Pierre Miramand

Distribution of trace elements in the tissues of benthic and pelagic fish from the Kerguelen Islands

New information on the concentrations of Cd, Cu, Hg and Zn in the liver, kidney and muscles of eight marine benthic and pelagic sub-Antarctic fish species are presented to determine the importance of these metals in the marine systems of the Kerguelen Islands. Compared to the reported metal concentrations in other Antarctic fish species, the present results are globally within the same range of concentrations, although Cd displayed a very high interspecific variability in liver and kidney. Indeed, the highest Cd concentrations in liver, ranging from 10.0 to 52.1 microg x g(-1) dry wt. but also the lowest Cd concentrations in muscles (<0.030 microg x g(-1) dry wt.) have been displayed by the pelagic Myctophidae Gymnoscopelus piabilis. Metal concentrations differences might be related to diet and feeding habits of benthic and pelagic fish species. However, Cd and Hg concentrations in the edible muscle are lower than the French limit values (<or=0.155 microg x Cd x g(-1) dry wt. and <or=1.51 microg x Hg x g(-1) dry wt.) for these toxic metals as well as for edible and non-commercially interesting fish species. Results for Cd in fish tissues are consistent with the hypothesis of Cd-enrichment in the polar food webs typically explained by essential elements depletion. In fact, Zn concentrations in fish from the Kerguelen Islands are comparable to those of other areas but low Cu concentrations in fish livers, ranging from 0.9 to 24.7 microg x g(-1) dry wt., might indicate low availability of this essential element in these sub-Antarctic waters.

Cadmium detoxification processes in the digestive gland of cephalopods in relation to accumulated cadmium concentrations.

The high concentrations of cadmium recorded in the digestive gland of cephalopods from various temperate and subpolar waters suggest that these molluscs have developed efficient cadmium detoxification mechanisms. The subcellular distribution of cadmium in the digestive gland cells was investigated in seven cephalopod species from the Bay of Biscay (France) and the Faroe Islands. In most species, cadmium was mainly found in the cytosolic fraction of the digestive gland cells, reaching up to 86% of the total cadmium for the squid Loligo vulgaris from the Bay of Biscay. But species with the highest total level of cadmium showed a higher percentage of cadmium associated to insoluble compounds. The quantification of metallothioneins (MTs) by the polarographic method was performed in order to evaluate the involvement of these proteins in the detoxification of the high amounts of bioaccumulated cadmium. Metallothionein levels in cephalopods ranged form 742 +/- 270 to 3478 +/- 1572 microg/g wet weight. No relationship could be established between total cadmium, cytosolic cadmium and MT levels suggesting the occurrence of other Cd-binding ligands. Although these proteins have not been characterised, as cadmium in the digestive gland of cephalopods is mainly associated with soluble ligands, a high potential transfer to predators can be predicted.

Experimental studies of impacts of harbour sediments resuspension to marine invertebrates larvae : Bioavailability of Cd, Cu, Pb and Zn and toxicity

The larvae of three marine species (Artemia salina, Crassostrea gigas, Paracentrotus lividus) reared within the suspended particulate phases of contaminated sediments from harbours were used in bioassays firstly to assess their ability to accumulate four metals (Cd, Cu, Pb, Zn) and secondly to show the toxicity of such rearing media by recording delays in growth and possible abnormal larval development. The results show that resuspension processes of dredged harbour sediments may induce both a release of Cd, Cu and Pb which are bioavailable for larvae (levels of bioaccumulation depending on the species) and biological perturbations, i.e. abnormal development in C. gigas and P. lividus larvae for the more contaminated sediments and growth inhibition in all three larvae for slightly contaminated sediments. The concentrations of Pb reached in the C. gigas D-shaped larvae and the P. lividus pluteus were unusually high; in contrast, Zn was not accumulated by the three species. The impact of dumping operations thus appears to depend both on the metal considered and on the larvae used in such tests. In this context, Pb seems a more worrying metal than Zn and C. gigas and P. lividus are better indicator species than A. salina larvae.

