Scenarios for investigating the future of Canada’s oceans and marine fisheries under environmental and socioeconomic change

Regional Environmental Change - There is a critical need to develop effective strategies for the long-term sustainability of Canada’s oceans. However, this is challenged by uncertainty over...     

Arsenite transporters expression in rice (Oryza sativa L.) associated with arbuscular mycorrhizal fungi (AMF) colonization under different levels of arsenite stress

As a silicon hyperaccumulator, lowland rice takes up higher levels of As than many other plants due to silicic acid and arsenite sharing the same transporters (Lsi1 and Lsi2). Glomus intraradices (AH01) was inoculated to rice under different arsenite concentrations (0, 2 and 8 μM) in order to investigate the interactions between arbuscular mycorrhizal fungus and rice on the accumulation of arsenite. The relative mRNA expressions of Lsi1 and Lsi2 resulted in a down-regulating trend in mycorrhizal plants. Under 2 μM arsenite treatments, Lsi1 and Lsi2 were significantly decreased, by 0.7-fold (P < 0.05) and 0.5-fold (P < 0.01), respectively, in mycorrhizal plants when compared with non-mycorrhizal plants. This led to the decrease of arsenite uptake per unit of root dry mass. No organic As species were detected in both roots and shoots. The As(III)/As(V) ratios indicated that mycorrhizal plants immobilized most of the arsenite proportion in the roots and prevented its translocation from the roots to the shoots.     

A study of the partitioning behavior of Irgarol-1051 and its transformation products

Partitioning behavior of the antifouling booster biocide, Irgarol-1051 (2-methythio-4-tert-butylamino-6-cyclopropylamino-s-triazine), its production by-product, M3, and its environmental transformation products, M1 and M2, were studied. Octanol-water partition coefficients, log K(OW), and organic matter-water partition coefficients, log K(OC), of these s-triazines were measured by reversed-phase HPLC and a triphasic SPME equilibrium model, respectively. The average log K(OW) (+/-SD) of the four s-triazine species were: 4.39+/-0.07 (M3); 3.38+/-0.12 (Irgarol-1051); 2.92+/-0.12 (M2) and 2.54+/-0.11 (M1), while mean log K(OC) (+/-SD) of these species were: 2.47+/-0.03 (M3); 2.16+/-0.03 (Irgarol-1051); 1.97+/-0.03 (M2) and 1.79+/-0.04 (M1). These results were compared to reported physicochemical parameters of Irgarol-1051 in the literature. Partitioning behavior of these s-triazine species in the coastal environment revealed by their K(OW) and K(OC) were also discussed.     

Distribution of polycyclic aromatic hydrocarbons in soils at Guiyu area of China, affected by recycling of electronic waste using primitive technologies

The concentration, distribution, profile and possible source of polycyclic aromatic hydrocarbons (PAHs) in soil were studied in Guiyu, an electronic waste (E-waste) recycling center, using primitive technologies in Southeast China. Sixteen USEPA priority PAHs were analyzed in 49 soil samples (0-10 cm layer) in terms of individual and total concentrations, together with soil organic matter (SOM) concentrations. The concentrations of a sum of 16 PAHs ranged from 44.8 to 3206 microgkg(-1) (dry weight basis), in the descending order of E-waste open burning sites (2065 microgkg(-1))>areas near burning sites (851microgkg(-1))>rice fields (354 microgkg(-1))>reservoir areas (125microgkg(-1)). The dominant PAHs were naphthalene, phenanthrene and fluoranthene, which were mainly derived from incomplete combustion of E-waste (e.g. wire insulations and PVC materials), and partly from coal combustion and motorcycle exhausts. All individual and total PAH concentrations were significantly correlated with SOM except for naphthalene and acenaphthylene. Principal component analysis was performed, which indicated that PAHs were mainly distributed into three groups in accordance with their ring numbers and biological and anthropogenic source. In conclusion, PAH concentrations in the Guiyu soil were affected by the primitive E-waste recycling activities.     

