Chemical composition of burnt smell caused by accidental fires: environmental contaminants

The chemical composition of the odors typical of fires has recently been deciphered. Basically the constituents are mixtures of acetophenone, benzyl alcohol, hydroxylated derivatives of benzaldehyde, methoxylated and/or alkylated phenols and naphthalene. This finding makes it possible to develop objective, practical analytic measurement methods for the burnt smell as a contribution to improving fire damage assessment and remediation monitoring. With the aid of an artificially produced burnt smell and a panel of testers the odor detection threshold of a test mixture was determined olfactometrically to 2 μg m⁻³. Using a defined burnt-smell atmosphere in a test chamber, analytical methods with active sampling, the adsorbents XAD 7 and TENAX TA, and GC/MS measurement were then optimized and tested with a view to being able to carry out sensitive quantitative measurement of burnt smells. A further practical method with particular application to the qualitative characterization of this odor is based on the use of a new SPME (solid-phase microextraction) field sampler with DVB/CAR/PDMS (divinylbenzene/Carboxen™/polydimethylsiloxane) fibers.     

Speciation and transport of arsenic in an acid sulfate soil-dominated catchment, eastern Australia

Factors controlling the transport of geogenically-derived arsenic from a coastal acid sulfate soil into downstream sediments are identified in this study with both solid-phase associations and aqueous speciation clearly critical to the mobility and toxicity of arsenic. The data from both sequential extractions and X-ray adsorption spectroscopy indicate that arsenic in the unoxidised Holocene acid sulfate soils is essentially non-labile in the absence of prolonged oxidation, existing primarily as arsenopyrite or as an arsenopyrite-like species, likely arsenian pyrite. Anthropogenically-accelerated pedogenic processes, which have oxidised this material over time, have greatly enhanced the potential bioavailability of arsenic, with solid-phase arsenic almost solely present as As(V) associated with secondary Fe(III) minerals present. Analyses of downstream sediments reveal that a portion of the arsenic is retained as a mixed As(III)/As(V) solid-phase, though not at levels considered to be environmentally deleterious. Determination of arsenic speciation in pore waters using high performance liquid chromatography/Inductively Coupled Plasma-Mass Spectrometry shows a dominance of As(III) in upstream pore waters whilst an unidentified As species reaches comparative levels within the downstream, estuarine locations. Pore water As(V) was detected at trace concentrations only. The results demonstrate the importance of landscape processes to arsenic transport and availability within acid sulfate soil environments.     

湖北省"两圈"生物资源生态足迹动态分析

本文对1998-2008年湖北省武汉城市圈和鄂西生态文化旅游圈的生物资源生态足迹及其组成、人均生物资源生态足迹、生物资源生态承载量和生物资源生态赤字(盈余)进行了动态分析.研究表明,武汉城市圈生物资源生态足迹组成以耕地为主,其他生态生产性用地的足迹比例较小,各市州生物资源生态足迹整体呈现逐年增加的趋势,人均生物资源生态足迹小于省均值,生物资源生态承载量先升高后降低,各市州生物资源生态承载量由大到小排序为:黄冈、孝感、武汉、咸宁、天门、黄石、仙桃、鄂州、潜江,生态赤字呈增大趋势;鄂西生态圈除神农架外其他各市州的生物资源生态足迹均较大,林地足迹占主要地位,其总量对全省的贡献较大;人均生物资源生态足迹大于省均值,生物资源生态承载量呈增高趋势,各市州由大到小排序为:宜昌、十堰、襄樊、荆州、恩施、随州、荆门、神农架,该圈一直保持很高的生物资源生态盈余,但盈余值有减小的趋势.     

农业资源型技术创新三环模式及链接特性

本文将农业资源系统理论与农业技术创新学的理论与方法相结合,重点阐述了基于科技价值链的农业资源型技术创新三环模式及链接机制.农业资源型技术创新实质上就是以提高各类农业资源利用率为核心的农业技术改造和技术革新.农业资源型技术创新价值链是指从农业技术创新源到科技成果产业化开发的全过程中,由一系列相互独立、相互联系的创新主体链接起来的,使其科技开发价值不断增值的农业资源型技术创新链条集合体.其技术生命有机体在其发育成长的三个阶段形成了由相关功能节点链接而成的三个关键创新环,即研发创新环、孵化创新环和市场创新环,称为农业资源型技术创新三环模式.在农业资源型技术创新过程中,由各功能节点组配链接成链接单元,再由链接单元链接成关键创新环,进而构成三环模式链条集合体系统网络,这一"点→元→环→链→网"的逐级链接过程,表现出定向有序性、无限多样性、互利共生性和价值递增性等创新价值链接的规律性特性.     

贵州省经济弱县的确定及其特征分析

应用层次分析法,测算出贵州每个年度全部县域的经济社会发展综合实力排序值及其排序位次。由此得出排在前列的一部分县域,列为该年度经济强县,排在末尾的另一部分县域,列为经济弱县。贵州经济弱县一般特征是:人均GDP较低;农村贫困面较大;边际地理区位;属于民族自治的经济弱县较多;山地面积较广。当前分布格局为:东部经济弱县较多,西部较少。相对集中的经济弱县,形成4个片区。从每个片区的自然条件出发,论述维护生态环境与发展经济的有利和不利因素,揭示片区差异,提出必须解决的问题。     

The formation of bound residues of diazinon in four UK soils: implications for risk assessment

The behaviour of diazinon in the soil determines the likelihood of further pollution incidents, particularly leaching to water. The most significant processes in the control of the fate of diazinon in the soil are microbial degradation and the formation of bound residues. Soils from four sites in the UK were amended with diazinon and its ¹⁴C labelled analogue and incubated for 100 days. After 0, 10, 21, 50 and 100 days, the formation of bound residues was assessed by solvent extraction, and the microbial degradation of diazinon by mineralisation assay. In microbially active soils, diazinon is degraded rapidly, reducing the risk of future pollution incidents. However, where there was limited mineralisation there was also significantly lower formation of bound residues, which may lead to water pollution via leaching. The formation of bound residues was dependent on extraction type. Acetonitrile extraction identified bound residues in all soils, with the bound residue fraction increasing with increasing incubation time.     

