Carcinogenic effects of chronic exposure to very low levels of toxic substances.
نویسنده
چکیده
The sort of situation that I wish to consider is contamination of the air around vinyl chloride plants with low levels of vinyl chloride monomer. People living nearby would be exposed to it continuously for however many decades they lived there. If some cancers are caused by ambient levels of (say) 0.01 ppm, I want to discuss the likely effects on the numbers of cancers and the age distribution of these cancers that would result from a different ambient concentration-0.00I ppm, or 0.1 ppm, for example. I believe that what should in general be expected in such circumstances is that the age distribution of the cancers that are caused will be the same whatever the dose rate may be; lower dose rates will simply cause fewer cancers than higher dose rates would do, but the age distribution will be almost identical. Moreover, the actual number of extra cancers will, when the dose rate is sufficiently low, simply be proportional to the dose rate: if the dose rate is low, halving it will halve the numbers of cancers, quartering it will just quarter the number of cancers, and so on; no "threshold" should be anticipated. I would, of course, expect to find the same sort of results in other circumstances where humans are exposed to chronic low doses of other toxic agents, and I would also expect to find this in animal experiments involving chronic exposure of animals to low dosage rates.
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ورودعنوان ژورنال:
- Environmental Health Perspectives
دوره 22 شماره
صفحات -
تاریخ انتشار 1978