Size characteristics of asbestiform fibers in lung tissue of animals that grazed in areas rich in ophiolitic outcrops in Central Calabria (Southern Italy).

In Calabria (Southern Italy) naturally occurring asbestos (NOA) mainly occurs in the ophiolitic sequences cropping in the Mount Reventino area. The most common type of asbestos detected was the amphibole tremolite; fibrous antigorite and minor chrysotile were also found. The development of asbestos-related diseases depends on, among other things, the morphological characteristics of fibers, length and width, affecting the durability of asbestos fibers in the lung. In this work fifteen lung samples of sheep, goats and wild boars, grazing around the Mount Reventino area were collected and asbestos fibers analysed. Observed fibers (357), of which 97 % were tremolite and 3 % antigorite fibers, were grouped according to species, grazing area and age of the animals. The aim of this work was to highlight any differences among the groupings and to compare our size results with data in literature related to exposed populations. Principal Component Analysis (PCA) highlighted a positive correlation between tremolite fiber length and width and revealed groupings in terms of animal age. The Kruskal-Wallis test showed statistically significant differences between fiber mean widths in young and old animals. 63 % observed asbestiform fibers were longer than 5 µm and 7 % of the fibers were longer than 20 µm (critical fiber length connected to the frustrated phagocytosis by the macrophage). Fibers conforming to the Stanton Hypothesis size (predictor of the carcinogenic potency of fibers) were 1 %. Our size parameters of fibers detected in the animal lungs were in fairly good agreement with literature data for human asbestos exposure to tremolite. These results confirmed that an animal-sentinel system could be used to monitor the natural background of the airborne breathable fibers exposure. In addition, the size correlation of animal-human breathed fibers could be useful to study their potential toxicity. Additional data are necessary for improving the agreement with human exposure data.

Round-Robin Tests with Relocatable Coverslips Improve Asbestos Fibre Counting.

Asbestos fibre counting by phase-contrast microscope is subject to many sources of variation, including those dependent on the analyst. In this study, asbestos sample slides prepared with relocatable coverslips have been used for fibre counting among voluntary analysts to evaluate their proficiency. One slide of amosite and one of chrysotile were distributed to all the analysts, and three proficiency testing rounds were conducted for amosite and four for chrysotile. Each relocatable coverslip has a report in which are reported for each viewing field both the number of certified fibres (Verified Fibres) and a drawing representing the shape and position of the individual fibres. In the first round, the analysts were asked to report only the number of fibres counted in each of the predesignated fields of view. In the other rounds, subsequently developed, the analysts had to report the number and the position of the fibres for each field. The reported number of fibres and their position in each of the designed fields were evaluated against their respective verified fibres, to identify types of error. Discrepancies between reported fibres and verified fibres in each field of view have been used to evaluate the proficiency of the analysts. The discrepancies can be positive (D+) or negative (D-) depending on whether the analyst counts, for a specific field of view, more or less fibres compared to the verified fibres. The score is calculated using the following equation: Score = (1 - ∑D+ + ∑│D-│/VF) × 100. An analyst obtaining a score of ≥60, which corresponds to (∑D+ + ∑│D-│)/VF ≤ 0.40, is proficient. The number of laboratories that participating in this study varied from 13 to 17 depending on the rounds. For amosite fibre counts, the results were generally good compared to a proficiency score of 60. The major error made by analysts was the counting of fibres shorter than 5 µm, where this error was of 62% of extra fibres and accounted for 8% over-estimation of amosite fibres. For chrysotile, a score of ≥50 has been used to consider an analyst as proficient. The results of chrysotile fibres showed that in the first round all analysts counted less than fifty per cent of the verified fibres. In the second round 10 analysts out of 13 reached a score of ≥50, 8 of 16 in the third and 10 of 12 in the fourth. For chrysotile fibres, the error relating to the counting of fibres shorter than 5 µm was of 56% of extra fibres, but the error that most influenced the results was the number of oversight-missing fibres. This type of error accounted for 97% of the missing fibres and for the 29% under-estimation of the chrysotile fibres. For amosite fibre counting, results of this study show an improvement of the analyst's performance. For the chrysotile fibre count, although there is a significant improvement in the comparison between some rounds, this is not continuous over time.

Environmental contamination by naturally occurring asbestos (NOA): Analysis of sentinel animal lung tissue.

