Nature and extent of the exposure to fibrous amphiboles in Biancavilla

Indoor release of asbestiform fibers from naturally contaminated water and related health risk

This study investigates the occurrence of airborne asbestiform fibers released in indoor ambient due to the use of asbestos naturally contaminated water. Some experiments employed a laboratory physical model using an ultrasonic humidifier charged with contaminated groundwater. Other experiments were carried out at full scale to assess the release of asbestiform fibers during showering. Obtained results show that the concentration of the airborne asbestiform fibers released in the bathroom during showering is higher than the limit value set by the European and Italian Regulations, while the concentration of fibers released by the humidifier is much lower. However, it is noteworthy that the use of the humidifier at high exposure time results in similar health risk. Strong correlations were found between the concentration of the airborne asbestiform fibers and a novel surrogate parameter (i.e. the exposure-specific-water-consumption). These correlations can be used to monitor the asbestiform fibers concentration at varying operating conditions and therefore, to control the resulting health risk.

Fluoro-edenite induces fibulin-3 overexpression in non-malignant human mesothelial cells

Exposure to asbestos is associated with the development of mesothelioma. In addition to asbestos, other fibers have been identified as risk factors for malignant and non-malignant diseases of the lungs. Among these, fluoro-edenite (FE) was found in patients from Biancavilla (Sicily, Italy) with pleural and lung disease, suggesting its role for tumor expansion. In this context, the identification of early biomarkers useful for the diagnosis of cancer is mandatory. Fibulin-3 represents an important marker for the diagnosis of mesothelioma. However, it remains to be determined whether it is directly associated with exposure to asbestos-like fibers. In the present study, peripheral blood levels of fibulin-3 from 40 asbestos-exposed workers were compared with those detected in 27 street cleaners from Biancavilla. Intriguingly, the results showed that fibulin-3 levels were higher in the group of street cleaners compared with those of the asbestos-exposed workers, suggesting that these workers used the personal protective equipment according to the current regulations. These data suggest that subjects exposed to FE should be monitored for the risk of mesothelioma. FE and volcanic particulates are probably contained within dust inhaled by street cleaners from Biancavilla during their work activities. Based on these criteria, in this study, such fibers were used to treat mesothelial cells (MeT5A) in order to verify whether fibulin-3 levels are affected by these treatments. The results showed that only treatment with FE was associated with fibulin-3 overexpression at both the transcript and protein levels. It was previously demonstrated that mesothelial cells exhibited low levels of p27 following treatment with FE. Notably, p27 downregulation is associated with stathmin upregulation in cancer, conferring an aggressive phenotype of tumor cells. This observation prompted us to perform a computational evaluation demonstrating the activation of stathmin in lung cancer in patients exposed to asbestos. Overall, it can be speculated that both fibulin-3 and stathmin overexpression may be associated with the malignant transformation of mesothelial cells following exposure to asbestos-like fibers.

Occupational exposure to carcinogens: Benzene, pesticides and fibers (Review)

It is well known that the occupational exposure to contaminants and carcinogens leads to the development of cancer in exposed workers. In the 18th century, Percivall Pott was the first to hypothesize that chronic exposure to dust in the London chimney sweeps was associated with an increased risk of developing cancer. Subsequently a growing body of evidence indicated that other physical factors were also responsible for oncogenic mutations. Over the past decades, many carcinogens have been found in the occupational environment and their presence is often associated with an increased incidence of cancer. Occupational exposure involves several factors and the association between carcinogens, occupational exposure and cancer is still unclear. Only a fraction of factors is recognized as occupational carcinogens and for each factor, there is an increased risk of cancer development associated with a specific work activity. According to the International Agency for Research on Cancer (IARC), the majority of carcinogens are classified as 'probable' and 'possible' human carcinogens, while, direct evidence of carcinogenicity is provided in epidemiological and experimental studies. In the present review, exposures to benzene, pesticides and mineral fibers are discussed as the most important cancer risk factors during work activities.

