The ubiquitous β-Proteobacterium Gallionella ferruginea is known as stalk-forming, microaerophilic iron(II) oxidizer, which rapidly produces iron oxyhydroxide precipitates. Uranium and neptunium sorption on the resulting intermixes of G. ferruginea cells, stalks, extracellular exudates, and precipitated iron oxyhydroxides (BIOS) was compared to sorption to abiotically formed iron oxides and oxyhydroxides. The results show a high sorption capacity of BIOS towards radionuclides at circumneutral pH values with an apparent bulk distribution coefficient (Kd) of 1.23 × 104 L kg?1 for uranium and 3.07 × 105 L kg?1 for neptunium. The spectroscopic approach by X-ray absorption spectroscopy (XAS) and ATR FT-IR spectroscopy, which was applied on BIOS samples, showed the formation of inner-sphere complexes. The structural data obtained at the uranium LIII-edge and the neptunium LIII-edge indicate the formation of bidentate edge-sharing surface complexes, which are known as the main sorption species on abiotic ferrihydrite. Since the rate of iron precipitation in G. ferruginea-dominated systems is 60 times faster than in abiotic systems, more ferrihydrite will be available for immobilization processes of heavy metals and radionuclides in contaminated environments and even in the far-field of high-level nuclear waste repositories.
This paper explores the relationship between worker representation and the prevention and control of psycho-social risks at work. It argues that to understand this relationship it is helpful to position it within the labour relations context in which it occurs and which helps explain the strengths and limitations of interventions involving worker representation.The paper opens with some important questions of definition with regard to psycho-social risks and worker representation and consultation on health and safety. It goes on to review the evidence for the success or otherwise of worker representation in health and safety generally and discusses this evidence in relation to the control of psycho-social risks specifically. It discusses the problems that the restructuring of work pose for the sustainability of the preconditions for the effectiveness of the statutory model on which worker representation on psycho-social risk is predicated. In so doing the paper notes that many of the features of current restructuring of work that present problems for traditional model of worker representation are the same ones that lead to the increased prevalence of psycho-social risks at the workplace.The paper identifies both barriers and opportunities presented by the changing world of work for achieving an improved preventive scenario for psycho-social risks and discusses the implications of these for current and future strategies of trade unions. It concludes that in the present political and economic climate the state cannot be relied upon for effective regulatory strategies on the psycho-social risks of work. In the absence, or much reduced presence, of this support, some joined up thinking on the part of organised labour is required. Interventions by health and safety representatives on psycho-social risks at the workplace level need to be fully integrated in such thinking if they are to be effective. 相似文献
OBJECTIVE: The purpose of this study was to examine predictors of subsequent motor vehicle collision injuries, with a particular focus on health-related variables, using the longitudinal dataset from the Canadian National Population Health Survey (NPHS) for the years 1994-2002. METHODS: Multiple logistic regression analysis was used to determine the relations between motor vehicle collision injury and four risk factors: binge drinking, health status, distress, and medication use. Age and sex were included as control variables. The total sample size was 14,529. RESULTS: A higher percentage of females and younger persons reported a motor vehicle collision injury. Binge drinkers, respondents with poor health, respondents with distress, and respondents reported using two or more medications reported a higher percentage of subsequent injuries. Logistic regression analysis found that persons with poorer health status and persons who used more medications had higher odds of motor vehicle injuries. Only one statistically significant interaction effect was found: alcohol bingeing and medication use. CONCLUSIONS: Among a nationally representative sample of Canadians, various demographic and risk factors predict subsequent injuries. Given that this number represents a considerable economic burden, this study underscores the need for continued research and countermeasures on alcohol, drugs, and driving. 相似文献
The production of accurate and reliable data on copper ecotoxicology of marine algae depends on the use of trace metal clean techniques during experimentation. We reviewed the methodologies used in the literature on copper ecotoxicology of marine macro- and microalgae, specifically the use of trace metal clean procedures such as the labware used (glassware vs. plasticware), methods of cleaning the labware (acid soaking and ultrapure water rinsing), stock solution preparation (copper source and acidification), and measurement and reporting of dissolved copper concentrations. In terms of taxonomic classification, the most studied algal groups were the Phyla Ochrophyta, Bacillariophyta, Rhodophyta, and Chlorophyta. In terms of methodology, ~50% of the articles did not specify the labware, ~25% used glassware, and ~25% plasticware; ~30% of the studies specified cleaning protocols for labware to remove trace metal impurities; the copper form used to prepare the stock solutions was specified in ~80% of studies but acidification to stabilise the dissolved copper was performed in only ~20%; and the dissolved copper concentration was measured in only ~40% of studies. We discuss the importance of following trace metal clean techniques for the comparison and interpretation of data obtained on copper ecotoxicology in algae. 相似文献
