Trace-metal detoxification and tolerance of the estuarine worm<Emphasis Type="Italic"> Hediste diversicolor</Emphasis> chronically exposed in their environment

Polychaete worms (Hediste diversicolor) originating from a strongly metal-contaminated area (Restronguet Creek) and a relatively clean site (Blackwater estuary) were exposed to a range of experimental doses of Ag, Cd, Cu and Zn. Specimens from both populations were compared to assess their relative sensitivity to metal stress and the physiological mechanisms involved in their respective adaptive strategies for coping with increased metal exposures. Taking into account the LC₅₀ values, increased tolerance to Cd, Cu and Zn of the Restronguet Creek worms over that of the Blackwater was demonstrated, whereas the opposite was shown for Ag. An abundant secretion of mucus in response to toxicants was observed, possibly reducing metal availability for uptake, at least under laboratory conditions. This mechanism was particularly active in specimens from Restronguet Creek exposed to Ag and Cu. Unexpectedly, of the two worm populations, Blackwater worms contained significantly higher concentrations of cytosolic heat-stable compounds (CHSTC), a category of cytosolic components that includes metallothioneins, the detoxificatory role of which is well documented, and other compounds binding trace metals via sulphur bonds. However, the concentration of such compounds is not totally representative in itself of their involvement in metal detoxification, because a high rate of their turnover in metal-exposed worms might be responsible for (at least) the Cu storage associated with S in lysosomes as a consequence of the breakdown of Cu-thionein. Cu-containing lysosomes were abundant in epidermal cells of Restronguet Creek worms, but were lacking in Blackwater worms. Extracellular granules present in the epicuticle also contained S and Cu, their number and size being much more important in Restronguet Creek worms, and they appear to be a major detoxificatory store for accumulated Cu. Spherocrystals in cells of the gut wall seem to be the major detoxified store of Zn in Restronguet Creek worms, whereas in specimens from the Blackwater they were also present but contained only S and Ca at detectable levels. Evidence was also found for the presence of detoxificatory intracellular structures containing other metals and metalloids in the tegument and gut epithelium of Restronguet Creek worms.Communicated by S.A. Poulet, Roscoff     

Transfer of 65Zn from sediments by marine polychaete worms

Silty marine sediments spiked with ⁶⁵Zn lose only small fractions of their radioactivity when exposed to slowly flowing seawater for several weeks. However, polychaete worms (Nereis diversicolor), burrowing through the sediment, cause ⁶⁵Zn losses 3 to 7 times higher than in sediment without worms. Long-term experiments on the uptake and loss of ⁶⁵Zn by the polychaete Hermione hystrix indicate that 60 or more days exposure are required for this worm to approach steady state with ⁶⁵Zn in the sediment. Biological half-life estimates for ⁶⁵Zn accumulated from sediment by H. hystrix are extremely variable (52 to 197 days), depending on the loss-time interval chosen for the calculation. Following 5 days exposure to 16 cm³ of radioactive sediment, N. diversicolor individuals contained an average of 0.2% of the total ⁶⁵Zn in the sediment. When these worms were transferred to non-radioactive sediment, estimates of biological half-life for ⁶⁵Zn averaged 14 to 17 days during the loss period Day 3 to Day 15. Based on these experimental results, it is estimated that a population of N. diversicolor could cause an annual loss of 3% or more of the ⁶⁵Zn in the upper 2 cm of the sediment of a hypothetical radioactive estuary.     

Arsenic accumulation in the shore crab Carcinus maenas: the influence of nutritional state,sex and exposure concentration

The accumulation of arsenate from seawater by the shore crab Carcinus maenas L. (collected from Odense Fjord, Denmark in 1991 and from Restronguet Creek, UK in 1991) was investigated in a series of laboratory experiments. A field study was also carried out to determine the effects of raised environmental arsenic concentrations on intra-organismal distribution and tissue concentrations. Studies on the influence of nutritional state and sex on accumulation of As(5) from seawater indicated that most of the arsenic taken up from seawater in laboratory experiments was retained in the gills and the midgut gland. Arsenic accumulation exhibited sex-dependent differences which were also evident in correlation analyses carried out between total lipid contents and total arsenic contents of midgut glands of individual crabs. Arsenic concentrations in the gonads of both sexes were strongly influenced by the nutritional state of the crabs. Elevated arsenic concentrations in seawater and food at an arsenic polluted site (Restronguet Creek) significantly influenced arsenic concentrations and distribution among the tissues of C. maenas. Arsenic concentrations and distribution patterns differed markedly from those crabs from an unpolluted site in Odense Fjord. The gills of the crabs from Restronguet Creek contained extremely high arsenic concentrations ranging from 179 to 483 g As g^-1 dry wt. These values were even higher than those measured in the gills of Odense crabs that had been exposed to 3 mgl^-1 As(5) for 2 wk in the laboratory. Arsenic concentrations in the exoskeleton of Odense Fjord crabs were 15 times lower than those measured in exoskeletons of Restronguet Creek crabs. Approximately 69% of the total body burden of arsenic was located in muscle tissue of crabs from Odense Fjord, whereas the major pool of arsenic (46%) in Restronguet Creek crabs was located in the exoskeleton.     

