Trace metal content in the American oyster

Information about the transfer of pollutants from adult aquatic animals to their progeny is relatively unknown. The present study was designed to measure the transfer of metals from adults to eggs of the American oyster. Two groups of oysters containing significantly different levels of copper and cadmium were induced to spawn, the eggs were collected and trace metal contents measured. The eggs from both groups of oysters contained the same amount of copper, while cadmium levels were below detectable limits in both groups of eggs. Silver, lead, and zinc concentrations also were determined. The concentrations of these metals were similar for both groups of adults and eggs; thus, no conclusion could be made about the transfer of these three metals from adults to eggs of oysters.     

Heavy metal residues in tissues of marine turtles

Heavy metal concentrations in the tissues of marine turtles are presented. The most frequently monitored elements are mercury, cadmium and lead; and the tissues mainly analysed in nearly all the stranded individuals are muscle, liver and kidney. The highest mercury and cadmium levels were found in liver and kidney respectively; the majority of the lead burden existed in bones and carapace, while arsenic was present mainly in muscle tissue. Mercury occurred quite completely as methylmercury in muscle, whereas in liver the main form was the inorganic one. Arsenic was exclusively present in the metallorganic form either in muscle tissue or in liver. Metals in the eggs were mainly present in the yolk. Significantly higher concentration of mercury, copper, zinc and iron were found in yolk than albumen, while shell contained highest levels of manganese and copper. The load of trace metals in these animals strictly correlated with the species seems to depend on their different food behaviour.     

Statistical analysis of trend monitoring data of heavy metals in flounder (Platichthys flesus)

Six years trend monitoring data of mercury, cadmium, copper, lead, and zinc in flounder from the Sound and the Great Belt (Danish coastal waters) are statistically assessed using a series of multilinear, regressive models in terms of the measurements of metal levels and various biological parameters (e.g. length) for individual fish. With the exception of zinc in females from the Great Belt, each element exhibited no significant differences in relation to biological parameters from year to year at the two areas. Linearly increasing trends in the concentrations were found for cadmium without sex dependance from the two areas and for zinc and copper in females from the Sound and zinc in males from the Great Belt. Zinc is, in both areas, significantly correlated with the sex as is copper in the flounder from the Sound. The statistical models used have been found very useful and easy to interpret.     

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.     

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.     

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).     

Heavy metals in organisms of the Atlantic coast of S.W. Spain and Portugal

Very high concentrations of copper lead, zinc, and to a lesser extent mercury, are present in the estuary of the Rio Tinto in South-West Spain. At the mouth of the estuary, the concentrations of these metals fall very sharply towards the natural levels of these metals in organisms living in this part of the Atlantic.     

Trace metals in tissues of gray whale (Eschrichtius robustus) carcasses from the Northern Pacific Mexican Coast

Samples of liver, lung, heart, muscle, and blubber tissue from the carcasses of juvenile gray whales (Eschrichtius robustus) found stranded on the coast off the Sea of Cortez, México were analyzed for a range of trace metals (Cu, Fe, Zn, Mn, Ni, Pb, and Cd). The highest concentrations of copper, iron, zinc, and manganese were found in liver; nickel and lead in heart, and cadmium in kidney. In all tissues analyzed, iron, zinc and copper were present in the highest concentrations; however, some whales also showed high levels of cadmium in the kidney which could be related to their diet. Elevated concentrations of copper were found only in the liver of one whale. In general, where low levels of iron were found in the liver, they were associated with poor nutrition. Lead, nickel, manganese and zinc levels in liver were within the normal range, indicating that these whales had not been exposed to high levels of these metals.     

MELIMEX,an experimental heavy metal pollution study: Behaviour of heavy metals in an aquatic food chain

Phytoplankton, periphyton and zooplankton samples, chironomid andSialis sp. larvae, and fry of trout and bream collected from unpolluted and artificially metal-polluted limno-corrals were analyzed for mercury, copper, cadmium, zinc and lead. The results indicate that these metals are not accumulated through the food chain and suggest that increased metal concentrations in the environment favor the growth of phytoplankton organisms with a low metal sorption capacity.     

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.     

