The degradation characteristics of four phthalic acid esters (PAEs), i.e. di-methyl phthalate (DMP), di-ethyl phthalate (DEP), di-n-butyl phthalate (DBP) and di-n-octyl phthalate (DOP) in the soil augmented with acclimated sludge was investigated in order to assess the efficacy of bioaugmentation as a strategy for remediating PAEs-contaminated soil and correlate the degradation rate of PAEs with their alkyl chain length. The results demonstrated that PAEs with shorter alkyl chain, that is, DMP and DEP could be degraded more quickly than DBP and DOP. The degradation of four PAEs in the soil conformed to a first-order reaction kinetic equation. The half-lives of PAEs degradation decreased significantly with increasing carbon number of the alcohol moiety. Half-lives decreased from 2.29 days for DMP to 28.4 days for DOP when the carbon number of alkyl chain increased from one for DMP to eight for DOP. The degradation rate of PAEs and the corresponding half-lives could correlate with the alkyl chain length and their octanol-water partition coefficients (K,,) quite well for the four PAEs tested in this study. (C) 2003 Elsevier Ltd. All rights reserved.
<正> 《建立 CEO 资本》是国际知名的公关公司博雅公司(Burson-Marsteller)的一项研究的名称。这项研究从1997年开始,不断通过对有影响力的商业人士的调查,关注 CEO 及其领导的企业的声誉。最新一次的调查显示,CEO 的表现和企业声誉之间的直接关联度有上升的趋势:1997年,商业人士认为一家公司的声誉有40名依靠其 CEO 的个人声望;这一比例在1999年为45%,2001年升至48%,到2003年更达到50%。在泡沫经济破裂和"后安然"的时代里,我们见证了太多CEO 的命运沉浮,但 CEO 表现的好坏决定了企业一半的声誉。博雅的全球 CEO 科米萨耶夫斯基(Komisajerevsky)说:"在充满不确定因素的经济环境中,我们的研究发现,CEO 的声誉比以往更
From 13 August-1 September 2001, a number of gaseous chemical compounds were measured at three sites in the Lower Fraser Valley, British Columbia: (1) Slocan-in the city of Vancouver; (2) Langley-in a rural, agricultural area about 35 km southeast of Vancouver; and (3) Sumas-about 65 km inland on a forested mountain (300m asl). Although the Langley and Sumas sites were located away from major emission sources, CO, NOx and NOy mixing ratios indicate that these sites were often impacted by anthropogenic emissions. At Langley and Slocan, NO and CO mixing ratios were highest between 0400-0700 PDT (UT=PDT-8h) due to the buildup of fresh vehicular emissions under a nocturnal inversion. At the elevated Sumas site, during the growth of the boundary layer, upward mixing of fresh emissions was observed, delayed by 3 h compared to the other two sites. NOx was the largest component of NOy at Langley and Sumas, averaging 75-80%. At Langley, the HNO3 fraction of NOy during the afternoon ranged from 15% to 28%, compared to <10% at the other two sites. PAN was significantly lower than HNO3 at <5% of NOy at all three sites. The sum of all individual nitrogen oxide species, SigmaNO(yi) accounted for 85% and 93% of NOy on average at Langley and Sumas, respectively. The chemical age was estimated at the three sites using the ratio (HONO+HNO3+PAN)/NOy. The daytime (1400-1800 PDT) ratios at Langley (0.19-0.40) were higher than those at either Slocan (0.04-0.12) or Sumas (0.09-0.19), mainly driven by higher HNO3 contributions to NOy. The higher ratios at Langley suggest that the extent of processing in air masses at the site during the daytime was greater than at Slocan or Sumas. At Sumas, the elevated nighttime ratios (0.05-0.29) were attributed to transport of more aged air masses to the site and the contribution of HNO3 from N2O5 hydrolysis. O-3 was only weakly correlated with the oxidation products of NOx at Langley (m = 2.5 +/- 9.1) and Sumas (m = 7.3 +/- 8.2). Meteorological conditions (lower radiation levels, cooler temperatures) were not favourable for photochemical pollutant processing. The dominant NOx fraction of NOy (see Section 3.2.1) clearly shows that most of the oxidized nitrogen remained in the form of NOx with very limited chemical processing and relatively low O-3 levels. Crown Copyright (C) 2004 Published by Elsevier Ltd. All rights reserved.
Two Aerodyne Aerosol Mass Spectrometers (AMS) were deployed at three sites representing urban, semi-rural and rural areas during the Pacific 2001 experiment in the Lower Fraser Valley (LFV), British Columbia, Canada in August 2001. The AMS provides on-line quantitative measurements of the size and chemical composition of the non-refractory fraction of submicron aerosol particles. A significant accumulation mode with a peak around 400-500 nm was observed at all sites that was principally composed of sulphate, organics, ammonium and some nitrate. Another significant mode with a peak below 200 nm was also observed at the urban site and when urban plumes affected the other sites. This paper focuses on the variability of the organic particulate composition and size distribution as a function of location and photochemical activity with a particular emphasis on the urban and rural areas. The small organic mode at the urban site was well correlated with gas phase CO, 1,3-butadiene, benzene and toluene with Pearson's r values of 0.76, 0.71, 0.79 and 0.69, respectively, suggesting that combustion-related emissions are likely to be the main source of the small organic mode at this site. The mass spectra of the urban organic particulate are similar to those of internal combustion engine lubricating oil, and of diesel exhaust aerosol particles, implying that they were composed of a mixture of n-alkanes, branched alkanes, cycloalkanes, and aromatics. In contrast, organic particulate at the rural site was dominated by shorter chain oxidized organic compounds. Correlations between the two organic modes and gas phase compounds at the rural site indicated that a significant part of the small mode originated from combustion sources, while the large accumulation organic mode appeared to be the result of photochemical processing. Processing of organic particulate during a relatively high O-3 episode at the rural site appeared to increase the modal diameter of the accumulation mode from about 400 to 600 nm and almost doubled its mass loading. (C) 2004 Elsevier Ltd. All rights reserved.