Trace-metal detoxification in the ventral caeca of Orchestia gammarellus (Crustacea: Amphipoda)

The talitrid amphipod crustacean Orchestia gammarellus (Pallas) was collected from metal-contaminated (Dulas Bay, Gironde) and control (Millport) sites in the UK and France. Irrespective of site of origin, the amphipods showed the same physiological mechanism of trace-metal detoxification, involving the ventral caeca. Copper was always present in lysosomal residual bodies in the ventral caeca. Following laboratory exposure to zinc and cadmium, the lysosomes usually contained both copper and zinc but cadmium was not detectable. The lysosomal copper concentration is positively correlated to that of sulphur, while the concentration of lysosomal zinc is related to that of phosphorus. Results are interpreted in terms of the differential rates of turnover of metallothioneins chelating copper, zinc or cadmium. Received: 9 February 1999 / Accepted: 2 December 1999     

Plutonium and Americium: Uptake from contaminated sediments by the polychaete Nereis diversicolor

The polychaete Nereis diversicolor O.F. Müller was exposed to marine sediments which had been contaminated with plutonium and americium either through the testing of nuclear devices or by the release of liquid waste effluent from a nuclear fuel reprocessing plant. The uptake of both plutonium and americium was small, about 0.5% of the concentration of these transuranics in the sediments. The degree of relative uptake of plutonium from both sediments was comparable; relative uptake of americium from sediments contaminated by waste effluent was greater than that from nuclear sediment and those previously determined from water-uptake experiments to environmentally determined plutonium concentrations in sediments and overlying waters leads to the tentative conclusion that water may be the predominant pathway for plutonium accumulation by deposit-feeding worms like N. diversicolor.     

Toxicity of zinc,cadmium and copper to the shrimp Callianassa australiensis. III. Accumulation of metals

Callianassa australiensis (Dana) that survived 14 d acute lethality studies were analysed to determine the concentrations of zinc, cadmium and copper in the whole shrimp and in various parts of the body. Using regression analysis, the influence of each metal upon the uptake of the others was studied. Zinc and cadmium appeared to enhance the uptake of each other. In a mixture of zinc and copper, the uptake of zinc was enhanced and that of copper was inhibited. In a mixture of cadmium and copper, the uptake of copper was inhibited by the presence of cadmium, but cadmium uptake was unaffected in the presence of copper. In a mixture of all three metals, similar effects were observed except that zinc and copper, occurring together, appeared to have no effect upon cadmium uptake. Additional 14 d experiments with cadmium suggested that accumulation of this metal was a function of metal concentration in the water and of duration of exposure. The whole shrimp cadmium concentration also appeared to be a function of the size of the shrimp. The variation in concentration factors is described and the need for further research on the effects of combinations of metals on various organisms is emphasized.     

The common mussel Mytilus edulis as an indicator of pollution by zinc,cadmium, lead and copper. I. Effects of environmental variables on uptake of metals

The net uptake of zinc, cadmium, lead and copper by the common mussel Mytilus edulis (L.) exposed to different conditions was investigated with a view to using this species as an indicator of contamination of the marine environment by these metals. The variables studied were season, position of the mussel in the water column, water salinity, water temperature, and the simultaneous presence of all four metals. Each of these 5 variables affected the net uptake of some or all of the metals studied under some conditions. Seasonal variation in concentrations of zinc, cadmium and copper was found in samples collected at three separate locations. The relationship of seasonal variation to tissue weight and absorption route of the metals is discussed. Near to freshwater inputs of trace metals, the concentrations of zinc, cadmium and lead in mussels were found to vary according to the depth at which the mussels were collected; in summer when freshwater run-off is less, this effect was absent. Low salinities did not affect the net uptake of zinc by mussels, but increased the net uptake of cadmium and decreased that of lead. Low temperatures had no effect on the net uptake of zinc or lead; the net uptake of cadmium was unaffected by low temperatures at high salinities but was decreased by low temperatures at low salinities. The presence of the other metals had no effect on the individual net uptake of either zinc, cadmium or lead. A sampling programme was devised to eliminate the effects of these environmental variables and to allow the use of M. edulis as an indicator of zinc, cadmium and lead in marine and estuarine environments. In contrast to the other metals, the net uptake of copper by the mussel was extremely erratic, and was affected by salinity and temperature changes and by the presence of the other metals and changes in their relative concentrations. The effects of other metals on the net uptake of copper cannot be easily eliminated or allowed for; it is, therefore, suggested that the mussel should not be used as an indicator of copper in the marine environment.     

