Ambient monitoring of asbestos in selected Italian living areas

Our plain-English summary of Ambient monitoring of asbestos in selected Italian living areas, by A.F. Gualtieri, D. Mangano, M.L. Gualtieri, et al (Journal of Environmental Management, 2009).

The study

• Authors: A.F. Gualtieri, D. Mangano, M.L. Gualtieri, A. Ricchi, E. Foresti, G. Lesci, N. Roveri, M. Mariotti, G. Pecchini
• Journal: Journal of Environmental Management
• Published: 2009;90(11):3540-52
• Cited by: 21 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

This paper presents the results of an intensive monitoring activity of the particulate, fall-out and soil of selected living areas in Italy with the aim to detect the asbestos concentration in air and subsequent risk of exposure for the population in ambient living environments, and to assess the nature of the other mineral phases composing the particulate matrix. Some areas were sorted out because of the presence of asbestos containing materials on site whereas others were used as blank spots in the attempt to detect the background environmental concentration of asbestos in air. Because the concentration of asbestos in ambient environments is presumably very low, and it is well known that conventional low-medium flow sampling systems with filters of small diameter (25mm) may collect only a very small fraction of particulate over a short period, for the first time here, an intense monitoring activity was conducted with a high flow sampling system. The high flow system requires the use of large cellulose filters with the advantage that, increasing the amount of collected dust, the probability to collect asbestos fibers increases. Both the protocol of monitoring and analysis are novel and prompted by the need to increase the sensitivity towards the small number of expected fibers. With this goal, the collection of fall-out samples (the particulate falling into a collector filled with distilled water during the monitoring shift) and soil samples was also accomplished. The analytical protocol of the matrix particulate included preliminary X-ray powder diffraction (XRPD), optical microscopy and quantitative electron microscopy (SEM and TEM). Correlations with climatic trends and PM10 concentration data were also attempted. The surprising outcome of this work is that, despite the nature of the investigated site, the amount of dispersed asbestos fibers is very low and invariably lower than the theoretical method detection limits of the SEM and TEM techniques for identification and counting of asbestos fibers. The results are compared to the literature data worldwide and an updated model for asbestos fibers dispersion in ambient environments is proposed.

In plain English

This outdoor monitoring study sampled air, fall-out and soil at nine sites in the Bologna, Modena and Reggio Emilia districts of Italy. Some sites had possible asbestos sources: ceramic tile plants with cement-asbestos roofs, a storage centre for asbestos waste, a railway station with asbestos-containing stone ballast, and a warehouse during removal of its cement-asbestos roof. Other sites served as clean or background sites. A high-flow air sampler generally ran for one week each season, and samples were examined by electron microscopy (SEM and TEM). The only asbestos type found was serpentine asbestos. Among samples containing asbestos, the highest airborne level was 0.0125 fibers per litre, on a filter from the Pavullo ceramic plant (site 3). The authors reported that the amounts found were below the theoretical detection limits of SEM and TEM, and that the estimated errors were always larger than the measured quantities. They found no substantial difference in airborne asbestos between background sites and possible source sites. The authors concluded that some degree of risk exists in living environments, but that there is no scientific evidence emphasizing the danger of urban asbestos pollution.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Environmental (outdoor ambient) monitoring study of air particulate, fall-out and soil, using a high-flow air sampler run continuously for 7 days in each season, with analysis by X-ray powder diffraction (XRPD), polarized light optical microscopy (PLOM), SEM and TEM
• Who was studied: Nine outdoor sites in the districts of Bologna, Modena and Reggio Emilia (Emilia Romagna region, Italy), monitored in 2005–2006. Five were dispersion spots (a special-waste storage centre, two ceramic factories, Bologna Central Railway Station, and an industrial warehouse being renovated). Four were blank or background sites (a residential area in Sassuolo, Monte Cimone, the Bologna University Chemistry Department, and a bowling ground near a primary school in Roncocesi).
• Exposure: Possible sources of outdoor asbestos fibers: cement-asbestos roofing on civil and industrial buildings, temporary storage of asbestos-containing waste, removal of cement-asbestos roofing, and railway ballast of serpentinized ophiolitic rock (greenstones) containing asbestos
• Main results:
  • Serpentine asbestos was the only asbestos type identified in any sample (air filters, fall-out or soil).
  • Among all samples containing asbestos fibers, the highest airborne concentration was 0.0125 f/l, on a filter from site 3 (the ceramic factory near Pavullo).
  • The quantities of fibers identified were lower than the theoretical method detection limits of SEM and TEM (given as about 1 f/l for SEM and 0.1 f/l for TEM).
  • The estimated errors, calculated using the Poisson distribution, were always greater than the fiber quantities determined.
  • There was no substantial difference in asbestos fiber concentrations between the blank sites and the sites considered sources of dispersion.
  • The Pavullo ceramic plant (site 3, foothills) had twice the airborne asbestos concentration of the Sassuolo ceramic plant (site 4, plain).
  • At site 4, asbestos fibers were observed only at the monitoring station about 1 m from the cement-asbestos roofing, not at the station about 50 m away.
  • At site 9, fiber levels in the environmental particulate were very low during removal of the cement-asbestos roofing.
  • Asbestos fibers were found in the soil sample from site 2, a residential background site in Sassuolo.
  • Precipitation was the only weather parameter that showed a trend with asbestos fiber concentration, which increased as rainfall increased. No statistical analysis was possible.
  • In general, no clear correlation was found between PM10 concentration and asbestos fiber concentration.
• The authors' conclusion: The authors concluded that, although there is some degree of risk for living environments, there is no scientific evidence emphasizing the danger of urban asbestos pollution.
• Limitations the authors state:
  • The measurements were below the SEM detection limit, where the authors describe results as rather unreliable because the estimated error becomes larger than the estimate itself.
  • No statistical analysis of the weather correlations was possible because there were very few data points in each plot.
  • The apparent decrease in fiber concentration with distance from the roofing at site 4 could not be tested statistically and was described as speculation.

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