Dechlorination of PCE in the presence of Fe0 enhanced by a mixed culture containing two Dehalococcoides strains

A mixed culture capable of supplying its energy requirements by the oxidation of zero-valent iron (Fe0) and concomitant reduction of chlorinated ethenes was established. The culture contained Dehalococcoides species as determined by polymerase chain reaction (PCR) with genus specific primers. The use of a newly designed ARDRA procedure and subsequent sequencing revealed the presence of two Dehalococcoides strains, one closely related to Dehalococcoides ethenogenes strain 195, a bacterium respiring with chlorinated ethenes, and one closely related to strain CBDB1 a chlorobenzene and dioxin dehalogenating anaerobe. The mixed culture was used to study dechlorination of tetrachloroethene (PCE) to ethene in the presence of Fe0. Whereas abiotic transformation of PCE by Fe0 led to incomplete dechlorination, the mixed culture mediated fast and complete dechlorination of PCE to ethene with Fe0 as electron donor. Compared to cultures with hydrogen added as electron donor, cultures with Fe0 as electron donor showed the same or higher rates of PCE dechlorination. Growth of the Dehalococcoides strains in the mixed culture is linked to the presence of Fe0 as electron donor and PCE as electron acceptor demonstrating that Dehalococcoides spp. play a pivotal role in the dechlorination of chlorinated ethenes in Fe0 systems.     

Chorionic villus sampling for prenatal diagnosis in wales using DNA probes—5 years' experience

Chorionic villi were sampled from 125 women who requested prenatal diagnosis, either for genetic disorders or because of advanced maternal age. Of these, 105 samples were obtained by the transcervical route and 20 were obtained by the transabdominal approach. The sampling success rate was 97 per cent (122/125). The mean maternal age of the patients was 31 years (range 17–44) and the mean gestational age at which the chorionic villus sampling was performed was 10 weeks (range 7–13 weeks). Seventy-four of these diagnoses involved the use of DNA markers. The minimal size of the sample used for DNA diagnosis was 5 mg. Maternal contamination was detected in two samples. A diagnosis was provided on all but two samples. The fetal loss rate was high initially but fell to 1·9 per cent in 1988.     

Monitoring the levels of brominated and organophosphate flame retardants in passenger cars: Utilisation of car air filters as active samplers

Filters in residential and office air conditioning(A/C) systems have been used as sampling devices for monitoring different pollutants.However,cabin air filters(CAFs) in the A/C system of passenger cars have not been utilised for this purpose.In this study,we collected22 used CAFs from passenger cars in Hanoi,Vietnam to analyse for 8 polybrominated diphenyl ethers(PBDEs) and 10 organophosphate esters(OPEs).All the analytes were detected in more than 50% of samples with the exception of BDE153 and BDE154.The average concentrations of ∑_(10)OPEs and ∑_8 BDEs in the captured dust were 2600 and 40 ng/g,respectively with Tris(1-chloro-2-propyl) phosphate(TCIPP) and BDE209 as the dominant congener in OPE and BDE groups,respectively.CAFs are a potential tool to qualitatively assess the levels of semi-volatile chemicals in suspended dust in cars as a screening step for exposure assessment of those chemicals.     

Environmental Surveillance of Enteroviruses in Central Argentina: First Detection and Evolutionary Analyses of E14

Environmental surveillance is an effective approach to investigate the circulation of human enteroviruses in the population. Enteroviruses E14, CVA9, E-6, E16, E20, E25, E13, and CVA24 were detected in sewage and a watercourse in central Argentina. E14 was the most frequent serotype and was found for the first time in environmental samples in our region. Phylogenetic and coalescence analyses showed at least two recent introduction events.     

Two-phase modeling of sediment clouds

A sediment cloud release in stagnant ambient fluid occurs in many engineering applications. Examples include land reclamation and disposal of dredged materials. The detailed modeling of the distinct characteristics of both the solid and fluid phases of the sediment cloud is hitherto unavailable in the literature despite their importance in practice. In this paper, the two-phase mixing characteristics of the sediment cloud are investigated both experimentally and theoretically. Experiments were carried out to measure the transient depth penetration and the lateral spread of the sediment cloud and its entrained fluid using the laser induced fluorescence technique, with a range of particle sizes frequently encountered in the field (modeled at laboratory scale). A two-phase model of the sediment cloud that provides detailed predictions of the mixing characteristics of the individual phases is also proposed. The entrained fluid characteristics are solved by an integral model accounting for the buoyancy loss (due to particle separation) in each time step. The flow field induced by the sediment cloud is approximated by a Hill’s spherical vortex centered at the centroid and with the size of the entrained fluid. The particle equation of motion under the effect of the induced flow governs each computational particle. A random walk model using the hydrodynamic diffusion coefficient is used to account for the random fluctuation of particles in the dispersive regime. Overall, the model predictions of the two-phase mixing characteristics are in good agreement with the experimental data for a wide range of release conditions.     