Bioaccumulation of Cadmium, Copper and Zinc in some Tissues of Three Species of Marine Turtles Stranded Along the French Atlantic Coasts

Cadmium, copper and zinc have been analysed in some tissues and organs of Loggerhead, Kemps Ridley (only muscle for this species) and Leatherback turtles stranded along the Atlantic coasts of France. The pancreas analysed only in Leatherback turtles exhibited the highest metal concentrations, which is very surprising for an organ which does not play a role in the detoxification processes. The distribution of these elements in kidney, liver and muscle were quite similar to that found in marine mammals or seabirds. Nevertheless, mean cadmium concentrations in the kidney were as high as 13.3 µg g-1 wet weight in the Loggerhead turtles and 30.3 µg g-1 wet weight in the Leatherback turtles. Such high concentrations in the Leatherback turtles have never been recorded before. The main source of cadmium for marine turtles is probably the food. The Leatherback turtles are known to feed mainly on jellyfish in this area. Ten times higher cadmium concentrations have been determined in jellyfish compared to fish. This would imply a greater exposure to cadmium for Leatherback turtles, which probably need to eat great quantities of jellyfish to cover their needs.

Bioaccumulation of 12 Trace Elements in the Tissues of the Nautilus Nautilus macromphalus from New Caledonia

Soils in New Caledonia are particularly rich in metals among which Fe and Ni are intensively exploited. Due to important natural erosion in tropical latitudes and to mining activities, coastal waters are enriched in Co, Cr, Fe and Ni. In deeper waters lives a cephalopod species which is considered as a living fossil, the nautilus Nautilus macromphalus. In this study, 12 trace elements were analysed in the tissues of 4 nautilus specimens. Results showed high metal concentrations compared to data available for cephalopods from temperate waters. These concentrations were often in the same order as those encountered in bivalves or gastropods from contaminated areas. Relatively high concentrations of Ni and Cr in the haemolymph strongly suggest a high exposure of N. macromphalus to these metals. Among the tissues, the digestive gland has the highest concentrations of Cd, Co, Fe, V and Zn while for Ag, Al, As, Cr and Ni, renal and pericardial appendages exhibited the highest values. Despite this, the digestive gland contained the largest quantities of all metals with the exception of As and Mn which were mainly found in the body muscular remains. These results highlighted the major role of digestive gland and excreting organs in the metabolism of metals in these cephalopod species.

Cadmium, copper and zinc in octopuses from Kerguelen Islands, Southern Indian Ocean

Abstract Concentrations of cadmium, copper and zinc were measured in 34 octopuses over a large range of size and weight, caught in the Kerguelen shelf waters. Compared with levels normally encountered in European cephalopods, Cd concentrations in both species were very high: 30.7–47.1 and 27.3–54.4 μg/g dry weight in Graneledone sp. and Benthoctopus thielei, respectively; Cu concentrations were generally low while Zn concentrations exhibited similar levels. Distribution of Cd in tissues showed that the high levels of Cd in Kerguelen octopuses resulted from very high levels of the metal in the digestive gland (369 and 215 μg/g dry wt in Graneledone sp. and Benthoctopus thielei, respectively). The digestive gland accumulated about 90% of the total Cd in the whole animal. Due to the very high concentrations of Cd in the Kerguelen octopuses, we hypothesize that these species play an important role in the process of Cd transfer throughout the food chain to top vertebrate predators in this area.

Bioaccumulation and toxicity of four dissolved metals in Paracentrotus lividus sea-urchin embryo

The bioaccumulation of four metals (Cd, Cu, Pb, Zn) dissolved in water was assessed measuring the concentrations recorded within sea-urchin larvae (Paracentrotus lividus, Lmk.) after a 48-h exposure period. Concurrently, the frequencies of abnormalities were evaluated at the 48-h pluteus stage to check the actual toxicity of such contaminants with regards to larval development. Maximum metal concentrations in the larvae reached 43.8 +/- 6.7 micrograms Cd g-1 dry weight (d.w.), 1269 +/- 392 micrograms Cu g-1 d.w., 3106 +/- 679 micrograms Pb g-1 d.w., 534 +/- 62 micrograms Zn g-1 d.w. Bioconcentration factors (BCFs) reached very high values for Pb (maximum value: 16,282 +/- 973) and indicated that the concentrations of Pb and Cd were directly related to the water concentration at least in the range of concentrations tested. Zn appeared to be partially regulated above a certain threshold concentration (between 5 and 25 micrograms l-1). Cu was accumulated with an active uptake at least below lethal threshold level (100 micrograms l-1). Nevertheless, above these thresholds, high mortality of embryos prevent any interpretation of Zn and Cu bioconcentration factors. Concurrent studies carried out on embryotoxicity confirmed the high toxicity of Cu towards sea-urchin pluteus larvae and highlighted the different behaviour of Cd. The internal Cd concentrations were directly related to the external ones, comparable to other non-essential metals, but Cd had little toxic effect on the initial larval development.

