BackgroundLead is well known environmental pollutant, which can cause toxic effects in multiple organ systems. However, the influence of lead oxide nanoparticles, frequently emitted to the environment by high temperature technological processes, is still concealed. Therefore, we investigate lead oxide nanoparticle distribution through the body upon their entry into lungs and determine the microscopic and ultramicroscopic changes caused by the nanoparticles in primary and secondary target organs.MethodsAdult female mice (ICR strain) were continuously exposed to lead oxide nanoparticles (PbO-NPs) with an average concentration approximately 106 particles/cm3 for 6 weeks (24 h/day, 7 days/week). At the end of the exposure period, lung, brain, liver, kidney, spleen, and blood were collected for chemical, histological, immunohistochemical and electron microscopic analyses.ResultsLead content was found to be the highest in the kidney and lungs, followed by the liver and spleen; the smallest content of lead was found in brain. Nanoparticles were located in all analysed tissues and their highest number was found in the lung and liver. Kidney, spleen and brain contained lower number of nanoparticles, being about the same in all three organs. Lungs of animals exposed to lead oxide nanoparticles exhibited hyperaemia, small areas of atelectasis, alveolar emphysema, focal acute catarrhal bronchiolitis and also haemostasis with presence of siderophages in some animals. Nanoparticles were located in phagosomes or formed clusters within cytoplasmic vesicles. In the liver, lead oxide nanoparticle exposure caused hepatic remodeling with enlargement and hydropic degeneration of hepatocytes, centrilobular hypertrophy of hepatocytes with karyomegaly, areas of hepatic necrosis, occasional periportal inflammation, and extensive accumulation of lipid droplets. Nanoparticles were accumulated within mitochondria and peroxisomes forming aggregates enveloped by an electron-dense mitochondrial matrix. Only in some kidney samples, we observed areas of inflammatory infiltrates around renal corpuscles, tubules or vessels in the cortex. Lead oxide nanoparticles were dispersed in the cytoplasm, but not within cell organelles. There were no significant morphological changes in the spleen as a secondary target organ. Thus, pathological changes correlated with the amount of nanoparticles found in cells rather than with the concentration of lead in a given organ.ConclusionsSub-chronic exposure to lead oxide nanoparticles has profound negative effects at both cellular and tissue levels. Notably, the fate and arrangement of lead oxide nanoparticles were dependent on the type of organs.Electronic supplementary materialThe online version of this article (10.1186/s12989-017-0236-y) contains supplementary material, which is available to authorized users.

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Sampling and analysis of carbonaceous compounds in particulate matter presents a number of difficulties related to artefacts during sampling and to the distinction between organic (OC) and elemental carbon (EC) during analysis. Our study reports on a comparative analysis of OC, EC and WSOC (water-soluble organic carbon) concentrations, as well as sampling artefacts, for PM2.5 aerosol in three European cities (Amsterdam, Barcelona and Ghent) representing Southern and Western European urban environments. Comparability of results was ensured by using a single system for sample analysis from the different sites. OC and EC concentrations were higher in the vicinity of roads, thus having higher levels in Amsterdam (3.9-6.7 and 1.7-1.9 mg m À3 , respectively) and Barcelona (3.6-6.9 and 1.5-2.6 mg m À3) than in Ghent (2.7-5.4 and 0.8-1.2 mg m À3). A relatively larger influence of secondary organic aerosols (SOA), as deduced from a larger OC/EC ratio, was observed in Ghent. In absolute sense, WSOC concentrations were similar at the three sites (1.0-2.3 mg m À3). Positive artefacts were higher in Southern (11-16% of the OC concentration in Barcelona) than in Western Europe (5-12% in Amsterdam, 5-7% in Ghent). During special episodes, the contribution of carbonaceous aerosols from nonlocal sources accounted for 67-69% of the OC concentration in Western Europe, and for 44% in Southern Europe.

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Sampling of particulate matter (PM) with filter media is subject to the influence of positive and negative artefacts. The complexity of these measurements derives from the use of different instrumentation, face velocities, and filter types. Carbonaceous compounds are one of the main PM chemical components affected by these artefacts. In this study, two main types of artefacts were evaluated at an urban site in Ghent (Belgium) during the summer period: those related to the sampling procedure (high-or low-volume samplers) and those related to the adsorption and/or volatilization of carbonaceous species. For their measurement, two high-volume (PM10 and PM2.5) samplers with single quartz fiber filters and two low-volume PM2.5 samplers (one of them coupled to an annular diffusion denuder) with double quartz fiber filters (front and backup) were used. PM2.5 mass concentrations measured by means of the lowvolume sampler (front filter) were, on average, 31% higher than those registered with the high-volume sampler. PM2.5 mass concentrations registered with the low-volume sampler coupled to the diffusion denuder represented 88% of the PM2.5 mass collected with the undenuded low-volume sampler. Similar values for organic carbon (OC) were recorded for the high-and low-volume samplers. Front filter OC levels for the denuded samples represented 66% of the front filter OC mass on the undenuded samples. Using the backup filter OC data to apply a correction to the front filter data as suggested by Mader et al. (2003) only marginally reduced the discrepancy between the undenuded and denuded OC data, indicating that such correction does not result in consistent OC data for an urban area in Western Europe during summer.