A mixed methods approach to urban ecosystem services: experienced environmental quality and its role in ecosystem assessment within an inner-city estate

This paper contributes to the notion of ecosystem services (ES) and dis-services (EDS) through an exploration of how they are experienced in an inner-city neighbourhood. We contrast the findings of a science-led assessment with qualitative interview and visual data from the residents of the Woodberry Down Estate (London, UK). We use the ontology of co-production and co-construction to understand how material and interpretative factors condition the translation of identified service-providing units (SPUs) into directly experienced ES and EDS. Findings demonstrate that aspects contributing to the perceived liveability of a neighbourhood also condition the experienced ES and EDS. In our case study, the history of the estate translates into subjective feelings of safety which influence whether individuals access parts of the regenerated estate. While the regeneration project provides a broad range of new and improved SPUs with significant ES potential, the access and recreational functions these offer are especially appreciated for the increased opportunities for social interaction and visitors they provide. However, new SPUs such as landscape vistas and formal gardens that attract people are also assigned further significance as markers of new divisions among social housing residents. We suggest that in order to realise the much-prophesised health and wellbeing benefits of urban ES in an equitable manner, a science-led approach to designing and assessing potential ES should be accompanied by a context-sensitive assessment of community needs and liveability aspects

Metal size distribution in rainfall and snowmelt-induced runoff from three urban catchments

The size distribution of metals transported by urban runoff has implications for treatment type and design, predicting their mobility and evaluating their potential impact on receiving waters. There is an urgent need to better understand the distribution of metals between fractions, particularly those in the sub-dissolved fractions. As a contribution to addressing this need, this study characterises the size distribution of Cd, Cr, Cu, Ni, V and Zn using conventional and novel techniques. Data is presented as event mean concentrations (EMC) of a total of 18 rainfall and snowmelt events at three urban sites. For all studied metals in all events and at all sites, the contribution of the truly dissolved fraction made a greater contribution to the total concentrations than the colloidal fraction. Truly dissolved Cd and Zn concentrations contributed (on average) 26% and 28% respectively, of the total EMCs with truly dissolved Cu and Ni contributing (on average) 18%. In contrast, only 1% (V) and 3% (Cr) were identified in the truly dissolved fraction. The greatest contribution of truly dissolved Cd, Cu and Zn concentrations (relative to total oncentrations) were reported during rainfall events. However, no seasonal differences were identified and differences between the sites regarding the EMCs distribution by fractions were not at a statistically significant level (p N 0.05) for any metal or event. The loads of truly dissolved and colloidal metals did not follow the patterns of particulate metal loads indicating particulates are not the main source of subdissolved metals. The data suggests that ultrafiltration as a treatment technique would not efficiently mitigate the risks posed by metals to receiving water cologie

The sources, impact and management of car park runoff pollution: a review

Traffic emissions contribute significantly to the build-up of diffuse pollution loads on urban surfaces with their subsequent mobilisation and direct discharge posing problems for receiving water quality. This review focuses on the impact and mitigation of solids, metals, nutrients and organic pollutants in the runoff deriving from car parks. Variabilities in the discharged pollutant levels and in the potentials for pollutant mitigation complicate an impact assessment of car park runoff. The different available stormwater best management practices and proprietary devices are reported to be capable of reductions of between 20% and almost 100% for both suspended solids and a range of metals. This review contributes to prioritising the treatment options which can achieve the appropriate pollutant reductions whilst conforming to the site requirements of a typical car park. By applying different treatment scenarios to the runoff from a hypothetical car park, it is shown that optimal performance, in terms of ecological benefits for the receiving water, can be achieved using a treatment train incorporating permeable paving and bioretention systems. The review identifies existing research gaps and emphasises the pertinent management practices as well as design issues which are relevant to the mitigation of car park pollution

An assessment of gully pot sediment scour behaviour under current and potential future rainfall conditions

