Asbestos-contaminated drinking water: its impact on household air

Our plain-English summary of Asbestos-contaminated drinking water: its impact on household air, by J.S. Webber, S. Syrotynski, M.V. King (Environmental Research, 1988).

The study

• Authors: J.S. Webber, S. Syrotynski, M.V. King
• Journal: Environmental Research
• Published: 1988;46(2):153-67
• Cited by: 16 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 004744).

Abstract

Asbestos contamination in excess of 10 billion fibers per liter was detected in a community's drinking water. To assess the possibility of waterborne asbestos becoming airborne, air samples were collected from impacted houses receiving contaminated water from three control houses. Collected within each house were three samples on 0.6-micrometer-pore Nuclepore filters and three samples on 0.8-micrometer-pore Millipore filters. In addition, bulk samples of suspect material and water samples were collected. Mean waterborne asbestos concentrations were 24 million fibers per liter (MFL) in the impacted houses versus only 1.1 MFL in the control houses. Transmission electron microscopy revealed that airborne asbestos concentrations were highest in impacted houses, with airborne asbestos concentrations positively correlated with waterborne concentrations. For fiber and mass measurements on both filter types, airborne asbestos concentrations were significantly higher in the impacted houses: mean concentrations in impacted houses were 0.12 fibers/cm3 and 1.7 ng/m3 on Nuclepore filters and 0.053 fibers/cm3 and 2.3 ng/m3 on Millipore filters versus only 0.037 fibers/cm3 and 0.31 ng/m3 on Nuclepore filters and 0.0077 fibers/cm3 and 0.14 ng/m3 on Millipore filters from control houses. Also detected in the air samples from impacted houses were clusters of chrysotile, often with several hundreds of fibers. When estimates of these individual fibers were added to the total fiber count, the difference between the impacted and control houses became even greater. The increased concentrations in impacted houses were due primarily to short (less than 1 micrometer) fibers. Bulk samples did not reveal likely materials within the impacted houses to account for these differences. Thus high levels of waterborne asbestos were apparently the source of increased concentrations of airborne asbestos within these houses.

In plain English

In late 1985, Woodstock, New York, drinking water was contaminated with chrysotile and crocidolite asbestos from deteriorated asbestos-cement pipe. In the last week of 1985 and first week of 1986, the authors sampled tap water and indoor air in three houses on this supply and three control houses. One impacted house's water sample could not be analyzed; in the other two, mean waterborne asbestos was 24 million fibers per liter, versus 1.1 in controls. On Nuclepore filters, mean airborne asbestos was 0.12 fibers/cm3 in impacted houses versus 0.037 in controls, and 1.7 versus 0.31 ng/m3 by mass. This excess was statistically significant under most sampling conditions and consisted mainly of fibers shorter than 1 micrometer. Chrysotile clusters appeared in 6 of 15 impacted-house and 2 of 18 control samples. Few other likely asbestos sources were found in impacted houses. The authors concluded that the contaminated water apparently raised indoor airborne asbestos and that most fibers were short and probably had negligible health effect. They noted sampling began almost two months after the acute episode and may have missed peak levels.