Ophiolites are known sources of naturally occurring asbestos (NOA). In Calabria (Southern Italy) NOA are mainly concentrated in the ophiolitic sequences cropping in the Mount Reventino area, in the southern part of the Sila massif, and along the Coastal Chain. The most common type of asbestos identified in the rocks of these areas belongs to the tremolite-actinolite series. Another identified asbestiform mineral is fibrous antigorite belonging to the serpentine mineral group with a minor amount of chrysotile. The purpose of the present study is to evaluate the diffusion of natural asbestiform fibers from NOA using sentinel animals. Fifteen lung samples of sheep, goats and wild boars from Mount Reventino area and two from an area free from NOA were collected. The lung samples were subjected to anatomopathological examination and lung fiber burden analysis by electron microscopy. Abundant tremolite and few antigorite fibers were detected in the lung samples coming from the NOA area. No corpuscle of asbestos was observed. No fiber was found in the two lung samples of sheet from the area free from NOA. These concentrations of fibers per gram of dry weight of lung tissue (f/gdw) ranged from 104 to 106 f/gdw. The asbestos fibers detected in the lungs of the examined animals reflect the geological features of the areas where they grazed and lived. The anatomopathological analysis showed that 60% of the examined animals had macroscopic lesions affecting their lungs. The presence of tremolite fibers in the lungs confirms the diffusion of mineral fibers in the environment and the real advantage of using animal populations in the study areas.

[Health impact of asbestos fibres naturally occurring in Mount Pollino area (Basilicata Region, Southern Italy)]. / Impatto sulla salute delle fibre di amianto presenti in affioramenti naturali nell'area del Pollino (Basilicata).

OBJECTIVES: to estimate the health impact of asbestos fibres naturally occurring in Mount Pollino area (Basilicata Region, Southern Italy). DESIGN: geographic mortality, hospitalization, and incidence study. Setting and participant s: population resident in 12 Municipalities of Mount Pollino area with naturally occurring asbestos fibres. MAIN OUTCOME MEASURES: standardized mortality ratio (SMR) and standardized hospitalization rate (SHR) for asbestos-related diseases; standardized incidence ratio (SIR) for mesotheliomas. Result s: in the area of Mount Pollino, where asbestos fibres naturally occur, especially in the sub-area in which fibres are close to dwellings and settlements, it was observed: • a significant excess of mesothelioma incidence (SIR: 208; CI95% 111-355; 13 observed); • a non-significant excess of hospitalization for malignant pleural neoplasms (SHR: 176; CI95% 93-335; 9 observed); • a significant excess for mortality and hospitalization for pneumoconiosis (SMR: 534; CI95% 345-824; 20 observed - SHR: 245; CI95% 149-405; 15 observed); • a significant excess for hospitalization (SHR: 852; CI95% 290-2,506; 3 observed) for asbestosis. CONCLUSION: it is necessary to continue environmental monitoring and environmental remediation in the area with higher asbestos exposure. It is suggested to implement a permanent process of epidemiological surveillance in this same area. A communication plan with local administrators, general practitioners, school teachers, media, and the resident population at large should be realized.

Environmental concentrations of fibers with fluoro-edenitic composition and population exposure in Biancavilla (Sicily, Italy).

INTRODUCTION: The town of Biancavilla (Sicily) was included in the National Priorities List of Contaminated Sites due to environmental dispersion of amphibole fibers owing to the extraction of materials from a local quarry. The present report summarizes results from several, hitherto unpublished, environmental surveys carried out in the area, as well as from published analyses of the chemistry and composition of fibers. METHODS: Data included here comprises environmental fiber concentrations by scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) analysis in soil, indoor and outdoor air, personal monitoring, as well as a chemical characterization of the fibers. The full chemical structure and spectroscopic characterization of fibers were obtained through a multi-analytical approach: SEM-EDS, X-ray powder diffraction (XRPD), as well as Mössbauer (MS) and Fourier transform infrared (FT-IR) spectroscopies. RESULTS: Data analyzed provided a spatial and temporal picture of fiber concentrations in Biancavilla, and a qualitative assessment of population exposure. Results suggest that until 2000, the population had been exposed to high levels of amphibole fibers. Mitigation measures adopted since 2001, gradually reduced exposure levels to about 0.1-0.4 ff/l. Previous studies on fibrous amphiboles from Biancavilla reported considerable chemical variability. Differences in composition, especially concerning the presence of Si, Ca, Fe, and Na, were found both within and between samples. Compared to the previously investigated prismatic fluoro-edenite, these fibrous fluorine amphiboles consistently showed higher average values of Si and Fe content, whereas Ca was significantly lower, which we consider a distinctive characteristic of the fluorine fibrous variety. CONCLUSIONS: The population of Biancavilla had been highly exposed to a suite of fibrous amphiboles for over 50 years. Dust mitigation measures have gradually reduced exposure, but continuous environmental follow-up is necessary in order to monitor exposure levels and prevent adverse health effects for future generations.