Metallothionein in intestine of red mullet, Mullus barbatus as a biomarker of copper exposure in the coastal marine areas

Dietary metal exposure in fish is studied in native red mullet, Mullus barbatus, involving metallothionein (MT) response in the intestine, a primary site for metal uptake. Intestinal MTs (microg mg(-1) proteins), total proteins (mgml(-1) S50), Cu, Zn, Fe, Mn and Cd (microg ml(-1) S50) are considered as indicators of metal exposure in specimens from near-shore and off-shore locations of the Eastern Adriatic Sea. Metallothionein and Cu are statistically significantly higher in 68 specimens from the Kastela Bay, a near-shore area (30.0+/-6.71microg MT mg(-1) proteins; 0.30+/-0.08microg Cu ml(-1) S50), in comparison to 51 specimens from off-shore area, Solta Island (25.9+/-4.21microg MT mg(-1) proteins; 0.26+/-0.09microg Cu ml(-1) S50). Cytosolic Cu, a MT inducer, is significantly correlated (p<0.05, r=0.44) with MT in specimens from the Kastela Bay, independent on fish biometry. Our study indicates that cytosolic intestinal Cu and MT represent a measurable biochemical response in red mullet specimens, dwelling above sediments contaminated with Cu.     

A micro-dilution method for detecting oxytetracycline-resistant bacteria in marine sediments from salmon and mussel aquaculture sites and an urbanized harbour in Atlantic Canada

A micro-dilution technique with changes in optical density (OD) used to measure bacterial growth over 72 h in culture media containing 0, 5, 10, 20, 40, 80 and 160 microg OTC (oxytetracycline)ml(-1) was applied to determine growth inhibition (GI) in mixed bacterial strains cultured from samples of marine sediments and salmon feed pellets. Growth of control cultures (Aeromonas salmonicida) was inhibited at all OTC concentrations. Some feed pellet samples and under-cage sediments from salmon aquaculture sites in the Bay of Fundy showed GI up to > or = 160 microg OTCml(-1). Lower values (40 to 80 microg OTC ml(-1)) occurred in subsurface (5-18 cm) sediments, > 100 m from salmon pens and adjacent to sewage outfalls in Halifax Harbour. GI values < 20 microg OTC ml(-1) in sediment from reference locations in Halifax Harbour and mussel aquaculture sites are considered to reflect natural background levels for OTC resistance.     

Comparative concentrations of metals in marine species from French Frigate Shoals, North Pacific Ocean.

Concentrations of arsenic, cadmium, chromium, copper, lead, mercury, selenium, and zinc were measured in coral, crab, eel, fish, lobster, and sediment samples collected from French Frigate Shoals, North Pacific Ocean. The sediments contained relatively high concentrations of selenium; moderate concentrations of arsenic, cadmium, copper and lead; and low concentrations of chromium and zinc. Metal concentrations were also determined in coral and crabs collected from the island of Oahu. Notably, a crab (Grapsus tenuicrustatus) and the undulated moray eel (Gymnothorax undulatus) exhibited high levels of copper and arsenic, respectively, relative to the other species studied. The concentrations of arsenic in the eel averaged 225 microg g(-1) dry wt, which was 3-12 times higher than that in all of the other species tested. The average concentration of copper in the crab was 343 microg g(-1) dry wt, 3-86 times greater than that in the other species studied. These data indicate background and comparative levels of the metals among the studied species. Lead levels in the coral (9-10 microg g(-1) dry wt) and crab (42-57 microg g(-1) dry wt) from Tern and Disappearing Islands were 23-283-fold greater than those from Oahu (0.4 and 0.2 microg g(-1) dry wt, respectively).     

