Spatial and temporal variations in Pb concentrations and isotopic composition in road dust, farmland soil and vegetation in proximity to roads since cessation of use of leaded petrol in the UK

Results are presented for a study of spatial distributions and temporal trends in concentrations of lead (Pb) from different sources in soil and vegetation of an arable farm in central Scotland in the decade since the use of leaded petrol was terminated. Isotopic analyses revealed that in all of the samples analysed, the Pb conformed to a binary mixture of petrol Pb and Pb from industrial or indigenous geological sources and that locally enhanced levels of petrol Pb were restricted to within 10 m of a motorway and 3 m of a minor road. Overall, the dominant source of Pb was historical emissions from nearby industrial areas. There was no discernible change in concentration or isotopic composition of Pb in surface soil or vegetation over the decade since the ban on the sale of leaded petrol. There was an order of magnitude decrease in Pb concentrations in road dust over the study period, but petrol Pb persisted at up to 43% of the total Pb concentration in 2010. Similar concentrations and spatial distributions of petrol Pb and non petrol Pb in vegetation in both 2001 and 2010, with enhanced concentrations near roads, suggested that redistribution of previously deposited material has operated continuously over that period, maintaining a transfer pathway of Pb into the biosphere. The results for vegetation and soil transects near minor roads provided evidence of a non petrol Pb source associated with roads/traffic, but surface soil samples from the vicinity of a motorway failed to show evidence of such a source

Integrated Assessment of Heavy Metal Contamination in Sediments from a Coastal Industrial Basin, NE China

The purpose of this study is to investigate the current status of metal pollution of the sediments from urban-stream, estuary and Jinzhou Bay of the coastal industrial city, NE China. Forty surface sediment samples from river, estuary and bay and one sediment core from Jinzhou bay were collected and analyzed for heavy metal concentrations of Cu, Zn, Pb, Cd, Ni and Mn. The data reveals that there was a remarkable change in the contents of heavy metals among the sampling sediments, and all the mean values of heavy metal concentration were higher than the national guideline values of marine sediment quality of China (GB 18668-2002). This is one of the most polluted of the world’s impacted coastal systems. Both the correlation analyses and geostatistical analyses showed that Cu, Zn, Pb and Cd have a very similar spatial pattern and come from the industrial activities, and the concentration of Mn mainly caused by natural factors. The estuary is the most polluted area with extremely high potential ecological risk; however the contamination decreased with distance seaward of the river estuary. This study clearly highlights the urgent need to make great efforts to control the industrial emission and the exceptionally severe heavy metal pollution in the coastal area, and the immediate measures should be carried out to minimize the rate of contamination, and extent of future pollution problems

