Light requirements for growth of six shade-acclimated Mediterranean macroalgae

Six mediterranean macroalgae were cultivated for more than 2 yr under shade culture conditions, after which light requirements for growth were investigated at 16±2°C. The saturation light levels for growth in the logarithmic phase were related to the bathymetric distribution of the algae on the shore. The eulittoral to supralittoral red alga Bangia atropurpurea was saturated at a photon fluence rate of 71 mol photons m^-2 s^-1, the upper sublittoral to eulittoral brown algae Scytosiphon lomentaria, Colpomenia peregrina and Kuckuckia spinosa and the sublittoral brown alga Stictyosiphon soriferus at 39 to 71 mol photons m^-2 s^-1, and the deep-water alga Choristocarpus tenellus at 19 mol photons m^-2 s^-1. The minimum light requirements for growth of B. atropurpurea and C. tenellus were determined by observing length increase for 56 d under limiting light conditions. The compensation and minimum irradiances required for growth of B. atropurpurea were 0.5 and 1 mol photons m^-2 s^-1 respectively. The corresponding values for C. tenellus were 0.15 to 0.28 and 0.5 mol photons m^-2 s^-1 respectively. C. tenellus was the siowest-growing species tested at saturating light conditions, but it grew faster than B. atropurpurea at 1 mol photons m^-2 s^-1. Both B. atropurpurea and C. tenellus were able to survive 56 d in darkness, but only the latter grew under darkness in the first 14 d.     

Defining length-at-metamorphosis in fishes: a multi-character approach

The present study attempts to highlight the value of multi-character approaches for defining thresholds in fish ontogeny, like the onset of the juvenile period. We developed techniques to objectively define the transition from larval to juvenile development using morphometric as well as morphological characters and exemplify the multi-character approach on newly settled white sea-breams (Diplodus sargus sargus) collected from the eastern Mediterranean. The morphometric analysis was based on principles of multivariate allometry whereas the analysis of morphology, on assigning a suite of selected characters (here related to external morphology and osteological development) into larval, transforming and juvenile states. The size-at-change in multivariate allometric growth (L _m) is considered here to denote mean length-at-metamorphosis. An almost perfect match is demonstrated between L _m (‘multivariate morphometry’) and mean size-at-morphological change (‘multivariate morphology’) in white sea-bream.     

Comparative evaluation of nitrogen oxides and ozone passive diffusion tubes for exposure studies

Passive diffusion tubes are recognised as a cost-effective sampling method for characterising the spatial variability, as well as the seasonal and annual trends, of NO₂ concentrations in urban areas. In addition, NO_X and O₃ passive diffusion tubes have been developed and deployed in urban and rural areas. Despite their many advantages (e.g. low operational and analysis cost, small size and no need for power supply), they have certain limitations mainly related to their accuracy and precision. In particular, the absorbent solution used, the length of the exposure period, the exact location and use of protective devices, and other environmental conditions (e.g. wind, ambient temperature and relative humidity) may have a significant impact on the performance of passive diffusion tubes. The aim of this study is to evaluate the performance of co-located NO₂, NO_X and O₃ diffusion tubes in an urban environment.A one-year passive sampling campaign was carried out in Birmingham (UK) for this purpose. NO₂, NO_X and O₃ diffusion tubes (including triplicate sets of each) were co-located at one urban background and two roadside permanent air quality monitoring stations equipped with standard gas analysers. In addition, meteorological data, such as wind speed and direction, ambient temperature and relative humidity, were obtained during the same period of time. A thorough QA/QC procedure, including storage and laboratory blanks was followed throughout the campaign. The analysis of results showed a very good agreement of NO₂ passive samplers with co-located chemiluminescence analysers, but substantial underestimations of total NO_X levels by the diffusion tubes. The O₃ diffusion sampler appeared to marginally overestimate the automatic UV analyser results, especially during warm weather periods.     

An integrated tool to assess the role of new planting in PM10 capture and the human health benefits: A case study in London

The role of vegetation in mitigating the effects of PM₁₀ pollution has been highlighted as one potential benefit of urban greenspace. An integrated modelling approach is presented which utilises air dispersion (ADMS-Urban) and particulate interception (UFORE) to predict the PM₁₀ concentrations both before and after greenspace establishment, using a 10 × 10 km area of East London Green Grid (ELGG) as a case study. The corresponding health benefits, in terms of premature mortality and respiratory hospital admissions, as a result of the reduced exposure of the local population are also modelled. PM₁₀ capture from the scenario comprising 75% grassland, 20% sycamore maple (Acer pseudoplatanus L.) and 5% Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) was estimated to be 90.41 t yr⁻¹, equating to 0.009 t ha⁻¹ yr⁻¹ over the whole study area. The human health modelling estimated that 2 deaths and 2 hospital admissions would be averted per year.     

An integrated approach to assessing the environmental and health impacts of pollution in the urban environment: Methodology and a case study

This paper presents a new decision-support methodology and software tool for sustainable management of urban pollution. A number of different methods and tools are integrated within the same platform, including GIS, LCA, fate and transport modelling, health impact assessment and multi-criteria decision analysis. The application of the framework is illustrated on a case study which investigates the environmental and health impacts of pollution arising from different industrial, domestic and transport sources in a city. The example city chosen for the study is Sheffield, UK, and the main pollutants considered are NO_x, SO₂ and PM10. The results suggest that the absence of the current large industrial sources in the city would lead to a 90% reduction of the SO₂ and 70% of the NO₂ ground concentrations, consequently preventing 27 deaths and 18 respiratory hospital admissions per annum for a population of 500,000. Based on the total annual mortality and hospital admissions in Sheffield for the year of the assessment, this means that 0.53% of premature deaths and 0.49% of respiratory hospital admissions would be prevented by the estimated reduction in air pollution.     

