Bioaccumulation of persistent organic pollutants in female common dolphins (Delphinus delphis) and harbour porpoises (Phocoena phocoena) from western European seas: geographical trends, causal factors and effects on reproduction and mortality

Concentrations of polychlorinated biphenyls (PCBs) in blubber of female common dolphins and harbour porpoises from the Atlantic coast of Europe were frequently above the threshold at which effects on reproduction could be expected, in 40% and 47% of cases respectively. This rose to 74% for porpoises from the southern North Sea. PCB concentrations were also high in southern North Sea fish. The average pregnancy rate recorded in porpoises (42%) in the study area was lower than in the western Atlantic but that in common dolphins (25%) was similar to that of the western Atlantic population. Porpoises that died from disease or parasitic infection had higher concentrations of persistent organic pollutants (POPs) than animals dying from other causes. Few of the common dolphins sampled had died from disease or parasitic infection. POP profiles in common dolphin blubber were related to individual feeding history while those in porpoises were more strongly related to condition.     

Spatial variability of metallic and organic contamination of anguilliform fish in New Caledonia

New Caledonia is one of the main hot spots of biodiversity on the planet. Large amounts of contaminants are discharged into the lagoon as a result of increasing anthropogenic activities such as intense mining, urbanization, and industrialization. Concentrations of 14 trace elements and 26 persistent organic pollutants (POPs: PCBs and pesticides) were measured in the muscles of two anguilliform fish species, over a coast to barrier reef gradient in two lagoon areas differently exposed to anthropic disturbances. This study emphasizes the high trace element contamination status of anguilliform fish and also highlights slight but perceptible organic pollution. The contamination extends throughout the lagoon, from coast to barrier reef, even in areas remote from emission points. High levels of trace elements, especially those linked to mining activities (i.e., Co, Cr, Fe, Mn, and Ni), were detected in coastal sites. Furthermore, the large dispersion of most POPs throughout the entire lagoon poses the question of their potential toxicity on marine organisms from numerous habitats. Our results underline the need for long-term monitoring of various contaminants over large spatial and time scales.     

Carbon conservation strategy for the management of pig slurry by composting: Initial study of the bulking agent influence

The intensification of the livestock production systems implies a potential environmental risk, associated with the great generation of animal wastes and slurries and their storage and management. Manure management is associated with considerable emissions of ammonia (NH₃) and greenhouse gases (GHG). However, the potential for GHG mitigation is highly dependent on the waste treatment strategy considered. This laboratory study aims to evaluate the influence of the type of bulking agent used on the potential reduction of the carbon dioxide (CO₂) emission, dealing with carbon (C) conservation when the solid fraction of pig (Sus scrofa domesticus) slurry is managed by composting. For this, a composting experiment in batch reactors was run with four mixtures elaborated using the solid fraction of pig slurry (SPS) and different materials (maize (Zea mays) stalks, barley (Hordeum vulgare L.) straw, cotton (Gossypium hirsutum) gin and garden prunings) as bulking agents. The potential C conservation in the mixtures was evaluated by determining the CO₂ emissions; the evolution of the mixtures, the thermal profile developed and the thermodynamics of the process were also studied. The mixtures elaborated with cotton gin and garden prunings showed the fastest temperature development, and also the highest CO₂ emissions. However, the use of maize stalks as bulking agent reduced CO₂ emissions due to its slow degradability: this could constitute a suitable strategy to promote C conservation during the management of pig slurry by composting.     

Ocean acidification and temperature rise: effects on calcification during early development of the cuttlefish Sepia officinalis

This study investigated the effects of seawater pH (i.e., 8.10, 7.85 and 7.60) and temperature (16 and 19 °C) on (a) the abiotic conditions in the fluid surrounding the embryo (viz. the perivitelline fluid), (b) growth, development and (c) cuttlebone calcification of embryonic and juvenile stages of the cephalopod Sepia officinalis. Egg swelling increased in response to acidification or warming, leading to an increase in egg surface while the interactive effects suggested a limited plasticity of the swelling modulation. Embryos experienced elevated pCO₂ conditions in the perivitelline fluid (>3-fold higher pCO₂ than that of ambient seawater), rendering the medium under-saturated even under ambient conditions. The growth of both embryos and juveniles was unaffected by pH, whereas ⁴⁵Ca incorporation in cuttlebone increased significantly with decreasing pH at both temperatures. This phenomenon of hypercalcification is limited to only a number of animals but does not guarantee functional performance and calls for better mechanistic understanding of calcification processes.     