Characteristics of arsenic accumulation by the seaweeds Fucus spiralis and Ascophyllum nodosum

This study examines the accumulation of ⁷⁴As-arsenic in the seaweeds Fucus spiralis (L.) and Ascophyllum nodosum (L.) collected from Restronguet Creek in southwest England during 1978. Also, the influence of environmental factors (valence state of arsenic, pH, salinity, temperature, phosphate concentration) and metabolic inhibitors on the uptake of arsenic by F. spiralis is examined. Most of the arsenic in the seaweeds was non-exchangeable with labelled arsenic in the medium. The accumulation of ⁷⁴As reached a steady state in 1 to 8 d, depending on the species and external arsenic concentration. At steady state the accumulated arsenic is proportional to external arsenate concentration. F. spiralis accumulated 4 times more arsenate than arsenite. The short-term uptake of arsenic increased in proportion to the external arsenic concentration up to a level of 1000 g l^-1; it then remained constant at higher levels of arsenic. Arsenic uptake increased in direct proportion to increasing temperature. Variation of pH or salinity had no effect on arsenic incorporation. The accumulation of arsenic occurred only in living tissue and was inhibited by KCN in a concentration-dependent manner. The uptake of arsenic by F. spiralis in the presence of photo-synthetic inhibitors (DCMU or CMU) or in the dark was greater than in the light controls. Thus, it was concluded that energy is required for arsenic uptake and this is derived from respiration rather than photosynthesis. There was no evidence for a common mechanism of phosphate and arsenate uptake by macroalgae, although high concentrations of phosphate (40 to 400 M) initially inhibited arsenate uptake.     

Microbial reaction rates and bacterial communities in sediment surrounding burrows of two nereidid polychaetes (Nereis diversicolor and N. virens)

The effects of infaunal mode of life on sediment properties, microbial reaction rates, as well as abundance and composition of bacterial communities were studied in sediment surrounding burrows (mucus lining, oxidised wall, ambient anoxic and surface sediment) of two closely related, but behaviourally different, nereidid polychaete worms: the facultative suspension-feeder Nereis (Hediste) diversicolor and the obligate deposit-feeder Nereis (Neanthes) virens. Burrow sediment of the two species was collected from two adjacent (50 m distance) shallow sandy locations (Kertinge Nor, Denmark). The burrow lining and wall of both polychaete species were enriched in organic matter originating from mucous secretions by the inhabitants and phytoplankton trapped through irrigation. This was more evident for N. diversicolor that shows a significantly higher irrigation rate than N. virens. Both the organic matter mineralisation rates (based on anaerobic incubations) and bacterial abundance were higher along the burrow linings and walls. However, accumulation of porewater TCO₂ and dissolved organic carbon in sediments adjacent to burrows increased most rapidly in the presence of N. diversicolor, suggesting higher heterotrophic activity associated with this species. Surprisingly, bacterial abundance was lower around burrows of N. diversicolor than those from N. virens indicating that burrow environments from the first species harbour a more active bacterial community. Molecular fingerprints of the 16S rRNA gene from bacterial communities showed that the composition of the burrow linings and walls resembled the ambient anoxic sediment rather than the oxic sediment surface. On the other hand, the bacterial fingerprints of the sediment surrounding the burrows of the two polychaete species were markedly different suggesting either a site-specific difference in sediment parameters or a significant species-specific impact of the burrow inhabitants.     

海河流域沉积物中典型重金属的生态风险评估及验证

沉积物重金属污染及其生态风险评估日益受到关注,而沉积物质量基准是开展生态风险评估的有力工具。本研究通过物种敏感度分布法(species sensitivity distributions, SSD)和急慢性毒性比(acute to chronic ratios, ACR)推导了镍、铜、锌、镉和铅的沉积物质量基准(sediment quality guideline, SQG)。在获得合理的重金属沉积物慢性毒性数据的基础上,采用S-Logistic模型拟合镍、铜、镉和铅的慢性SSD曲线,采用S-Gompertz模型拟合锌的慢性SSD曲线。得到镍、铜、锌、镉和铅沉积物质量基准低值(sediment quality guideline low value, SQGlow)分别为18.6、69.9、107、1.26和38.4 mg·kg~(-1),应用ACRs,得到相应的沉积物质量基准高值(sediment quality guideline high value, SQGhigh)分别为167、226、556、10.1和384 mg·kg~(-1)。与加拿大和澳大利亚重金属沉积物基准值具有一定的可比性。选择花翅摇蚊(Chironomus kiiensis)、伸展摇蚊(Chironomus tentans)和霍甫水丝蚓(Limnodrilus hoffmeisteri)3种底栖生物作为受试生物,验证基准值对海河流域沉积物重金属毒性的预测能力。结果表明,利用SQGs预测沉积物毒性的总准确率为76.2%,3种底栖生物验证准确率从高至低为:花翅摇蚊>伸展摇蚊>霍甫水丝蚓。     