Electrochemical conversion of chromium from tannery effluents for potential reuse in industrial applications

Environmental Science and Pollution Research - Electrochemical oxidation of trivalent chromium from leather tanning mud waste leachates (containing ca 6 g.L?1 Cr(III)) to its...     

Human mortality in Cyprus: the role of temperature and particulate air pollution

Climatic change results in increased occurrence of heat waves, and the thermal stress caused by such phenomena is leading to higher levels of heat-related mortality worldwide. This study is the first to examine the effect of extreme weather on mortality in Cyprus. It investigates the individual effect of meteorological indicators on mortality, as well as the role of particulate air pollution (PM₁₀). A generalized linear model (GLM) with quasi-Poisson regression was implemented. GLM included a temperature function and was adjusted for relative humidity and seasonality. The temperature function was developed under a newly developed framework of distributed lag nonlinear models, which capture nonlinearities and delayed effects of heat simultaneously. GLM was extended to examine the confounding effect of air pollution. All the results on heat effects are presented. High temperatures had a significant effect on mortality with increased mortality rates, independent of humidity and seasonality. Mortality risk increased steeply above a temperature threshold. A direct heat effect was shown, with higher risk on the current and next day of a severe heat event. PM₁₀ was not found to have a confounding effect on the temperature–mortality relationship, since the strength of this relationship remained after the inclusion of PM₁₀ in the model. Differences existed between urban and coastal areas.     

Numerical Model Inter-comparison for Wind Flow and Turbulence Around Single-Block Buildings

Wind flow and turbulence within the urban canopy layer can influence the heating and ventilation of buildings, affecting the health and comfort of pedestrians, commuters and building occupants. In addition, the predictive capability of pollutant dispersion models is heavily dependent on wind flow models. For that reason, well-validated microscale models are needed for the simulation of wind fields within built-up urban microenvironments. To address this need, an inter-comparison study of several such models was carried out within the European research network ATREUS. This work was conducted as part of an evaluation study for microscale numerical models, so they could be further implemented to provide reliable wind fields for building energy simulation and pollutant dispersion codes. Four computational fluid dynamics (CFD) models (CHENSI, MIMO, VADIS and FLUENT) were applied to reduced-scale single-block buildings, for which quality-assured and fully documented experimental data were obtained. Simulated wind and turbulence fields around two surface-mounted cubes of different dimensions and wall roughness were compared against experimental data produced in the wind tunnels of the Meteorological Institute of Hamburg University under different inflow and boundary conditions. The models reproduced reasonably well the general flow patterns around the single-block buildings, although over-predictions of the turbulent kinetic energy were observed near stagnation points in the upwind impingement region. Certain discrepancies between the CFD models were also identified and interpreted. Finally, some general recommendations for CFD model evaluation and use in environmental applications are presented.     

Modelling dispersion of traffic pollution in a deep street canyon: Application of CFD and operational models

In this study, numerical modelling of the flow and concentration fields has been undertaken for a deep street canyon in Naples (Italy), having aspect ratio (i.e. ratio of the building height H to the street width W) H/W = 5.7. Two different modelling techniques have been employed: computational fluid dynamics (CFD) and operational dispersion modelling. The CFD simulations have been carried out by using the RNG k–? turbulence model included in the commercial suite FLUENT, while operational modelling has been conducted by means of the WinOSPM model. Concentration fields obtained from model simulations have been compared with experimental data of CO concentrations measured at two vertical locations within the canyon. The CFD results are in good agreement with the experimental data, while poor agreement is observed for the WinOSPM results. This is because WinOSPM was originally developed and tested for street canyons with aspect ratio H/W ≌ 1. Large discrepancies in wind profiles simulated within the canyon are observed between CFD and OSPM models. Therefore, a modification of the wind profile within the canyon is introduced in WinOSPM for extending its applicability to deeper canyons, leading to an improved agreement between modelled and experimental data. Further development of the operational dispersion model is required in order to reproduce the distinct air circulation patterns within deep street canyons.     

A review of the characteristics of nanoparticles in the urban atmosphere and the prospects for developing regulatory controls

The likely health and environmental implications associated with atmospheric nanoparticles have prompted considerable recent research activity. Knowledge of the characteristics of these particles has improved considerably due to an ever growing interest in the scientific community, though not yet sufficient to enable regulatory decision making on a particle number basis. This review synthesizes the existing knowledge of nanoparticles in the urban atmosphere, highlights recent advances in our understanding and discusses research priorities and emerging aspects of the subject. The article begins by describing the characteristics of the particles and in doing so treats their formation, chemical composition and number concentrations, as well as the role of removal mechanisms of various kinds. This is followed by an overview of emerging classes of nanoparticles (i.e. manufactured and bio-fuel derived), together with a brief discussion of other sources. The subsequent section provides a comprehensive review of the working principles, capabilities and limitations of the main classes of advanced instrumentation that are currently deployed to measure number and size distributions of nanoparticles in the atmosphere. A further section focuses on the dispersion modelling of nanoparticles and associated challenges. Recent toxicological and epidemiological studies are reviewed so as to highlight both current trends and the research needs relating to exposure to particles and the associated health implications. The review then addresses regulatory concerns by providing an historical perspective of recent developments together with the associated challenges involved in the control of airborne nanoparticle concentrations. The article concludes with a critical discussion of the topic areas covered.