Abstra~t-~~Sr/Ca ratios were determined in diet and urine samples taken from 40 teenagers during the period February 1965-May 1966. The mean value of the ORurine,food for the period was 1.03 0.03. The small standard error of the mean seems to indicate that by pooling urine from a large number of persons, large individual variation can be eliminated to a satisfactory degree.IT WAS proposed to base the monitoring of exposure of human beings to sOSr on the relationship between the soSr/Ca ratios in diet and urine.(lS2) The advantages ofthis procedure have been discussed in the l i t e r a t~r e . ( l ,~,~) The usefulness of this approach depends on the relative constancy of the ORurine,food. However, results of several ~t u d i e s (~-~) show that the average ORurine/food values obtained for individuals vary from 0.4 to 1.4. Because of this relatively large variation in the ORurineIfood, the monitoring of soSr/Ca ratio in urine would not be suitable for determination of the sOSr/Ca ratio in the diet of individuals. O n the other hand, agreement of the average ORurine/food values, found by various authors to be 0.82 0.07,(6) 0.75 7 0.05(') and 0.97 0.08(5) for groups of adults, seems to indicate that this procedure would be applicable for estimating the dietary strontium-90 levels averaged for groups of humans.This fact would suggest that bulk sampling of urine can be used to predict the soSr/Ca level in the average diet. Results of the authors' previous study(*) seem to support this assumption. Relatively good agreement between the goSr/Ca ratios of composite urine samples from large groups of randomly chosen adults, taken during a period of approximately constant soSr/Ca level in the diet, seems to indicate that large individual variation can be eliminated by the pooling procedure. Since there are only limited data on this point, the present study was undertaken to estimate the relationship between the soSr/Ca ratio in diet and that in urine for a selected group of the population. In this work, a group of teenagers was studied.
METHODS
Une étude menée dans le bassin ferrifère lorrain a permis de mettre en évidence des émanations de mélanges gazeux sous-oxygénés et chargés en certains gaz nocifs (dioxyde de carbone, radon...), dans des agglomérations, en relation avec d'anciens travaux miniers souterrains. Les investigations effectuées in situ ont montré que les écoulements gazeux à l'origine de ces émanations sont liés au phénomène de tirage naturel. Une étude est en cours afin d'expliquer l'origine de la modification de la composition de l'air au sein des vieux travaux miniers.M ots-clés : gaz, émanation, mine, écoulement, pyrite.
Gas emissions from mining voids in the iron basin of Lorraine A bstractA study carried out in the iron basin of Lorraine (France) put the spot on the existence of under-oxygenated and noxious gas emissions (carbon dioxyde, radon...) in built-up areas related to former mining works. Site investigations showed that the gas flow was mainly due to natural ventilation mechanisms. A further study is in progress in order to better understand the origin of the atmosphere modification within the old mine workings.
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