PubMed · 4445476
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1974. Interstate carrier drinking water analysis program, 1972.. https://pubmed.ncbi.nlm.nih.gov/4445476/
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The search for effective radioprotectors is of major concern in the medical, military, environmental, and space sciences. Conventional radioprotectors are generally effective only during a single irradiation and display their radioprotective properties only at high, toxic concentrations. In addition, they reduce somatic radiation effects but are poorly efficient in protecting from hereditary stochastic radiation effects. In this respect, the pigment melanin merits attention. Experiments referring to potential melanin effects on the ionising radiation response have been carried out with different biological systems, both in vivo and in vitro. In this paper, we present results on the response to high- and low-linear energy transfer (LET) radiation of a human mammary epithelial cell line, H184B5 F5-1 M/10, supplemented by melanin. The incorporation of auto-oxidative (L-dopa) melanin was linear for concentrations from 3 to 10 micrograms/ml in the growth medium. Concentrations of up to 250 micrograms/ml did not significantly impair the cells proliferative ability. No significant protective effect of melanin on the survival of cultured cells after exposure to alpha-particles (130 keV/micron) or x-rays was observed.
The comprehensive monitoring and analysis of NORM is extremely difficult and involves a wide range of equipment and techniques. The instruments to be used can depend on both the national legislation of the country in which the measurements are being undertaken and the operational conditions under which they are carried out. These can dictate whether dose rate, alpha/beta contamination or gamma contamination measurements are taken. In some circumstances the total activity of the samples can be estimated using the gamma activities of the radionuclides present, while in others only full gamma and alpha spectral analysis will suffice.
Gross alpha- and beta-activities were determined on 37 fresh water samples collected from 14 artificial basins, 13 deep drilled wells, two dug wells, two lakes, two rivers, one spring, and a tap belonging to 30 locations scattered throughout the eastern and central parts of the Brazilian state of Rio Grande do Norte. The surveyed area was about 35,000 km2 with a lithology including both crystalline (18 towns) and sedimentary (12 towns) rocks. Concentrations ranging from < 2.8 to 354 Bq m-3 and from 50.5 to 580 Bq m-3 were observed for the gross alpha- and beta-activities, respectively. For the gross beta-activity, which was always higher than the corresponding alpha-activity, the arithmetic mean with its standard deviation was 226 +/- 154 Bq m-3. In order to evaluate the radioactive dose due to the ingestion of these waters, a conservative dosimetric calculation was carried out using the dose conversion factors suggested by the ICRP. An average annual effective dose equivalent of 60 +/- 42 microSv was obtained together with a range of 14-161 microSv y-1.