Factors influencing PM10 emissions from road pavement wear

Accelerated pavement wear is one of the major environmental disadvantages of studded tyres in northern regions and results in increased levels of PM₁₀. Measurements of PM₁₀ in a road simulator hall have been used to study the influence of pavement properties, tyre type and vehicle speed on pavement wear. The test set-up included three different pavements (one granite and two quartzite with different aggregate sizes), three different tyre types (studded, non-studded, and summer tyres) and different speeds (30–70 km h^?1). The results show that the granite pavement was more prone to PM₁₀ production compared to the quartzite pavements. Studded winter tyres yield tens of times higher PM₁₀ concentrations compared to non-studded winter tyres. Wear from summer tyres was negligible in comparison. It was also shown that wear is strongly dependent on speed; every 10 km h^?1 increase yielded an increase of the PM₁₀ concentration of 680 μg m^?3 in one of the simulator experiments.     

How to assess exposure of aquatic organisms to manufactured nanoparticles?

Ecological risk of chemicals is measured by the quotient of predicted no-effect concentrations and predicted exposure concentrations, which are hard to assess for manufactured nanomaterials (NMs). This paper proposes modifications to currently used models, in order to make them suitable for estimating exposure concentrations of NMs in the aquatic environment. We have evaluated the adequacy of the current guidance documents for use with NMs and conclude that nano-specific fate processes, such as sedimentation and dissolution need to be incorporated. We have reviewed the literature on sedimentation and dissolution of NMs in environmentally relevant systems. We deduce that the overall kinetics of water-sediment transport of NMs should be close to first order. The lack of data on dissolution of NMs under environmentally realistic conditions calls for a pragmatic decision on which rates to be used in modeling. We find that first order removal kinetics for dissolution seems adequate. Based on limited data from literature, probable removal rates range from 0 to 10(-4)s(-1) for sedimentation, and from 0 to 10(-5)s(-1) for dissolution. Further experimental data at environmentally relevant conditions for sedimentation and dissolution of NMs is needed.     

A Native Species with Invasive Behaviour in Coastal Dunes: Evidence for Progressing Decay and Homogenization of Habitat Types

A new species has recently invaded coastal dune ecosystems in North West Europe. The native and expansive inland grass, Deschampsia flexuosa, progressively dominating inland heaths, has recently invaded coastal dunes in Denmark, occasionally even as a dominant species. A total of 222 coastal locations with 5,000 random sample plots have been investigated. These findings are in contrast to historical records, and D. flexuosa has never been considered belonging to coastal dune ecosystems. The occurrence of the typical inland grass in the coastal dunes is a strong indication of increase in nutrient level and that human influences may cause a native species to be invasive in new ecosystems. This could be a radical example of change in species composition due to a long lasting exceedance of critical load of nitrogen. The investigation also showed a general increase in cover of the most dominant species.     

Indications of Recovery from Hypoxia in the Inner Stockholm Archipelago

Improved benthic conditions compared to the 1990s were found during benthic investigations, including sediment and benthic macrofauna in the inner Stockholm archipelago during 2008. In the 1990s, these areas were dominated by black and laminated surface sediments and very sparse fauna. A clear relationship was found when comparing sediment status with the benthic macrofauna. Reduced surface sediment and impoverished macroinvertebrate community was only found at one sampling station representing an enclosed part of the inner archipelago, whereas the other seven stations, with depths ranging from 20 to 50 m, had oxidized surface sediments and considerable biomasses of benthic macrofauna (6–65 g m⁻²) dominated by the invading polychaete Marenzelleria neglecta. An extrapolation of the results shows that, within the investigated area, the coverage of reduced surface sediments had decreased from approximately 17% in the late 1990s to 4% in 2008.     

Thermo- and fluid-dynamical modelling of two-phase multi-component carbon dioxide mixtures

A method for calculating the transport and depressurization of a two-phase multi-component CO₂ mixture is presented. The thermodynamical and transport properties for a CO₂–CH₄ mixture are calculated using the Soave–Redlich–Kwong equation of state (SRK). The fluid flow is described by a drift-flux model, which is solved using the multi-stage (MUSTA) centred scheme. Numerical results are shown, illustrating the effect of mixture composition and the feasibility of the approach.     

Brominated phenols,anisoles, and dioxins present in blue mussels from the Swedish coastline

Introduction  

Naturally occurring hydroxylated polybrominated diphenyl ethers (OH-PBDEs), their methoxylated counterparts (MeO-PBDEs), and polybrominated dibenzo-p-dioxins (PBDDs), together with their potential precursors polybrominated phenols (PBPs) and polybrominated anisoles (PBAs), were analyzed in blue mussels (Mytilus edulis) gathered along the east coast (bordering the Baltic Sea) and west coast of Sweden (bordering the North Sea). Brown algae (Dictyosiphon foenicolaceus) and cyanobacteria (Nodularia spumigena) from the Baltic Sea, considered to be among the primary producers of these compounds, were also analyzed for comparison.     