Acute toxicity of heavy metals to some marine larvae

The toxicity of copper, mercury and zinc to the larvae of oysters, shrimp, crab and lobsters has been examined over periods of up to 64 hours. Mercury was found to be more toxic than copper and zinc, which had similar levels of toxicity. Over the experimental period, the relationship between toxicity and concentration was linear. Larvae were from 14 to 1,000 times more susceptible than adults of the same species. The median lethal concentrations (LC₅₀) of each metal to the most sensitive species of larvae, tested over a 48 hour period, exceeded the concentrations found in natural sea water by a factor of 100. For longer test periods, the LC₅₀ would be considerably less and this factor would then be considerably reduced. Hence the continued addition of these metals to confined waters should give cause for concern.     

Heavy metal distribution in Newark Bay sediments

Bottom sediments have been analysed from Newark Bay, New Jersey, for zinc, lead, cadmium, and mercury. The bottom sediment analyses show that the bay sediments are enriched over background levels up to 65 times for zinc, 128 times for lead, 180 times for cadmium, and 155 times for mercury. Analyses of the metal distribution and of available tidal hydraulic data indicate the metal concentrations are due to a combination of source and tidal hydraulics. Dye tracer experiments gathering Lagrangiantype data appear to yield the best result in the investigation of metal trasport phenomena.     

The speciation of dissolved copper,cadmium and zinc in Manila Bay,Philippines

At present, there is a very limited information on the levels and distribution of dissolved metals in Manila Bay. In this study, the horizontal and vertical distribution of operationally defined species (labile, bound and total) of dissolved copper (Cu), cadmium (Cd) and zinc (Zn) were determined using differential pulse anodic and cathodic stripping voltammetry in water samples obtained from 18 stations in November 1998. In addition, the 24-h variability in the concentrations of these species at different depths in the water column was determined. These measurements were complemented by the determination of temperature, salinity, dissolved oxygen, chlorophyll a, particulate organic carbon and nutrients. Results showed that more than 50% of total dissolved copper and cadmium were labile while 50% of total dissolved zinc was organically bound. Vertical profiles showed that Cu, Cd and Zn concentrations were generally high at the surface. Zinc and cadmium were characterised by the presence of a mid-depth minimum while copper did not show any clear vertical trend.

Dissolved Cu concentrations during the spatial and diurnal samplings ranged from 0.32 to 6.95 nM and 1.52 to 45.65 nM, respectively. For Cd, the concentrations in 18 stations ranged from 0.05 to 2.92 nM, and from 0.03 to 2.42 nM over a 24-h period. Zn concentrations ranged from 2.48 to 147.43 nM and 2.87 to 88.27 nM during the spatial and diurnal samplings, respectively. The large variation in the concentration of Cu, Cd and Zn in the bay was observed to be associated with the presence of a large vertical density gradient in the water column, which appeared to limit the exchange of materials between the surface and bottom waters. Elevated levels of these metals near point sources suggest anthropogenic inputs in the bay.     

Measurement of environmental trace-metal levels with transplanted mussels and diffusive gradients in thin films (DGT): a comparison of techniques

Transplanted mussels and diffusive gradients in thin films (DGT) were used to assess levels of cadmium, copper, lead and zinc at four sites situated inside and outside of two enclosed marinas, near Melbourne, Australia. Mussels accumulated all metals except cadmium. Over one year, there were large temporal differences in tissue metal levels in mussels, but differences between sites were only apparent for copper and lead. DGT showed temporal differences of the same kind as those seen in the mussels, but appeared to have more power to discriminate between sites. DGT found higher copper levels inside marinas than outside, and high levels of zinc were found inside one marina. Levels of copper and zinc were high enough to be of environmental concern for one site. The effect of fouling on DGT measurements will have to be quantified, or avoided by the use of multiple short-term exposures, if the technique is to become a widespread in situ monitoring tool.     

Laboratory tests as a basis for the control of sewage sludge dumping at sea

Toxicity and bioaccumulation studies were carried out on a number of UK sewage sludges to determine whether laboratory experiments could be used to regulate sludge dumping at sea. Whilst the acute toxicity of sewage sludges to adult marine organisms was generally low, shrimp larvae were found to be up to 500 times more sensitive than adults of the same species. No significant bioaccumulation of mercury or cadmium could be detected following up to 60 days exposure of fish, shrimps and mussels to the most heavily contaminated sludges available, although there was some uptake of lead, zinc and copper.     

