小球藻(Chlorella vulgaris)净化沼液和提纯沼气

为了研究同时提纯沼气和净化沼液的可能,利用沼液作为小球藻(Chlorella vulgaris)的培养基,同时把沼气中的CO2作为小球藻培养的碳源。在无菌培养条件下,得出了最适生长条件为沼液浓度50%、初始pH值6.0、接种小球藻干重为0.20 mg/mL、光质为红光。在此条件下沼液中的COD、TN、TP和BOD5的去除率分别达到了88.5%、91.2%、95.3%和87.6%,沼气中甲烷含量由原先的40%提升到60.2%。很好地同时解决了沼气品质低下和高浓度污染物沼液污染环境的问题。     

Toxicity and genotoxic evaluations in African catfish Clarias gariepinus (Burchell 1822) exposed to Act Force Gold®, Butaforce®, and Atraforce®

Act Force Gold^®, Butaforce^®, and Atraforce^® are among the most commonly used pesticides in Nigeria. The lethal concentrations and the respective toxic units for the three pesticides were determined. The genotoxic effects of the three pesticides were investigated in the red blood cells of Clarias gariepinus using micronucleus (MN) assay. The 96 h LC₅₀ was 4.75, 4.84, and 54.74 mg L⁻¹ for Act Force Gold^®, Butaforce^®, and Atraforce^®, respectively. The toxic units in ascending order of toxicity were 1.83, 20.66, and 21.05 for Act Force Gold^®, Butaforce^®, and Atraforce^® respectively. The estimated safe levels based on NAS/NAE varied from 4.75 × 10⁻¹–4.75 × 10⁻⁵ in Act Force Gold^® through 4.64 × 10⁻¹–4.85 × 10⁻⁵ in Butaforce^® to 5.74–5.74 × 10⁻⁵ in Atraforce^®. Fish specimens were exposed to the pesticides and sampling was done at regular intervals at days 1, 7, 14, and 21 and after another 7-day recovery period. The results obtained indicated concentration- and duration-dependent increase in % MN formation with maximum values of 3.40 ± 0.25 for Act Force Gold^® on day 14 and 3.05 ± 0.36 and 2.35 ± 0.14 for Butaforce^® and Atraforce^® respectively on day 7 of exposure. The 7-day recovery period could not reverse the trend as the % MN values obtained were significantly different from the control. The results further support the use of MN assay in assessing the toxicity of aquatic pollutants and can be used in the monitoring of aquatic ecosystems.

     

Long-term evaluation of activated carbon as an adsorbent for biogas desulfurization

ABSTRACT

In this study, granular activated carbon (GAC) was used as an adsorbent for biogas desulfurization. Biogas containing 932–2,350 ppm of H₂S was collected from an anaerobic digester to treat the wastewater from a dairy farm with about 200 cows. An adsorption test was performed by introducing the biogas to a column that was packed with approximately 50 L of commercial GAC. The operation ceased if the effluent gas had an H₂S concentration of over 100 ppm. The GAC was replaced by a given weight of new GAC in a subsequent test. According to the results, for H₂S concentrations in the range of 932–1,560 ppm (average±SD = 1,260 ± 256 ppm), 1 kg of the GAC yielded biogas treatment capacities of 568 ± 112 m³ and H₂S adsorption capacities of 979 ± 235 g. For the higher influent H₂S concentrations of 2,110 ± 219 ppm, the biogas treatment and H₂S-adsorption capacities decreased to 229 ± 18 m³ and 668 ± 47 g, respectively. An estimation indicated a requisite cost of US$16.5 for the purification of 1,000 m³ of biogas containing 2,110 ppm of H₂S. This cost is approximately 5% of US$330, the value of 1,000 m³ of biogas.     

