Environmental Engineering Reference
In-Depth Information
The mortality of miners was studied according to registry ofice records. For all men older
than 18 year (the minimum age for underground work) from mining settlements, who died from
breathing organs illness, special iles were set up. Then according to the data from the personnel
department, the duration of underground work, professional itinerary, and number of underground
workers per year, including miners in the drilling group, were established. Data on male popula-
tions of the mining settlement were taken from local Soviet authorities according to the 1959 and
1970 census.
A study of lung cancer mortality was provided by means of long-time observations of miners
in mines, where radiation—hygienic conditions were studied. As a control, the average of three
very close mortality rate data of men older than 18 year was used: the population of all cities of
Tadjikistan, mining settlements, and miners who worked in mines with a very low radon progeny
concentration.
Measurements of the radon progeny concentrations were provided by means of the procedure;
in some of the cases, direct measurements of gamma-activity (dose) in the lungs of miners were
provided.
Besides this, the gamma-ray intensity, thoron decay products concentration, and 210 Po in the air
were measured, but it is known that from a dosimetric point of view the contribution of these factors
is very small.
For every group of miners, the annual intake was calculated based on the average radon decay
products concentration and the FAL. In order to diminish the inluence of other factors such as dust
concentration (and correspondingly, silicosis) and smoking habits of the miners as much as possible,
data on these factors were collected.
According to Alterman (1974), the sickness and mortality of miners in this region from 1949
to 1959 was registered for those with a duration of work of 3 years. In 1959-1961, when the dust
concentration was diminished to the level of some mg/m 3 , only eight workers were diagnosed with
silicosis from miners with a duration of work of more than 10 years. At the end of the 60th year,
only a single occurrence of silicosis took place.
As far as the problem of smoking is concerned, there is a high probability that the distribution
of smokers among underground workers is very similar as for the population of mining settlements
(control group) of the same age. Moreover, it is dificult to imagine that the distribution of smokers
should be different for different groups of miners, working in sites with different levels of radon
decay products concentrations.
However, it was shown that the lung cancer mortality of nonuranium miners in this study
(Alterman, 1974) differs substantially for different groups of miners, with the highest level for the
drilling group.
Lung cancer mortality was studied in connection with the level of exposure. For this purpose, all
mines were divided into two groups:
1. Mines with the median concentration of radon decay products in the working sites ( q )
lower than APC
2. Mines with q larger than APC
These data suggest that the mortality of miners exceeded the mortality of the control group only in
the second group of mines, with concentrations larger than APC according to the ordinary index by
3.5 times and according to the standard index by 3.1 times. At the same time, the mortality of drill-
ing workers was greater than for the control group by 5.4 and 6.5 times, respectively.
The mortality of the drilling workers of the irst group of mines, and the mortality of other min-
ers in both groups did not differ from the mortality of the control group.
Thus, the higher lung cancer mortality of miners in this mining region was caused mainly by the
high level of mortality of drilling workers of the second group. Apparently, it is dificult to consider
it accidental that this group also had the highest intake of radon decay products.
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