Impact of carbon nanomaterials on the behaviour of 14C-phenanthrene and 14C-benzo-[a] pyrene in soil

The impact of fullerene soot (FS), single-walled (SWCNTs) and multi-walled (MWCNTs) carbon nanotubes on the behaviour of two ¹⁴C-PAHs in sterile soil was investigated. Different concentrations of carbon nanomaterials (0, 0.05, 0.1 and 0.5%) were added to soil, and ¹⁴C-phenanthrene and ¹⁴C-benzo[a]pyrene extractability assessed over 80 d through dichloromethane (DCM) and hydroxypropyl-β-cyclodextrin (HPCD) shake extractions. Total ¹⁴C-PAH activity in soils was determined by combustion, and mineralisation of ¹⁴C-phenanthrene was monitored over 14 d, using a catabolically active pseudomonad inoculum. No significant loss of ¹⁴C-PAH-associated activity from CNM-amended soils was observed over the ‘aging’ period. CNMs had a significant impact on HPCD-extractability of ¹⁴C-PAHS; extractability decreased with increasing CNM concentration. Additionally, ¹⁴C-phenanthrene mineralisation was inhibited by the presence of CNMs at concentrations of ≥0.05%. Differences in overall extents of ¹⁴C-mineralisation were also apparent between CNM types. It is suggested the addition of CNMs to soil can reduce PAH extractability and bioaccessibility, with PAH sorption to CNMs influenced by CNM type and concentration.     

Biomarker responsiveness in different tissues of caged Ruditapes philippinarum and its use within an integrated sediment quality assessment

Biomarkers comprising activities of biotransformation enzymes (ethoxyresorufin-O-deethylase -EROD-, dibenzylfluorescein dealkylase -DBF-, glutathione S-transferase -GST), antioxidant enzymes (glutathione reductase -GR- and glutathione peroxidase -GPX), lipid peroxidation -LPO- and DNA strand breaks were analyzed in the clam Ruditapes philippinarum caged at Cádiz Bay, Santander Bay and Las Palmas de Gran Canaria (LPGC) Port (Spain). Sediments were characterized. Digestive gland was the most sensitive tissue to sediment contamination. In Cádiz Bay, changes in LPO regarding day 0 were related with metals. In LPGC Port, DBF, EROD, and GST activity responses suggested the presence of undetermined contaminants which might have led to DNA damage. In Santander Bay, PAHs were related with EROD activity, organic and metal contamination was found to be associated with GR and GST activities and DNA damage presented significant (p < 0.05) induction. R. philippinarum was sensitive to sediment contamination at biochemical level. Biomarkers allowed chemical exposure and sediment quality assessment.     

Biodegradation of nicotine by a novel Strain Shinella sp. HZN1 isolated from activated sludge

The nicotine-degrading bacterium HZN1 was isolated from activated sludge and identified as Shinella sp. based on its physiological characteristics and analysis of 16S rDNA gene. Strain HZN1 is capable of using nicotine as the sole carbon source in the mineral salts medium. The optimum temperature and pH for strain HZN1 growth and nicotine degradation were 30°C and 7.0, respectively. It could degrade approximately 100 % of 0.5 g L(-1) of nicotine within 9 h. Three intermediate metabolites were produced by the strain HZN1 and identified as cotinine, myosmine and nicotyrine using gas chromatography-mass spectrometry. This is the first report of nicotine-degrading strain from the genus of Shinella. The results showed that strain HZN1 could be potentially employed in bioremediation of nicotine. Our findings would provide a new insight into the biodegradation of nicotine.     

Molecular cloning and expression of novel metallothionein (MT) gene in the polychaete Perinereis nuntia exposed to metals

To report a novel metallothionein (MT) gene and evaluate its potency as a biomarker, we clone this MT gene and measured the expression levels in the metal-exposed polychaete Perinereis nuntia. Accumulated metal contents and metallothionein-like proteins (MTLPs), which have been recognized as potential biomarkers, were compared with the relative mRNA expressions of the MT gene of P. nuntia (Pn-MT). In addition, the metal-binding affinity was estimated by recombinant Pn-MT protein. Pn-MT having high cysteine residues with three metal response elements in the promoter region closely clusters with those of other invertebrates. The accumulation patterns of metals were dependent on the exposure times in lead (Pb), cadmium (Cd), and copper (Cu) exposure. Particularly, both MTLP levels and relative mRNA expressions of MT were increased with accumulated metal contents and exposure time in P. nuntia exposed to Pb and Cd. There was no significant modulation of the Pn-MT gene in polychaetes exposed to Zn and As. However, the metal-binding ability of the recombinant Pn-MT protein provides a clear evidence for a high affinity of MT to several metal elements. These results suggest that Pn-MT would play an important role in the detoxification and/or sequestration of specific metals (e.g., Pb and Cd) in P. nuntia and have potential as a molecular biomarker in the monitoring of the marine environment using a polychaete.