Shelled molluscs frequently exhibit a record of damage on exterior surfaces that can evidence past predation attempts and
may affect survival and growth. In South Carolina populations of the ribbed marsh mussel, Geukensia demissa, >90% of the individuals and up to 60% of the total shell area are damaged. A trend toward greater amounts of damage occurred
on mid-marsh compared to oyster reef mussels from the barrier beach side of inlets. Shell damage effects on survivorship and
shell and tissue growth were assessed seasonally during multi- and single-season field experiments. Mussels from a common
mid-marsh site were divided into size classes (~50 or 70 mm), treated to create two damage levels (undamaged and damaged),
and replaced within mid-marsh exclusion cages to minimize additional shell damage. In both multi- and single-season experiments
increased shell damage resulted in significantly greater mortality. Linear shell growth was unaffected by increased damage,
but 50 mm mussels grew twice as fast. Shell mass increased 16–50% in the multi-season and single-season winter period, but
decreased 7–12% during the single-season summer period. Tissue mass significantly decreased 31–43% in 50 mm damaged mussels,
but increased by 33% for 70 mm mussels in both multi-season and the single-season winter period experiments. Shell damage
did reduce tissue mass 43% in 70 mm single-season summer mussels. Experimental results indicate shell damage from a simulated
increase in predation can affect negatively both survival and growth of marsh mussels. Seasonal timing of shell damage and
initial mussel size also influenced the effects of sublethal predation on shell and tissue growth. The previously unrecognized
importance of sublethal predation and the resultant significant negative effects of shell damage on survival and growth will
affect the distribution and population dynamics of G. demissa in coastal marshes and will influence the overall contribution of ribbed mussels to estuarine ecosystems. 相似文献
Repeated manure application can lead to excessive soil test P (STP) levels and increased P concentration in runoff, but also to improved water infiltration and reduced runoff. Research was conducted to evaluate soil P tests in prediction of P concentration in runoff and to determine the residual effects of composted manure on runoff P loss and leaching of P. The research was conducted from 2001 to 2004 under natural runoff events with plots of 11-m length. Low-P and high-P compost had been applied during the previous 3 yr, resulting in total applications of 750 and 1150 kg P ha(-1). Bray-P1 in the surface 5 cm of soil was increased from 16 to 780 mg kg(-1) with application of high-P compost. Runoff and sediment losses were 69 and 120% greater with no compost than with residual compost treatments. Runoff P concentration increased as STP increased, but much P loss occurred with the no-compost treatment as well. Agronomic soil tests were predictive of mean runoff P concentration, but increases in STP resulted in relatively small increases in runoff P concentration. Downward movement of P was not detected below 0.3 m. In conclusion, agronomic soil tests are useful in predicting long-term runoff P concentration, and risk of P loss may be of concern even at moderate soil P levels. The residual effect of compost application in reducing sediment and runoff loss was evident more than 3 yr after application and should be considered in P indices. 相似文献
Faith-based organizations (FBOs) have played a significant role in environment-related forms of development and governance in Melanesia, including the Solomon Islands. Yet despite their centrality, there remain significant gaps in understandings of processes and outcomes associated with FBO engagement in environment-related development interventions. This paper addresses this gap by analysing the place of the Christian Fellowship Church (CFC), an indigenous FBO active in plantation forestry (and other activities) in the Western Province in the Solomon Islands. We find that the CFC possesses impressive income-generating potential and political networks; however this does not always translate into positive social, economic or environmental outcomes at the village level. While FBOs such as CFC are often championed as playing an important role in environmental governance in an under-resourced nation state, the reality is that they can fall well short in delivering appropriate outcomes for poor communities or the environment despite, and because of, their close ties to target communities. 相似文献
Bioventing is a relatively new technology that uses forced air movement to deliver supplemental oxygen to contaminated soils to stimulate the biodegradation of contaminants by indigenous microorganisms. A bioventing pilot test was initiated at Offutt Air Force Base, Nebraska, in August 1992, at a site contaminated with jet fuel. Air was injected into the subsurface over a period of 15 months, and tests were conducted at 6 months, and again at 15 months, to determine the effectiveness of the system. This article describes the bioventing process and its application at this test site. The results of the pilot test are discussed to illustrate the extent of the remediation accomplished through bioventing. 相似文献