Transuranic and fission product contamination in lake sediments from an alpine wetland, Boréon (France)

Transuranics and fission products have been measured in lake sediment samples, collected in an alpine wetland, to determine their vertical distribution and calculate inventories. The radionuclides considered are 90Sr, 137Cs, 238Pu, 239/240Pu and 241Am. From the results, a better knowledge of radionuclide accumulation mode and behaviour was obtained. In addition, the origins of the individual pollutants could be deduced from activity ratios. Analyses were made on different sediment cores. The sampling sites were chosen to enable future determination of the mass balances of the radiopollutants. As the selected study area is in a recreational area used by urban populations, a rough estimate was made of the mean external dose from 137Cs for comparison with the French regulation.     

Element mobility during metasomatism of granitic rocks in the Saint-Chély d'Apcher area (Lozère,France)

This paper summarises the behaviour of major and trace elements during hydrothermal alteration processes in the Vareilles albite deposit, Saint-Chély d' Apcher area (Lozère, France). Sampling focused mainly on fine- to medium-grained two-mica granite facies surrounding albitite veins in two open pits. The primary chemical variability inherent in sampling parent rock and analytical uncertainties can seriously affect element mobility calculations. Here we present a simple model that allows to discriminate between magmatic and alteration effects and to make a proper evaluation of the chemical changes that have caused the alteration. For this reason, a range of unaltered granites and albitites were sampled to evaluate the degree of parent rock heterogeneity. Duplicate measurements were performed by epithermal neutron activation analysis (ENAA) to obtain a reliable mean concentration for trace elements and to evaluate results reproducibility. ENAA measurements are completed by analysis of major elements by inductively coupled plasma-mass spectrometry (ICP-MS). The enrichment or depletion of an element during alteration, relative to its concentration in fresh parent rock, can be calculated on the basis of the assumed immobility of some elements during the process. In this study, we have assumed Ta as immobile element on the basis for his inert behaviour. The distinct differences in chemical change between altered and unaltered granite suggest the need to consider alteration event as an important parameter in evaluating granitic rocks for nuclear waste disposal.     

Selection of (bio) indicators to assess effects of freshwater use in wetlands: a case study of s’Albufera de Mallorca, Spain

Parc Natural sAlbufera de Mallorca is an internationally recognised resting area for a wide array of migratory birds, and like most wetlands it has many other ecological functions and socio-economic values. In the catchment, in which the wetland is situated, expanding tourism and intensification of agriculture place much pressure on a limited amount of freshwater. The freshwater supply to the wetland decreased due to water-extraction mainly driven by intensification of agriculture in the catchment. As a result saltwater intrusion increased since 1983–1985. This had considerable impacts on the ecological integrity of the wetland as reflected by changes in the state of the aquatic ecosystem. The distribution of submerged plants, less tolerant of salinity, declined or disappeared, while the distribution of species, known to prefer high salinity increased. As a contribution to the development of monitoring programs and management strategies that address both socio-economic and natural water demand, this article will formulate ecological criteria to assess the natural water demand by selection of (bio)indicators within the aquatic ecosystem.     

Sedimentation rates and trace metal input history in intertidal sediments from San Simón Bay (Ría de Vigo, NW Spain) derived from 210Pb and 137Cs chronology

(210)Pb and (137)Cs dating methods, accompanied by a high-resolution geochemical study, were applied to intertidal sediments containing both fine and coarse-grained particles and also, anthropogenic Pb in order to establish sedimentation rates and historical trends in heavy metal input. Sedimentation rates were established according to the "Constant Flux:Constant Sedimentation" (CF:CS) (210)Pb dating model, which was preferred rather than the "Constant Rate of Supply-Minimum Variance" (CRS-MV) model. Variations in sediment grain-size were accounted for by application of several normalization procedures. Al was selected for grain-size correction. Corrected sedimentation rates obtained from (210)Pb dating were corroborated through a second independent radionuclide tracer and by comparison of peak trace metal inputs into the environment with peaks in the sediment. The Chernobyl maximum was identified in the normalized (137)Cs activity profile. Sedimentation rates of 6.2+/-1.2 mm y(-1) and 3.1+/-0.5 mm y(-1) for the upper (two muddy layers) and 6.0+/-2.0 mm y(-1) for the lower (sandy) intertidal mud flat deposits of San Simón Bay were determined. According to the established chronology, human-induced environmental changes were detected in total metal concentrations (Cu, Pb, Zn) and in sediment grain-size and composition.     

Unexpected high PCB and total DDT levels in the breeding population of red kite (Milvus milvus) from Doñana National Park, south-western Spain

This study provides information on the current status of contamination by organochlorines (DDTs, PCBs, PCDDs and PCDFs) in the declining red kite (Milvus milvus L.) population breeding in the Do?ana National Park (DNP), south-western Spain. Analyses were performed in addled eggs collected between 1999 and 2001. DDE concentrations ranged from 0.1 to 33.5 microg/g ww, representing more than 86% of the total DDTs. Of the samples studied, 50% showed DDE levels above those associated with reproductive impairment in other raptor species. Concentrations of ortho PCBs (average 36.8 microg/g ww+/-37.7) in 50% of the eggs were much higher than levels reported to cause reduced hatching success, embryo mortality, and deformities in birds (>20 microg/g ww). It is remarkable that average ortho PCB and DDE concentrations showed an increase of one order of magnitude compared to previous data for the species during the 80s. Total PCDD/Fs showed levels in the low pg/g range (7.2-42 pg/g ww), having PCDDs and PCDFs similar contributions in most samples. Total mean TEQs were 238 pg/g (ww), being the range 7.02-667 pg/g (ww). Spatial variation within DNP was observed for PCBs, DDTs, as well as for TEQs. Since some eggs exceeded the NOEL (67%) and LOEL (33%) reported for other raptor species, we would expect the red kite to experience detrimental effects to dioxin-like toxicity. Our results suggest that organochlorine contaminants should be regarded as an element of concern in the population under study, in addition to other conservation problems already reported. Further investigations should be undertaken to identify potential sources of these chemicals in DNP, and to find out if organochlorine contamination is present in other predator species in the area, as well as their potential health effects on individuals and/or populations.