Radiobiological Aspects and Radiation Levels Associated With the Milling of Monazite Sand

Abstract

One of the chief problems in industrial radiological health in Brazil concerns 420 people in a plant processing monazite sand, a rare earth mineral containing up to 6 per cent Tho, and 0.3 per cent U,08.Radiation hazards associated with ore concentration and chemical treatment were assessed by sampling and measurement of airborne radioactivity, 210Po bioassay in urine and chromosomal analysis in peripheral blood lymphocytes collected from plant personnel.Results showed that 2lzPb (t1/2 = 10.64 hr) airborne concentrations range from 0.002 up to 3.9 pCi/l. A size distribution analysis showed that in 88 per cent of 212Pb-bearing aerosols the mean count diameter is below 0.4 pm. Calculated values of airborne long-lived activity as 232Th ranged from 6 x lo* up to 1 x IO-*pCi/l.A few workers had a slight increase in the urinary concentration of 210Po, although results did not show a statistically significant difference between these values and those found in control population.Chromosomal analysis revealed a statistically significant difference in the yield of aberrations for the ore mill workers in one of the plant sections, showing the highest airborne 212Pb concentration.

The Cellular and Molecular Carcinogenic Effects of Radon Exposure: A Review

“…One particular difficulty when using miner cohorts can be ascribing any observed biological effects to a particular exposure, as mining environments are known to contain a number of toxic agents (e.g., arsenic, lead and silica). Despite this limitation, a number of reports have identified an increase in CA frequencies among miners exposed to high radon concentrations, in addition to studies investigating uranium [159] or plutonium [160] compounds.…”

“…A continuation of the Costa-Ribeiro et al [159] study investigated 202 subjects from a Brazilian population environmentally exposed to high background radiation concentrations [173]. An increase of chromosome breaks was identified in blood lymphocytes of subjects who had a local residency of at least eight-years when compared to a control group of 147 individuals from a region of similar socio-economic status but with normal background levels of radiation.…”

hprt mutant frequencies, nonpulmonary malignancies, and domestic radon exposure: ?Postmortem? analysis of an interesting hypothesis

“…The first epidemiologic studies reported in the literature evaluated the relation between measured radon exposures and cytogenetic markers (primarily structural changes in chromosomes) in peripheral lymphocytes [Kilibarda et al, 1969;Barcinski et al, 1975;Costa-Ribeiro et al, 1975;Brandom et al, 1978;Pohl-Ruling and Fischer, 1979]. Though a number of these studies reported increases related to radon exposures, the results were not adjusted for confounding variables, influential data points, and outliers; moreover, the radon doses may have been inaccurate.…”

Chromosome Damage in Peripheral Lymphocytes from American Thorium Workers

“…The sole published report is that of Costa-Ribeiro et al (Co75) who studied a population of Brazilian workers from a monazite processing mill. The sole published report is that of Costa-Ribeiro et al (Co75) who studied a population of Brazilian workers from a monazite processing mill.…”