Natural Radioactivity in the Principal Constituents of French River Ecosystems

Abstract

The study is based on data covering the water, sediments, plants and fish sampled over a 20-year period at 15 stations along French rivers. Three geographic zones were investigated: one containing a uranium mining complex (Zone 1), another including five major rivers along which nuclear power plants are sited (Zone II) and a third unaffected by nuclear activities (Zone III). Natural radioactivity basically involves 238U, 226Ra and 210Pb in the uranium series, 232Th from the thorium series, 40K and 7Be. The natural radioactivity in Zone II is not different from Zone III, and is thus unaffected by waste discharges from nuclear power plants. The most abundant radionuclide is 40K, while the other nuclides are often found in trace amounts near the detection threshold of the analysis method used (Ge gamma spectrometry with a 15-hour counting period). The 226Ra and 238U concentrations observed in Zone I are at least an order of magnitude higher than in the other two zones due to authorised waste discharges from the Lodève mining complex, but only a small stream is affected. The measured 226Ra concentrations would result in an annual whole body committed dose equivalent attributable to a 200 g weekly fish consumption from this stream of 4.4 x 10-5 Sv.y-1, or 0.86% of the maximum permissible dose (5 mSv).

Simultaneous measurement of 226Ra and 228Ra in natural water by liquid scintillation counting

“…Others reported lower radioactivity levels in certain types of studied samples, due to losses in volume reduction by evaporation without suitable monitoring of the radiochemical yield (El Afifi et al, 2004). Compared to several other data of 226 Ra levels in different types of bottled water in other countries, the present results lie within the range reported for bottled water in France (Descamps and Foulquier, 1988), Germany (Gans, 1985;Glöbel and Muth, 1980), Italy (Sgorbati and Forte, 1997), China (Zhuo et al, 2001), Australia (Koulouris et al, 1996;Tinker and Smith, 1998), Austria (Karlik et al, 2003) and in several others (Almeida et al, 2004;Baradacs et al, 2001;Bomben, 2000).…”

The importance of physico-chemical parameters on the speciation of natural radionuclides in riverine ecosystems

“…However, the activity of 210 Po and 210 Pb in the river bank soil is comparable with the reported values of 9.5 Bq kg À1 and 45.2 Bq kg À1 for soil samples of Ullal and Mangalore regions of coastal Karnataka (Radhakrishna et al, 1993). 63 AE 8 Bq kg À1 for the Brebovscica River of Slovenia (Vrecek et al, 2004) and 56 Bq kg À1 for French river sediment (Decamps and Foulquier, 1988). The 210 Pb activity is less than the value (24 Bq kg À1 ) reported for the Guadimar, a Spanish river affected by mining activities (Gonzalez-Labajo et al, 2001).…”

The distribution of U, Th and 226Ra derived from the phosphate fertilizer industries on an estuarine system in Southwest Spain

“…The isotope radioactivity in bottom sediments in the Tinto river are given in Table 7. If compared to published U data for bottom sediments in other river systems (Scott, 1982;Descamps & Foulquier, 1988;Morón et al, 1988;Plater et al, 1992) it becomes clear that the river bottom sediments fire accumulating U and its daughters. The concentrations of 238 U, 234 U, 226 R a and 23 ºTh are lower than those reported in Table 3 for the Odiel river but significantly higher than the published levels for undisturbed river systems, always below 60 mBq/g for all of them (Scott, 1982;Martínez Aguirre , 1991;Martínez-Aguirre & García-León, 1992;Plater et al, 1992).…”