Efficacy of supplementation of selected medicinal mushrooms with inorganic selenium salts

The aim of the study was to evaluate the possibility of supplementation with inorganic forms of selenium (Na₂SeO₄ and Na₂SeO₃) in concentrations of 0, 0.1, 0.2, 0.4, 0.6, 0.8, 1.0 and 1.5 mM of three medicinal mushroom species: Agrocybe aegerita, Hericium erinaceus and Ganoderma lucidum. Tested mushroom species grew in Se additions of 0–0.6 mM (A. aegerita and H. erinaceus), while growth of G. lucidum bodies was observed for 0–0.8 mM. For the latter mushroom species, the total Se content was the highest. Content of Se_org was diverse; for control bodies it was the highest for G. lucidum (only organic forms were present), lower for A. aegerita (84% organic forms) and the lowest for H. erinaceus (56% organic forms). Accumulation of Se(IV) was generally significantly higher than Se(VI) for all tested mushroom species. There was no significant decrease of A. aegerita or G. lucidum biomass with the exception of G. lucidum bodies growing under 0.8 mM of Se species addition (15.51 ± 6.53 g). Biomass of H. erinaceus bodies was the highest under 0.2 (197.04 ± 8.73 g), control (191.80 ± 6.06 g) and 0.1 mM (185.04 ± 8.73 g) of both inorganic salts. The addition to the medium of Se salts brought about macroscopic changes in the fruiting bodies of the examined mushrooms. Concentrations exceeding 0.4 mM caused diminution of carpophores or even their total absence. In addition, colour changes of fruiting bodies were also recorded. At Se concentrations of 0.4 and 0.6 mM, A. aegerita fruiting bodies were distinctly lighter and those of H. erinaceus changed colour from purely white to white-pink.     

Pilot‐scale field study for ammonia removal from lagoon biogas using an acid wet scrubber

The anaerobic activities in swine slurry storage and treatment generate biogas containing gaseous ammonia component which is a chemical agent that can cause adverse environmental impacts when released to the atmosphere. The aim of this pilot plant study was to remove ammonia from biogas generated in a covered lagoon, using a sulfuric acid wet scrubber. The data showed that, on average, the biogas contained 43.7 ppm of ammonia and its concentration was found to be exponentially related to the air temperature inside the lagoon. When the air temperature rose to 35°C and the biogas ammonia concentration reached 90 ppm, the mass transfer of ammonia/ammonium from the deeper liquid body to the interface between the air and liquid became a limiting factor. The biogas velocity was critical in affecting ammonia removal efficiency of the wet scrubber. A biogas flow velocity of 8 to 12 mm s^?1 was recommended to achieve a removal efficiency of greater than 60%. Stepwise regression revealed that the biogas velocity and air temperature, not the inlet ammonia concentration in biogas, affected the ammonia removal efficiency. Overall, when 73 g L^?1 (or 0.75 M) sulfuric acid solution was used as the scrubber solution, removal efficiencies varied from 0% to 100% with an average of 55% over a 40‐d measurement period. Mass balance calculation based on ammonium–nitrogen concentration in final scrubber liquid showed that about 21.3 g of ammonia was collected from a total volume of 1169 m³ of biogas, while the scrubber solution should still maintain its ammonia absorbing ability until its concentration reaches up to 1 M. These results showed promising use of sulfuric acid wet scrubber for ammonia removal in the digester biogas.     

Association of human cohorts exposed to blood and urinary biomarkers of PAHs with adult asthma in a South Asian metropolitan city