Clam burrowing behaviour: Inhibition by copper-enriched sediment

Burrowing behaviour is adaptive and allows clams to escape predation; yet the effects of potentially toxic metals on such behaviour have not been adequately investigated. In natural marine sediment contaminated with copper the time for littleneck clams (Protothaca staminea) to achieve complete burial was recorded. Above a threshold of 5.8 μg g⁻¹ Cu added to dry sediment, the time for 50% of the clams to burrow (ET₅₀) increased logarithmically with increasing sediment copper concentration according to:

logET₅₀ = 0.15 (CU) - 1.37 (n = 4, r² = 0.98)

where ET₅₀=time in hours for 50% of clams to burrow and Cu=μg g⁻¹ Cu in dry sediment. Previously exposed clams had both a lower threshold to Cu and a longer reburrowing time (ET₅₀). Clams exposed to sediment mixed with Chelex-100®-sorbed copper showed no significant change in burrowing time. Bioassays based on claim burrowing behaviour can measure both bioeffectiveness of sediment-sorbed metals and a sublethal effect with ecological meaning.     

Protective effect of phospholipid hydroperoxide glutathione peroxidase (PHGPx) against lipid peroxidation in mussels Perna perna exposed to different metals

Levels of antioxidant defenses and lipid peroxidation were evaluated in mussels exposed to lead (200 mg/l), iron (500 microg/l), cadmium (200 microg/l) and copper (40 microg/l), for 12, 24, 72 and 120 h. Glutathione S-transferase (GST) activity was unchanged with all treatments. Catalase (CAT) increased after 120 h of exposure to all metals. Mussels exposed to Cd for 12 h, and to Cu and Fe for 120 h had increased lipid peroxidation, which might be associated to decreased levels of reduced glutathione (GSH) and glutathione peroxidase (GPx) activity. Pb exposure caused GSH depletion after 12 h and increased GPx activity after 120 h. Negative correlations were observed between the enzyme phospholipid hydroperoxide glutathione peroxidase (PHGPx) and malonaldehyde (MDA) levels after Fe and Cu exposure, indicating a protective role of PHGPx against lipid peroxidation, and suggesting the use of this enzyme as a new potential biomarker of toxicity associated with contaminant exposure in mussels.     

Development of a growth inhibition test with the marine and brackish water red alga Ceramium tenuicorne

The marine red macroalga Ceramium tenuicorne is cosmopolitan and naturally found in both brackish and marine waters. A growth inhibition test with this species can be carried out in salinities from 4 per thousand to 32 per thousand. The species is easily held in culture in the laboratory and the test can be performed in a completely defined medium. The robustness of the method is good with a CV of 14.6% of the controls. The EC calculations can be performed on linear regression on the length data. EC50 values of repetitive tests for zinc (20-33 microg Zn(2+)/l in 7 per thousand and 32-61 microg Zn(2+)/l in 20 per thousand) and copper (1.9-3.8 Cu(2+)/l in 7 per thousand and 7.9-13 Cu(2+)/l in 20 per thousand) show high sensitivity. This test is a good complement to any test battery with the purpose of estimating the hazard of substances to the brackish and marine environment.     

Effects of antifouling paint components (TBTO,copper and triazine) on the early development of embryos in cod (Gadus morhua L.)

To assess the risk of antifoulant use to the commercially important cod (Gadus morhua L.), fertilised cod eggs were exposed to triazine, copper and TBTO singly or combined in laboratory tests with running seawater. At the highest tested concentrations (11.5 microg Cu l(-1); 5 microg TBTO l(-1)) larval mortality was increased. The highest concentration of triazine (40 microg l(-1)) did not cause any significant mortality. Fertilised eggs that had been exposed to all the three chemicals singly for five days showed a higher buoyancy than the controls. No synergistic or antagonistic effects were indicated. Embryos/larvae exposed to 0.004-0.8 microg TBTO l(-1) did not show any changed respiration compared to the controls after hatching. It is concluded that existing known field concentrations of the three antifoulants are hardly expected to cause detectable effects on fish embryonic/larval development.     