Modelling the potential damage-reducing benefits of flood warnings using European cases

In most OECD countries, emergency response to accidents and natural disasters is very dependent on a trained workforce of emergency services volunteers: fire, rescue, medical, care and relief. With its large area, sparsely settled population, and frequent periods of low rainfall, Australia is particularly vulnerable to the threat posed by wildfires. There are an estimated 220,000 rural fire volunteers (in a population of 20 million) in eight state and territory volunteer rural fire services. These fire services have experienced significant decreases in volunteer numbers over the past decade, a trend which is true also of North American volunteer fire services. An investigation suggests that the decrease is driven by two related sets of factors: economic and demographic. Globalisation and deregulation of the economy, and technological innovation, have resulted in structural changes in the nature of work: privatisation, casualisation, self-employment, and demands for increased productivity. These factors make it more difficult for members of communities to volunteer, regardless of their motivation to do so. Further, like many other OECD countries, Australia's birth rate has fallen over the last three decades, resulting in a decline in the proportion of the population aged between 25 and 45 years—a trend that is unlikely to be reversed in the foreseeable future. These economic and demographic changes make it difficult for Australian volunteer rural fire agencies to meet their community protection responsibilities. Responding to these challenges may require radical changes in the way that these fire services are organised and supported.     

Local Sustainable Development: Land-use Planning's Contribution to Modern Local Government

This paper assesses the contribution of land-use planning to the objectives of local sustainable development in some of the UK's most urbanized areas. Sustainable development provides the context within which local planning policies are now being prepared, and can be seen to be a potentially important aspect of central government's proposals for modernizing local government. Using the results from a comprehensive survey of development plans in metropolitan authorities, the paper assesses both the strengths and the weaknesses of land-use planning in terms of sustainable development and speculates upon the lessons they may offer to the government's more recent proposals on modernizing local government.     

Trends over time in the risk of driver death: what if vehicle designs had not improved?

OBJECTIVES: Passenger vehicle driver death rates per million vehicle registrations declined steadily during calendar years 1985-2004. The present study sought to separate the effect of vehicle design changes from this trend. METHODS: Restricting the trend to a fixed set of model years removed the vehicle design effects, but there were still effects due to vehicle aging. Risk of driver death was found to increase each year vehicles aged, probably due to changes in vehicle use patterns. RESULTS: After separating out the vehicle design effects and making adjustments for the vehicle age effects, a different picture emerged of trends in death rates over time. Absent the vehicle design changes, the historical decline in driver fatality risk would have ended in 1993, with risk climbing ever since. This underlying trend has been obscured by changes in the vehicle fleet. CONCLUSIONS: The push for vehicle improvements has been worthwhile and can be credited with saving thousands of lives. However, the analysis shows that the gains in occupant protection from vehicle design improvements have been offset partially by an increasingly risky environment in recent years. Therefore, more attention needs to be paid to programs targeting improvement in roadway design and driver behavior.     

Possible chemical causes of skeletal deformities in grey heron nestlings (Ardea cinerea) in North Nottinghamshire, UK

Dead and deformed grey heron (Ardea cinerea) chicks were reported at a large heronry in North Nottinghamshire, UK between 1996 (when systematic visits to the heronry started) and 2002. Many of the birds died for no obvious reason but deformities in others included multiple fractures of the tarsus and tibia and metacarpal bones (angel wings). This study aimed to investigate possible chemical causes of these deformities. Analysis of eggs and nestling tissue for a range of metals showed no levels of concern and no significant differences between unaffected and deformed birds. However, the levels of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) detected in affected heron nestlings in 2002 and in eggs taken from nests in 2003 were sufficiently high to suggest that this may be the underlying cause of the deformities, possibly due to effects on deposition of calcium in bone. Further work is underway to identify where the parent birds of the affected nestlings are feeding and identify the possible source of the pollution.     

Isomeric analysis of PCDD/PCDF in waste incinerator fly ash by GC-MS/MS

The development of an analytical method for the analysis of PCDD/PCDF in flyash using a bench analytical system comprising of a gas chromatograph fitted with an ion trap detector operated in the tandem MS mode is described. The optimum settings for the most important MS/MS parameters are given, including those for the less reported mono- to tri-chlorinated dioxin and furan congener groups. Flyash samples from three waste incineration plants representing a decommissioned 1970s plant design, an upgraded and still operating plant originally designed in the 1970s, and a modern 1990s design operating plant have been analysed for PCDD/PCDF. The flyash samples were analysed for PCDD/PCDF using the methods developed and the total PCDD/PCDF, I-TEQ values and isomeric profiles are reported. The flyash from the older decommissioned incinerator had very significantly higher concentrations of PCDD/PCDF compared to the modern incinerator flyash.