Ecological tracers and at-sea observations document the foraging ecology of southern long-finned pilot whales (<Emphasis Type="Italic">Globicephala melas edwardii</Emphasis>) in Kerguelen waters

The food and feeding ecology of the poorly known southern long-finned pilot whale (Globicephala melas edwardii) was investigated using ecological tracers (muscle and skin δ¹³C and δ¹⁵N, and total mercury, Hg) on individuals from two mass strandings together with at-sea observations of live animals in Kerguelen waters, southern Indian Ocean. Sightings of cetaceans from longliners over 9 years (2003–2012) emphasized the regular occurrence of pilot whales in slope waters surrounding the archipelago. Tissue δ¹³C values (a proxy of consumer foraging habitat) suggest that pilot whales fed in slope waters and in oceanic subantarctic waters over the last months preceding stranding. Tissue δ¹⁵N values and Hg concentration (dietary proxies) indicate a high trophic position (~4.7) for the pilot whales, likely corresponding to a mixed diet of fish and squid (not crustaceans) of undetermined species. Both skin and muscle Hg concentrations were positively and linearly correlated to individual size with no concomitant δ¹⁵N changes, which can be interpreted as a progressive Hg accumulation in tissues of individuals throughout life with no parallel dietary shift. Skin and muscle Hg concentrations were linearly and positively related; hence, Hg skin could be used as a proxy of Hg concentration in muscle (a main Hg reservoir of the body). Kerguelen southern long-finned pilot whales were less Hg contaminated than most pilot whale populations studied so far, thus suggesting that they are not at a high risk to Hg-induced damages in the remote islands of the Southern Ocean.     

Characterization of ²⁴¹ Am and ¹³⁴Cs bioaccumulation in the king scallop Pecten maximus: investigation via three exposure pathways

In order to understand the bioaccumulation of ²⁴¹Am and ¹³⁴Cs in scallops living in sediments, the uptake and depuration kinetics of these two elements were investigated in the king scallop Pecten maximus exposed via seawater, food, or sediment under laboratory conditions. Generally, ²⁴¹Am accumulation was higher and its retention was stronger than ¹³⁴Cs. This was especially obvious when considering whole animals exposed through seawater with whole-body concentration factors (CF_7d) of 62 vs. 1, absorption efficiencies (A_0l) of 78 vs. 45 for seawater and biological half-lives (T_b½l) of 892 d vs. 22 d for ²⁴¹Am and ¹³⁴Cs, respectively. In contrast, following a single feeding with radiolabelled phytoplankton, the assimilation efficiency (AE) and T_b½l of ¹³⁴Cs were higher than those of ²⁴¹Am (AE: 28% vs. 20%; T_b½l: 14 d vs. 9 d). Among scallop tissues, the shells always contained the higher proportion of the total body burden of ²⁴¹Am whatever the exposure pathway. In contrast, the whole soft parts presented the major fraction of whole-body burden of ¹³⁴Cs, which was generally associated with muscular tissues. Our results showed that the two radionuclides have contrasting behaviors in scallops, in relation to their physico-chemical properties.     

Interspecific and geographical variations of trace element concentrations in Pectinidae from European waters

