Relative source contributions of diet and air to ingested asbestos exposure

Our plain-English summary of Relative source contributions of diet and air to ingested asbestos exposure, by J.N. Rowe (Environmental Health Perspectives, 1983).

The study

• Author: J.N. Rowe
• Journal: Environmental Health Perspectives
• Published: 1983;53:115-20
• Cited by: 12 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Reliable assessments of the relative contributions of diet (food, beverages, and orally administered drugs) and air (inhaled fibers) to total ingested asbestos exposure are not feasible due to the paucity of quantitative data on the subject. Instead, scenarios for both modes of exposure were developed from the limited information available to give crude estimates of ingestion of asbestos from these routes. They suggest that such sources are potentially significant relative to the contribution of asbestos exposure derived from drinking water. Research recommendations are discussed.

In plain English

This paper was not a study of people. From limited published data, the author built rough "scenarios" of how much asbestos a person might swallow yearly from diet (food, drinks and oral drugs) and from inhaled airborne fibers that are later swallowed. These were compared with drinking-water estimates drawn from existing analyses. The diet scenario imagined an "average" person who daily drank one beer, ate 84 g of Japanese-style rice and took three aspirin. The paper notes that tremolite asbestos is found in talc-coated rice. With talc-coated rice, the estimated yearly dose was 1.4 x 10^14 fibers (Table 2 prints 1.14 x 10^14) or 2.85 x 10^12 fibers, depending on the conversion factor used. Without it, the estimate was 2.35 x 10^9 fibers. The author estimated that airborne sources deliver 1.2 x 10^9 to 9 x 10^12 fibers a year to the gut, and drinking water 9 x 10^5 to 4 x 10^11. Diet ranked highest, air second and water lowest. The airborne estimates relied on studies of non-asbestiform particles. The author described the estimates as crude and concluded that diet and air are potentially significant sources compared with drinking water.

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: Exposure-estimation analysis: hypothetical scenarios built from limited published and agency data to give crude estimates of yearly ingested asbestos from diet and air, compared with drinking-water estimates developed from existing analyses of waterborne asbestos
• Who was studied: No human subjects. The dietary calculation used a hypothetical "average" individual ("John Q. Public"). Airborne and water estimates used reported concentrations from U.S. settings such as city air, mill sites in California, schools, workers' homes, workplaces and municipal water systems.
• Exposure: Asbestos fibers swallowed from diet (beer, other beverages, talc-coated rice, aspirin), from inhaled fibers later swallowed (ambient and occupational air), and from drinking water. Tremolite asbestos is described as occurring in talc-coated rice, chewing gum and talc-containing oral drugs. The diet scenario assumed one beer (0.36 L), 84 g of Japanese-style rice and three aspirin (0.9 g) daily.
• Main results:
  • Diet scenario including talc-coated rice, as given in the text: estimated yearly dose of 1.4 x 10^14 fibers (maximum conversion factor) or 2.85 x 10^12 fibers (minimum conversion factor)
  • Table 2 gives the same with-talc yearly dose as 1.14 x 10^14 or 2.85 x 10^12 fibers, which differs from the 1.4 x 10^14 in the text
  • Diet scenario without talc-coated rice: estimated yearly ingested dose of 2.35 x 10^9 fibers
  • Airborne sources (ambient and occupational): estimated 1.2 x 10^9 to 9 x 10^12 asbestos fibers delivered to the gut per year
  • Drinking water in the United States: estimated annual ingested doses of 9 x 10^5 to 4 x 10^11 fibers, based on the present analysis and estimates by other authors
  • Comparing the routes, diet gave the highest estimated contribution, air the second highest and drinking water the lowest
• The authors' conclusion: The author concluded that diet and air are potentially significant sources of ingested asbestos compared with drinking water, and recommended research to define their contributions more accurately
• Limitations the authors state:
  • Information gaps prevent an accurate measure of the total amount of asbestos swallowed
  • The airborne estimates relied on deposition and clearance studies of non-asbestiform particles, with only some data on asbestos and man-made fibers
  • The analysis assumed that environmental fibers are "small", although Nicholson had more recently indicated that environmental fiber sizes may be more like occupational ones
  • How much inhaled asbestos ends up being swallowed has not been critically examined

Topics

Medical terms in this study, explained in our Lexicon: Asbestos Exposure.

Related studies

• Diet and other risk factors for laryngeal cancer in Shanghai, China — W. Zheng, W.J. Blot, et al. (1992)
• Association between diet and lung cancer location — B.W. Lee, J.C. Wain, et al. (1998)
• The role of intervention studies in ascertaining the contribution of dietary factors in lung cancer. The Seattle chemoprevention trial of retinoids in asbestos-exposed workers — G.S. Omenn, G.E. Goodman, et al. (1988)
• Critical review of epidemiologic studies related to ingested asbestos — G.M. Marsh (1983)
• Relative congener scaling of Polychlorinated dibenzo-p-dioxins and dibenzofurans to estimate building fire contributions in air, surface wipes, and dust samples — J.D. Pleil, M.N. Lorber (2007)
• Comparing epidemiologic studies of ingested asbestos for use in risk assessment — L.S. Erdreich (1983)

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