Evidence of traffic-related pollutant control in soil-based Sustainable Urban Drainage Systems (SUDS)

SUDS are being increasingly employed to control highway runoff and have the potential to protect groundwater and surface water quality by minimising the risks of both point and diffuse sources of pollution. While these systems are effective at retaining polluted solids by filtration and sedimentation processes, less is known of the detail of pollutant behaviour within SUDS structures. This paper reports on investigations carried out as part of a co-ordinated programme of controlled studies and field measurements at soft-engineered SUDS undertaken in the UK, observing the accumulation and behaviour of traffic-related heavy metals, oil and PAHs. The field data presented were collected from two extended detention basins serving the M74 motorway in the south-west of Scotland. Additional data were supplied from an experimental lysimeter soil core leaching study. Results show that basin design influences pollutant accumulation and behaviour in the basins. Management and/or control strategies are discussed for reducing the impact of traffic-related pollutants on the aqueous environment

Medium-term performance and maintenance of SUDS:a case-study of Hopwood Park Motorway Service Area, UK

One of the main barriers to implementing SUDS is concern about performance and maintenance costs since there are few well-documented case-studies. This paper summarizes studies conducted between 2000 and 2008 of the performance and maintenance of four SUDS management trains constructed in 1999 at the Hopwood Park Motorway Service Area, central England. Assessments were made of the wildlife value and sedimentation in the SUDS ponds, the hydraulic performance of the coach park management train, water quality in all management trains, and soil/sediment composition in the grass filter strip, interceptor and ponds. Maintenance procedures and costs were also reviewed. Results demonstrate the benefits of a management train approach over individual SUDS units for flow attenuation, water treatment, spillage containment and maintenance. Peak flows, pond sediment depth and contaminant concentrations in sediment and water decreased through the coach park management train. Of the 2007 annual landscape budget of £15,000 for the whole site, the maintenance costs for SUDS only accounted for £2,500 compared to £4,000 for conventional drainage structures. Furthermore, since sediment has been attenuated in the management trains, the cost of sediment removal after the recommended period of three years was only £554 and, if the design is not compromised, less frequent removal will be required in future

Effect of a single prophylactic preoperative oral antibiotic dose on surgical site infection following complex dermatological procedures on the nose and ear: a prospective, randomised, controlled, double-blinded trial

Objectives: There is limited published research studying the effect of antibiotic prophylaxis on surgical site infection (SSI) in dermatological surgery, and there is no consensus for its use in higher-risk cases. The objective of this study was to determine the effectiveness of a single oral preoperative 2g dose of cephalexin in preventing SSI following flap and graft dermatological closures on the nose and ear. Design: Prospective double-blinded, randomised, placebo controlled trial testing for difference in infection rates. Setting: Primary care skin cancer clinics in North Queensland, Australia, were randomised to 2 g oral cephalexin or placebo 40–60min prior to skin incision. Participants: 154 consecutive eligible patients booked for flap or graft closure following skin cancer excision on the ear and nose. Intervention: 2 g dose of cephalexin administered 40–60min prior to surgery. Results: Overall 8/69 (11.6%) controls and 1/73 (1.4%) in the intervention group developed SSI (p=0.015; absolute SSI reduction 10.2%; number needed to treat (NNT) for benefit 9.8, 95%CI 5.5 to 45.5). In males, 7/44 controls and 0/33 in the intervention group developed SSI (p=0.018; absolute SSI reduction 15.9%; NNT for benefit 6.3, 95%CI 3.8 to 19.2). SSI was much lower in female controls (1/25) and antibiotic prophylaxis did not further reduce this (p=1.0). There was no difference between the study groups in adverse symptoms attributable to highdose antibiotic administration (p=0.871). Conclusion: A single oral 2 g dose of cephalexin given before complex skin closure on the nose and ear reduced SSI

Effect of a single preoperative dose of oral antibiotic to reduce the incidence of surgical site infection following below-knee dermatological flap and graft repair

Background: Surgical site infection (SSI) rates for below-knee dermatological surgery are unacceptably high, particularly following complex flap and graft closures. The role of antibiotic prophylaxis for these surgical cases is uncertain. Objective: To determine whether SSI following complex dermatological closures on the leg could be reduced by antibiotic prophylaxis administered as a single oral preoperative dose. Methods: A total of 115 participants were randomized to 2 g of oral cephalexin or placebo 40–60 minutes prior to surgical incision in a prospective, randomized, double-blind, placebo-controlled trial at a primary care skin cancer clinic in North Queensland, Australia. Results: Overall 17/55 (30.9%) controls and 14/55 (25.5%) intervention participants developed infection (P = 0.525). There was no difference between the study groups in adverse symptoms that could be attributed to high-dose antibiotic administration (P = 1). Conclusion: A single oral 2-g dose of cephalexin given before complex below-knee dermatological closure did not reduce SSI