Semi-volatile organic compounds (SVOCs) are a major global problem that causes the greatest impact on urban settings and have been linked to bronchial asthma in both children and adults in Pakistan. The association between exposure of polycyclic aromatic hydrocarbons (PAHs) and asthma in the adult population is less clear. The current study aimed to assess the clinico-chemical parameters and blood levels of naphthalene phenanthrene, pyrene, and 1,2-benzanthracene and urinary levels of 1-OH pyrene and 1-OH phenanthrene as well as asthma-related biomarkers immunoglobulin E (IgE), resistin, and superoxide dismutase (SOD) of oxidative stress and other hematologic parameters in adults and their relationship with bronchial asthma. The GC/MS analysis showed higher mean concentrations of blood PAHs in asthma respondents (4.48 ± 1.34, 3.46 ± 1.04, 0.10 ± 0.03, and 0.29 ± 0.09) (ng/mL) as compared to controls (3.07 ± 0.92, 1.71 ± 0.51, 0.06 ± 0.02, and 0.11 ± 0.03) (ng/mL), with p = .006, p = .001, p = .050, and p = .001. Similarly, urinary levels of 1-OHpyr and 1-OHphe were significantly increased in adults with bronchial asthma (0.54 ± 0.16; 0.13 ± 0.04) (μmol/mol-Cr) than in controls (0.30 ± 0.09; 0.05 ± 0.02) (μmol/mol-Cr), with p = .002 and p = .0001, respectively, with a significant positive correlation to asthma severity. The asthma-related biomarkers IgE, resistin, and SOD were significantly higher (p 0.0001, 0.0001, and 0.0001) in people with asthma than in control persons. The findings showed that higher blood and urine PAHs levels were linked to higher asthma risk in adults and significant interaction with participants who smoked, had allergies, had a family history of asthma, and were exposed to dust. The current study’s findings will be useful to local regulatory agencies in Lahore in terms of managing exposure and advocating efforts to minimize PAH pollution and manage health.

     

Control measure implications of COVID-19 infection in healthcare facilities reconsidered from human physiological and engineering aspects

The Wells-Riley model invokes human physiological and engineering parameters to successfully treat airborne transmission of infectious diseases. Applications of this model would have high potentiality on evaluating policy actions and interventions intended to improve public safety efforts on preventing the spread of COVID-19 in an enclosed space. Here, we constructed the interaction relationships among basic reproduction number (R₀) − exposure time − indoor population number by using the Wells-Riley model to provide a robust means to assist in planning containment efforts. We quantified SARS-CoV-2 changes in a case study of two Wuhan (Fangcang and Renmin) hospitals. We conducted similar approach to develop control measures in various hospital functional units by taking all accountable factors. We showed that inhalation rates of individuals proved crucial for influencing the transmissibility of SARS-CoV-2, followed by air supply rate and exposure time. We suggest a minimum air change per hour (ACH) of 7 h⁻¹ would be at least appropriate with current room volume requirements in healthcare buildings when indoor population number is < 10 and exposure time is < 1 h with one infector and low activity levels being considered. However, higher ACH (> 16 h⁻¹) with optimal arranged-exposure time/people and high-efficiency air filters would be suggested if more infectors or higher activity levels are presented. Our models lay out a practical metric for evaluating the efficacy of control measures on COVID-19 infection in built environments. Our case studies further indicate that the Wells-Riley model provides a predictive and mechanistic basis for empirical COVID-19 impact reduction planning and gives a framework to treat highly transmissible but mechanically heterogeneous airborne SARS-CoV-2.

     

Aerosol scattering properties in northern China

The aerosol scattering properties were investigated at two continental sites in northern China in 2004. Aerosol light scattering coefficient (σ_sp) at 525 nm, PM₁₀, and aerosol mass scattering efficiencies (α) at Dunhuang had a mean value of 165.1±148.8 M m⁻¹, 157.6±270.0 μg m⁻³, and 2.30±3.41 m² g⁻¹, respectively, while these values at Dongsheng were, respectively, 180.2±151.9 M m⁻¹, 119.0±112.9 μg m⁻³, and 1.87±1.41 m² g⁻¹. There existed a seasonal variability of aerosol scattering properties. In spring, at Dunhuang PM₁₀, σ_sp, and α were 184.1±211.548 μg m⁻³, 126.3±89.6 M m⁻¹, and 1.05±0.97 m² g⁻¹, respectively, and these values at Dongsheng were 146.4±142.1 μg m⁻³, 183.4±81.7 M m⁻¹, and 1.98±1.52 m² g⁻¹, respectively. However, in winter at Dunhuang PM₁₀, σ_sp, and α were 158.1±261.4 μg m⁻³, 303.3±165.2 M m⁻¹, and 3.17±1.93 m² g⁻¹, respectively, and these values at Dongsheng were 155.7±170.1 μg m⁻³, 304.4±158.1 M m⁻¹, and 2.90±1.72 m² g⁻¹, respectively. σ_sp and α in winter were higher than that in spring at both the sites, which coincides with the characteristics of dust aerosol and pollution aerosol. Overall, the dominant aerosol types in spring and winter at both sites in northern China are dust aerosol and pollution aerosol, respectively.     

