entire volatility range, including non-methane volatile organic compounds (NMVOCs, effective saturation concentration, C* = 3 Ă 106 to 1011 ÎŒg mâ3), intermediate-volatility organic compounds (IVOCs, C* = 300 to 3 Ă 106 ÎŒg mâ3), semi-volatile organic compounds (SVOCs, C* = 0.3â300 ÎŒg mâ3) as well as low- and extremely low-volatility organic compounds (L/ELVOCs, where LVOC C* †0.3 ÎŒg mâ3). The profiles predicted that IVOCs would contribute significantly to SOA production and that the combustion of fuel wood and charcoal released some of the smallest proportions of SVOCs. A model was developed to examine SOA production from burning emissions which estimated that phenolics would contribute 10â70% of the SOA. Furanics were the most important reactive species, contributing 9â48% of the OH reactivity and 9â58% of the SOA. Different combustion sources were also compared, with emissions from fuel wood, crop residue, cow dung cake and municipal solid waste (MSW) burning shown to be 30, 90, 120 and 230 times more reactive with the OH radical than emissions from liquefied petroleum gas (LPG) fuel. This study also estimated 3â4 times more SOA from cow dung cake combustion and 6â7 more from MSW combustion than fuel wood under comparable combustion conditions. The results of this study suggest that emissions from the combustion of domestic solid fuel sources in Delhi have the potential to significantly degrade local and regional air quality. As a result, more effective mitigation strategies are required to limit the impacts of solid fuel combustion on human health in countries like India
micrograms per day Reference
This proposed regulation sets forth a maximum allowable dose level (MADL) fo
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