A Systematic Study of the Cryogenic Milling of Chrysotile Asbestos

Mechanisms of action of mineral fibres in a placental syncytiotrophoblast model: An in vitro toxicology study

Asbestos has been widely used due to its unique characteristics. It is known that exposure to asbestos causes serious damage to health but one species, chrysolite, is still used because it is considered less toxic and not biopersistent in some countries. The aim of our study was to investigate if cellular process underlying the proliferation, differentiation and cell death of placental tissues could be modify in presence of asbestos fibres (50 μg/ml final concentration), long chrysolite fibres (CHR-L) and short chrysolite fibres (CHR-S), using BeWo cell line, an in vitro model that mimics the syncytiotrophoblast (STB), the outer layer of placental villi. Our data demonstrated that none of the fibres analysed alter syncytiotrophoblast formation but all of them induce ROS formation and reduced cell proliferation. Moreover, we showed that only CHR-L fibre induced was able to induce irreversible DNA alterations that carried cells to apoptosis. In fact, BeWo cells exposed to CHR-L fibre showed a significant increase in cleaved CASP3 protein, a marker of apoptosis. These data suggest that CHR-L may induce death of the placental villi leading to impaired placental development. The impairment of placental development is the basis of many gestational pathologies such as preeclampsia and intrauterine growth retardation. Since these pathologies are very dangerous for foetal and maternal life, we suggest to the gynaecologists to carefully evaluate the area of maternal residence, the working environment, the food used, and the materials used daily to avoid contact with these fibres as much as possible.

Is asbestos still a problem in the world? A current review

Asbestos has been used by automobile, construction, manufacturing, power, and chemical industries for many years due to its particular properties, i.e. high tensile strength, non-flammable, thermal and electrical resistance and stability, and chemical resistance. However, such a mineral causes harmful effects to human health, including different types of cancer (e.g., mesothelioma). As a result, the use of asbestos has been banned since the 1980s in many countries. Nonetheless, asbestos is still part of the daily life of the population as asbestos-containing materials (ACMs) are still present in many buildings constructed and renovated before the 1990s. This work aims to present a current literature review about asbestos. The literature review was composed mainly of research articles published in international journals from the medical and engineering disciplines to provide an overview of asbestos use effects reported in interdisciplinary areas. The literature review comprised asbestos characteristics and its relationship to the risks of human exposure, countries where asbestos use is permitted or banned, reducing asbestos in the built environment, and environmental impact due to use and disposal of asbestos. The main findings were that ACMs are still responsible for severe human diseases, particularly in areas where there is a lack of coordinated asbestos management plans, reduced awareness about asbestos health risks, or even a delay in the implementation of asbestos-ban. Such issues may be more prevailing in developing countries. The current research in many countries contemplates several methodologies and techniques to process ACMs into inert and recyclable materials. The identification and coordinated management of ACM hazardous waste is a significant challenge to be faced by countries, and its inadequate disposal causes severe risk of exposure to asbestos fibres. Based on this work, it was concluded that banning asbestos is indicated in all countries in the world.

Chrysotile asbestos migration in air from contaminated water: An experimental simulation

In Naturally Occurring Asbestos (NOA) rich areas, water flows through asbestos bearing rocks and soils and generates waterborne fibres that may migrate in air and become a risk for humans. Research on the migration and dispersion after water vaporisation has been so far only marginally evaluated. This study investigates the migration in air of asbestos from a set of suspensions contaminated by chrysotile from Balangero (Italy), under controlled laboratory conditions. We evaluated i) the morphological modifications that might occur to chrysotile during migration from water to air, and ii) the amount of airborne chrysotile mobilised from standardised suspensions. Morphological alteration of asbestos fibres occurred during water-air migration and impacted on the analytical response of electron microscopy. Waterborne asbestos concentration higher than 40 ∙ 10⁶ f/L generates in air concentration higher than 1 fibre per litre [f/L], the alarm threshold limit set by World Health Organization for airborne asbestos. A possible correlation between the waterborne fibre concentration as mass or number of fibres per volume unit [μg/L or f/L] was observed.