Biogenic nitric oxide emissions from cropland soils

Emissions of nitric oxide (NO) were determined during late spring and summer 1995 and the spring of 1996 from four agricultural soils on which four different crops were grown. These agricultural soils were located at four different sites throughout North Carolina. Emission rates were calculated using a dynamic flow-through chamber system coupled to a mobile laboratory for in-situ analysis. Average NO fluxes during late spring 1995 were: 50.9±47.7 ng N m⁻² s⁻¹ from soil planted with corn in the lower coastal plain. Average NO fluxes during summer 1995 were: 6.4±4.6 and 20.2±19.0 ng N m⁻² s⁻¹, respectively, from soils planted with corn and soybean in the coastal region; 4.2±1.7 ng N m⁻² s⁻¹ from soils planted with tobacco in the piedmont region; and 8.5±4.9 ng N m⁻² s⁻¹ from soils planted with corn in the upper piedmont region. Average NO fluxes for spring 1996 were: 66.7±60.7 ng N m⁻² s⁻¹ from soils planted with wheat in the lower coastal plain; 9.5±2.9 ng N m⁻² s⁻¹ from soils planted with wheat in the coastal plain; 2.7±3.4 ng N m⁻² s⁻¹ from soils planted with wheat in the piedmont region; and 56.1±53.7 ng N m⁻² s⁻¹ from soils planted with corn in the upper piedmont region. An apparent increase in NO flux with soil temperature was present at all of the locations. The composite data from all the research sites revealed a general positive trend of increasing NO flux with soil water content. In general, increases in total extractable nitrogen (TEN) appeared to be related to increased NO emissions within each site, however a consistent trend was not evident across all sites.     

Immunostimulating effects of Ginkgo biloba extract against toxicity induced by organophosphate pesticide,diazinon in rainbow trout,Oncorhynchus mykiss: innate immunity components and immune-related genes

The immunostimulating and therapeutic properties of Ginkgo biloba (GB) have always been the focus of traditional medicine over thousands of years. During last decade, special attentions were paid to use of GB in aquaculture to enhance fish health and survival. In the present study, we investigated for the first time the immunogenic effects of dietary GB against oxidative and toxicity induced by organophosphate pesticide, diazinon. In non-diazinon-exposed fish, the plasma total immunoglobulin, lysozyme activity, and peroxidase activity significantly elevated after 60-day experiment in fish supplemented with 1 and 2 g GB/kg diet (p < 0.05). The respiratory burst activity and complement activity significantly increased only in groups supplemented with 0.5 g GB/kg diet (p < 0.05). Furthermore, the peroxidase activity, total immunoglobulin, and lysozyme activity significantly declined in groups supplemented with 4 g GB/kg diet during feeding trial (p < 0.05). There were no significant differences in expression of interleukin 1 beta (IL-1β) and transforming growth factor beta 1 (TGF-β1) genes in kidney between control group (non-GB-supplemented fish) and GB-supplemented fish (p > 0.05). In diazinon-exposed fish, all immunity components significantly decreased during exposure in control and those fed 0.5 and 4 g GB/kg diet (p < 0.05). In fish fed 1 and 2 g GB/kg diet, no alternations were found in immunity components during exposure period (p > 0.05). In addition, diazinon induced the expression of IL-1β and TGF-β1 genes in control and fish fed 0.5 and 4 g GB/kg diet (p < 0.05). No significant changes were observed in expression of IL-1β and TGF-β1 genes in fish supplemented with 1 and 2 g GB/kg (p > 0.05). In conclusion, the results of the present study suggest an immunogenic role for dietary GB at optimum dietary levels (1–2 g GB/kg diet) against toxicity induced by diazinon. Nevertheless, GB at high dietary levels (4 g GB/kg diet) showed immunosuppressive effects, which makes it necessary to optimize its levels in diet.