Environmental risk of mesothelioma in the United States: An emerging concern-epidemiological issues

Despite predictions of decline in mesothelioma following the ban of asbestos in most industrial countries, the incidence is still increasing globally, particularly in women. Because occupational exposure to asbestos is the main cause of mesothelioma, it occurs four- to eightfold more frequently in men than women, at a median age of 74 years. When mesothelioma is due to an environmental exposure, the M:F sex ratio is 1:1 and the median age at diagnosis is ~60 years. Studying environmental risk of mesothelioma is challenging because of the long latency period and small numbers, and because this type of exposure is involuntary and unknown. Individual-based methods cannot be used, and new approaches need to be found. To better understand the most recent trends of mesothelioma in the United States, all mesothelioma deaths reported to the Centers for Disease Control and Prevention (CDC) during 1999-2010 were analyzed. Among all mesothelioma deaths in the United States, the 1920s birth cohort significantly predominated, and the proportion of younger cohorts constantly decreased with time, suggesting a decline in occupational exposure in these cohorts. The M:F mesothelioma sex ratio fell with time, suggesting an increased proportion of environmental cases. Environmental exposures occur in specific geographic areas. At the large scale of a state, mesotheliomas related to environmental exposure are diluted among occupational cases. The spatial analysis at a smaller scale, such as county, enables detection of areas with higher proportions of female and young mesothelioma cases, thus indicating possible environmental exposure, where geological and environmental investigations need to be carried out.

The health impact of nonoccupational exposure to asbestos: what do we know?

The objective of this study was to examine the epidemiological data that confirm the risks of pleural mesothelioma, lung cancer, and other respiratory damage associated with nonoccupational exposure to asbestos, in circumstances where exposure levels are usually lower than those found in the workplace: domestic and paraoccupational exposure to asbestos-containing material among people living with asbestos workers or near asbestos mines and manufacturing plants, environmental exposure from naturally occurring asbestos in soil, and nonoccupational exposure to asbestos-containing material in buildings. Studies concerning natural asbestos in the environment show that the exposure that begins at birth does not seem to affect the duration of the latency period, but the studies do not show whether early exposure increases susceptibility; they do not suggest that susceptibility differs according to sex. Solid evidence shows an increased risk of mesothelioma among people whose exposure comes from a paraoccupational or domestic source. The risk of mesothelioma associated with exposure as result of living near an industrial asbestos source (mines, mills, asbestos processing plants) is clearly confirmed. No solid epidemiological data currently justify any judgment about the health effects associated with passive exposure in buildings containing asbestos. Most of the studies on nonoccupational sources reported mainly amphibole exposure, but it cannot be ruled out that environmental exposure to chrysotile may also cause cancer. Nonoccupational exposure to asbestos may explain approximately 20% of the mesotheliomas in industrialized countries, but it is does not seem possible to estimate the number of lung cancers caused by these circumstances of exposure.

Identification and enumeration of asbestos fibers in the mining environment: mission and modification to the Federal Asbestos Standard

Since the promulgation of the first Federal Asbestos Standard by the Occupational Safety and Health Administration in 1972, other federal agencies have modified the standard to better carry on their own unique missions. The instruments used to identify and measure asbestos, the sampling protocol, and the criteria used to define asbestos, have been modified to some degree. The Mine Safety and Health Administration regulates and controls asbestos dust in the mining and mineral commodity industries. However, crushed stone and processed ores contain mineral fragments that are frequently difficult to distinguish from asbestos. Mineral nomenclature, instruments for particle analysis, and sampling strategy must be accommodated to some degree to make asbestos control workable and meaningful. Precedent in other agencies has made consideration of these changes possible. Newly identified amphibole asbestos minerals have further complicated the agency's regulatory charge. Changes in its Asbestos Standard are now being considered. Crushed taconite ore in the Eastern Mesabi highlights many of these issues.