Environmental asbestos exposure and risk of mesothelioma

Abstract

Mesothelioma is commonly considered an occupational disease occurring as a result of asbestos exposure in the workplace. Several avenues for environmental asbestos exposures have been described and may be associated with asbestos related disease, including mesothelioma. Worker take-home asbestos, or para-occupational exposure, has been well documented and is the most commonly reported pathway for asbestos exposure among mesothelioma cases that do not have history of occupational asbestos exposure. Observational studies have evaluated several communities with elevated mesothelioma incidence and environmental exposures attributed to local asbestos-related industries. Potential, but uncertain, mesothelioma risk also may be associated with general population asbestos exposure through contact with asbestos-containing commercial products, particularly housing materials that can be easily disturbed through normal activity. Finally, studies have described elevated mesothelioma incidence in several areas where populations are exposed to naturally occurring asbestos materials. These various environmental asbestos exposure pathways are poorly understood, and further studies should be pursued to evaluate their respective importance for population mesothelioma risk.

Keywords: Asbestos; environmental; mesothelioma; naturally occurring asbestos; para-occupational.

Figure 1

Potential pathways for environmental exposure to asbestos. (A) Para-occupational exposure occurs when asbestos-exposed workers function as vectors for transporting fibers. Household contacts can be exposed in worker vehicles (A1) or through contact with worker clothes or other dust deposits in the home (A2). (B) Environmental exposure from industrial operations. Airborne contamination to communities can be attributed to emissions from nearby mining operations (B1) or asbestos industry (B2). Communities can also be exposed to tailings or asbestos-laden industrial waste materials when used in roadways or soils (B3). (C) Exposure to commercial asbestos-containing products. Asbestos is in numerous products, including automotive brakes (C1) and several housing materials that can be readily disturbed during home maintenance or renovation projects (C2). (D) Naturally occurring asbestos (NOA). In several parts of the world humans have been exposed to asbestos through local use of NOA materials for roads and soil amendments (D1) and as a component in whitewash, stucco or other building materials (D2). Human contact with locations of exposed NOA can result in fiber release through recreational interaction (D3) and development projects (D4). NOA materials can also be released through natural erosion and wind (D5).