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Castricum, Netherlands

Walraven N.,GeoConnect | van Gaans P.F.M.,Deltares | van der Veer G.,RIKILT Institute of Food Safety | van Os B.J.H.,Rijksdienst voor Archeologie | And 4 more authors.
Applied Geochemistry | Year: 2013

Knowledge of the cause and source of Pb pollution is important to abate environmental Pb pollution by taking source-related actions. Lead isotope analysis is a potentially powerful tool to identify anthropogenic Pb and its sources in the environment. Spatial information on the variation of anthropogenic Pb content and anthropogenic Pb sources in rural topsoils is remarkably limited. This study presents results of a survey of approximately 350 topsoil samples from rural locations covering the entire Netherlands, for which the bulk geochemical and Pb isotope compositions were determined. The specific aim of this study is to determine the anthropogenic Pb sources in the topsoils from rural areas in The Netherlands. The spatial distribution of anthropogenic Pb in soils in The Netherlands will be explained in terms of land use and pollution sources.Nearly all studied topsoils display Pb contents that exceed the amount expected based on the soil lithology. The range in Pb isotope ratios of the additional Pb fraction in rural Dutch topsoils is established at 1.056-1.199, 2.336-2.486 and 0.452-0.490 for 206Pb/207Pb, 207Pb/208Pb and 206Pb/208Pb, respectively. Five land use types are distinguished (forest, open nature, moor, arable land and grassland) with distinct isotopic compositions for added Pb. Additional Pb in soils of natural areas (forest, open nature and moor) has on average lower 206Pb/207Pb, 208Pb/207Pb and 206Pb/208Pb ratios than the agricultural soils (arable land and grassland). Additional Pb in both natural area soils and agricultural soils is interpreted to be of anthropogenic origin: most likely a mixture of coal/galena, incinerator ashes and gasoline Pb. The dominant sources of additional Pb in the topsoil of open nature areas are most likely incinerator ash and gasoline Pb. In contrast, the on average higher 206Pb/207Pb, 208Pb/207Pb and 206Pb/208Pb ratios of additional Pb in agricultural soils are most likely caused by the presence of animal manure and N-P fertilizers.Several areas are observed with notably high additional Pb contents (26-211. mg/kg on an organic matter-free basis) in the topsoil. The largest area is the Randstad area, which has the highest population and traffic density, and hosts a considerable fraction of the Dutch chemical industry. Two other areas with high additional Pb contents in the topsoil are located near the Dutch borders and are most likely influenced by German and Belgian chemical industries. The topsoils in the coastal dunes and southern, central and northern forests are characterized by relatively low additional Pb contents (<10. mg/kg on an organic matter-free basis). The population, traffic and chemical industry density is low in these areas and no fertilizers are applied. © 2013 Elsevier Ltd.


Walraven N.,GeoConnect | van Os B.J.H.,Rijksdienst voor Archeologie | Klaver G.,Bureau de Recherches Geologiques et Minieres | Middelburg J.J.,University Utrecht | Davies G.R.,VU University Amsterdam
Science of the Total Environment | Year: 2014

In this study the origin, behaviour and fate of anthropogenic Pb in sandy roadside soils were assessed by measuring soil characteristics, Pb isotope composition and content. In 1991 and 2003 samples were taken at different depth intervals at approximately 8 and 75m from two highways in The Netherlands. The Pb isotope composition of the litter layer (206Pb/207Pb=1.12-1.14) differs from the deeper soil samples (206Pb/207Pb=1.20-1.21). Based on a mixing model it is concluded that the samples contain two Pb sources: natural Pb and anthropogenic Pb, the latter mainly derived from gasoline.206Pb/207Pb ratios demonstrate that the roadside soils were polluted to a depth of ~15cm. Within this depth interval, anthropogenic Pb content is associated with organic matter. Although Pb pollution only reached a depth of ~15cm, this does not mean that the topsoils retain all anthropogenic Pb. Due to the low pH and negligible binding capacity of soils at depths >15cm, anthropogenic Pb migrated towards groundwater after reaching depths of >15cm. The Pb isotope composition of the groundwater (206Pb/207Pb=1.135-1.185) establishes that groundwater is polluted with anthropogenic Pb. The contribution of anthropogenic Pb to the groundwater varies between ~30 and 100%.Based on the difference in soil Pb content and Pb isotope compositions over a period of 12years, downward Pb migration is calculated to vary from 72±95 to 324±279mgm-2y-1. Assuming that the downward Pb flux is constant over time, it is calculated that 35-90% of the atmospherically delivered Pb has migrated to the groundwater. © 2013.