     

Biogenic VOC emissions from fresh leaf mulch and wood chips of Grevillea robusta (Australian Silky Oak)

The emissions of VOC from freshly cut and shredded Grevillea robusta (Australian Silky Oak) leaves and wood have been measured. The VOC emissions from fresh leaf mulch and wood chips lasted typically for 30 and 20 h respectively, and consisted primarily of ethanol, (E)-2-hexenal, (Z)-3-hexen-1-ol and acetaldehyde. The integrated emissions of the VOCs were 0.38±0.04 g kg⁻¹ from leaf mulch, and 0.022±0.003 g kg⁻¹ from wood chips. These emissions represent a source of VOCs in urban and rural air that has previously been unquantified and is currently unaccounted for. These VOCs from leaf mulch and wood chips will contribute to both urban photochemistry and secondary organic aerosol formation. Any CH₄ emissions from leaf mulch and wood chips were <1×10⁻¹¹ g g dry mass⁻¹ s⁻¹.     

Photooxidation of methylhydroperoxide and ethylhydroperoxide in the aqueous phase under simulated cloud droplet conditions

The photooxidation of methylhydroperoxide (MHP) and ethylhydroperoxide (EHP) was studied in the aqueous phase under simulated cloud droplet conditions. The kinetics and the reaction products of direct photolysis and OH-oxidation were studied for both compounds. The photolysis frequencies obtained were J_MHP=4.5 (±1.0)×10⁻⁵ s⁻¹ and J_EHP=3.8 (±1.0)×10⁻⁵ s⁻¹ for MHP and EHP respectively at 6 °C. The rate constants of OH-oxidation of MHP at 6 °C were 6.3 (±2.6)×10⁸ M⁻¹ s⁻¹ and 5.8 (±1.9)×10⁸ M⁻¹ s⁻¹ relative to ethanol and 2-propanol respectively, and the rate constant of OH-oxidation of EHP was 2.1 (±0.6)×10⁹ M⁻¹ s⁻¹ relative to 2-propanol at 6 °C. The reaction products obtained were not only the corresponding aldehydes, but also the corresponding acids, and hydroxyhydroperoxides as primary reaction products. The yields for these products were sensitive to the pH value. The carbon balance was higher than 85% for all experiments, showing that most reaction products were detected. A chemical mechanism was proposed for each reaction, and the atmospheric implications were discussed.     

Green synthesis silver nanoparticles Bougainvillea glabra Choisy/LED light with high catalytic activity in the removal of methylene blue aqueous solution

In this study, we evaluated, in a pioneering way, the influence of wavelengths from the decomposition of white light on the production and physicochemical properties of silver nanoparticles (AgNPs). Bearing in mind a process of green synthesis, an extract of the bracts of Bougainvillea glabra Choisy (BgC) was used, a species native to tropical and subtropical regions and frequently used in ornamentation, possessing in its photochemical composition, biomolecules capable of acting as reducing agents for convert Ag⁺ to Ag⁰. We used light-emitting diodes (LED) to obtain the desired wavelengths (violet, blue, green, yellow, orange, and red) in the test called rainbow, and we evaluated the obtaining of AgNPs compared to white LED light, nature, and absence of light. In the rainbow assay, we obtained a gradual increase in the intensity of the plasmonic band resonance from the red wavelength (0.124 ± 0.067 a.u.) to violet (0.680 ± 0.199 a.u.), indicating a higher reaction yield in obtaining AgNPs. Smaller hydrodynamic sizes (approximately 150 nm) at more energetic wavelengths (violet, blue, and green) about less energetic wavelengths (yellow, orange, and red) (approximately 400 nm) were obtained. Analysis by SEM microscopy, FTIR spectroscopy, and X-ray diffraction indicates the presence of silver nanoparticles in all LED colors used together with white LED light and Laboratory light (natural light). Due to the high environmental demand to remove pollutants from water sources, including textile dyes, we applied AgNPs/BgC to remove methylene blue (MB) dye from an aqueous solution. A minimum removal percentage greater than 65%, with emphasis on formulations synthesized by the colors of violet LED (84.27 ± 2.65%) and orange LED (85.91 ± 1.95%), was obtained.