Concentration and subcellular distribution of trace elements in liver of small cetaceans incidentally caught along the Brazilian coast

Concentrations of trace elements (V, Cr, Mn, Fe, Co, Cu, Zn, Ga, As, Se, Rb, Sr, Mo, Ag, Cd, Sb, Cs, Ba, T-Hg, Org-Hg, Tl and Pb) were determined in liver samples of estuarine dolphin (Sotalia guianensis; n = 20), Franciscana dolphin (Pontoporia blainvillei; n = 23), Atlantic spotted dolphin (Stenella frontalis; n = 2), common dolphin (Delphinus capensis; n = 1) and striped dolphin (Stenella coeruleoalba; n = 1) incidentally caught along the coast of Sao Paulo State and Parana State, Brazil, from 1997 to 1999. The hepatic concentrations of trace elements in the Brazilian cetaceans were comparable to the data available in literature on marine mammals from Northern Hemisphere. Concentrations of V, Se, Mo, Cd, T-Hg and Org-Hg increased with increasing age in liver of both estuarine and Franciscana dolphins. Very high concentrations of Cu (range, 262-1970 microg/g dry wt.) and Zn (range, 242-369 microg/g dry wt.) were observed in liver of sucklings of estuarine dolphin. Hepatic concentrations of V, Se, T-Hg, Org-Hg and Pb were significantly higher in estuarine dolphin, whereas Franciscana dolphin showed higher concentrations of Mn, Co, As and Rb. Ratio of Org-Hg to T-Hg in liver was significantly higher in Franciscana dolphin than estuarine dolphin, suggesting that demethylation ability of methyl Hg might be lower in liver of Franciscana than estuarine dolphins. High hepatic concentrations of Ag were found in some specimens of Franciscana dolphin (maximum, 20 microg/g dry wt.), and 17% of Franciscana showed higher concentrations of Ag than Hg. These samples with high Ag concentration also exhibited elevated hepatic Se concentration, implying that Ag might be detoxified by Se in the liver. Higher correlation coefficient between (Hg+0.5 Ag) and Se than between Hg and Se and the large distribution of Ag in non-soluble fraction in nuclear and mitochondrial fraction of the liver also suggests that Ag might be detoxified by Se via formation of Ag2Se in the liver of Franciscana dolphin.     

Copper toxicity in the marine copepod Tigropus japonicus: low variability and high reproducibility of repeated acute and life-cycle tests

The intertidal copeopod Tigriopus japonicus, which is abundant and widely distributed along the coasts of Western Pacific, has been suggested to be a good marine ecotoxicity testing organism. In this study, a series of experiments were conducted to investigate the reproducibility and variability of copper (Cu) sensitivity of T. japonicus so as to evaluate its potential to serve as an appropriate test species. To understand the seasonal variation of Cu sensitivity, individuals of T. japonicus were collected from the field in summer and winter, and subjected to standard 96 h acute (static renewal) toxicity tests. 96 h-LC50 values of T. japonicus collected from the two seasons were marginally different (p = 0.05), with an overall coefficient of variation (CV) of 33%. Most importantly, our results indicated that chronic Cu sensitivity of T. japonicus was highly reproducible. The CVs of intrinsic rates of increase in the population of the control and Cu treatment (10 microg Cu l(-1)) groups were only 10-11% between 10 runs of a standardised complete life-cycle test. Moreover, different Cu(II) salts generally resulted in a similar 96 h-LC50 value while Cu(I) chloride was consistently slightly less toxic than Cu(II) salts. Given such a high reproducibility of toxic responses, it is advocated to use T. japonicus as a routine testing organism.     

