Characteristics of current roadside pollution using test-monitoring plots

Search for effective eluent for Pd separation on ion-exchange sorbent before voltammetric determination

Determination of Pd traces in environmental samples is still a challenging analytical task. The aim of this study was to propose an efficient system (i.e. ion-exchange resin and eluent) for Pd elution from SPE column after the analyte preconcentration. Moreover, the search was focused on solvents that would not interfere voltammetric determination of Pd, as well as ICP-MS analysis. Five ion-exchange sorbents were compared in terms of effective Pd separation from matrix components when using different eluents. The highest recovery (up to 91%) of palladium was obtained for Dowex 1 and ammonium buffer as the eluent. This solution not only provides relatively high palladium elution efficiency but also allows both voltammetric and ICP-MS determinations, without any additional sample preparation. It was proven that the proposed procedure including SPE separation and determination with AdSV and/or ICP-MS could be used for quantitative Pd measurement in environmental samples, such as quartz sand used for the monitoring of Pd emission in the areas of high traffic density.

Geochemical characteristics of solid particles deposited on experimental plots established for traffic pollution monitoring in different countries

The main aim of this research was to identify the mineralogical, morphological, and chemical characteristics of solid particles emitted by vehicular traffic and deposited on special monitoring plots located on the roadside of five countries with different climatic conditions and traffic structure. Within 24 months of exposure, the composition of the matrix used at the monitoring plots changed. Percentage quartz content decreased in all locations, and due to the input from local sources, the share of other mineral phases increased. In some locations, an increase in the share of mineral phases associated with local parent rock and soil erosion was noted (e.g. Helsinki, Böblingen). In other places, material associated with abrasion of the road surface was characteristic (e.g. Gliwice, Opole). The composition of pollutants accumulated at all the monitoring plots was varied, however the common feature was the presence of technogenic magnetic particles in the matrix after exposure. Analyses showed that numerous irregular, angular particles of iron oxides with porous surface, which are carriers for a number of metals and metalloids were present in the samples. Angular iron oxides containing zinc, chromium, and copper are usually considered as non-exhaust traffic emissions. Another type of iron oxides particles found in the samples were magnetic spherules related to exhaust emissions (smaller spherules, < 20 μm). Study of results confirmed the effectiveness of the testing method for roadside pollution monitoring related to currently emitted solid particles accumulated on matrix of known mineral composition.

Airborne, Vehicle-Derived Fe-Bearing Nanoparticles in the Urban Environment: A Review

Airborne particulate matter poses a serious threat to human health. Exposure to nanosized (<0.1 μm), vehicle-derived particulates may be hazardous due to their bioreactivity, their ability to penetrate every organ, including the brain, and their abundance in the urban atmosphere. Fe-bearing nanoparticles (<0.1 μm) in urban environments may be especially important because of their pathogenicity and possible association with neurodegenerative diseases, such as Alzheimer's and Parkinson's diseases. This review examines current knowledge regarding the sources of vehicle-derived Fe-bearing nanoparticles, their chemical and mineralogical compositions, grain size distribution and potential hazard to human health. We focus on data reported for the following sources of Fe-bearing nanoparticles: exhaust emissions (both diesel and gasoline), brake wear, tire and road surface wear, resuspension of roadside dust, underground, train and tram emissions, and aircraft and shipping emissions. We identify limitations and gaps in existing knowledge as well as future challenges and perspectives for studies of airborne Fe-bearing nanoparticles.

Effective and universal tool for evaluating heavy metals-passive dust samplers

The study presents designating, accomplishing, optimizing, and validating a new tool - "passive sampler" (PS) that can be effectively used as a proxy to assess the level of traffic-related pollution. To construct the PS, a drainage pipe filled with a mixture of coarse sand and peat in a volume ratio of 1:1 was used; this was previously verified to exhibit high ability to accumulate pollutants. Magnetic methods supplemented with chemical method evaluating heavy metal content and electron microscopic observations were used to detect the effectiveness of the PS. The PS was validated in Warsaw, Poland, by observing the capacity and trends in the accumulation of traffic-related heavy metals as well as magnetic particles and by comparison of the properties of magnetic fraction of PS filling and street dust collected from the surface of road. A depth decreasing trend in distributions of magnetic susceptibility related to the concentration of magnetic particles and the content of heavy metals confirmed a very strong accumulation of pollution in the surface layer of samplers and their depth-migration. Magnetic fraction of PS filling and street dust revealed similarities in terms of magnetic mineralogy, grain size, domain state, morphology, and chemical composition. The good correlation of concentration of magnetic particles with traffic-related heavy metals indicates their similar transport pathway from road to sampler. Passive sampler is a compact, mobile, low-cost tool that does not require electricity for installation and can be effectively used for the identification of traffic-derived pollution. Moreover, the PS can overcome disadvantages of street dust arising from different geological backgrounds, cleaning of the road surface, runoff of deposited dust, etc., which cause the underestimation of pollution level.

Road Environments: Impact of Metals on Human Health in Heavily Congested Cities of Poland

Road dust as a by-product of exhaust and non-exhaust emissions can be a major cause of systemic oxidative stress and multiple disorders. Substantial amounts of road dust are repeatedly resuspended, in particular at traffic lights and junctions where more braking is involved, causing potential threat to pedestrians, especially children. In order to determine the degree of contamination in the heavily traffic-congested cities of Poland, a total of 148 samples of road dust (RD), sludge from storm drains (SL) and roadside soil (RS) were collected. Sixteen metals were analysed using inductively coupled plasma mass spectrometry (ICP-MS), inductively coupled plasma atomic emission spectroscopy (ICP-OES) and atomic absorption spectroscopy (AAS) in all samples. Chemical evaluation followed by Principal Component Analysis (PCA) revealed that road environments have been severely contaminated with traffic-related elements. Concentration of copper in all road-environment samples is even higher, exceeding even up to 15 times its average concentrations established for the surrounding soils. Non-carcinogenic health risk assessment revealed that the hazard index (HI) for children in all road-environment samples exceeds the safe level of 1. Therefore, greater attention should be paid to potential health risks caused by the ingestion of traffic-related particles during outdoor activities.