Rigidity analysis of HIV-1 protease

We present a rigidity analysis on a large number of X-ray crystal structures of the enzyme HIV-1 protease using the 'pebble game' algorithm of the software FIRST. We find that although the rigidity profile remains similar across a comprehensive set of high resolution structures, the profile changes significantly in the presence of an inhibitor. Our study shows that the action of the inhibitors is to restrict the flexibility of the beta-hairpin flaps which allow access to the active site. The results are discussed in the context of full molecular dynamics simulations as well as data from NMR experiments.Comment: 4 pages, 3 figures. Conference proceedings for CMMP conference 2010 which was held at the University of Warwic

Chemical climatology: a case study for ozone

In 1872 Scottish chemist Robert Angus Smith established the basis of ‘chemical climatology’ explicitly designed to assess the human health impact of the ‘man-made climates’ in cities. Since then usage of chemical climatology has been sporadic. However with large volumes of atmospheric composition datasets available from campaign measurements, monitoring and modelling, as well as pollutant impact studies, an updated framework based on Angus Smith’s principles would be useful as a resource for both scientists and policy makers. Through analogy with the use of the term climate in other areas (e.g. meteorological or political) a modern chemical climatology framework is described, highlighting impact-focused principles. To derive the chemical climatology the impact of atmospheric composition is first identified (e.g. damage to human health) The impact is linked to the state of atmospheric composition in time and space (e.g. ozone concentrations in the UK 1990 -2010). Finally the drivers of the state are assessed (e.g. emissions, chemical background, chemical precursors, meteorology). Two chemical climates are presented: O3-human health and ozone-vegetation. The chemical climates are derived from measurements at the two UK European Monitoring and Evaluation Programme (EMEP) monitoring ‘supersites’: Auchencorth Moss and Harwell. The impacts of O3 on human health and on vegetation are assessed using the SOMO35 and AOT40 metrics respectively. Drivers of significant spatial variation in these impacts across the UK, and temporal changes at Harwell between 1990 and 2011 are discussed, as well as the relative importance of hemispheric, regional and local O3 chemical processing and its precursors. The individual site assessments are placed in regional context through the statistical evaluation of O3 variation across Europe. The chemical climatology framework allows integration of individual scientific studies focussing on specific processes within the impact-state and driver space into a synthesised and more general understanding. This approach provides opportunities for developing understanding of multiple impacts are considered for each chemical component allow identification of common drivers of impacts, and potentially holistically considered mitigation strategies

Women's breastfeeding experiences following a significant primary postpartum haemorrhage: A multicentre cohort study

<p>Abstract</p> <p>Background</p> <p>Postpartum haemorrhage (PPH) is a significant and increasing contributor to maternal mortality and morbidity. Following a PPH, women may have difficulties initiating and sustaining breastfeeding, although little has been published on this issue. The aim of this study was to describe breastfeeding experiences in a cohort of women following a significant PPH.</p> <p>Methods</p> <p>This is a descriptive study based on quantitative and qualitative data collected via questionnaires completed in the first week postpartum and at two and four months postpartum, by 206 women participating in a multicentre study of women's experiences of a significant primary postpartum haemorrhage (blood loss of 1500 mL or more in the 24 hours following childbirth, and/or a peripartum fall in haemoglobin (Hb) concentration to 7g/dL or less, or of ≥ 4g/dL).</p> <p>Results</p> <p>Among women with a significant PPH, 63% fully breastfed their babies from birth, whereas 85% said they had hoped to do so (p < 0.001). Only 52% of mothers who intended to either fully or partially breastfeed were able to give their baby the opportunity to suckle within an hour of the birth. Delays were longer in women with greater estimated blood loss and women with the longest delays in breastfeeding were less likely to initiate full breastfeeding. 70% of women with PPH of < 2000 mL were fully breastfeeding in the first postpartum week, whereas less than 50% of those with blood loss ≥ 3000 mL were able to do so. Overall, 58% of women with significant PPH were fully breastfeeding at two and 45% at four months postpartum.</p> <p>In qualitative data, three major themes were identified: 1) Difficulty initiating or sustaining breastfeeding, 2) Need for education and support; and 3) Emotional sequelae.</p> <p>Conclusions</p> <p>Following a significant PPH, women with greater blood loss are less likely to initiate and sustain full breastfeeding and this may be related, in part, to delays in initial contact with their baby as a consequence of the PPH. These findings have implications for postnatal care as these women may require greater support, education and assistance in initiating and sustaining breastfeeding. In particular, enabling the opportunity for the newborn to suckle as soon as is practicable should be encouraged.</p

VOC chemical climate and O3 variation: impact of emissions on regional O3 increment

