A comparison of European and North American atmospheric deposition networks: polycyclic aromatic hydrocarbons and lindane

A comparison between the sampling and analytical methods used by Canadian (IADN) and German (OSPAR) regional monitoring networks for persistent organic pollutants was conducted from September 2002 to October 2003 at a rural site in Ontario, Canada. Polycyclic aromatic hydrocarbons (PAHs) and the currently-used pesticide lindane were measured in precipitation and ambient air samples. Overall the two networks sampling and analytical methods agreed well in their results of deposition (wet and dry particulate). Lindane concentrations between the two networks agreed well in the air samples while too few precipitation samples could be compared to conclude on agreement. The lindane seasonal profile with a peak in spring-early summer was consistent with previous results pointing to the continued use of this pesticide in 2002-2003 in Canada. Annual lindane wet depositions were comparable between the two network methodologies. PAHs concentrations in precipitation and in gas phase agreed well while there was a discrepancy for particulate PAHs in air. This study confirmed that the use of data from the two regional POPs monitoring networks for hemispherical modelling studies is warranted.     

Reducing hazard vulnerability: towards a common approach between disaster risk reduction and climate adaptation

Over the past few decades, four distinct and largely independent research and policy communities--disaster risk reduction, climate change adaptation, environmental management and poverty reduction--have been actively engaged in reducing socio-economic vulnerability to natural hazards. However, despite the significant efforts of these communities, the vulnerability of many individuals and communities to natural hazards continues to increase considerably. In particular, it is hydro-meteorological hazards that affect an increasing number of people and cause increasingly large economic losses. Arising from the realisation that these four communities have been largely working in isolation and enjoyed only limited success in reducing vulnerability, there is an emerging perceived need to strengthen significantly collaboration and to facilitate learning and information exchange between them. This article examines key communalities and differences between the climate change adaptation and disaster risk reduction communities, and proposes three exercises that would help to structure a multi-community dialogue and learning process.     

Comparison of Streambed Sediment and Aquatic Biota as Media for Characterizing Trace Elements and Organochlorine Compounds in the Willamette Basin, Oregon

During 1992–93, 27 organochlorine compounds (pesticides plus total PCB) and 17 trace elements were analyzed in bed sediment and aquatic biota from 20 stream sites in the Willamette Basin as part of the U.S. Geological Survey's National Water-Quality Assessment Program. Data from each medium were compared to evaluate their relative effectiveness for assessing occurrence (broadly defined as documentation of important concentrations) of these constituents. Except for Cd, Hg, Se, and Ag, trace element concentrations generally were higher in bed sediment than in biota. Conversely, although frequencies of detection for organochlorine compounds in biota were only slightly greater than in bed sediment, actual concentrations in biota (normalized to lipid) were as much as 19 times those in sediment (normalized to organic carbon). Sculpin (Cottus spp.) and Asiatic clams (Corbicula fluminea), found at 14 and 7 sites, respectively, were the most widespread taxa collected during the study. Concentrations of trace elements, particularly As and Cu, were typically greater in Asiatic clams than in sculpin. In contrast, almost half of the organochlorine compounds analyzed were found in sculpin, but only DDT and its degradation products were detected in Asiatic clams; this may be related to the lipid content of sculpin, which was about three times higher than for clams. Thus, the medium of choice for assessing occurrence depends largely on the constituent(s) of interest.     

When the going gets tough: Employee reactions to large-scale organizational change and the role of employee Machiavellianism

Large-scale, long-term change initiatives take time to unfold, which can be a source of uncertainty and strain. Investigating the initial 19 months of a large-scale change, we argue that during these stages, employees' change-related beliefs become more negative over time, which negatively affects their work engagement and, ultimately, increases their turnover intentions. Furthermore, we investigate the impact of a trait, Machiavellianism, on change reactions and propose that employees high in Machiavellianism react more negatively during change processes as they are especially susceptible to uncertainty and stress. We test our (cross-level) moderated mediation model in a three-wave longitudinal study among employees undergoing a large-scale change (T1: n = 1,602; T2: n = 1,113; T3: n = 759). We find that employees' beliefs about the impact and value of the change are indeed negatively related to change duration and that decreases in these perceptions come with a decline in engagement and increases in turnover intentions. Moreover, employees high in Machiavellianism react more strongly to a deterioration in change-related beliefs, showing stronger reductions in engagement and stronger increases in turnover intentions than employees low in Machiavellianism. Our study offers explanations for the negative effects of large-scale changes including an explanatory factor for disparate employee reactions to change over time.     