Gully pots actively trap sediments transported by urban runoff to prevent in-pipe blockages and surface flooding. However, due to poor maintenance (resulting in sediment build-up) and increasingly extreme wet weather events, the scour of previously-deposited sediments from gully pots is identified as a potential contributor to EU Water Framework Directive failure. While basal sediment scour deterministic models have been developed and validated using laboratory and field gully pot data sets, the ability of these models to predict behaviour at sites other than those for which they were established has not been addressed. Nor has the impact of future rainfall predictions on the role of gully pots as sediment sources been systematically examined. As a contribution to addressing these knowledge gaps, the performance of two gully pot basal sediment scour models of distinct complexity levels are evaluated under current and future rainfall conditions. The output from Model One suggests that the scour-induced total suspended solids in gully pot discharge can be kept well below 25 mg/L if the gully pot fullness level is maintained at under 60%. Results identify the opportunity to incorporate the actual/targeted ecological status of recipients in scheduling gully pot maintenance operations and that proactive gully pots maintenance will reduce the impacts of increased rainfall intensity/duration on the magnitude of sediment scour. Results from Model Two suggest that fine sediments are particularly susceptible to in-pot scour. For example, sediment with a specific gravity of 1.1 and diameter of >63 μm accounts for 50% of scour-induced total suspended solids in gully pot discharge. The effluent suspended solids concentrations predicted by the two models differ by up to two orders of magnitude. However, without further empirical field data pertaining to their respective competences/applications, neither model could be discounted at this stage. For example, the use of Model One is more appropriate in the establishment of gully pot maintenance schedules, with Model Two more suited to the dimensioning of gully pots based on performance requirements. This application, however, relies on the development and adoption of a more stringent regulation on gully pots discharge

Evaluation of measured dissolved and bio-met predicted bioavailable Cu, Ni and Zn concentrations in runoff from three urban catchments

Urban runoff is a diffuse source of pollution contributing to the poor ecological and chemical status of surface waters. Whilst the EU Priority Hazardous Substances Directive now identifies environmental quality standards for selected metals in relation to the bioavailable metal fraction the relationship between analytically determined metal size fractions transported by urban runoff and the often variably defined concept of bioavailability has not been thoroughly evaluated. This paper provides a review of the terminology used within urban runoff studies to characterise metal fractions and behaviour. Measured dissolved and truly dissolved (determined by ultrafiltration; <3000 molecular weight cutoff) Cu, Ni, and Zn concentrations are also compared to the bioavailable metal fraction (as predicted using Bio-met, a simplified biotic ligand model) in snowmelt and rainfall derived runoff samples from three urban catchments. The study shows that predicted bioavailable concentrations were significantly lower than truly dissolved concentrations for all metals and discusses current bioavailability modelling parameters in relation to rainfall and snowmelt runoff data sets. Statistical analysis of relationships between field and predicted bioavailable data sets indicate that the bioavailable fractions originate from both colloidal and truly dissolved fractions

Nearly sign-nonsingular matrices

AbstractA real matrix A is nearly sign-nonsingular if every term in the expansion of det A but one has the same sign. We show such matrices can be put into a normal form in which all diagonal entries are negative, all other nonzero entries are positive, and the directed graph of the matrix is intercyclic. With the help of recent results of Metzlar, McCuaig, and Thomassen on intercyclic digraphs, we are able to separate the nearly sign-nonsingular matrices into five classes and to characterize each of these classes. We also obtain two results showing where real matrices having intercyclic digraphs can or cannot be signed in such a way as to belong both to the class of sign-nonsingular matrices and the class of nearly sign-nonsingular matrices

Promoting Commodities through Comic Books: A Framing Analysis of the Captain Citrus Campaign

The communication campaign starring Captain Citrus, first released in 2011, was aimed at elementary school students with the goals of encouraging health and agricultural literacy, as well as promoting the consumption of Florida orange juice. This study was designed as a qualitative, inductive framing analysis of the Captain Citrus comic book series featured in the campaign. The goal was to identify the prominent frames along with evidence of agricultural perspective and promotion throughout the series. The first two editions of the series, totaling 38 pages, were evaluated for the study. The results indicated the presence of four predominate frames: “Amazing Inside,” health, responsibility, and empowerment. A majority of the agricultural perspective and promotion was found in the form of images, followed by textual mentions, and symbolic references. It was determined that the “Amazing Inside” and health frames contributed to meeting the campaign objective to boost health literacy. The second objective, to promote agricultural literacy, was somewhat endorsed through the agricultural references, however there is an opportunity for this to be strengthened. The presence of all four frames aided in the achievement of the final goal, to promote Florida citrus through the sale of orange juice. It is recommended that further research be conducted to measure the effects of framing on the attitudes and behaviors of elementary school students before and after they are exposed to the campaign materials