Identification of Heavy Metal Pollution Derived From Traffic in Roadside Soil Using Magnetic Susceptibility

The study integrates surface and vertical distribution of magnetic susceptibility and heavy metal contents (Pb, Cu, Zn and Fe) to characterize the signature of vehicle pollutants in roadside soils at Linfen city, China. Sites with reforestation and without vegetation cover were investigated. The results showed that magnetic susceptibility and heavy metal contents were higher at the roadside without trees than in the reforest belt. The variations of magnetic susceptibility and heavy metal contents decreased both with distance and with depth. The maximum value was observed at 5-10 m away from the roadside edge. The vertical distribution in soil revealed accumulation of pollutants in 0-5 cm topsoils. The average contents were higher than the background values and in the order Fe (107.21 g kg^-1), Zn (99.72 mg kg^-1), Pb (90.99 mg kg^-1), Cu (36.14 mg kg^-1). Coarse multi domain grains were identified as the dominating magnetic particles. Multivariate statistical and SEM/EDX analyses suggested that the heavy metals derived from traffic sources. Trees act as efficient receptors and green barrier, which can reduce vehicle derived pollution.

Impact of highway traffic and the acoustic screen on the content and spatial distribution of heavy metals in soils

Recent years have witnessed intensification of road traffic and, with it, the amount of substances emitted by vehicles. Such emissions need to be monitored for public health purposes. The aim of this study was to evaluate the impact of the highway traffic on the total content and bioavailability of Zn, Cu, Ni, Cd, Cr and Pb in nearby soils as well as influence of an acoustic screen on spatial distribution of the metals. The material included 40 soil samples collected from 15 research points located 5, 10, 25 and 50 m away from the road acoustic screen and from 4 points between the screen and the highway. Additionally, 5 research points were located next to the metal barrier. Selected physicochemical properties of soils were determined: soil texture, soil pH, TOC and CaCO₃ content. The total content of heavy metals in the soils was determined by AAS after digestion in aqua regia and bioavailable forms in 1 M diethylenetriaminepentaacetic acid. The research found low impact of the highway traffic on the content of heavy metals in soils; however, due to a very short period of this potential impact (5 years), the moderately polluted category of geo-accumulation index of cadmium and high bioavailability of lead indicate the need of repeating the research within the next several years. Furthermore, the road acoustic screen significantly influenced spatial distribution of the metals in soils.

Metal and metalloid accumulation in cultivated urban soils: A medium-term study of trends in Toronto, Canada

This study aims to examine the elemental enrichment patterns in low to medium traffic areas over a three year period in Toronto, Canada. Soils were sampled at three locations with different volumes of traffic between 2010 and 2013. A range of elements, including V, Cr, Mn, Cu, Cd, As, Sb and Pb, were measured in acid digested samples using ICP-MS. While the concentrations of Cd, Sb and Pb were found to be relatively low, a significant, albeit small increase in their levels over time was determined for all sites. For the low traffic areas, median Cd, Sb and Pb concentrations increased from 0.18mg Cd/kg, 0.14mg Sb/kg and 12mg Pb/kg in 2010 to 0.38mg Cd/kg, 0.21mg Sb/kg and 15mg Pb/kg in 2012, respectively. For the medium traffic site, the respective levels of Cd and Sb rose from 0.19mg Cd/kg and 0.14mg Sb/kg in 2010 to 0.49mg Cd/kg and 0.28mg Sb/kg in 2012. Median Pb concentrations at the medium traffic site were comparable to those at the low traffic sites (13mg/kg in 2010 and 15mg/kg in 2012). Principal Component Analysis (PCA) revealed the existence of two components (rotated), which explained 77% of the variance for all sites: 1. PC1 with large loadings of V, Cr, Co and Cu that likely originate from the commercial soil originally used for monitoring purposes, and 2. PC2 with high correlations between Cd, Sb and Pb, attributed to traffic sources of emissions. The resuspension and transport of more mobile fractions of contaminated dust and soil particles is hypothesized to be contributing to an elemental enrichment of soils located in low traffic areas.

Coke industry and steel metallurgy as the source of soil contamination by technogenic magnetic particles, heavy metals and polycyclic aromatic hydrocarbons

Application of integrated magnetic, geochemical and mineralogical methods for qualitative and quantitative assessment of forest topsoils exposed to the industrial emissions was the objective of this manuscript. Volume magnetic susceptibility (κ) in three areas of southern Poland close to the coke and metallurgical plants was measured directly in the field. Representative topsoil samples were collected for further chemical and mineralogical analyses. Topsoil magnetic susceptibility in the studied areas depended mainly on the content of technogenic magnetic particles (TMPs) and decreased downwind at increasing distance from the emitters. In the vicinity of coking plants a high amount of polycyclic aromatic hydrocarbons (PAHs) was observed, especially the most carcinogenic ones with four- and five-member rings. No significant concentration of TMPs (estimated on the base of κ values) and heavy metals (HM) was observed in area where the coke plant was the only pollution source. In areas with both coke and metallurgical industry, higher amounts of TMPs, PAHs and HM were detected. Morphological and mineralogical analyses of TMPs separated from contaminated soil samples revealed their high heterogeneity in respect of morphology, grain size, mineral and chemical constitution. Pollution load index and toxicity equivalent concentration of PAHs used for soil quality assessment indicated its high level of pollution.