Trophic contamination by pyrolytic polycyclic aromatic hydrocarbons does not affect aerobic metabolic scope in zebrafish Danio rerio.

The effect of trophic exposure to pyrolitic polycyclic aromatic hydrocarbons (PAH) on aerobic metabolism of zebrafish Danio rerio was investigated. There were no significant differences in standard metabolic rate (SMR), active metabolic rate (AMR) or aerobic metabolic scope (AS) at any sublethal concentration of PAH in the diet of adult or juvenile fish. This suggests that under these experimental conditions, exposure to PAH in food did not influence aerobic metabolism of this species.

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 squid's 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 mobilization of Cd, Cu, Pb and Zn by meiofauna populations living in harbour sediment: their role in the heavy metal flux from sediment to food web.

The bioavailability of Cd, Cu, Pb and Zn was assessed in different harbours of the Atlantic coast (France). The responses of the two dominant meiobenthic groups (nematodes and copepods) to a heavy metal contamination gradient measured in similar subtidal sediments were observed in field surveys. Heavy metal concentrations were measured in nematodes and copepods. Nematodes have higher Cd, Cu, Pb and Zn transfer factors than copepods or other benthic species. The flux of heavy metal through nematodes was estimated and appears to be important compared to plankton in the process of heavy metal transfer to benthic or pelagic food webs.

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 (

Cephalopods as a vector for the transfer of cadmium to top marine predators in the north-east Atlantic Ocean.

Three hundred and fifty individuals of 12 species of cephalopods which differed in their feeding habitats were sampled from the French Atlantic coast to the sub-Arctic region (Bay of Biscay, English Channel, west Irish coast and Faroe Islands) and analysed for their cadmium contents. Comparison of the Cd levels of the cephalopods showed that those from the sub-Arctic area contained very high Cd concentrations compared to those from lower latitudes such as along the French Atlantic coast. High Cd levels in cephalopods from the sub-Arctic zone correspond closely to the reported high Cd concentrations in the tissues of top vertebrate predators from the same area. Comparison of the weekly Cd intakes for the Faroe Island pilot whales with the 'Provisional Tolerable Weekly Intake' for humans recommended by the World Health Organisation, showed that top vertebrate predators are often subjected to Cd doses far in excess of those recommended for humans. Our limited survey results suggest that cephalopods constitute an important source of Cd for cephalopod predators, and that this bioaccumulation effect is most evident at high latitudes.

Reproductive cycle and heavy metals in the organs of red mullet, Mullus barbatus (L.), from the northwestern Mediterranean.

Concentrations of the heavy metals Cd, Cu, Fe Mn, V and Zn have been measured in the principal tissues of the red mullet, Mullus barbatus (L.), during a complete sexual cycle. By comparison of metal levels during the reproductive and non-reproductive periods, it was found that concentrations as well as total amounts of Cu, Mn and Zn in liver and gonads of male and female mullets were dependent upon the stage of the sexual cycle. No relationship with the sexual cycle was noted for these metals measured in muscle, kidney, spleen or pyloric caecum. Because of the observed variation in liver and gonad metal concentrations, these tissues appear to be poor indicators of ambient levels of metals in the surrounding waters. However, muscle may prove useful as an indicator tissue owing to its apparent independence of effects of the sexual cycle.

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.

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.

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.

[Presence if a new oyster predator, Ocinebrellus inornatus (Recluz, 1851), in the shellfish culture bay of Marennes-Oleron]. / Présence d'un nouveau prédateur de l'huître creuse, Ocinebrellus inornatus (Récluz, 1851), dans le bassin conchylicole de Marennes-Oléron.

The muricid gastropod, Ocinebrellus inornatus, originates from the coasts of the Korean Sea and southern Japan. This species has been regularly sampled in the bay of Marennes-Oléron (France) since spring 1997, and allowed us to validate the taxonomic status of a previous report of the species in the bay in April 1995. O. inornatus was sampled only in the bay of Marennes-Oléron and has not been observed in the other areas along the Charente-Maritime coast. O. inornatus lives mainly in the same biotope as the local muricid Ocenebra erinacea (i.e. the level of Fucus serratus between MLWN and ELWS) Now, this alien species seems to be very well settled in the bay of Marennes-Oléron, where it causes damage to the farming oyster beds. In the areas of highest densities of Ocinebrellus inornatus, the local species Ocenebra erinacea is observed in comparatively reduced numbers. The probable causes of introduction of O. inornatus in the bay are discussed.

Cadmium-containing granules in kidney tissue of the Atlantic white-sided dolphin (Lagenorhyncus acutus) off the Faroe Islands.

Top predators from the northern sub-polar and polar areas exhibit high cadmium concentrations in their tissues. In the aim to reveal possible adverse effects, samples of five Atlantic white-sided dolphins Lagenorhyncus acutus have been collected on the occasion of the drive fishery in the Faroe Islands, for ultrastructural investigations and energy dispersive X-ray microanalyses. Cadmium concentrations were less than the limit of detection in both immature individuals and ranged from 22.7 to 31.1 microg x g(-1) wet weight in the mature individuals. Two individuals with the highest cadmium concentrations exhibited electron dense mineral concretions in the basal membranes of the proximal tubules. They are spherocrystals made up of numerous strata mineral deposit of calcium and phosphorus together with cadmium. Cadmium has been detected with a molar ratio of Ca:Cd of 10:1 in the middle of these concretions. To our knowledge, this is the first report of such granules in a wild vertebrate. The role of these granules in the detoxification of the metal and the possible pathological effects are considered.