Browsing by Author "Bordado, J."
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- Characterization of airborne emission of nanoparticles in the ceramic industry in PortugalPublication . Esteves, Hélder; Bordado, J.; Gomes, João; Miranda, R.; Albuquerque, PaulaThe objective of this study was to evaluate occupational exposure to nanoparticles during some tasks performed in different production processes of different ceramic industries in Portugal, to select the places of greatest occupational exposure through the analysis of the sampled data, to verify what is the pulmonary accumulation in these places, to identify the composition of the released nanoparticles, apply a Control Banding Tool and try to understand which companies require more risk control measures. The study was carried out in three different national ceramics production industries, one for sanitary ceramics production, another for porcelain crockery production and finally another for the production of ornamental crockery (red paste). It is concluded that occupational exposure values to nanoparticles are high in all cases and that nanoparticles are very small in size (11.5 to 15.4 nm). Existing risk control measures are insufficient and verified risk levels are high (Risk Level 3 and 4). The chemical composition of the analyzed nanoparticles is similar regardless of the typology of the ceramic production plant and their chemical composition as a percentage of certain materials has a direct influence on crystallinity.
- Characterization of airborne emission of nanoparticles in the ceramic industry in PortugalPublication . Esteves, H.; Bordado, J.; Gomes, João; Miranda, R.; Albuquerque, PaulaThe objective of this study was to evaluate occupational exposure to nanoparticles during some tasks performed in different production processes of different ceramic industries in Portugal, to select the places of greatest occupational exposure through the analysis of the sampled data, to verify what is the pulmonary accumulation in these places, to identify the composition of the released nanoparticles, apply a Control Banding Tool and try to understand which companies require more risk control measures. The study was carried out in three different national ceramics production industries, one for sanitary ceramics production, another for porcelain crockery production, and finally another for the production of ornamental crockery (red paste). It is concluded that occupational exposure values to nanoparticles are high in all cases and that nanoparticles are very small in size (11.5 to 15.4 nm). Existing risk control measures are insufficient and verified risk levels are high (Risk Level 3 and 4). The chemical composition of the analyzed nanoparticles is similar regardless of the typology of the ceramic production plant and their chemical composition as a percentage of certain materials has a direct influence on crystallinity.
- Monitorization of alveolar deposited surface area of nanoparticles and ultrafine particles in different environmentsPublication . Albuquerque, Paula; Gomes, João P.; Bordado, J.; Reis, M.Nanotechnology is an important emerging industry with a projected annual market of around one trillion dollars by 2015. It involves the control of atoms and molecules to create new materials with a variety of useful functions. Although there are advantages on the utilization of these nano-scale materials, questions related with its impact over the environment and human health must be addressed too, so that potential risks can be limited at early stages of development. At this time, occupational health risks associated with manufacturing and use of nanoparticles are not yet clearly understood. However, workers may be exposed to nanoparticles through inhalation at levels that can greatly exceed ambient concentrations. Current workplace exposure limits are based on particle mass, but this criteria could not be adequate in this case as nanoparticles are characterized by very large surface area, which has been pointed out as the distinctive characteristic that could even turn out an inert substance into another substance exhibiting very different interactions with biological fluids and cells. Therefore, it seems that, when assessing human exposure based on the mass concentration of particles, which is widely adopted for particles over 1 μm, would not work in this particular case. In fact, nanoparticles have far more surface area for the equivalent mass of larger particles, which increases the chance they may react with body tissues. Thus, it has been claimed that surface area should be used for nanoparticle exposure and dosing. As a result, assessing exposure based on the measurement of particle surface area is of increasing interest. It is well known that lung deposition is the most efficient way for airborne particles to enter the body and cause adverse health effects. If nanoparticles can deposit in the lung and remain there, have an active surface chemistry and interact with the body, then, there is potential for exposure. It was showed that surface area plays an important role in the toxicity of nanoparticles and this is the metric that best correlates with particle-induced adverse health effects. The potential for adverse health effects seems to be directly proportional to particle surface area. The objective of the study is to identify and validate methods and tools for measuring nanoparticles during production, manipulation and use of nanomaterials.
- Toxicological Assessment of Coated versus Uncoated Rubber Granulates Obtained from Used Tires for Use in Sport FacilitiesPublication . Gomes, J.; Mota, H.; Bordado, J.; Cadete, M.; Sarmento, G.; Ribeiro, A.; Baião, Miguel; Fernandes, J.; Pampulim, V.; Custódio, M.; Veloso, I.Reuse of tire crumb in sport facilities is currently a very cost-effective waste management measure. Considering that incorporation of the waste materials in artificial turf would be facilitated if the rubber materials were already colored green, coatings were specifically developed for this purpose. This paper presents an experimental toxicological and environmental assessment aimed at comparing the obtained emissions to the environment in terms of polycyclic aromatic hydrocarbons (PAHs), heavy metals, and ecotoxicity for coated and noncoated rubber granulates. This study is a comprehensive evaluation of the major potential critical factors related with the release of all of these classes of pollutants because previous studies were not systematically performed. It was concluded that between the two types of coatings tested, one is particularly effective in reducing emissions to the environment, simultaneously meeting the requirements of adherence and color stability.