Toxicities of antifouling biocide Irgarol 1051 and its major degraded product to marine primary producers

Irgarol 1051 (2-methythiol-4-tert-butylamino-6-cyclopropylamino-s-triazine) is an algaecide commonly used in antifouling paints. It undergoes photodegradation which yields M1 (2-methylthio-4-tert-butylamino-6-amino-s-triazine) as its major and most stable degradant. Elevated levels of both Irgarol and M1 have been detected in coastal waters worldwide; however, ecotoxicity effects of M1 to various marine autotrophs such as cyanobacteria are still largely unknown. This study firstly examined and compared the 96 h toxicities of Irgarol and M1 to the cyanobacterium Chroococcus minor and two marine diatom species, Skeletonema costatum and Thalassiosira pseudonana. Our results suggested that Irgarol was consistently more toxic to all of the three species than M1 (96 h EC50 values: C. minor, 7.71 microug L(-1) Irgarol vs. > 200 microg L(-1) M1; S. costatum, 0.29 microg L(-1) Irgarol vs. 11.32 microg L(-1)M1; and T. pseudonana, 0.41 microg L(-1) Irgarol vs. 16.50 microg L(-1)M1). Secondly, we conducted a meta-analysis of currently available data on toxicities of Irgarol and M1 to both freshwater and marine primary producers based on species sensitivity distributions (SSDs). Interestingly, freshwater autotrophs are more sensitive to Irgarol than their marine counterparts. For marine autotrophs, microalgae are generally more sensitive to Irgarol than macroalgae and cyanobacteria. With very limited available data on M1 (i.e. five species), M1 might be less toxic than Irgarol; nonetheless this finding warrants further confirmation with additional data on other autotrophic species.     

Application of trichloroacetic acid (TCA) to extraction of soft body for the determination of tissue Cd, Cu, Pb and Zn in the prosobranch Hydrobia ulvae (Pennant)

The application of trichloroacetic acid (TCA) as a shell extractant for preparation of soft body parts with reference to tissue metal concentrations (Cd, Cu, Pb, Zn) in shellfish has been evaluated on the example of the mud snail Hydrobia ulvae, a small marine prosobranch densely present in rocky and soft-bottom habitats of the eastern Atlantic. A solution of 0.1 M TCA was tested on individuals treated according to two different protocols: (1) thawed after freezing ("non-dried") and (2) thawed and air-dried to a constant weight ("dried"). Two points were investigated in detail to improve the method: individual soft tissue dry weight and tissue metal concentration following a standard digestion method. In both instances, the results were compared with those from manually dissected snails. Conditions for total shell decalcification of 60 individuals (3-4 mm long) were 5.5 h in 20 ml of 0.1 M TCA.No differences in individual soft tissue weight were observed between the treatments, indicating good efficiency of the TCA extraction with respect to weight of soft body parts. In contrast, tissue metal concentrations varied among treatments. The TCA extraction of the dried animals had a good recovery for Cd, most likely due to the lower solubility of Cd vital cellular components (proteins and mineral concretions) from the dried tissue. Satisfactory recoveries of the tissue concentrations of Cu and Pb were obtained for the non-dried individuals. This might be related to the specific distribution of metals in the organism (namely in the digestive glands and gonads) and their different chemical reactivity with TCA after the tissue was dried. Limited susceptibility of Zn-bearing protein bindings to complexing with TCA also accounts for significantly lower concentrations of Zn in the mud snail's soft tissue that was extracted. The 0.1 M TCA solution is therefore recommended for extraction of the shells of Hydrobia ulvae for tissue determination of Cd, Cu and Pb; however the treatment protocol does affect metal recovery and thus a consistent procedure should be followed.The extracted metals from the soft tissues and shells of the mud snails (on the basis of both metal concentrations and contents) were ranked in order of increasing contribution of soft body parts to the total (shell+tissue): Pb相似文献   

Effects of deposit feeder Stichopus japonicus on algal bloom and organic matter contents of bottom sediments of the enclosed sea

