Biosensing of an indoor volatile organic compound on the basis of fungal growth

A fungal biosensor plate was applied to assessment of the harmfulness of air polluted by formaldehyde. Alternariaalternata, Eurotiumherbariorum and Aspergilluspenicillioides were used as fungal species. Fungal mycelium length and optical transparency of the biosensor plate were employed as indices of the fungal growth. Formaldehyde in air was detected on the basis of growth inhibition, reflected by suppression of the growth indices. Dynamic range of the measurement was 700-4000 microg m(-3) or broader. Eurotiumherbariorum and Aspergilluspenicillioides were the most suitable fungal species to formaldehyde sensing based on the mycelium length and that based on the transparency, respectively.     

Toxicological effects of marine palytoxin evaluated by FETAX assay

The FETAX (frog embryo teratogenesis assay Xenopus) is considered a useful bioassay to detect health hazard substances. In the study of the marine toxin palytoxin (PTX), FETAX has revealed evident impacts on embryo mortality, teratogenesis and growth at the two highest (370 and 37nM) concentrations used. Significant mortality rates, peaks in the number of malformed embryos and delays in growth were found, while the total sample number fell by about 80% at the end of the assay with the concentrated dose. The histological analysis to evaluate the morpho-functional induced modifications demonstrated damage to the nervous and muscle tissue, a general reduction in the size of the main inner visceral organs and severe injury to the heart structure in some specimens. No inflammatory response was observed.     

Antioxidant enzyme activities as affected by trivalent and hexavalent chromium species in Fontinalis antipyretica Hedw

The detoxification mechanisms of the aquatic moss, Fontinalis antipyretica Hedw., exposed to Cr was analyzed. In addition, the influence of Cr salts (as Cr nitrate, chloride and potassium bichromate) on these mechanisms has also been studied. The activity of antioxidant enzymes superoxide dismutase (SOD, EC 1.15.1.1.), catalase (EC 1.11.1.6.), ascorbate peroxidase (APX, EC 1.11.1.11.), guaiacol peroxidase (GPX, EC 1.11.1.7.) and glutathione reductase (GR, EC 1.6.4.2.) increased in plants treated with Cr concentrations ranging from 6.25x10(-5) to 6.25mM when given as Cr(NO(3))(3). Antioxidant enzymes responded to the other two salts CrCl(3) and K(2)Cr(2)O(7) only with Cr concentrations higher than 6.25x10(-2)mM. Glutathione level and GSSG/GSH ratio also responded to Cr exposure but no dose-effect relationship could be observed. Moreover, two unknown thiol compounds were observed in mosses exposed to the highest Cr concentrations. Effects on chlorophyll contents and chlorophyll a/b ratios were also shown even at low Cr concentrations. Our results indicated that environmentally realistic concentrations of Cr could lead to impairment of the cellular activity towards F. antipyretica and that Cr(III), when present as a nitrate salt, was as harmful as Cr(VI).     

Minimization of the environmental impact in the unhairing of bovine hides

This study tests an alternative method to the traditional unhairing method used during the process of tanning the hides. The new method is based on the substitution of sodium sulfide by hydrogen peroxide as an unhairing agent in both hair recovery and recirculation of the floats employed in the process. The properties of the hides obtained using the two methods have been compared and the results indicate that those hides have similar physical, chemical, and organoleptic properties. However, the differences existing from an environmental point of view are significant. These include reductions of water consumption (approx 70%), chemical oxygen demand (approx 35%), toxicity (98%) and total kjendhal nitrogen (50%). Also, the risk associated with the production of hydrogen sulfide is eliminated, which implies a great improvement in terms of safety for the workers. Given the large amounts of water and chemical pollution discharged in the process, the reductions in absolute values represent a significant improvement. A financial assessment was carried out to demonstrate that the proposed new system is 16% more economic than the traditional one.     

