Influence of particle surface area on the toxicity of insoluble manganese dioxide dusts

Abstract

The objective of this study was to examine the influence of specific surface area on the biological activity of insoluble manganese dioxide (MnO2) particles. The biological responses to various MnO2 dusts with different specific surface area (0.16, 0.5, 17 and 62 m2/g) were compared in vitro and in vivo. A mouse peritoneal macrophage model was used to evaluate the in vitro cytotoxic potential of the particles via lactate dehydrogenase (LDH) release. In vivo, the lung inflammatory response was assessed by analysis of bronchoalveolar lavage after intratracheal instillation in mice (LDH activity, protein concentration and cellular recruitment). In both systems, the results show that the amplitude of the response is dependent on the total surface area which is in contact with the biological system, indicating that surface chemistry phenomena are involved in the biological reactivity. Freshly ground particles with a specific surface area of 5 m2/g were also examined in vitro. These particles exhibited an enhanced cytotoxic activity, which was almost equivalent to that of 62 m2/g particles, indicating that undefined reactive sites produced at the particle surface by mechanical cleavage may also contribute to the toxicity of insoluble particles. We conclude that, when conducting studies to elucidate the effect of particles on the lung, it is important for insoluble particles such as manganese dioxide to consider the administered dose in terms of surface area (e.g. m2/kg) rather than in gravimetric terms (e.g. mg/kg).

Long-term ambient air pollution levels in four Chinese cities: inter-city and intra-city concentration gradients for epidemiological studies

“…However, caution must be exercised in the interpretation of results because cluster analysis is highly empirical and may often have significant shortcomings (Everitt, 1993 ) . In our analysis, for example, all input concentration data were not weighted to consider differences in toxicological importance of different pollutants (Lison et al, 1997;Osier and Oberdorster, 1997;Oberdorster et al, 1994;Li et al, 1999 ). Furthermore, since the clusters are not known a priori, it is usually difficult to judge whether the results make sense in the context of the problem being studied.…”

General safe practices for working with engineered nanomaterials in research laboratories.

“…Experimental studies in rodents and cell cultures have shown that the toxicity of ultrafine or nanoparticles is greater than that of the same mass of larger particles of similar chemical composition [Oberdörster et al 1992;Oberdörster et al 1994;Lison et al 1997;Tran et al 1999;Tran et al 2000;Brown et al 2001;Barlow et al 2005;Duffin et al 2007]. In addition to particle size and surface area, other particle characteristics may influence toxicity, including surface functional groups or coatings, solubility, shape, and the ability to generate reactive oxygen species [Duffin et al 2002;Maynard and Kuempel 2005;Oberdörster et al 2005;Donaldson et al 2006].…”

A New Method for Estimation of Emissions and Sources of Measurements Error in the Silicon Refining Process

“…[3][4][5][6][7] The adverse health effects caused by long-term exposure and inhalation of fume are numerous and the workers are at risk of developing respiratory problems, including chronic obstructive pulmonary disease (COPD). [8][9][10][11][12] For that reason, the use of dust masks is mandatory in exposed areas in most silicon plants in Norway. Today's environmental authority reporting from the ferroalloys industry is based primarily on overall tapped material compositions and standard calculations of the distribution of major elements among products, solid waste, and fugitive emissions, in addition to ad-hoc industrial measuring campaigns. For most major elements, the reporting accuracy for a plant would be in the order of thousands of kilograms, whereas for some toxic elements like mercury, cadmium, etc., accuracies in the range of kilograms are expected.…”