Cd, Cu and Zn were analysed in the organs and tissues of the three scallop species from the Bay of Biscay, the variegated Chlamys varia L., the queen scallop Aequipecten opercularis L. and the common scallop Pecten maximus L. for interspecific comparisons. In P. maximus the greatest concentrations of Cd and Cu were found in the digestive gland, whereas the two other species showed similar levels of Cd between digestive gland and kidneys and higher renal Cu concentrations. However, the digestive gland of all Pectinidae species contained from 75% to 93% and 52% to 74% of the total body burdens of Cd and Cu, respectively. Whatever the species, kidneys displayed the highest Zn concentrations, which therefore contained from 53% to 97% of the total body burden of this metal. Also using reported results, ratios between the concentrations in the digestive gland and that in the kidneys discriminated two groups of Pectinidae: (1) the Pecten group (P. maximus, P. jacobeus and Adamussium colbecki) with a Cd ratio > or = 4, a Cu ratio > or = 1 and a Zn ratio > 20x10(-3); (2) the Chlamys group with a Cd ratio < or = 1, a Cu ratio < or = 1 and a Zn ratio < or = 6x10(-3). However, no differences in the detoxification processes in the digestive gland were found between groups in this study. 72-80% of the total Cd was found to be soluble, probably bound to metalloproteins such as metallothioneins, while Cu and Zn were mainly found associated to the insoluble fraction of the digestive gland cells whatever the species. Queen scallops from the Faroe Islands were also considered to examine variations of the metal concentrations due to the geographical origin. In this northern area, queen scallops displayed Cd concentrations 2, 4 and 6 times higher in kidneys, muscle and digestive gland, respectively, compared to those from the Bay of Biscay. Consequently, the Cd concentrations in the whole soft parts of the queen scallops were more than 6 times higher in the Faroe Islands than in the Bay of Biscay. In contrast to Cd, both Cu and Zn concentrations in the whole soft parts were 2 times lower in the Faroe Islands, suggesting lower bioavailability of these essential elements.     

Trace elements in two odontocete species (Kogia breviceps and Globicephala macrorhynchus) stranded in New Caledonia (South Pacific)

Liver, muscle and blubber tissues of two short-finned pilot whales (Globicephala macrorhynchus) and two pygmy sperm whales(Kogia breviceps) stranded on the coast of New Caledonia have been analysed for 12 trace elements (Al, Cd, Co, Cr, Cu. Fe, organic and total Hg, Mn, Ni, Se, V, and Zn). Liver was shown to be the most important accumulating organ for Cd, Cu, Fe, Hg, Se, and Zn in both species, G. macrorhynchus having the highest Cd, Hg, Se and Zn levels. In this species, concentrations of total Hg are particularly elevated, reaching up to 1452 microg g(-1) dry wt. Only a very low percentage of the total Hg was organic. In both species,the levels of Hg are directly related to Se in liver. Thus, a molar ratio of Hg:Se close to 1.0 was found for all specimens, except for the youngest K. breviceps. Our results suggest that G. macrorhynchus have a physiology promoting the accumulation of high levels of naturally occurring toxic elements. Furthermore, concentrations of Ni, Cr and Co are close to or below the detection limit in the liver and muscles of all specimens. This suggests that mining activity in New Caledonia, which typically elevates the levels of these contaminants in the marine environment, does not seem to be a significant source of contamination for these pelagic marine mammals.     

Seasonal variation of pollution biomarkers to assess the impact on the health status of juvenile Pacific oysters <Emphasis Type="BoldItalic">Crassostrea gigas</Emphasis> exposed in situ

Background, aim, and scope  

In this study, a suite of sublethal stress biomarkers were analyzed in juveniles of the sentinel species, the Pacific oyster Crassostrea gigas, with a view to using them as pollution monitoring tools. The aim of this work was (1) to study baseline seasonal variations of biomarkers in different body compartments of C. gigas in the reference site and, after selecting biomarkers presenting no seasonal variations, (2) to compare responses of these biomarkers between contaminated and reference sites.     

Evaluation of composted sewage sludge as nutritional source for horticultural soils

Water deficit and soil degradation have become some of the major problems for crop production in semi-arid regions, as it is the South East of Spain. As a matter of fact, considerable productivity loss and risk of erosion have to be taken into account in these areas, especially those with an horticultural use (Davis, 1989). Utilization of sewage sludge in agriculture. Agricultural Progress 64, 72-80]. Horticultural soils are highly vulnerable and prone to erosion, as vegetables are generally fast-growing species under intensive exploitation regimes. High-rate chemical inputs contribute to horticultural soil degradation and have a dramatic effect on soil microbial population and nutrient balance whilst, at the same time, have a counter-effect on price competitiveness of the vegetables to be commercialized. In this paper we monitored variations in physical, chemical and biological properties of a cauliflower plot where four increasing quantities of compost were applied. We carried out a three-stage sampling schedule in order to check the effect of compost applications doses. We conclude that a 2 kg compost/m2 application had a positive effect on physical and biological properties of the soil and provides a supply of nutrients to grow cauliflowers on its surface under intensive exploitation regimes without loss in biomass yield.