Trace elements in farmed and wild gilthead seabream, Sparus aurata

In the present study, we sought to determine the concentration of several trace elements (total and organic mercury, selenium, cadmium, lead, arsenic, copper, chromium, iron, manganese, molybdenum, vanadium and zinc) in muscle tissue of gilthead seabream (Sparus aurata), an edible finfish species that is widely cultured in the Mediterranean area. The phenomenon of bioaccumulation and bioamplification (especially of mercury) was investigated by comparing farmed fish with wild specimens of the same species. Farmed specimens showed mercury and arsenic concentrations significantly lower than wild specimens, and no relationship was found between mercury concentration and body size. The lower level of methylmercury in farmed fish has important implications for consumer health.     

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).     

Trace metals in fish and invertebrates of three California coastal Wetlands

Metal concentrations were measured in selected fish and invertebrate species from Mugu Lagoon, Malibu Lagoon and Ballona Wetlands in southern California in order to assess the extent of metal contamination in these three wetlands. Ranges of element concentrations (in microgram/g) found in biota were: Zn 12-650; Cu 1.9-440; Ni < 1-37; Cr < 1-55; Pb < 0.5-6.8; As < 1-8.5; Se < 1-3.8; Cd < 0.2-0.90; and Ag < 0.3-5.9. Relative to previous studies of California biota, the highest metal concentrations found were for chromium and nickel. The highest levels were in one of the two bottom-dwelling fish (juvenile Leptocottus armatus) (55 micrograms/g) and the two water-column fish sampled (Fundulus parvipinnis and Atherinops affinis) (30 and 24 micrograms/g). At Ballona Lagoon, elevated levels of copper and silver were found in the bivalve Tagelus californianus (440 and 5.9 micrograms/g). Chromium and nickel appeared to be most persistent in fish from Mugu (4.6-55 and 2.6-37 micrograms/g), the most northern site and an active military base, and Ballona (< 1-30 and < 1-16 micrograms/g), believed to be the most metal-contaminated site. Compared to previously measured metal concentrations in species of California coastal waters, these regions revealed higher levels of chromium, nickel, silver, arsenic, zinc, copper and, to a lesser extent, cadmium and selenium. Chromium and silver were present at high enough levels at all three sites to be considered environmental health hazards.     

Trace elements in Acartia clausi from Elefsis bay of the Upper Saronikos Gulf,Greece

Twelve trace elements (antimony, arsenic, cadmium, chromium, cobalt, copper, iron, managenese, mercury, scandium, selenium and zinc) were determined by neutron activation analysis in a planktonic copepod (Acartia clausi) from Elefsis Bay of the Upper Saronikos Gulf, Greece. During the first cruise (January 1974) higher levels of most of these trace elements were found in this copepod collected from a polluted area of the bay. This trend however was not observed during the second cruise (February 1974) possibly due to the termination of the active vertical convection. Lower levels of cobalt, similar levels of iron and slightly increased levels of chromium were found in Elefsis Bay Acartia clausi from those reportedin Acartia clausi from the Bay of Roquebrune. Slightly increased concentrations of antimony and zinc as well as lower concentrations of arsenic and cadmium were found in Acartia clausi than those reported in other Copepoda. No significant differences were found for copper, manganese and mercury. More data are needed to confirm if higher levels of antimony, chromium and zinc found in Acartia clausi are due to the pollution of the bay.     

Stable isotopes and metal contamination in caged marine mussel Mytilus galloprovincialis

Metal concentrations and isotopic composition were measured in different tissues of the mussel Mytilus galloprovincialis in waters of the Balearic Islands (Western Mediterranean) in order to assess pollution levels. The isotopic composition was correlated with lead, cadmium, selenium and nickel obtained from the digestive gland and foot of the mussels. Significant negative correlations were found between cadmium, selenium and zinc and the mussel foot, mainly for ¹³C. Significant correlations were also found between lead and cadmium and the digestive gland. Pearson correlations indicated that the ¹³C isotopic signal in foot is a good proxy for the concentration of metals such as lead, cadmium, selenium and zinc. Similarly, ¹⁵N isotopic signatures in the digestive gland reflected the lead and cadmium concentration.     