Algae growing in an enclosed sea may inhibit eutrophication because they absorb nutrients in the water. However, dead algae often cause anaerobic conditions in the water just above and on sediment after they are deposited on the bottom. We found that Stichopus japonicus inhibited the anaerobic processes coupling water sulfite production in sediment. The present study investigates whether S. japonicus inhibits algal flourish and influences sediment properties such as organic matter contents. Aquarium experiments were carried out at Komatsushima port in Tokushima Prefecture, western Japan. The aquaria used in the experiments were supplied with water directly from the adjacent sea (6 L/min), laid with sand of 10 cm depths, and lighted at 12 h intervals. Six aquaria each containing a sea cucumber from Komatsushima port and six aquaria without any were used in the experiments. Water temperature ranged between 9 and 15 degrees C during December 2000 and April 2001. Salinity ranged between 32 per thousand and 34 per thousand. Algae began to cover the bottom of the aquaria without S. japonicus after 2 weeks, whereas no growth was evident in the aquaria containing sea cucumbers. Chlorophyll a concentration in the surface sediment of the aquaria with S. japonicus (6.1+/-3.6 microg/g, mean S.D.+/-standard deviation) was significantly lower than that without it (60+/-17 microg/g, U-test, p<0.05). Phaeophytin concentration in the surface sediment of the aquaria with S. japonicus (0.9+/-0.09 microg/g) was also significantly lower than that without it (4.5+/-1.0 microg/g, U-test, p<0.05). TOC concentration in the surface sediment of the aquaria with S. japonicus (2.6+/-1.3 microg/g) was slightly lower than that without it (4.0+/-1.2 microg/g). These results showed that algal biomass and organic matter concentration of the bottom were decreased in the presence of S. japonicus. Therefore, S. japonicus inhibits algal bloom and decrease the contents of organic matter deposited on the bottom of enclosed sea areas.     

Marine risk assessment: linear alkylbenzenesulponates (LAS) in the North Sea

The fate of linear alkylbenzenesulponates (LAS) in estuaries and coastal areas of the North Sea has been characterized with simple environmental models. The predicted concentration range in the estuaries around the North Sea (0.9-9 microg LAS l(-1)) was validated by monitoring data (1-9 microg LAS l(-1)). In offshore sites of the North Sea, it is estimated--and experimentally verified for a few sites--that the LAS concentration is below analytical detection limit (i.e., 0.5 microg LAS l(-1)). The effects of LAS on marine organisms have been reviewed. For short-term acute tests, there was no significant difference (p = 0.83) between the mean LC50 values of freshwater and marine organisms (mainly pelagic species tested, 4.1 and 4.3 mg LAS l(-1), respectively). For longer-term chronic tests, it appeared that the sensitivity (mean no-observed effect concentration (NOEC) value) of marine and freshwater organisms (0.3 and 2.3 mg LAS l(-1), respectively) was significantly different pt-test = 0.007). The predicted no-effect-concentrations (PNEC) were 360 and 31 microg LAS l(-1), for freshwater and marine pelagic communities, respectively. Given that the maximum expected estuarine and marine concentrations are 3 to > 30 times lower than the PNEC, the risk of LAS to pelagic organisms in these environments is judged to be low.     

Copper bioavailability and toxicity to Mytilus galloprovincialis in Shelter Island Yacht Basin,San Diego,CA

The bioavailability and toxicity of copper (Cu) in Shelter Island Yacht Basin (SIYB), San Diego, CA, USA, was assessed with simultaneous toxicological, chemical, and modeling approaches. Toxicological measurements included laboratory toxicity testing with Mytilus galloprovincialis (Mediterranean mussel) embryos added to both site water (ambient) and site water spiked with multiple Cu concentrations. Chemical assessment of ambient samples included total and dissolved Cu concentrations, and Cu complexation capacity measurements. Modeling was based on chemical speciation and predictions of bioavailability and toxicity using a marine Biotic Ligand Model (BLM). Cumulatively, these methods assessed the natural buffering capacity of Cu in SIYB during singular wet and dry season sampling events. Overall, the three approaches suggested negligible bioavailability, and isolated observed or predicted toxicity, despite an observed gradient of increasing Cu concentration, both horizontally and vertically within the water body, exceeding current water quality criteria for saltwater.     