Elimination of phenol and aromatic compounds by zero valent iron and EDTA at low temperature and atmospheric pressure

This work deals with a new abiotic oxidation process designed as a suitable pre-treatment step within a biological depuration of wastewater containing phenol or its derivatives (o-cresol, 2-chlorophenol and p-nitrophenol) or aniline. The reaction was carried out in a stirred tank reactor at 20 degrees C and atmospheric pressure in presence of the organic compound, 150mgl(-1), zero valent iron particles (10g), ethylenediamine tetraacetic acid (EDTA, 101mgl(-1)) and air. The experimental results show that 85% of phenol conversion can be achieved after 360min. 2-Chlorophenol was found to be more easily degradable and it is completely eliminated after 300min. The oxidation of o-cresol and aniline behaved more closely to phenol obtaining after 360min 70% and 68% of conversion respectively. p-Nitrophenol was a very refractory compound, giving only 28% of conversion after 360min. Moreover, the influence of some operating variables was studied over the following ranges: temperature from 20 to 50 degrees C, initial phenol concentration from 150 to 1000mgl(-1), EDTA concentration from 50 to 200mgl(-1) and iron particles from 5 to 20g. As expected, temperature strongly enhances phenol conversion. Also, an increase of the catalyst to phenol ratio or the iron or EDTA to phenol ratio improves the reaction rate. A preliminary kinetic analysis of the data shown that the rate of phenol disappearance is not first order with respect to the phenol.     

A robust nonparametric method for quantifying undetected extinctions

How many species have gone extinct in modern times before being described by science? To answer this question, and thereby get a full assessment of humanity's impact on biodiversity, statistical methods that quantify undetected extinctions are required. Such methods have been developed recently, but they are limited by their reliance on parametric assumptions; specifically, they assume the pools of extant and undetected species decay exponentially, whereas real detection rates vary temporally with survey effort and real extinction rates vary with the waxing and waning of threatening processes. We devised a new, nonparametric method for estimating undetected extinctions. As inputs, the method requires only the first and last date at which each species in an ensemble was recorded. As outputs, the method provides estimates of the proportion of species that have gone extinct, detected, or undetected and, in the special case where the number of undetected extant species in the present day is assumed close to zero, of the absolute number of undetected extinct species. The main assumption of the method is that the per‐species extinction rate is independent of whether a species has been detected or not. We applied the method to the resident native bird fauna of Singapore. Of 195 recorded species, 58 (29.7%) have gone extinct in the last 200 years. Our method projected that an additional 9.6 species (95% CI 3.4, 19.8) have gone extinct without first being recorded, implying a true extinction rate of 33.0% (95% CI 31.0%, 36.2%). We provide R code for implementing our method. Because our method does not depend on strong assumptions, we expect it to be broadly useful for quantifying undetected extinctions.     

Combining steam injection with hydraulic fracturing for the in situ remediation of the unsaturated zone of a fractured soil polluted by jet fuel

A steam injection pilot-scale experiment was performed on the unsaturated zone of a strongly heterogeneous fractured soil contaminated by jet fuel. Before the treatment, the soil was stimulated by creating sub-horizontal sand-filled hydraulic fractures at three depths. The steam was injected through one hydraulic fracture and gas/water/non-aqueous phase liquid (NAPL) was extracted from the remaining fractures by applying a vacuum to extraction wells. The injection strategy was designed to maximize the heat delivery over the entire cell (10 m × 10 m × 5 m). The soil temperature profile, the recovered NAPL, the extracted water, and the concentrations of volatile organic compounds (VOCs) in the gas phase were monitored during the field test. GC-MS chemical analyses of pre- and post-treatment soil samples allowed for the quantitative assessment of the remediation efficiency. The growth of the heat front followed the configuration of hydraulic fractures. The average concentration of total hydrocarbons (g/kg of soil) was reduced by ～ 43% in the upper target zone (depth = 1.5-3.9 m) and by ～ 72% over the entire zone (depth = 1.5-5.5 m). The total NAPL mass removal based on gas and liquid stream measurements and the free-NAPL product were almost 30% and 2%, respectively, of those estimated from chemical analyses of pre- and post-treatment soil samples. The dominant mechanisms of soil remediation was the vaporization of jet fuel compounds at temperatures lower than their normal boiling points (steam distillation) enhanced by the ventilation of porous matrix due to the forced convective flow of air. In addition, the significant reduction of the NAPL mass in the less-heated deeper zone may be attributed to the counter-current imbibition of condensed water from natural fractures into the porous matrix and the gravity drainage associated with seasonal fluctuations of the water table.