     

Emission factors of PAHs,methoxyphenols, levoglucosan,elemental carbon and organic carbon from simulated wheat and Kentucky bluegrass stubble burns

Emission factors (EFs) of pollutants from post-harvest agricultural burning are required for predicting downwind impacts of smoke and inventorying emissions. EFs of polycyclic aromatic hydrocarbons (PAH), methoxyphenols (MP), levoglucosan (LG), elemental carbon (EC) and organic carbon (OC) from wheat and Kentucky bluegrass (KBG) stubble burning were quantified in a US EPA test burn facility. The PAH and MP EFs for combined solid+gas phases are 17±8.2 mg kg⁻¹ and 79±36 mg kg⁻¹, respectively, for wheat and 21±15 mg kg⁻¹ and 35±24 mg kg⁻¹, respectively, for KBG. LG, particulate EC and artifact-corrected OC EFs are 150±130 mg kg⁻¹, 0.35±0.16 g kg⁻¹ and 1.9±1.1 g kg⁻¹, respectively, for wheat and 350±510 mg kg⁻¹, 0.63±0.056 g kg⁻¹ and 6.9±0.85 g kg⁻¹, respectively, for KBG. Positive artifacts associated with OC sampling were evaluated and remedied with a two-filter system. EC and OC accounted for almost two-thirds of PM_2.5 mass, while LG accounted for just under 3% of the PM_2.5 mass. Since EFs of these pollutants generally decreased with increasing combustion efficiency (CE), identifying and implementing methods of increasing the CEs of burns would help reduce their emissions from agricultural field burning. PAH, OC and EC EFs are comparable to other similar studies reported in literature. MP EFs appear dependent on the stubble type and are lower than the EFs for hard and softwoods reported in literature, possibly due to the lower lignin content in wheat and KBG.     

Effect of fipronil on biogas production performance during anaerobic digestion of chicken manure and corn straw

Fipronil is a broad-spectrum insecticide that has a good control effect on pests of commercial poultry. Although many studies have reported the environmental fate of fipronil, the influence of residual fipronil in poultry waste on biogas production has not been further explored yet. In this article, an experimental comparative study on anaerobic digestion (AD) of chicken manure (CM) and corn straw (CS) with different fipronil concentrations (FCs) was carried at 8% of total solid (TS) and mid-temperature (35?±?1)°C. The results showed that fipronil had a significant effect on biogas production during AD of CM and CS. When the FC is at a low level (≤10?mg·kg^?1), the biogas production rate is increased and the digestion period was shortened, while higher FC (≥ 20?mg·kg^?1) showed an inhibitory effect. During the monitoring of enzyme activity, low FC showed no significant effect on cellulase and saccharase, but the urease activity increased in the early stage. High FC showed inhibition of activity of cellulase and urease, but the saccharase activity was significantly inhibited until FC reached 40?mg·kg^?1. This study also confirms that the environment in anaerobic digester is favorable for the degradation of fipronil, and its half-life is about 15.83?days.     