Carbon black nanoparticles promote the maturation and function of mouse bone marrow-derived dendritic cells

Particulate matter including carbon black (CB) nanoparticles can enhance antigen-related inflammation and immunoglobulin production in vivo. Dendritic cells (DC) as antigen-presenting cells (APC) are the most capable inducers of immune responses. The present study was designed to determine whether CB nanoparticles affect the maturation/activation and function of DC in vitro. DC were differentiated from bone marrow (BM) cells of BALB/c mice by culture with granulocyte macrophage colony stimulating factor (GM-CSF). At day 8 of culture, BM-derived DC (BMDC) were exposed to CB nanoparticles with a diameter of 14nm or 56nm for 24h. The expression of major histocompatibility complex (MHC) class II, DEC205, CD80, and CD86 (maturation/activation markers of BMDC) was measured by flow cytometry. BMDC function was evaluated by an allogeneic mixed lymphocyte reaction (MLR) assay. CB nanoparticles significantly increased the expression of DEC205 and CD86 in BMDC and tended to increase MHC class II and CD80 expression; however, a size-dependent effect was not observed. On the other hand, BMDC-mediated MLR was significantly enhanced by the CB nanoparticles and the enhancement was greater by 14nm CB nanoparticles than by 56nm CB nanoparticles. Taken together, CB nanoparticles can promote the maturation/activation and function of BMDC, which could be related to their effects on allergic diseases and/or responses. In addition, BMDC-mediated MLR might be useful assay for in vitro screening for adjuvant activity of environmental toxicants.     

Diffusion of PAH and PCB from contaminated sediments with and without mineral capping; measurement and modelling

A novel laboratory microcosm test was developed to measure the diffusion of native PAHs and PCBs from sediments in the presence and absence of a capping layer. Diffusive flux of 15 PAHs and 7 PCBs from uncapped sediment from Oslo harbour was 3.8+/-0.9 microg m(-2)d(-1) and 0.010+/-0.003 microg m(-2)d(-1), respectively. The flux from sediments capped with 1cm mineral cap (crushed limestone or crushed gneiss (0-2mm)), observed during the first 410 d, was 3.5-7.3% of the flux from uncapped sediments. By measuring freely dissolved pore water concentrations of 10 PAHs the flux in the microcosm was modelled with steady state and transient diffusion models. The measured flux from uncapped sediment was 27-290% of modelled steady state flux. Good agreement was also found between the measured flux of pyrene from capped sediment and the flux modelled with the transient model when fitting only with the distribution coefficients for pyrene between the cap material and water (Kd_pyr). Fitted Kd_pyr, (210 and 23 l kg(-1) for limestone and gneiss, respectively) was in the same order of magnitude as K(d) calculated from organic carbon content in the cap materials (68 and 14 l kg(-1) respectively). Calculation of the efficiency of a hypothetical cap with 10 cm diffusion path shows that the increased diffusion path length alone can yield a flux reduction >99% through a strong increase in the stagnant diffusive boundary layer from <1 to 100mm.     

Regio- and stereoselective isomerization of hexabromocyclododecanes (HBCDs): kinetics and mechanism of gamma- to alpha-HBCD isomerization

Hexabromocyclododecanes (HBCDs) are high production volume chemicals (>20000 ty(-1)) used as flame retardants for plastics and textiles. Lately, we reported on the stereoselective isomerization of beta-HBCDs. Herein we present insights into the mechanism and kinetics of (+)gamma- to (+)alpha- and of (-)gamma- to (-)alpha-HBCD isomerization. Only two of the six bromine atoms migrated, indicating that rearrangements of gamma- to alpha-HBCDs are regio- and stereoselective as well. The apparent first-order isomerization rate constants increased from 0.0013 to 0.0031 to 0.0070 min(-1) at 120, 130, and 140 degrees C, respectively, corresponding to half-lives of 540, 230, and 99 min. Thus, a thermal treatment of materials containing gamma-HBCDs at temperatures >100 degrees C may induce the formation of alpha-HBCDs and, hence, may alter the diastereomeric ratio of a HBCD mixture. The inversion of vicinal dibromides in like-configurations (RR/SS) prevailed, whereas unlike-configurations (RS/SR) were not affected. An intramolecular, stereoselective migration of neighboring bromine atoms via a four-center transition state would explain the observed stereoisomer pattern and first-order kinetics. Despite the fact that vicinal dibromides in HBCDs prefer synclinal (gauche) conformations, antiperiplanar (staggered) conformations are assumed to facilitate concerted 1.2-shifts of both bromine atoms. A conformation analysis revealed that under kinetic control, only those bromine atoms in the more flexible part of the molecules are migrating, whereas those in the conserved triple-turn motive were not affected. Thus, this structural motive, common to all alpha-, beta-, and gamma-HBCDs, is more rigid and less reactive than the flexible part, containing the reacting dibromides in like-configurations.     