Trace elements in two marine fish species during estuarine residency: Non-essential versus essential

Trace element levels in fish are of particular interest, owing the potential risk to human health. In accordance, juveniles of Dicentrarchus labrax and of Liza aurata were sampled and arsenic, cadmium, chromium, selenium and zinc were determined in the muscle. The levels of trace elements in muscle demonstrated to be similar for both species and sites, with the exception of selenium levels at reference, which seemed to be higher in D. labrax. Moreover, apart from arsenic levels in muscle, all elements were in conformity with the existent regulatory guidelines for fish consumption. The dietary intake of each element was also calculated, with arsenic and selenium showing intakes above the recommended dietary allowances. Nevertheless, no arsenic speciation was carried out and thus no accurate risk evaluation could be established. Additionally, selenium levels never exceeded the dietary allowances more than five times, which are considered safe.     

Trace metals in finfish from the New York Bight and Long Island Sound

Concentrations of silver, cadmium, chromium, copper, mercury, manganese, nickel, lead and zinc were measured in five species of finfish collected from the New York Bight and two from Long Island Sound. With few exceptions the trace metal contents were similar for the various species examined and also for a single species when comparing catch locations. Metal levels also were similar to concentrations reported by two other investigators who studied fish from the North Atlantic.     

Embryotoxic and genotoxic effects of heavy metals and pesticides on early life stages of Pacific oyster (Crassostrea gigas)

This study evaluated embryotoxicity and genotoxicity of two dissolved metals copper and cadmium (Cu and Cd) and two pesticides (metolachlor and irgarol) occurring in Arcachon Bay (SW France) in Pacific oyster (Crassostrea gigas) larvae and investigated the relationship between those two endpoints. Embryotoxicity was measured by calculating the percentage of abnormal D-shaped larvae and genotoxicity was evaluated with DNA strand breaks using the comet assay. After 24 h exposure, significant increases of the percentage of abnormal D-larvae and the DNA strand breaks were observed from 0.1 μg L⁻¹ for Cu, 10 μg L⁻¹ for Cd and 0.01 μg L⁻¹ for both irgarol and metolachlor in comparison with the controls. A strong positive relationship between embryotoxicity and genotoxicity was recorded for Cu, Cd and metolachlor. The current study suggests that copper, irgarol and metolachlor can induce larval abnormalities and DNA damage in a population of exposed oysters at environmentally relevant concentrations.     

Seasonal variation in the trace metal content of Mytilus edulis

The possible seasonal variation in the trace metal content of the mollusc Mytilus edulis has been studied by analysing cadmium, cobalt, copper, lead, manganese, mercury, nickel and zinc in 560 individuals collected from the same mussel bed over a period of two years. A clearly discernible effect of size on metal concentration was detected. However, no seasonal trends could be seen in the data.     

Trace metals in southern Californian mussels

The intertidal mussel Mytilus californianus is a useful indicator of anthropogenic inputs of several trace metals off southern California. Highest metal concentrations were measured in the digestive glands, and no significant differences attibutable to sex were found for this tissue. The distribution of lead appears to be dominated by diffuse inputs, while those of copper, chromium, and silver are most related to urban point sources. No distinct pattern was observed for nickel or zinc.     

Tunicate species as marine pollution indicators

Tunicates may serve as marine pollution indicators for monitoring the release of industrial and/or radioactive wastes into the marine environment. Their ability to accumulate certain trace elements from the seawater can be employed in order to define a suitable organism as indicator for some specific pollutants. In this work the concentration of the elements cobalt, zinc, chromium, caesium, silver, iron, rubidium, selenium, scandium and antimony has been determined by instrumental neutron activation analysis and γ-ray spectroscopy, in two tunicates, Microcosmus sulcatus (Pyuridae) and Ciona intestinalis (Cionidae).According to the concentration factors found for these species Ciona intestinalis can be used as indicator for iron, while Microcosmus sulcatus as indicator for the elements selenium, chromium, zinc and cobalt.     