Dissolved trace metal distributions in Port Jackson estuary (Sydney Harbour), Australia

Concentrations of dissolved metals (Cd, Cu, Ni, Mn and Zn) were determined for summer and winter, under low-flow conditions in Port Jackson, a microtidal, well-mixed estuary in south-east Australia. Mean concentrations of Cd (0.04+/-0.02 microg/l), Ni (0.86+/-0.40 microg/l), Mn (20.0+/-25 microg/l) and Zn (6.47+/-2.0 microg/l) were below water quality guidelines. Concentrations of Cu (1.68+/-0.37 microg/l), however, slightly exceeded recommended values. Dissolved Ni and Mn behaved mostly conservatively, whereas Cd, Cu and Zn showed mid-estuarine maxima. Peaks in Cd, Cu and Zn concentrations were located in the upper estuary, independent of the salinity and suspended particulate matter loading, and were consistent with anthropogenic inputs of metals in the estuary. Concentrations of dissolved Cu were highest in summer, whereas concentrations of Cd, Ni and Mn were significantly lower in summer than winter (P< or =0.05). The increase in temperature and biological activity during summer explained the seasonal variation. The sequence of log K(d) values (20-30 salinity) was Mn>Zn>Cu>Ni. These results give unique information concerning the contemporaneous distribution of dissolved trace metals in the Port Jackson estuary and they provide a data set against which the long-term contamination may be assessed.     

Mercury and lead tolerance in hypersaline sulfate-reducing bacteria

Sulfate-reducing bacteria (SRB) HSR1, HSR4, and HSR14 isolated from the salt pans of Goa grew best at 90-100/1000 salinity on substrates like formate, acetate, lactate, butyrate, ethanol and benzoate. They were gram negative, non-sporulating, non-motile rods lacking in desulfoviridin and cytochromes. Examination of these isolates for heavy metal tolerance and response studies in terms of growth and sulfate-reducing activity (SRA) were carried out using HgCl2 and Pb(NO3)2 at final concentration of 50, 100, and 200 and 100, 200 and 500 microg ml(-1) respectively. With Hg, HSR1 showed approximately 80% of the control's growth at 100 and 200 microg ml(-1) but SRA reached only 60% of the control values at the end of 14 days. HSR14 could reach >100% of the control's growth at 200 microg ml(-1) but the SRA reached only up to 60% of the control without metal at 100 microg ml(-1). Though the concentration of Pb was double that of Hg, HSR4 could grow and respire better than the control, the growth being stimulated by 160% and respiration by 170% in the presence of 500 microg ml(-1) of Pb(NO3)2. It is probable that some hypersaline SRB are more tolerant to heavy metals than the mesohaline counterparts and could be more effectively used for precipitating these metals in bioremediatory measures. Further examination of their responses to varied concentration of metals under different salinities would indicate their range of applicability.     

Effects of the herbicide diuron on the early life history stages of coral

The effects of the herbicide diuron on the early life history stages of broadcast spawning and brooding corals were examined in laboratory experiments. Fertilisation of Acropora millepora and Montipora aequituberculata oocytes were not inhibited at diuron concentrations of up to 1000 microg l(-1). Metamorphosis of symbiont-free A. millepora larvae was only significantly inhibited at 300 microg l(-1) diuron. Pocillopora damicornis larvae, which contain symbiotic dinoflagellates, were able to undergo metamorphosis after 24 h exposure to diuron at 1000 microg l(-1). Two-week old P. damicornis recruits on the other hand were as susceptible to diuron as adult colonies, with expulsion of symbiotic dinoflagellates (bleaching) evident at 10 microg l(-1) diuron after 96 h exposure. Reversible metamorphosis was observed at high diuron concentrations, with fully bleached polyps escaping from their skeletons. Pulse amplitude modulation (PAM) chlorophyll fluorescence techniques demonstrated a reduction in photosynthetic efficiency (Delta F/F(m)') in illuminated P. damicornis recruits after a 2 h exposure to 1 microg l(-1) diuron. The dark-adapted quantum yields (F(v)/F(m)) also declined, indicating chronic photoinhibition and damage to photosystem II.     