Seasonal effect on N2O formation in nitrification in constructed wetlands

Constructed wetlands are considered to be important sources of nitrous oxide (N(2)O). In order to investigate the contribution of nitrification in N(2)O formation, some environmental factors, plant species and ammonia-oxidizing bacteria (AOB) in active layers have been compared. Vegetation cells indicated remarkable effect of seasons and different plant species on N(2)O emission and AOB amount. Nitrous oxide data showed large temporal and spatial fluctuations ranging 0-52.8 mg N(2)O m(-2)d(-1). Higher AOB amount and N(2)O flux rate were observed in the Zizania latifolia cell, reflecting high potential of global warming. Roles of plants as ecosystem engineers are summarized with rhizosphere oxygen release and organic matter transportation to affect nitrogen transformation. The Phragmites australis cell contributed to keeping high T-N removal performance and lower N(2)O emission. The distribution of AOB also supported this result. Statistical analysis showed several environmental parameters affecting the strength of observed greenhouse gases emission, such as water temperature, water level, TOC, plant species and plant cover.     

Congener-specific analysis of non-dioxin-like polychlorinated biphenyls in blood collected from 127 elderly residents in Nakagawa Town, Fukuoka Prefecture, Japan

We conducted congener-specific analysis of non-dioxin-like polychlorinated biphenyls (non-dioxin-like PCBs) in blood collected in February 2004 from 127 elderly residents living in Nakagawa Town, Fukuoka Prefecture, Japan. The present study is one of the few studies in which 56 non-dioxin-like PCBs congeners were measured in human blood. Of the 127 elderly residents, 51 were men (mean: 68.1 years) and 76 were women (mean: 68.1 years). Among 197 non-dioxin-like PCB congeners, 56 were identified in the blood of elderly residents. The arithmetic mean total concentrations of 56 non-dioxin-like PCBs congeners in the blood of elderly men and women in Nakagawa Town were 419 (median: 378) and 363 (median: 323)ngg(-1)lipid, respectively, and the concentrations were in the range of 172-1102 and 119-1226ngg(-1)lipid, respectively, indicating that the total concentrations in elderly men are significantly higher than those in elderly women. The contamination of non-dioxin-like PCBs in the blood of elderly men and women in Fukuoka Prefecture was found to have decreased compared to past levels. The ratios of hexachlorinated biphenyls (hexaCBs) to the total concentrations of 56 non-dioxin-like PCBs congeners in the blood of elderly men and women were 44.6% and 45.6%, respectively, which was particularly high compared with those of other congeners. 2,2',4,4',5,5'-HexaCB (#153) among hexaCBs congeners, the most abundant congener in the blood of elderly men and women, contributed approximately 23.0% and 23.5% to the total concentrations of 56 non-dioxin-like PCBs congeners, respectively. Furthermore, 2,2',3,4,4',5'-hexaCB (#138), 2,3,3',4',5,6-hexaCB (#163)/2,3,3',4',5',6-hexaCB (#164), 2,2',3,4,4',5,5'-heptaCB (#180), and 2,2',3,4,4',5,6'-heptaCB (#182)/2,2',3,4',5,5',6-heptaCB (#187) also showed high ratios to the total concentrations of 56 non-dioxin-like PCBs congeners detected in the blood of elderly men and women. A statistical examination of the relationship between the total concentrations of 56 non-dioxin-like PCBs congeners in blood and the age of elderly residents who were over 60 years indicated statistically significant correlations between the total concentrations of these PCBs congeners and the age of elderly women. However, similar correlations were not observed in elderly men. The results of the present study have indicated the current levels of non-dioxin-like PCBs in the blood of elderly men and women in Fukuoka Prefecture, Japan and can be used as baseline data for those over age 60.