Active methods of mercury removal from flue gases

Due to its adverse impact on health, as well as its global distribution, long atmospheric lifetime and propensity for deposition in the aquatic environment and in living tissue, the US Environmental Protection Agency (US EPA) has classified mercury and its compounds as a severe air quality threat. Such widespread presence of mercury in the environment originates from both natural and anthropogenic sources. Global anthropogenic emission of mercury is evaluated at 2000 Mg year⁻¹. According to the National Centre for Emissions Management (Pol. KOBiZE) report for 2014, Polish annual mercury emissions amount to approximately 10 Mg. Over 90% of mercury emissions in Poland originate from combustion of coal.

The purpose of this paper was to understand mercury behaviour during sub-bituminous coal and lignite combustion for flue gas purification in terms of reduction of emissions by active methods. The average mercury content in Polish sub-bituminous coal and lignite was 103.7 and 443.5 μg kg⁻¹. The concentration of mercury in flue gases emitted into the atmosphere was 5.3 μg m⁻³ for sub-bituminous coal and 17.5 μg m⁻³ for lignite. The study analysed six low-cost sorbents with the average achieved efficiency of mercury removal from 30.6 to 92.9% for sub-bituminous coal and 22.8 to 80.3% for lignite combustion. Also, the effect of coke dust grain size was examined for mercury sorptive properties. The fine fraction of coke dust (CD) adsorbed within 243–277 μg Hg kg⁻¹, while the largest fraction at only 95 μg Hg kg⁻¹. The CD fraction < 0.063 mm removed almost 92% of mercury during coal combustion, so the concentration of mercury in flue gas decreased from 5.3 to 0.4 μg Hg m⁻³. The same fraction of CD had removed 93% of mercury from lignite flue gas by reducing the concentration of mercury in the flow from 17.6 to 1.2 μg Hg m⁻³. The publication also presents the impact of photochemical oxidation of mercury on the effectiveness of Hg vapour removal during combustion of lignite. After physical oxidation of Hg in the flue gas, its effectiveness has increased twofold.

     

FT-IR kinetic and product study of the Br-radical initiated oxidation of α, β-unsaturated organic carbonyl compounds

Using the relative kinetic technique the kinetics of the gas-phase reactions of Br radicals with acrolein, methacrolein and methylvinyl ketone have been investigated at (301±3) K in 1013 mbar of (N₂+O₂) bath gas at varying proportions. In 1013 mbar of synthetic air the following rate coefficients have been obtained (in units of cm³ molecule⁻¹ s⁻¹): acrolein (3.21±0.11)×10⁻¹²; methacrolein (2.33±0.08)×10⁻¹¹; methyl vinyl ketone (1.87±0.06)×10⁻¹¹. This study represents the first determination of the rate coefficients for these compounds. As for other unsaturated hydrocarbons the rate coefficient with Br was found to increase with increasing partial pressure of O₂. From the product studies of the reactions it has been established that addition of Br radicals to the terminal C-atom is the major pathway in all three cases. However, for acrolein H atom abstraction from the -CO–H group is also significant. Mechanisms are proposed to explain the observed products, mainly β-brominated carbonyl compounds.     

Night-time tropospheric chemistry of the unsaturated alcohols (Z)-pent-2-en-1-ol and pent-1-en-3-ol: Kinetic studies of reactions of NO3 and N2O5 with stress-induced plant emissions

