An approach for assessing the inhalation bioaccessibility of Pb in the PM10 size fraction is presented, using an in vitro simulated epithelial lung fluid to represent the extracellular environment of the lung. The developed inhalation bioaccessibility method (IBM) is applied to a range of urban surface soils and mining wastes obtained from Mitrovica, Kosovo, a site where impacts upon human health following exposure to Pb have been internationally publicised. All Pb determinations were undertaken by inductively coupled plasma mass spectrometry (ICP-MS). The pseudo-total concentration of Pb (microwave acid digestion using aqua-regia) varied between matrices: smelter (20,900-72,800mgkg(-1)), topsoil (274-13,700mgkg(-1)), and tailings (2990mgkg(-1)-25,300mgkg(-1)). The in vitro inhalation bioaccessibility was typically several orders of magnitude lower: smelter (7.0-965mgkg(-1)), topsoil (9.8-1060mgkg(-1)), and tailings (0.7mgkg(-1)-49.2mgkg(-1)). The % inhalation bioaccessibility ranged from 0.02 to 11.0%, with the higher inhalation bioaccessible Pb concentrations being observed for samples from the Bosniak Mahalla area of Mitrovica (an area proposed for the relocation of internally displaced peoples). The estimated inhalation dose (for adults) calculated from the PM10 pseudo-total Pb concentration ranged from 0.369 to 1.284μgkg(-1)BWday(-1) (smelter), 0.005-0.242μgkg(-1)BWday(-1) (topsoil), and 0.053-0.446μgkg(-1)BWday(-1) (tailings). When daily inhalation doses were calculated using the bioaccessible Pb concentration the modelled exposure doses were much lower: smelter (0.0001-0.0170μgkg(-1)BWday(-1)), topsoil (0.0002-0.0187μgkg(-1)BWday(-1)) and tailings (0.0001-0.0009μgkg(-1)BWday(-1)). Modelled for the neutral pH conditions of the interstitial lung environment, the results indicate a low potential inhalation bioaccessibility for Pb in these samples. Given the already elevated environmental Pb burden experienced by the local population, where significant prolonged dust or particulate generating activities are taking place, or where the inhaled particles are phagocytized, then inhalation exposure has the potential to significantly add to the overall Pb burden. Such data are important for local policy makers to better enable them to assess risk, especially in areas where soils/dusts have elevated levels of contamination.

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AbstractThis work involved the production and thermal characterization of biomass briquettes produced by blending a major agricultural waste with coal dust. In the work, nine different compositions of coal dust/groundnut husk briquettes were produced using starch as the binder while Ca(OH2) was incorporated as the de-sulphurizing agent. The ash content, volatile matter, fixed carbon, moisture content, compressive strength, ignition time, calorific value, water boiling test and burning rate were carried out to determine the physical, mechanical and thermal properties of the briquettes produced. The results showed that moisture content values are in the range 2.43 - 6.44%, for compressive strength 7.72 - 10.85 N/mm3, for ash content 24.18 - 29.15 %, for calorific value 21714.17 - 25027.18 kJ/kg, for fixed carbon 16.77-53.22 %, for ignition time 22.23-45.20 s, for water boiling test 1.50-4.99 min and burning rate 16.10-28.32 g/min. These are appreciable values for the thermal properties of the bio-briquettes. Therefore, the agro-wastes briquettes are beneficial for heating purposes rather than open incineration of the wastes.