不同燃料汽车排放超细微粒特性的实验研究

利用底盘测功机和粒径范围0.015~0.7 m的扫描迁移微粒测定仪 SMPS,对柴油出租车、柴油小巴车、汽油私家车和LPG出租车进行了高低怠速和10 kmh-1到70 kmh-1不同运行工况条件下排放的超细微粒粒径分布试验研究。研究表明：不同燃料车在不同工况条件下排放的细微粒尤其是超细微粒特征呈现显著的不同。柴油车贡献更多的是粒径在30～150 nm的核模态和积聚模态微粒,LPG和汽油车贡献更多的是15～30 nm的核模态微粒。总体上,柴油车比汽油车和LPG燃料车排放更多的微粒数和微粒质量;柴油车、汽油车和LPG车排放的SMPS可测细微粒总数、总质量分别约为(0.3~3.6) 108 cm-3,0.03~0.6 gcm-3;2.3×104~1.2×107 cm-3,8×10-5~0.1 gcm-3; 8.2×103~8.8×106 cm-3, 1.7×10-5~0.09 gcm-3;对所有测试汽车,在低怠速和低行驶速度时,排放微粒数少,在高怠速和高行驶速度时,排放微粒数多。     

Characterizing driving patterns for Zhuhai for traffic emissions estimation

Zhuhai, a relatively less developed city on the western coast of the Pearl River Delta (PRD) of China, is planning to undergo major development in coming years. A Hong Kong-Zhuhai-Macao Bridge project has been approved by the Central Government of China. The project will have great impact on the driving pattern and vehicular emissions to the city. This baseline study collected speed-time data of two instrumented private cars in morning and evening periods, as well as a daytime nonpeak period of >10 consecutive days in the spring and winter of 2003. The authors used the microwave speed sensor and global positioning system installed in the instrumented cars and used car-chasing technique to perform the data collection. They used the statistical package SPSS to assess the consistency, as well as to evaluate the variability of the data. Nine parameters, namely, average speed, average running speed, average acceleration rate, average deceleration rate, mean length of a driving period, time proportions of driving modes, average number of acceleration-deceleration changes, root mean square acceleration, and positive acceleration kinetic energy are calculated to represent the driving characteristics. A driving cycle for private cars was developed. If emission tests were conducted using the Zhuhai driving cycle, the level of vehicle emissions measured is likely to be in between that of the Federal Test Procedure (FTP) cycle and the Melbourne Peak cycle.     

Economic and Political Factors that Lead to the Budget Deficit in Hong Kong from 1998 to 2003

Abstract

Despite the adverse impact of the budget deficit in Hong Kong has been alleviated since the economic recovery from 2003, the fiscal deficit may return when there is another downturn in the economy if the problem is not handled fundamentally. Based on the economic and political situation from 1998 to 2003, the factors that lead to the budget deficit in Hong Kong are analyzed in four perspectives, including (a) increase in public expenditure; (b) decrease in public revenues; (c) poor management of public money and (d) weak administration. With a better understanding on these factors, possible solutions to the fiscal problem faced by the government may be developed.     