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.     

Distribution of heavy metals in tissues of the common seal

The lead, cadmium and mercury content of soft tissues and bone were determined for the common seal (Phoca vitulina) collected from off the coast of East Anglia and the West of Scotland. Lead levels were low in all tissues, cadmium accumulated with age in the kidney of West Scotland seals and mercury accumulated to high levels in the liver of seals from both areas. Comparison of our results with those of other workers, suggests that the rate of mercury accumulation in the liver of seals increases in the order: Canadian Arctic and Atlantic coast < West Scotland < East Anglia < Netherlands coast. Accumulation of mercury in the kidney and spleen of older seals, lends tentative support to the hypothesis that a protective demethylation and retention process in the liver may begin to leak mercury to other tissues at the high concentrations which have been recorded in the liver of older seals, and at the high dose rates which have been used in toxicological experiments.     

Mercury in feathers from Chilean birds: influence of location,feeding strategy,and taxonomic affiliation

This study reports baseline concentrations of mercury (Hg) in feathers from different species of birds sampled at various locations off the Chilean coast (Southeastern Pacific). Hg concentrations were evaluated in relation to geographic location, taxonomic affiliation, and feeding strategies. Between January and March of 1995, we collected mature contour feathers from 116 birds belonging to 22 species, mostly seabirds. Birds were collected from 10 different locations (26 degrees 09'S, 70 degrees 40'W to 54 degrees 56'S, 67 degrees 37'W). Feather Hg concentrations ranged from 0.11 to 13 microg g(-1) dry weight. We found differences in feather Hg concentrations across taxonomic groups, with highest concentrations in petrels, shearwaters, and albatrosses (Procellaridae), followed by boobies (Sulidae), gulls, terns, skuas (Laridae) and cormorants (Phalacrocoracidae). Ibises and oystercatchers (Threskiornithidae and Charadriidae) had intermediate values, whereas ducks and geese (Anatidae) contained the least amount of Hg. Oceanic species preying on mesopelagic fish (the Procellariformes albatrosses, petrels, and fulmars) had over twice as much Hg (overall average of 3.9 microg g(-1)) when compared to the rest of the species sampled (overall average of 1.5 microg g(-1)). We did not find higher Hg concentrations in birds inhabiting the more heavily industrialized and urbanized areas of the country (central and northern regions), but in birds inhabiting the remote Juan Fernandez Archipelago. This is not surprising, since all the Procellariformes (the group with highest Hg values in this study) were collected from these islands. Except for Hg in Kermadec petrels (mean of 12 microg g(-1)), the range of Hg values reported here (0.11-7.3 microg g(-1)) fell below those known to cause adverse health and reproductive effects in birds.     

Copper,zinc and cadmium in coastal waters of the N.W. Mediterranean

The concentration levels of copper, zinc and cadmium in the coastal waters of the northwestern Mediterranean tend to match closely those of off-shore waters when there is no significant man-made contamination. The appearance of local high concentration for one metal by possible contamination does not necessarily correlate with high values for other metals, although some contamination sources elevate the concentrations of all three metals. In June 1974, the presence of a water mass having relatively high surface zinc-concentration was observed off the Marseille-Toulon area.     

滇池沉积物金属污染及环境质量评价

对滇池126个采样点沉积物0-5cm、5-10cm和10-20~m中Cu、Zn、Fb、Cr、CA、Hg和As等7种金属的含量进行了分析测定.用基于多方的基准中阈值效应含量TEC和可能效应含量PEC划分出5个沉积物环境质量等级.并借助灰色聚类分析方法对滇池沉积物环境质量进行了评价.结果表明,滇池沉积物环境质量整体上为Ⅲ类,存在中度的金属污染.其中0-5m和5-10cm为Ⅲ类沉积物,10-20Cm为Ⅱ类沉积物.沉积物环境质量下层优于上层,表明滇池沉积物金属污染仍存在不断加剧的趋势.