Measurement of copper release rates from antifouling paint under laboratory and in situ conditions: implications for loading estimation to marine water bodies

The release of biocides, such as copper (Cu), from antifouling (AF) coatings on vessel hulls represents a significant proportion of overall Cu loading in those harbors and estuaries where substantial numbers of small craft or large vessels are berthed. Copper release rates were measured on several self-polishing, tin-free coatings and an ablative Cu reference coating applied to steel panels using three measurement methods. The panels were exposed in natural seawater in San Diego Bay, and release rates were measured both in the laboratory and field over 2 years. Results with the static (20 cm x 30 cm) panels indicated that Cu release rates were initially high (25-65 microg Cu cm(-2)day(-1)), with a large range of values between paint types. Release rates declined to substantially lower rates (8-22 microg cm(-2)day(-1)) with reduced variability within 2 months. Release rates continued to decrease over time for approximately 6 months when relatively constant release rates were observed for most coatings. Over time, relative differences in Cu release rates measured by three exposure methods decreased, with all coatings exhibiting similar behavior toward the end of the study. Lowest overall Cu release rates were observed with the self-polishing experimental paint no. 7 in static-dynamic and in situ treatments. The highest periodic release rates were measured from panels that experienced periods of both static and dynamic exposure (8.7 ms(-1) rotation). The lowest release rates were measured from panels that experienced static, constant depth exposure, and where release rates were evaluated in situ, using a novel diver-deployed measurement system. Results from this in situ technique suggests that it more closely reflects actual Cu release rates on vessel hulls measured with intact natural biofilms under ambient conditions than measurements using standardized laboratory release rate methods. In situ measurements made directly on the AF surface of vessels demonstrated typically lower release rates than from the panel studies, averaging 8.2 microg cm(-2)day(-1) on pleasure craft, and 3.8 microg cm(-2)day(-1) on Navy vessels. The data suggest that the presence of an established biofilm likely serves to moderate the release of Cu from field-exposed antifouling coatings both on panels and hull surfaces.     

Atmospheric lead fallout over the last century recorded in Gulf of Lions sediments (Mediterranean Sea)

Six marine sediment cores from the Gulf of Lions continental slope (700-1700 m water depth) were analyzed for stable lead isotopes and (210)Pb geochronology in order to reconstruct lead atmospheric fallout pattern during the last century. The detrital lead contribution is 25 microg g(-1) and the mean sediment anthropogenic inventory is 110+/-7 microg cm(-2), a little bit higher than atmospheric deposition estimate. Anthropogenic lead accumulation in sediments peaked in early 1970s (1973+/-2) in agreement with lead emissions features. For the period 1986-1997, the sediment signal also reflect the decrease of atmospheric lead described by independent atmospheric fallout investigations. The anthropogenic Pb deposition in the late 1990s was similar to the 1950s deposition, attesting thus of the output of European environmental policies.     

Clam burrowing behaviour and mortality related to sediment copper

Gravel sediment freshly enriched with over 4.4 μg Cu g^?1 significantly increased the burrowing and reburrowing times of Littleneck marine clams (Protothaca staminea). Abnormal burrowing behaviour was observed with time-lapse video. Aged (1 day) copper-enriched sediment did not affect clam burrowing time. Copper in sediment porewater declined three days after sediment enrichment to background levels without change in total sediment copper. In a long-term experiment, clams with increased burrowing time into copper-enriched sediment had up to 25% mortality after 12–29 days burial in the sediment. The majority of clam mortality was found in clams burrowing within the first 48 h. Over 7 weeks there was blackening of sediment and clam shells proportional to sediment copper enrichment.