Radon progeny dose conversion coefficients for Chinese males and females

The airway dimensions for Caucasian males have been scaled by multiplying by factors 0.95 and 0.88 to give those for Chinese males and females, respectively. Employing the most recent data on physical and biological parameters, the radiation doses to the basal and secretory cells due to alpha particles from 218Po and 214Po, homogeneously distributed in the mucous layer, have been calculated. The emission of alpha particles has been simulated by a Monte Carlo method. For both basal and secretory cells, the dose conversion coefficients (DCCs) for physical conditions of sleep, rest, light and heavy exercise, have been obtained for Chinese males and females for unattached progeny, and for attached progeny of diameters 0.02, 0.15, 0.25, 0.30 and 0.50 micron. For basal cells, the coefficients lie in the range 0.69-6.82 mGy/(Js/m3) or 8.7-86 mGy/WLM for unattached progeny and in the range 0.045-1.98 mGy/(Js/m3) or 0.57-25 mGy/WLM for attached progeny. The corresponding ranges for Caucasian males are 1.27-8.81 mGy/(Js/m3) or 16-111 mGy/WLM-1 and 0.05-2.30 mGy/(Js/m3) or 0.64-29 mGy/WLM. For secretory cells, the coefficients lie in the range 0.095-16.82 mGy/(Js/m3) (1.2-212 mGy/WLM) for unattached progeny and in the range 0.095-6.67 mGy/(Js/m3) (1.2-84 mGy/WLM) for attached progeny. The corresponding ranges for Caucasian males are 0.34-21.51 mGy/(Js/m3) (4.3-271 mGy/WLM) and 0.1-7.78 mGy/(Js/m3) (1.3-98 mGy/WLM). The overall DCCs calculated for a typical home environment are 0.59 and 0.52 mSv/(Js/m3) (7.4 and 6.5 mSv/WLM) for Chinese males and females, respectively, which are 80 and 70% of the value, 0.73 mSv/(Js/m3) (9.2 mSv/WLM), for Caucasian males.     

Preparation of activated carbon using low temperature carbonisation and physical activation of high ash raw bagasse for acid dye adsorption

Activated carbons were prepared from bagasse through a low temperature (160 degrees C) chemical carbonisation treatment and gasification with carbon dioxide at 900 degrees C. The merit of low temperature chemical carbonisation in preparing chars for activation was assessed by comparing the physical and chemical properties of activated carbons developed by this technique to conventional methods involving the use of thermal and vacuum pyrolysis of bagasse. In addition, the adsorption properties (acid blue dye) of these bagasse activated carbons were also compared with a commercial activated carbon. The results suggest that despite the high ash content of the precursor, high surface areas (614-1433 m2 g(-1)) and microporous (median pore size from 0.45 to 1.2 nm) activated carbons can be generated through chemical carbonisation and gasification. The micropore area of the activated carbon developed from chars prepared by the low temperature chemical carbonisation provides favourable adsorption sites to acid blue dye (391 mg g(-1) of carbon). The alkalinity of the carbon surface and total surface area were shown to have complementary effects in promoting the adsorption of acid blue dye. Adsorption of the anionic coloured component of the acid dye was shown to be promoted in carbon exhibiting alkaline or positively charged surfaces. This study demonstrates that activated carbons with high acid dye adsorption capacities can be prepared from high ash bagasse based on low temperature chemical carbonisation and gasification.     

Factors controlling pathogen destruction during anaerobic digestion of biowastes

Anaerobic digestion is the principal method of stabilising biosolids from urban wastewater treatment in the UK, and it also has application for the treatment of other types of biowaste. Increasing awareness of the potential risks to human and animal health from environmental sources of pathogens has focused attention on the efficacy of waste treatment processes at destroying pathogenic microorganisms in biowastes recycled to agricultural land. The degree of disinfection achieved by a particular anaerobic digester is influenced by a variety of interacting operational variables and conditions, which can often deviate from the ideal. Experimental investigations demonstrate that Escherichia coli and Salmonella spp. are not damaged by mesophilic temperatures, whereas rapid inactivation occurs by thermophilic digestion. A hydraulic, biokinetic and thermodynamic model of pathogen inactivation during anaerobic digestion showed that a 2 log10 reduction in E. coli (the minimum removal required for agricultural use of conventionally treated biosolids) is likely to challenge most conventional mesophilic digesters, unless strict maintenance and management practices are adopted to minimise dead zones and by-pass flow. Efficient mixing and organic matter stabilisation are the main factors controlling the rate of inactivation under mesophilic conditions and not a direct effect of temperature per se on pathogenic organisms.