Responses of benthic macrofauna and biogeochemical fluxes to various levels of mussel biodeposition: An in situ “benthocosm” experiment

An in situ experiment was done to evaluate the dose-dependent response of mussel biodeposition on benthic communities and biogeochemical fluxes. Natural benthic communities were exposed to 7 different levels of mussel biodeposition (equivalent to that produced by 0-764 mussels m⁻²) over 50 days. Benthic communities responded as predicted from the Pearson, T.H., Rosenberg, R., 1978. Macrobenthic succession in relation to organic enrichment and pollution of the marine environment. Oceanogr. Mar. Biol. Annu. Rev. 16, 229-311 model of organic enrichment. Total abundance and species richness decreased with increasing biodeposition. The abundance and biomass of opportunistic species (Capitella spp.) increased in the mesocosms subject to the greatest biodeposition. Sensitive species Tellina agilis and Pherusa plumosa tended to decrease in abundance and biomass with increasing biodeposition. The biotic index M-AMBI responded clearly to increased biodeposition and may be a useful tool for assessing the effect of mussel biodeposition on the benthic environment. These results are important for the construction of predictive models for determining environmental carrying capacity for bivalve aquaculture.     

Why are hatching and emergence success low? Mercury and selenium concentrations in nesting leatherback sea turtles (Dermochelys coriacea) and their young in Florida

Leatherback sea turtles (Dermochelys coriacea) have low hatching and emergence success compared to other sea turtle species. Postmortem examinations of hatchlings showed degeneration of heart and skeletal muscle that was similar to that found in other neonates with selenium deficient mothers. Selenium deficiency can result from elevated concentrations of bodily mercury. Ingested mercury is detoxified by the liver through mercury-selenium compound formation. In animals persistently exposed to mercury, the liver’s ability to detoxify this element may decrease, especially if dietary selenium is insufficient. We measured mercury and selenium concentrations in nesting female leatherbacks and their hatchlings from Florida and compared the levels to hatching and emergence success. Both liver selenium and the liver selenium-to-mercury ratio positively correlated with leatherback hatching and emergence success. This study provides the first evidence for the roles of mercury and selenium in explaining low reproductive success in a globally imperiled species, the leatherback sea turtle.     

Possible effects of organotins on scallop recruitment

The adult populations of the scallop (Pecten maximus) and of flame shells (Lima hians) have declined in the North Water of Mulroy Bay on the north coast of Ireland. Settlements of these and some other bivalve species either failed or were reduced. These events relate well to the first introduction and subsequent increased use of organotin net-dips on salmonid farms in this Bay. The last use of these net-dips was during the spring of 1985. In 1986 these was a good settlement of scallops, and settlements of other bivalves were recorded except for flame shells. Levels of TBT in adult scallop tissue in the North Water are high, 0.7 μg g⁻¹ wet wt; levels determined in other species were much lower. Pacific oyster (Crassostrea gigas) shell thickening was used to monitor the presence of organotins in a number of areas including Mulroy Bay. In Kilkieran Bay, an area having a scallop fishery, this was greatest at the innermost station, suggesting higher levels there. Shell thickening and organotins in Pacific oysters were also measured in Cork Harbour.     

Multi-scale distribution and dynamics of bivalve larvae in a deep atoll lagoon (Ahe,French Polynesia)

Bivalve larvae and hydrographic parameters were sampled over a range of spatio-temporal scales in a deep atoll lagoon. Bivalve larvae abundances were very high throughout the year: 18,550 m⁻³ in average. Larvae were (i) concentrated at mid-depth with nocturnal ascent and diurnal descent, (ii) heterogeneously dispersed at the lagoon scale, (iii) subject to day-to-day variation in abundance and (iv) transferred between different parts of the lagoon providing evidence of intra-lagoonal connectivity. The primacy of physical factors was seen on large spatial scale with the diluting effect of water renewal and transfers by hydrodynamics. On smaller spatial scale, the primacy of biological processes was recognised, with larval swimming activity leading to dial vertical migration correlated with food concentration. Variations in larval abundance were driven by bivalve reproductive activity correlated with meteorological conditions (i.e. windy periods). Finally, relationship between bivalve larvae patterns and pearl oyster (Pinctada margaritifera) settlement structuring is discussed.     