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 sampling study comparing tap water, indoor air and bulk materials in houses receiving contaminated water with control houses
• Who was studied: Six houses: three supplied by the Woodstock, New York, water district (impacted) and three control houses outside the district (in Clifton Park, in Woodstock on a domestic well, and in Port Ewen). Sampling took place in the last week of 1985 and the first week of 1986. Outdoor air was also sampled outside one impacted and one control house. The water sample from impacted house No. 1 could not be analyzed, so water results come from two impacted houses and three control houses.
• Exposure: Drinking water contaminated with asbestos (identified as chrysotile and crocidolite) released from grossly deteriorated asbestos-cement pipe in use for about 30 years. Indoor air was sampled in three conditions: background, during and after a hot shower, and during and after carpet vacuuming.
• Main results:
  • Mean waterborne asbestos was 24 million fibers per liter (MFL) in the impacted houses versus 1.1 MFL in the control houses. Only two impacted houses had analyzable water samples (17.0 and 31.0 MFL).
  • On Nuclepore filters, mean airborne asbestos fiber concentration was 0.12 fibers/cm3 in impacted houses versus 0.037 fibers/cm3 in control houses.
  • On Nuclepore filters, mean airborne asbestos mass was 1.7 ng/m3 in impacted houses versus 0.31 ng/m3 in control houses, with some overlap between the groups.
  • On Millipore filters, mean airborne asbestos mass was 2.3 ng/m3 in impacted houses versus 0.14 ng/m3 in control houses. Mean fiber concentration was 0.053 versus 0.0077 fibers/cm3 in Table 2, while the text gives 0.052 versus 0.0076. Millipore results for impacted houses come from houses No. 2 and No. 3 only.
  • A one-sided Mann-Whitney test found a statistically significant excess of airborne asbestos in impacted houses under most sampling conditions. In Table 3, the background condition on Nuclepore filters was not significant (alpha greater than 0.1).
  • Sampling location and activity (background, shower, vacuuming) had no noticeable effect on airborne asbestos concentrations.
  • The main difference between impacted and control houses was a greater number of short (submicrometer) airborne fibers in the impacted houses.
  • Clusters of chrysotile fibers, sometimes hundreds of fibers, were seen in 6 of 15 samples from impacted houses and in 2 of 18 samples from control houses. These clusters were not included in the main counts.
  • When estimated cluster fibers were added, mean Nuclepore concentrations rose to 0.77 fibers/cm3 for impacted houses and remained at 0.055 fibers/cm3 for control houses. Millipore means rose to 0.53 fibers/cm3 for impacted houses and 0.036 fibers/cm3 for control houses.
  • Across the five houses with water results, mean airborne asbestos concentrations were correlated with waterborne concentrations. Correlation coefficients (r) in Table 6 ranged from 0.568 to 0.995.
  • Bulk sampling found few non-water asbestos sources in the impacted houses; the only one was a chrysotile glove in impacted house No. 3. Control houses had more potential sources: a chrysotile heat shield, a frayed asbestos-cement air duct, and flooring. No asbestos was found in dryer or vacuum-cleaner lint.
  • About 5 to 6% of airborne asbestos in both impacted and control houses was amphibole. X-ray analysis identified crocidolite and anthophyllite in both groups of houses.
• The authors' conclusion: The authors described their work as a limited study. They concluded that the asbestos-contaminated drinking water apparently increased airborne asbestos in the homes supplied with it, and judged that most fibers were short and probably had negligible effect on health.
• Limitations the authors state:
  • The investigation began almost two months after the acute episode and may have missed the highest airborne levels.
  • A water-use advisory issued two weeks before sampling may have reduced airborne fiber levels during the study.
  • Counts of fibers within chrysotile clusters carry large uncertainties because overlapping fibers made estimation difficult.
  • The direct-transfer preparation methods did not allow accurate counting of all fibers.
  • Only a small number of amphibole fibers gave identifiable elemental compositions, which limited conclusions about sources.
  • Some samples were lost: the Millipore air samples from impacted house No. 1 were voided, and that house's water sample could not be analyzed.
  • A thorough health risk assessment was beyond the scope of the paper.

Topics

Medical terms in this study, explained in our Lexicon: Transmission Electron Microscopy (TEM), Chrysotile.

Related studies

• Asbestos in public water supplies: discussion of future problems — J.P. Hills (1979)
• Drinking water and cancer — R.D. Morris (1995)
• Cancer incidence and asbestos in drinking water, Town of Woodstock, New York, 1980-1998 — M.L. Browne, D. Varadarajulu, et al. (2005)
• Cancer incidence in relation to asbestos in drinking water in the Puget Sound region — L. Polissar, R.K. Severson, et al. (1982)
• A case-control study of asbestos in drinking water and cancer risk — L. Polissar, R.K. Severson, et al. (1984)
• Asbestos in drinking water and cancer — K.D. MacRae (1988)

Browse more research in Environmental Research, or return to medical research.