Metal and metalloid concentrations in the giant squid Architeuthis dux from Iberian waters

This study investigated 14 trace elements (Ag, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, V and Zn) in the tissues of the giant squid Architeuthis dux from the Mediterranean and Atlantic Spanish waters. As for other families of cephalopods, the digestive gland and the branchial hearts of Architeuthis showed the highest concentrations of Ag, Cd, Co, Cu, Fe, Ni, Se, V and Zn, highlighting their major role in the bioaccumulation and detoxification processes. With the exception of Hg, the muscles showed relatively low trace element concentrations. Nevertheless, this tissue contained the main proportion of the total As, Cr, Hg, Mn, Ni, and Zn body burden because muscles represent the main proportion of the squid mass. These findings suggest that the metal metabolism is overall the same as other cephalopod families from neritic waters. In females, Zn concentrations increased in the digestive gland with the squids weight likely reflecting physiological changes during sexual maturation. Comparing the trace element concentrations in the tissues of Architeuthis, higher Ag, Cu, Hg and Zn concentrations in the squid from the Mediterranean reflected different exposure conditions. In comparison to other meso-pelagic squids from the Bay of Biscay, Cd concentrations recorded in the digestive gland suggest that Architeuthis might feed on more contaminated prey or that it displays a longer life span that other cephalopods.

Concentration and distribution of 210Po in the tissues of the scallop Chlamys varia and the mussel Mytilus edulis from the coasts of Charente-Maritime (France).

Polonium-210 (210Po) has been analysed in the soft parts of two bivalves species, the scallop Chlamys varia and the common mussel Mytilus edulis, from the Bay of La Rochelle and Ré Island, on the French Atlantic coast. Between those sites, the highest 210Po concentrations have been found in whole scallop soft parts from La Rochelle, reaching 1,181 +/- 29 Bq kg(-1) dry weight (dwt), a size effect being related to the highest 210Po concentration in the smallest scallops. The results show a significant difference in concentrations for similar size individuals between species in each site (C. varia > M. edulis) and between sites for each species (Ré Island > Bay of La Rochelle). Very high 210Po concentrations have been found in the digestive gland of C varia, ranging 3,150-4,637 Bq kg(-1) dwt. Thus, the digestive gland contains up to 60% of the radionuclide. Subcellular investigations have shown that approximately 40% of the 210Po contained in the digestive gland is in the cytosolic fraction, suggesting a high bioavailability of the 210Po from this fraction to the trophic upper level. Calculations will show that approximately 4 kg of scallops flesh intake would be necessary to reach the annual incorporation limit of 1 mSv.

Heavy metal concentrations in two biological indicators (Patella vulgata and Fucus serratus) collected near the French nuclear fuel reprocessing plant of La Hague

Abstract Concentrations of eight metals (Cd, Co, Cr, Cu, Fe, Ni, Pb, Zn) were determined in the brown seaweed Fucus serratus and the limpet Patella vulgata collected every 2 weeks for 13 months on the rocky shore of Goury near the outlet of the nuclear reprocessing plant of La Hague (France). During this period, the heavy metal concentrations in both algae and gastropods showed large variations (a factor of 2–5). Statistical analysis of the data showed that the concentrations of Cd, Co, Cr, Fe, Ni and Pb in Patella, and those of Cd, Co, Cu, Fe, Ni and Zn in Fucus exhibit a seasonal pattern at Goury showing a maximum in winter. The highest values found in our samples are within the range of lower values reported for other regions of the world, indicating an area not, or only slightly, influenced by industrial activities.