Road traffic metals : sources and emissions

As the environmental regulations and technical progress have forced the factories’ old “end of pipe” solutions to improve, the metal emissions from point sources have decreased. Instead, the diffuse consumption emissions from goods in use now are in focus. The increased awareness of traffic as a major diffuse metal emission source emphasizes the need for more detailed information on the various traffic related sources. The main scope of this thesis is to study specific parts of metal emissions from some road traffic related sub sources such as brake lining and tyres. The metals in focus are antimony (Sb), cadmium (Cd), copper (Cu), chromium (Cr), lead (Pb), nickel(Ni) and zinc (Zn), and the research quantifies emissions from the different sub sources, trace changes over time as well as dispersal patterns and metal mobility in the roadside environment. The results show that even if the road traffic associated metal stocks are small compared to total in use stocks, their emissions are of major importance. The updated figures show that despite material developments during the last 10 years, tyres still are one of the main sources of Zn and Cd, while it can be excluded as a source of concern for the other metals studied. Brake linings are shown to be an especially pronounced source for Cu and Sb. The Pb and Cd emissions from brake linings and tyres have decreased as a result of decreasing material concentrations in these sources, most likely a result of EU regulations. Further the results reveals galvanized goods to be a major road traffic related source for Zn. The results show that the total metal concentrations in roadside soils have increased 3-16 times compared to regional background during the last decades. Each metal has a limited dispersal distance from the roads as well as down in the soil profile. Most metals are found within 10 m from the road in the uppermost 10 cm of the topsoil. However, the sequential extractions show that a large part of the metals found in the soil are rather easily mobilized and can be redistributed if the roadside soils become disturbed. Metals emitted due to decelerating activities are not correlated to elevated concentrations near road junctions. Instead the metals appear to be more evenly spread along the whole driven distance. The study points out Sb as an element that might be problematic to analyse. For Sb, which is sparsely studied as a roadside contaminant, there is a need of more general knowledge as it has a high accumulation rate in roadside soils.I takt med ökade regleringar inom miljöområdet och en snabb teknikutveckling har fabrikerna allt mer spelat ut sin roll som emissionskällor till miljön. Istället har den diffusa emissionen som kommer från produktanvändning fått en större betydelse. En ökad medvetenhet om transporter och trafikens betydelse för samhällets konsumtionsemissioner understryker det ökade kunskapsbehovet för de trafikrelaterade emissionskällorna. Avhandlingens huvudsyfte är att studera specifika delar av metallemissionen från vissa trafikrelaterade källor så som bromsbelägg och däck. Metallerna som är i fokus är antimon (Sb), bly (Pb), kadmium (Cd), koppar (Cu), krom (Cr), nickel (Ni) och zink (Zn) och forskningen strävar efter att kvantifiera emissionerna från de olika källorna, spåra förändringar i emissioner över tid, kartlägga utsläppsmönster och metallrörlighet i vägnära jord. Resultaten pekar på att även om de trafikrelaterade källorna kvantitativt är små i jämförelse med de totala källorna så är deras emissioner av stor betydelse. De nya siffrorna visar att trots en materialutveckling inom området under det senaste årtiondet så är fortfarande däck en av de största källorna för Cd och Zn i stadsmiljö, medan de kan avfärdas som källa för de övriga studerade metallerna. Studien visar att bromsbelägg fortfarande är en viktig källa för Cu och Sb. Bly- och Cd-emissionerna från däck och bromsbelägg har däremot minskat drastiskt under samma period. Denna minskning beror troligen på en reglering på EU-nivå. Dessutom visar resultaten att galvaniserade ytor är den viktigaste källan till Zn i stadsmiljö. Metallkoncentrationerna i vägnära jord har ökat med 3 – 16 ggr jämfört med bakgrundshalterna i de undersökta områdena. Metallerna uppvisar endast en begränsad spridning från vägen och ner i jordprofilen. Den största metallpåverkan återfinns inom 10 m från vägen och i de översta 10 cm av jorden. Trots den begränsade spridningen så uppvisar de flesta metallerna en förhållandevis hög rörlighet, vilket innebär att de kan bli mobila vid störning av jorden. De bromsrelaterade metallerna uppvisar ingen korrelation till förhöjda halter nära korsningar utan är mer jämnt spridda över hela körsträckan. Studien pekar ut Sb som ett element som kan vara problematiskt att analysera på grund av dess flyktighet. Trots att Sb för närvarande har en snabb ackumulationstakt i trafikmiljö så är den endast sparsamt studerad. Mer generell kunskap om Sb är därför önskvärd

Real-World Emission Factors for Antimony and Other Brake Wear Related Trace Elements: Size-Segregated Values for Light and Heavy Duty Vehicles

Hourly trace element measurements were performed in an urban street canyon and next to an interurban freeway in Switzerland during more than one month each, deploying a rotating drum impactor (RDI) and subsequent sample analysis by synchrotron radiation X-ray fluorescence spectrometry (SR-XRF). Antimony and other brake wear associated elements were detected in three particle size ranges (2.5-10, 1-2.5, and 0.1-1 microm). The hourly measurements revealed that the effect of resuspended road dust has to be taken into account for the calculation of vehicle emission factors. Individual values for light and heavy duty vehicles were obtained for stop-and-go traffic in the urban street canyon. Mass based brake wear emissions were predominantly found in the coarse particle fraction. For antimony, determined emission factors were 11 +/- 7 and 86 +/- 42 microg km(-1) vehicle(-1) for light and heavy duty vehicles, respectively. Antimony emissions along the interurban freeway with free-flowing traffic were significantly lower. Relative patterns for brake wear related elements were very similar for both considered locations. Beside vehicle type specific brake wear emissions, road dust resuspension was found to be a dominant contributor of antimony in the street canyon