The night-time tropospheric chemistry of two stress-induced volatile organic compounds (VOCs), (Z)-pent-2-en-1-ol and pent-1-en-3-ol, has been studied at room temperature. Rate coefficients for reactions of the nitrate radical (NO₃) with these pentenols were measured using the discharge-flow technique. Because of the relatively low volatility of these compounds, we employed off-axis continuous-wave cavity-enhanced absorption spectroscopy for detection of NO₃ in order to be able to work in pseudo first-order conditions with the pentenols in large excess over NO₃. The rate coefficients were determined to be (1.53±0.23)×10⁻¹³ and (1.39±0.19)×10⁻¹⁴ cm³ molecule⁻¹ s⁻¹ for reactions of NO₃ with (Z)-pent-2-en-1-ol and pent-1-en-3-ol. An attempt to study the kinetics of these reactions with a relative-rate technique, using N₂O₅ as source of NO₃ resulted in significantly higher apparent rate coefficients. Performing relative-rate experiments in known excesses of NO₂ allowed us to determine the rate coefficients for the N₂O₅ reactions to be (5.0±2.8)×10⁻¹⁹ cm³ molecule⁻¹ s⁻¹ for (Z)-pent-2-en-1-ol, and (9.1±5.8)×10⁻¹⁹ cm³ molecule⁻¹ s⁻¹ for pent-1-en-3-ol. We show that these relatively slow reactions can indeed interfere with rate determinations in conventional relative-rate experiments.     

Characterization of emissions from portable household combustion devices: particle size distributions,emission rates and factors,and potential exposures

A series of source tests were conducted to characterize emissions of particulate matter (PM), carbon monoxide (CO), carbon dioxide (CO₂), methane (CH₄), and total hydrocarbon (THC ) from five types of portable combustion devices. Tested combustion devices included a kerosene lamp, an oil lamp, a kerosene space heater, a portable gas range, and four unscented candles. All tests were conducted either in a well-mixed chamber or a well-mixed room, which enables us to determine emission rates and emission factors using a single-compartment mass balance model. Particle mass concentrations and number concentrations were measured using a nephelometric particle monitor and an eight-channel optical particle counter, respectively. Real-time CO concentrations were measured with an electrochemical sensor CO monitor. CO₂, CH₄, and THC were measured using a GC-FID technique. The results indicate that all particles emitted during steady burning in each of the tested devices were smaller than 1.0 μm in diameter with the vast majority in the range between 0.1 and 0.3 μm. The PM mass emission rates and emission factors for the tested devices ranged from 5.6±0.1 to 142.3±40.8 mg h⁻¹ and from 0.35±0.06 to 9.04±4.0 mg g⁻¹, respectively. The CO emission rates and emission factors ranged from 4.7±3.0 to 226.7±100 mg h⁻¹ and from 0.25±0.12 to 1.56±0.7 mg g⁻¹, respectively. The CO₂ emission rates and emission factors ranged from 5500±700 to 210,000±90,000 mg h⁻¹ and from 387±45 to 1689±640 mg g⁻¹, respectively. The contributions of CH₄ and THC to emission inventories are expected to be insignificant due both to the small emission factors and to the relatively small quantity of fuel consumed by these portable devices. An exposure scenario analysis indicates that every-day use of the kerosene lamp in a village house can generate fine PM exposures easily exceeding the US promulgated NAAQS for PM_2.5.     

The effect of consumption of pork enriched by organic selenium on selenium status and lipid profile in blood serum of consumers

Abstract

The aim of the research was to evaluate the effect of consumption of selenium-enriched pork on selected health indicators of probands. The intake of feed mixture with increased organic selenium at the dose of 0.3?mg.kg^?1 probably increases selenium concentration in MSM (musculus semimembranosus). In the pork enriched with organic selenium, the concentration was higher by 1.045?±?0.10?mg.kg^?1 compared with the control group 0.701?±?0.05?mg.kg^?1 at significance P?<?0.001. Sixteen participants in the experiment were represented by 8 men at the average age of 41.5?±?11.9?years and 8 women at the average age of 41.4?±?7.9?years. All the probands consumed meat enriched with selenium three times a week during one month. By consumption of the enriched pork, there was an increase of the selenium concentration in blood serum of probands traced with selenium increase from 73.19?±?15.68?μg.L^?1 to 73.73?±?15.13?μg.L^?1 (P?>?0.05). From the results we can see that consumption of enriched pork with selenium was significantly manifested in lowering of total cholesterol levels, which was associated with LDL cholesterol lowering (P?<?0.05). Differences among the HDL cholesterol and triglycerides samples were not significant.