Walraven N.,GeoConnect | van Os B.J.H.,Rijksdienst voor Archeologie | Klaver G.,Bureau de Recherches Geologiques et Minieres | Middelburg J.J.,University Utrecht | Davies G.R.,VU University Amsterdam
Science of the Total Environment | Year: 2014

Lake sediments provide a record of atmospheric Pb deposition and changes in Pb isotope composition. To our knowledge, such an approach has not previously been performed in The Netherlands or linked to national air monitoring data. Results are presented for Pb content and isotope composition of 137Cs dated lake sediments from 2 Dutch urban lakes. Between 1942 and 2002A.D. anthropogenic atmospheric Pb deposition rates in the two lakes varied from 12±2 to 69±16μgcm-2year-1. The rise and fall of leaded gasoline is clearly reflected in the reconstructed atmospheric Pb deposition rates. After the ban on leaded gasoline, late 1970s/early 1980s, atmospheric Pb deposition rates decreased rapidly in the two urban lakes and the relative contributions of other anthropogenic Pb sources - incinerator ash (industrial Pb) and coal/galena - increased sharply. Atmospheric Pb deposition rates inferred from the lake record a clear relationship with nearby measured annual mean air Pb concentrations. Based on this relationship it was estimated that air Pb concentrations between 1942 and 2002A.D. varied between 5 and 293ng/m3. © 2014 Elsevier B.V.


Walraven N.,GeoConnect | Bakker M.,Rijksinstituut voor Volksgezondheid en Milieu RIVM | Van Os B.J.H.,Rijksdienst voor Archeologie | Klaver G.T.,Bureau de Recherches Geologiques et Minieres | And 2 more authors.
Science of the Total Environment | Year: 2015

In human risk assessment, ingestion of soil is considered a major route of toxic Pb exposure. A large body of research has focussed on the measurement of the 'total' Pb contents in sediment, soil and dust as a measure for the exposure to lead. We report that Pb bioaccessibility (i.e. the maximum bioavailability), determined with an in vitro test, does not necessarily depend on the total Pb content. In contrast, the Pb bioaccessibility is initially controlled by the chemical form and particle size of the Pb source, which in turn determine its solubility. Furthermore, when anthropogenic Pb resides within the soil, it may form new, more stable, minerals and/or binds to organic matter, clay, reactive iron or other reactive phases, changing its bioaccessibility.The bioaccessible Pb fraction of 28 soils, polluted with various Pb sources (including residues of Pb bullets and pellets, car battery Pb, city waste and diffuse Pb), was determined with an in vitro-test and varied from 0.5% to 79.0% of total Pb. The highest Pb bioaccessibility (60.7% to 79.0%) was measured in soils polluted with residues of Pb bullets and pellets (shooting range), while the lowest Pb bioaccessibility (0.5%-8.3%) was measured in soils polluted with city waste (including remnants of Pb glazed potsherds and rooftiles, Pb based paint flakes, and Pb sheets). Bioaccessibility of Pb was correlated with pH, organic matter and reactive Fe. These results indicate that soil characteristics play an important role in the oral bioaccessibility of lead in polluted soils. Instead of basing human risk assessment solely on total Pb contents we propose to incorporate in vitro bioaccessibility tests, taking factors such as soil pH, organic matter content and reactive iron content into account. This approach will result in a better insight into the actual risks of Pb polluted soils to children. © 2014.


Walraven N.,GeoConnect | van Gaans P.F.M.,Deltares | van der Veer G.,RIKILT Institute of Food Safety | van Os B.J.H.,Rijksdienst voor Archeologie | And 4 more authors.
Applied Geochemistry | Year: 2013

Knowledge on the lithologically inherited variation in present day Pb isotope ratios in soils is remarkably limited. Such information is essential to determine the anthropogenic Pb fraction and anthropogenic Pb sources in Pb-polluted soils. This study presents results of a survey of subsoil samples from approximately 350 rural locations covering the entire Netherlands, for which the bulk geochemical and Pb isotope composition was determined. The sample density was approximately 1 site per 70km2. The aim was to establish a geochemical reference for the lithologically inherited variation in Pb isotope ratios in Dutch soils based on the subsoil samples, with which to compare the topsoils (companion paper in this journal issue).The lithologically inherited variation in Pb isotope ratios of the subsoils in The Netherlands is established at 1.175-1.221, 2.441-2.494 and 0.478-0.492 for 206Pb/207Pb, 207Pb/208Pb and 206Pb/208Pb respectively. The four main lithologies distinguished, sand, clay, peat and loess, have distinct Pb isotope signatures. No significant difference in isotope signature was found between marine and fluviatile clays. Multiple regression analysis established that the observed variation can be primarily explained by the textural and mineralogical variation within Dutch subsoils, with Al and Zr content representing useful predictors for the observed Pb isotope variability. Clay soils are characterised by a radiogenic Pb isotope signature that is notably low in 207Pb. Soils with a high Zr content are especially high in 206Pb. Although the vast majority (~90%) of the Pb isotope variation in the subsoils appears to be controlled by lithological inheritance, some subsoils (mainly peats) are suspected of containing a component of non-lithologically derived Pb. © 2013 Elsevier Ltd.

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