Breadcrumbs Section. Click here to navigate to respective pages.
Chapter
Chapter
a specific point in time, with a fraction of the fallout reaching the eastern part of the north-west Mediterranean basin (2). Chernobyl fallout deposits assesment were led from aerosols and soils measurements and from atmospheric models results. These cesium latest deposits, which can be pinpointed to a specific time and place, can therefore be regarded as tracer elements, with a specific 137Cs/134 Cs close to 2.0, which can be plotted to determine the dynamics of the waters of the north-west Mediterranean basin. The radioelements released by the Chernobyl accident reached the marine environment via two routes: a direct route, whereby the atmospheric fallout fell to surface of the sea, and an indirect route via the rivers, after surface deposits on the soil had been washed away by rainwater. On the French section of the Mediterranean coast, two rivers of unequal importance flow out to sea: the Var and the Rhone. However, the waters of the RhOne carry not only the radioelements arising from the Chernobyl accident but also those associated with the discharge of low-level radioactive liquid effluents from various nuclear plants such as cesium isotopes, with a 137Cs/134Cs ratio greater than 4. The monitoring of radioelements arising from atmospheric fallout on the surface of the sea enables seasonal vertical changes to be detected, at regional level, in the various bodies of water whereas the monitoring of radioelements discharged by rivers leads to a definition of the limits of geographical areas under the influence of the deposits of coastal rivers. EQUIPMENT AND METHOD Radioactive tracers have been monitored during 7 oceanographic cruises in collaboration with research teams from the CNRS and the University. The cruises enabled us to cover a network of sampling points all over the French Mediterranean coast. After establishing the coastal area by means of 25 sampling points in the course of the CORSE86 (86.09.23-86.10.06), LITTORAL86A (86.02.03-10, 86.04.03-11, 86.04.21-29) and LITTORAL86B (86.11.05-13) cruises, efforts were concentrated in particular on the area reached by the waters of the Rhone, as defined by 15 sampling points during the DYPOLO1 (86.08.28-86.09.07) and DYPOLO2 (86.11.19-30) cruises, and the area of the Golfe du Lion covered by 24 sampling points as part of the PELAGOLIONO1 (86.09.02-11) and PELAGOLIONO2 (86.12.04-12) cruises. Over the network of sampling points, volumes of water between 90 and 120 litres were systematically pumped from a depth of 0.5m. At some points selected on the basis of results of vertical contours of salinity, temperature or turbidity obtained in real time with a bathymeter, the various bodies of water identified between the surface and 1700 m were sampled using 30 1 Niskin bottles.
DOI link for a specific point in time, with a fraction of the fallout reaching the eastern part of the north-west Mediterranean basin (2). Chernobyl fallout deposits assesment were led from aerosols and soils measurements and from atmospheric models results. These cesium latest deposits, which can be pinpointed to a specific time and place, can therefore be regarded as tracer elements, with a specific 137Cs/134 Cs close to 2.0, which can be plotted to determine the dynamics of the waters of the north-west Mediterranean basin. The radioelements released by the Chernobyl accident reached the marine environment via two routes: a direct route, whereby the atmospheric fallout fell to surface of the sea, and an indirect route via the rivers, after surface deposits on the soil had been washed away by rainwater. On the French section of the Mediterranean coast, two rivers of unequal importance flow out to sea: the Var and the Rhone. However, the waters of the RhOne carry not only the radioelements arising from the Chernobyl accident but also those associated with the discharge of low-level radioactive liquid effluents from various nuclear plants such as cesium isotopes, with a 137Cs/134Cs ratio greater than 4. The monitoring of radioelements arising from atmospheric fallout on the surface of the sea enables seasonal vertical changes to be detected, at regional level, in the various bodies of water whereas the monitoring of radioelements discharged by rivers leads to a definition of the limits of geographical areas under the influence of the deposits of coastal rivers. EQUIPMENT AND METHOD Radioactive tracers have been monitored during 7 oceanographic cruises in collaboration with research teams from the CNRS and the University. The cruises enabled us to cover a network of sampling points all over the French Mediterranean coast. After establishing the coastal area by means of 25 sampling points in the course of the CORSE86 (86.09.23-86.10.06), LITTORAL86A (86.02.03-10, 86.04.03-11, 86.04.21-29) and LITTORAL86B (86.11.05-13) cruises, efforts were concentrated in particular on the area reached by the waters of the Rhone, as defined by 15 sampling points during the DYPOLO1 (86.08.28-86.09.07) and DYPOLO2 (86.11.19-30) cruises, and the area of the Golfe du Lion covered by 24 sampling points as part of the PELAGOLIONO1 (86.09.02-11) and PELAGOLIONO2 (86.12.04-12) cruises. Over the network of sampling points, volumes of water between 90 and 120 litres were systematically pumped from a depth of 0.5m. At some points selected on the basis of results of vertical contours of salinity, temperature or turbidity obtained in real time with a bathymeter, the various bodies of water identified between the surface and 1700 m were sampled using 30 1 Niskin bottles.
a specific point in time, with a fraction of the fallout reaching the eastern part of the north-west Mediterranean basin (2). Chernobyl fallout deposits assesment were led from aerosols and soils measurements and from atmospheric models results. These cesium latest deposits, which can be pinpointed to a specific time and place, can therefore be regarded as tracer elements, with a specific 137Cs/134 Cs close to 2.0, which can be plotted to determine the dynamics of the waters of the north-west Mediterranean basin. The radioelements released by the Chernobyl accident reached the marine environment via two routes: a direct route, whereby the atmospheric fallout fell to surface of the sea, and an indirect route via the rivers, after surface deposits on the soil had been washed away by rainwater. On the French section of the Mediterranean coast, two rivers of unequal importance flow out to sea: the Var and the Rhone. However, the waters of the RhOne carry not only the radioelements arising from the Chernobyl accident but also those associated with the discharge of low-level radioactive liquid effluents from various nuclear plants such as cesium isotopes, with a 137Cs/134Cs ratio greater than 4. The monitoring of radioelements arising from atmospheric fallout on the surface of the sea enables seasonal vertical changes to be detected, at regional level, in the various bodies of water whereas the monitoring of radioelements discharged by rivers leads to a definition of the limits of geographical areas under the influence of the deposits of coastal rivers. EQUIPMENT AND METHOD Radioactive tracers have been monitored during 7 oceanographic cruises in collaboration with research teams from the CNRS and the University. The cruises enabled us to cover a network of sampling points all over the French Mediterranean coast. After establishing the coastal area by means of 25 sampling points in the course of the CORSE86 (86.09.23-86.10.06), LITTORAL86A (86.02.03-10, 86.04.03-11, 86.04.21-29) and LITTORAL86B (86.11.05-13) cruises, efforts were concentrated in particular on the area reached by the waters of the Rhone, as defined by 15 sampling points during the DYPOLO1 (86.08.28-86.09.07) and DYPOLO2 (86.11.19-30) cruises, and the area of the Golfe du Lion covered by 24 sampling points as part of the PELAGOLIONO1 (86.09.02-11) and PELAGOLIONO2 (86.12.04-12) cruises. Over the network of sampling points, volumes of water between 90 and 120 litres were systematically pumped from a depth of 0.5m. At some points selected on the basis of results of vertical contours of salinity, temperature or turbidity obtained in real time with a bathymeter, the various bodies of water identified between the surface and 1700 m were sampled using 30 1 Niskin bottles.
ABSTRACT
219