Distribution of chemical carcinogens in aquatic environments

Our plain-English summary of Distribution of chemical carcinogens in aquatic environments, by H.F. Kraybill (Progress in Experimental Tumor Research, 1976).

The study

• Author: H.F. Kraybill
• Journal: Progress in Experimental Tumor Research
• Published: 1976;20:3-34
• Type of article: Review
• Cited by: 13 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Summary of the article

This review, from the US National Cancer Institute, surveyed published and unpublished reports on chemical carcinogens found in rivers, lakes, seas and drinking water. The author described how contaminants enter water and the factors governing their persistence. He also described methods for extracting, identifying and bioassaying organic micropollutants, and criteria for classifying chemicals as proven, suspect or potential carcinogens. Survey data were tabulated for pesticides (DDT, BHC, dieldrin, chlordane, PCBs, mirex), polycyclic aromatic hydrocarbons such as benzo(a)pyrene, aromatic amines such as benzidine, vinyl chloride, halo ethers, metals and asbestos. Cited findings included a tumour incidence of 4.38% in 2,121 fish from a polluted watershed versus 1.03% in 4,369 fish from non-polluted water. Vinyl chloride levels in plant discharges ranged from 0.15 to 327 ppm. Among inorganic contaminants, the review described amphibole fibres from taconite tailings in Lake Superior and the Duluth, Minnesota, water supply, reported at 1 to 30 µg/litre. It also reported chrysotile in eastern US rivers and noted the 1973 conference on ingested asbestos and gastrointestinal cancer. The author concluded that water treatment could not remove the many chemicals present. He stated that tumours in fish and shellfish may serve as an early warning of human hazard. He called for systematic monitoring, surveillance and identification of aquatic tumours to guide epidemiology and cancer control.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.

In plain English

This 1976 article was a review, not a new study. The author, at the US National Cancer Institute, gathered reports on known and suspected cancer-causing substances in rivers, lakes, seas, drinking water and aquatic animals, mostly in the United States. These included pesticides, polycyclic aromatic hydrocarbons, vinyl chloride, chlorinated ethers, metals and asbestos. On asbestos, the review described reports that taconite tailings discharged into Lake Superior put mainly an amphibole, cummingtonite-grunerite, into the lake and into the water supply of Duluth, Minnesota. Duluth water samples from 1939-1940 and 1949-1950 held only trace amounts of amphibole. After dumping in 1964-1965, amphibole made up 31% of total solids. Low chrysotile levels in the lake may have been laboratory contamination. The author noted that there was little reliable evidence on cancer in people drinking polluted water, and that asbestos results could vary between laboratories by several orders of magnitude. The author concluded that water treatment plants apparently could not cope with the many chemicals in water, and called for monitoring, including of tumors in aquatic animals.

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: Narrative review of published and unpublished reports on carcinogens in aquatic environments
• Who was studied: No study population. The review covered reported contaminants in rivers, lakes, bays, estuaries, seas, municipal water supplies and aquatic animals, mostly in the US, with some data from Canada, Great Britain, France and the Netherlands.
• Exposure: Known and suspected carcinogens in water: organic pesticides, polycyclic aromatic hydrocarbons, aromatic amines, aromatic and aliphatic hydrocarbons (including vinyl chloride), halo ethers, and inorganic contaminants including metals and asbestos. For asbestos, the review covered amphibole (cummingtonite-grunerite) from taconite tailings in Lake Superior and chrysotile in western Lake Superior and eastern US rivers.
• Main results:
  • According to the review, the high asbestos levels in Lake Superior and the Duluth drinking water came from taconite tailings discharged by ore mills of a company the article names as the Revere Mining Company.
  • Citing Cook and colleagues (1974), the review reported that Duluth water samples from 1939-1940 and 1949-1950 contained only trace amounts of amphibole and no cummingtonite-grunerite. Since the dumping operation in 1964-1965, amphibole made up 31% of total solids.
  • The low chrysotile levels reported in western Lake Superior, below 1 x 10^6 fibers per liter, could have been laboratory contamination during processing.
  • Citing Nicholson and colleagues, the review reported chrysotile in eastern US river waters (Juniata and Connecticut Rivers) in the microgram-per-gallon range. The table gives averages of 1.3 to 5.9 micrograms per gallon across nine sampling sites.
  • The review reported that many water systems had asbestos concentrations above 10 micrograms per gallon. The source was described as ill-defined: possibly geological erosion, rain cleansing of the air, or pollution from human use of asbestos.
  • Citing Andrew, the review reported no detectable amphiboles in 31 streams in Minnesota and Wisconsin.
  • The review raised, as a possibility, that ingested asbestos fibers could migrate across the intestinal lining.
  • For asbestos, the author called for monitoring to assess its effect on tumor rates in aquatic animals.
  • Citing Brown and colleagues, the review reported a tumor incidence of 4.38% in 2,121 fish from a polluted part of the Fox River watershed. In 4,369 fish from so-called nonpolluted water in that watershed, the incidence was 1.03%.
• The authors' conclusion: The author concluded that water treatment plants apparently cannot cope with the many chemicals present in water sources.
• Limitations the authors state:
  • Little reliable evidence existed on cancer effects in human populations consuming polluted water.
  • Asbestos analyses of the same water sample could vary between laboratories by several orders of magnitude.
  • The review could not catalogue all carcinogens in water systems worldwide.

Topics

Medical terms in this study, explained in our Lexicon: Fluorescence In Situ Hybridization (FISH), Amphibole Group, Taconite, Tailings, Chrysotile, Epidemiology.

Related studies

• Epidemiological studies on ingested asbestos — J. Hopkins (1984)
• Asbestos-contaminated drinking water: its impact on household air — J.S. Webber, S. Syrotynski, et al. (1988)
• Asbestos in public water supplies: discussion of future problems — J.P. Hills (1979)
• Nongenotoxic carcinogens in the regulatory environment — B.E. Butterworth (1989)
• Ingested mineral fibers: elimination in human urine — P.M. Cook, G.F. Olson (1979)
• The contamination of Lake Superior with amphibole gangue minerals — A.M. Langer, C.M. Maggiore, et al. (1979)

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