Selenium and heavy metals in black marlin

Black marlin from the apparently unpolluted waters off north-eastern Australia have the highest muscle and liver concentrations of total mercury yet reported for a teleost species. Selenium concentrations are also high. There is a significant correlation between mercury and selenium concentrations, and concentrations of both those elements are significantly correlated to size of fish. Concentrations of cadmium, lead, zinc, copper or arsenic are not so correlated.The results of this study indicate there is a need for a moratorium on the use of this species for human consumption.     

Can the spread of non-native oysters (Crassostrea gigas) at the early stages of population expansion be managed?

The Pacific oyster (Crassostrea gigas) was introduced into Strangford Lough, Northern Ireland in the 1970s. It was assumed that local environmental conditions would not facilitate successful reproduction. However, in the 1990s there were reports of C. gigas outside licensed aquaculture sites and this investigation set out to ascertain the current distribution, years of likely recruitment and population structure of the species. C. gigas were found distributed widely throughout the northern basin during surveys; the frequency distribution suggesting C. gigas is not recruiting every year. Establishment of feral populations of C. gigas elsewhere have linked to habitat change. A pilot cull was initiated to assess the success rate of early intervention. This paper demonstrates the potential benefits of responding rapidly to initial reports of non-native species in a way that may curtail establishment and expansion. The method advocated in simple and can be recommended to the appropriate regulatory authorities.     

Quantities of some dangerous substances discharged to British coastal waters

Estimation of the quantities of cadmium, mercury, lindane, DDT, ‘drins’ (aldrin, dieldrin and endrin), PCBs, copper, lead, chromium, nickel, zinc and arsenic discharged to the tidal waters of the UK is described and the results are presented for the major geographic regions of the UK. Consideration is also given to the significance of different sources of discharge of these substances in terms of their contribution to the overall loads reaching the sea. For most of these substances, rivers contribute the major proportion of the quantities discharged.     

Heavy metals and high pup mortality in the Saimaa ringed seal population in eastern Finland

Hair nickel, mercury, cadmium, lead and chromium concentrations were measured from still-born ringed seal pups and from other ringed seal groups from Lake Saimaa in Finland. Nickel concentration was significantly higher in the hair samples of still-born pups as compared to live-born pups and to adult seals. There was assumed to be some connection between the stillbirth of the pups and nickel concentration of the hair. Mercury concentration of the natal hair of pups was significantly higher than the mercury concentration of the first adult hair but no clear connection between stillbirth and mercury pollution was observed. No differences were observed in cadmium, lead and chromium concentrations of the hair of still-born and other ringed seal groups.     

Evaluation of a Florida coastal golf complex as a local and watershed source of bioavailable contaminants

Contaminant fate in coastal areas impacted by golf course runoff is not well understood. This report summarizes trace metal, pesticide and PCB residues for colonized periphyton, Ruppia maritima (widgeon grass), Callinectes sapidus Rathbun (blue crabs) and Crassostrea virginica Gemlin (Eastern oyster) collected from areas adjacent to a Florida golf course complex which receive runoff containing reclaimed municipal wastewater. Concentrations of 19 chlorinated pesticides and 18 PCB congeners were usually below detection in the biota. In contrast, 8 trace metals were commonly detected although concentrations were not usually significantly different for biota collected from reference and non-reference coastal areas. Residue concentrations in decreasing order were typically: zinc, arsenic, copper, chromium, lead, nickel, cadmium and mercury. Mean BCF values for the eight trace metals ranged between 160-57000 (periphyton), 79-11033 (R. maritima), 87-162625 (C. virginica) and 12-9800 (C. sapidus). Most trace metal residues in periphyton colonized adjacent to the golf complex, were either similar to or significantly less than those reported for periphyton colonized in nearby coastal areas impacted by urban stormwater runoff and treated municipal and industrial wastewater discharges. Consequently, the recreational complex does not appear to be a major source of bioavailable contaminants locally nor in the immediate watershed based on results for the selected biota.