Exposure to NOA in residents: can represent an occupational risk?

Outcrops of ophiolites containing tremolite asbestos were found at the Basilicata-Calabria border, Italy. A previous study mapped the outcrops and assessed the exposure through environmental sampling of airborne asbestos fibers nearby towns, showing doses up to 22 ff/L. Our study assesses the presence and level of personal exposure to inhalable asbestiform fibers in residents employed in occupational activities involving earthmoving and soil disturbance and other activities. We recruited 20 workers employed in construction and agriculture and 10 people employed in other activities not involving movement of soil; in addition, were recruited 5 relatives of residents who died from malignant mesothelioma in areas with these outcrops. Personal sampling was performed during two summer days using portable suction pumps. Each sampling covered almost the whole work shift, however never less than 400 minutes; filters were analyzed with SEM/EDS. We observed personal values of tremolite fibers ranged 0.8 - 23.06 ff/L. In 50% of all samples exceeded the environmental level of 2 ff/L. 60% of farmers and 100% of construction workers reported a personal exposure exceeding 2 ff/L (range: 2.07 - 23.06 ff/L). The relatives exceeded also the limit values (range: 3,05 - 6,07 ff/L), suggesting an unconventional type exposure to tremolite asbestos suffered by relatives died from malignant mesothelioma. These results are in accordance with the data of regional mesothelioma register that counts, in these naturally-polluted areas, 19 cases of malignant mesothelioma in farmers and 9 in construction workers. There were no value above the limit in workers employed in activities not involving soil disturbance.