Understanding the role of individual volatile organic compounds (VOCs) in the formation of surface ozone is important for the effective targeting of ozone mitigation strategies. The UK operates two European Monitoring and Evaluation Programme (EMEP) monitoring ‘supersites’ where concurrent measurement of 27 VOCs, NOx and ozone allows the relationships between these precursors and ozone to be explored. This work presents the relative contribution of measured VOCs on ozone formation at the ‘supersites’, including spatial variation across the UK, and temporal changes between 1999 and 2012. The study was undertaken using the impact-centred chemical climatology framework (Malley et al 2014) VOC concentrations are made up from both regional and local emissions. Regional components of ozone concentrations are distinguished from hemispheric background ozone and measured ozone concentrations which show depletion due to the local NOx environment. Increased VOC photochemical cycling is observed during periods of regional ozone formation, and the contribution of individual VOCs to this total measured VOC cycling is discussed. The drivers of this photochemical depletion, such as meteorology and emissions are evaluated. Back trajectories are coupled with gridded VOC emission maps to estimate the exposure of trajectories to VOC emissions for the four days prior to their arrival at the receptor site. These emissions are disaggregated into 11 broad source sectors, and their contribution is evaluated. Finally the implications of the level of source disaggregation available are discussed in terms of its limitations on VOC emissions speciation to estimate the exposure of receptor sites to individual VOCs.. Using the SNAP sector and the NFR code sector data, it is demonstrated that a greater level of source sector disaggregation would be beneficial for atmospheric model studies and policy determination

Evaluation of local measurement-driven adjustments of modelled cloud-free atmospheric photolysis rate coefficients

Photolysis rate constants (j-values) play a crucial role in atmospheric chemistry modelling, but capturing the variability in local conditions needed for their accurate simulation is computationally challenging. One approach is to adjust modelled clear-sky estimates using ratios of measured-to-modelled j-values of a reference photolysis, typically j(NO2) or j(O1D). However, application of such adjustments to other photolysis reactions introduces uncertainty. Using spectral radiometer data from the UK, this study examines how hourly measurement driven adjustment factors (MDAF) across a set of 12 photolysis reactions group together using cluster analysis, and evaluates the uncertainties in using j(NO2) and j(O1D)-derived MDAF values to adjust modelled j-values of other photolysis reactions. The NO2-MDAF reference is suitable for adjusting photolysis reactions that absorb at λ > 360 nm (HONO, methylglyoxal, ClNO2, ClONO2 → Cl), which are largely independent of solar zenith angle and total ozone column (<31% error). In particular, NO2-MDAF is a good reference for j(HONO) and j(ClNO2). The O1D-MDAF performed better at adjusting modelled j-values for species that predominantly photodissociate at λ < 350 nm, such as HNO3, H2O2, CH3CHO, HCHO → H, HCHO → H2 and ClONO2 → ClO (errors ≤ 30%). However, j(O1D) radiometers require more data processing to account for local conditions. The maximum error determined using NO2-MDAF was within a factor of two (91% for j(H2O2)), which may still be acceptable in some instances. It is important that MDAFs are used to improve accuracy and uncertainty in simulated j-values caused by variation in local conditions

Analysis of the distributions of hourly NO2 concentrations contributing to annual average NO2 concentrations across the European monitoring network between 2000 and 2014

Exposure to nitrogen dioxide (NO2) is associated with negative human health effects, both for short-term peak concentrations and from long-term exposure to a wider range of NO2 concentrations. For the latter, the European Union has established an air quality limit value of 40 µg m−3 as an annual average. However, factors such as proximity and strength of local emissions, atmospheric chemistry, and meteorological conditions mean that there is substantial variation in the hourly NO2 concentrations contributing to an annual average concentration. The aim of this analysis was to quantify the nature of this variation at thousands of monitoring sites across Europe through the calculation of a standard set of chemical climatology statistics. Specifically, at each monitoring site that satisfied data capture criteria for inclusion in this analysis, annual NO2 concentrations, as well as the percentage contribution from each month, hour of the day, and hourly NO2 concentrations divided into 5 µg m−3 bins were calculated. Across Europe, 2010–2014 average annual NO2 concentrations (NO2AA) exceeded the annual NO2 limit value at 8 % of > 2500 monitoring sites. The application of this chemical climatology approach showed that sites with distinct monthly, hour of day, and hourly NO2 concentration bin contributions to NO2AA were not grouped into specific regions of Europe, furthermore, within relatively small geographic regions there were sites with similar NO2AA, but with differences in these contributions. Specifically, at sites with highest NO2AA, there were generally similar contributions from across the year, but there were also differences in the contribution of peak vs. moderate hourly NO2 concentrations to NO2AA, and from different hours across the day. Trends between 2000 and 2014 for 259 sites indicate that, in general, the contribution to NO2AA from winter months has increased, as has the contribution from the rush-hour periods of the day, while the contribution from peak hourly NO2 concentrations has decreased. The variety of monthly, hour of day and hourly NO2 concentration bin contributions to NO2AA, across cities, countries and regions of Europe indicate that within relatively small geographic areas different interactions between emissions, atmospheric chemistry and meteorology produce variation in NO2AA and the conditions that produce it. Therefore, measures implemented to reduce NO2AA in one location may not be as effective in others. The development of strategies to reduce NO2AA for an area should therefore consider (i) the variation in monthly, hour of day, and hourly NO2 concentration bin contributions to NO2AA within that area; and (ii) how specific mitigation actions will affect variability in hourly NO2 concentrations