Waste products from the steel industry with NiO as additive as oxygen carrier for chemical-looping combustion

Fe₂O₃-containing waste materials from the steel industry are proposed as oxygen carrier for chemical-looping combustion. Three such materials, red iron oxide, brown iron oxide and iron oxide scales, have been examined by oxidation and reduction experiments in a batch fluidized-bed reactor at temperatures between 800 and 950 °C. NiO-based particles have been used as additive, in order to examine if it is possible to utilize the catalytic properties of metallic Ni to facilitate decomposition of hydrocarbons into more reactive combustion intermediates such as CO and H₂. The experiments indicated modest reactivity between the waste materials and CH₄, which was used as reducing gas. Adding small amounts of NiO-based particles to the sample increased the yield of CO₂ in a standard experiment, typically by a factor of 1.5–3.5. The fraction of unconverted fuel typically was reduced by 70–90%. The conversion of CH₄ to CO₂ was 94% at best, corresponding to a combustion efficiency of 96%. This was achieved using a bed mass corresponding to 57 kg oxygen carrier per MW fuel, of which only 5 wt% was NiO-based synthetic particles. The different materials fared differently well during the experiments. Red iron oxide was fairly stable, while brown iron oxide was soft and subject to considerable erosion. Iron oxide scales experienced increased reactivity and porosity as function of the numbers of reduction cycles.     

Toxicity of leachate from bottom ash in a road construction

A test road constructed with municipal solid waste incineration (MSWI) bottom ash was monitored over a period of 36 months. Using chemical and toxicological characterisation, the environmental impact of leachates from bottom ash was evaluated and compared with leachates from gravel used as reference. Initial leaching of Cl, Cu, K, Na, NH4-N and TOC from bottom ash was of major concern. However, the quality of the bottom ash leachate approached that of the gravel leachate with time. Leachates from the two materials were compared regarding the concentration of pollutants using multivariate data analyses (MVDA). A standardized luminescent bacteria assay using Vibrio fischeri did not show any toxicity, most likely because saline contamination can mask the toxic response and stimulate luminescence in these marine bacteria. A mung bean assay using Phaseolus aureus revealed that the toxicity of bottom ash leachate collected at the very beginning of the experimental period (October 2001 and May 2002) might be attributed to the following components and their respective concentrations in mg l(-1): Al (34.2-39.2), Cl (2914-16,446), Cu (0.48-1.92), K (197-847), Na (766-4180), NH4-N (1.80-8.47), total-N (12.0-18.5), and TOC (34.0-99.0). The P. aureus assay was judged as a promising environmental tool in assessing the toxicity of bottom ash leachate.     

Evaluation of the critical factors controlling stability of chromium, copper, arsenic and zinc in iron-treated soil

Various environmental factors are expected to affect the mobility of elements in chemically stabilized soils. The aim of this study was to evaluate the effects of pH, oxidizing-reducing potential (Eh), liquid-to-solid ratio (L/S), presence of organic matter (OM) and microbial activity (MA) on the mobility of chromium, copper, arsenic and zinc in zerovalent iron (Fe(0))-stabilized soil. A 2(5) full factorial design was applied to assess the leaching of the elements from the treated soil. The factor having the most impact on the mobility of Cr, Cu and Zn was pH; low pH (3) led to the release of these elements. Arsenic remobilization was controlled by L/S and MA, whilst Eh, though also significant, had less influence. In the identified worst-case scenarios, more than half of the total Zn and Cu and 14% of As can be expected to remobilize from the treated soil. The leaching procedure concerning sample agitation and type of filtration showed to substantially affect the results of As leaching, especially in OM rich soil.     

Element contents and food safety of water spinach (Ipomoea aquatica Forssk.) cultivated with wastewater in Hanoi, Vietnam

Extensive aquatic or semi-aquatic production of water spinach (Ipomoea aquatica Forssk.) for human consumption takes place in Southeast Asia. The aim of this study was to assess the concentrations of 38 elements in soil and water spinach cultivated under different degrees of wastewater exposure in Hanoi, Vietnam. The results showed no effect of wastewater use on the overall element concentrations in soil and water spinach. Mean soil concentrations for selected potentially toxic elements at the studied field sites had the following ranges 9.11–18.7 As, 0.333–0.667 Cd, 10.8–14.5 Co, 68–122 Cr, 34.0–62.1 Cu, 29.9–52.8 Ni, 32.5–67.4 Pb, 0.578–0.765 Tl and 99–189 Zn mg kg⁻¹ dry weight (d.w.). In all samples Cd, Pb and Zn soil concentrations were below the Vietnamese Guideline Values (TCVN 7209-2002) for agricultural soils whereas As and Cu exceeded the guideline values. Maximum site element concentrations in water spinach were 0.139 As, 0.032 Cd, 0.135 Cr, 2.01 Cu, 39.1 Fe, 57.3 Mn, 0.16 Ni, 0.189 Pb and 6.01 Zn mg kg⁻¹ fresh weight (f.w.). The site and soil content of organic carbon were found to have high influence on the water spinach element concentrations whereas soil pH and the total soil element concentrations were of less importance. The estimated average daily intake of As, Cd, Cu, Fe, Pb and Zn for adult Vietnamese consumers amounts to <11% of the maximum tolerable intake proposed by FAO/WHO for each element. It is assessed that the occurrence of the investigated elements in water spinach will pose low health risk for the consumers.