Natural variations in tissue concentration of copper,zinc and iron in the polychaete Nereis diversicolor

This study was undertaken to investigate the natural variation of heavy metals in the polychaete Nereis diversicolor O. F. Müller and to examine this variation with respect to physiological and environmental parameters. During a 2 yr period from October 1980 to October 1982, concentrations of copper, zinc and iron in N. diversicolor from the Tees Estuary, North East England, were found to vary significantly with time. A seasonal influence on whole body copper concentration, in part related to the reproductive cycle, was observed. Zinc concentrations in N. diversicolor increased during periods of rapid growth and may represent a physiological demand for this metal. Whole body concentrations of iron appeared to be independent of size of worm, sexual maturation and sediment concentrations.     

Heavy metal action on transintegumentary absorption of glycine in two annelid species

Absorption of ¹⁴C-glycine from ambient sea water across the body surface of the oligochaete Enchytraeus albidus Henle was, after 6 h preincubation, significantly reduced in the presence of 0.1 to 0.15 ppm mercury, 0.25 ppm copper, 1.5 ppm silver, and 2 ppm cadmium. Addition of heavy metal salts reduced maximum uptake rates (V _max ), without affecting transport constants (K _t ). Influx of ¹⁴C-glycine remained unchanged in the presence of up to 10 ppm aluminium, chromium, iron, lead, molybdenum, vanadium, and zinc. Effects of up to 150 ppm nickel, manganese, cobalt and selenium were negligible. Inhibition of glycine absorption by mercury and cadmium in the polychaete Nereis diversicolor Müller is almost identical with results presented for E. albidus. Transintegumentary solute absorption in soft-bodied marine invertebrates obviously represents a suitable biological function for studies on heavy metal toxicity. The close relationship between rates of heavy metal absorption, inhibition of transintegumentary glycine uptake, and acute toxicity is discussed.     

Uptake of 55Fe from contaminated sediments by the polychaete Nereis diversicolor

The polychaete Nereis diversicolor O. F. Müller was exposed to marine sediments which had been contaminated with ⁵⁵Fe either through the testing of nuclear devices or by the release of liquid waste effluent from a nuclear fuel reprocessing plant. The amount of ⁵⁵Fe taken up reached a concentration in the worms about 6% of the concentration in both types of sediment. Bioavailability of ⁵⁵Fe was shown to depend on its concentration in sediment and not on sediment type, stable iron concentration, or the source of contamination. N. diversicolor may not extract from sediment the same fraction of ⁵⁵Fe as does 0.1N HCl and caution should be exercised in using such measurements to represent the bioavailable fraction.     

Interindividual variability in metal status in the shore crab<Emphasis Type="Italic"> Carcinus maenas</Emphasis>: the role of physiological condition and genetic variation

The relations between genetic variation, physiological condition, size and metal status in the shore crab Carcinus maenas (L.) were investigated. Shore crabs were collected at three sites around the island of Funen, Denmark, and carapace width, colour, moulting stage and major ions and protein in the haemolymph were determined. Concentrations of water, cadmium, copper and zinc in midgut glands, muscles and gills were measured, and allozyme variation at 15 loci was studied. Generally, tissue water content and copper, zinc and cadmium concentrations decreased from the moulting stages C₃ over C₄ to D crabs, whereas the opposite was true for copper and zinc concentrations in gills and muscle. However, the water content of the tissues increased with the size of the crabs. Since tissue water contents changed consistently over moulting stages, conclusions on changes in metal concentrations sometimes diverged when expressed on a dry versus wet weight basis. Regarding allozymes, esterase, malate dehydrogenase and phosphoglucomutase were polymorphic. The crabs showed a low level of genetic variability for both polymorphism (0.14) and for heterozygosity (0.07) at the three sites. Allelic frequencies showed very low levels of differentiation among the samples, no evidence of inbreeding and no population subdivision. Multilocus heterozygosity was positively correlated with size. Concentrations of copper and zinc in midgut gland, muscle tissue and gill were not correlated with genotype, whereas a weak correlation between phosphoglucomutase genotypes and concentrations of cadmium in the midgut gland was found.Communicated by M. Kühl, Helsingør     

Schwermetallbelastung von Dreissena polymorpha in Donau und Drau und ihre Bedeutung als Bioindikator

Goal and Scope

This study was undertaken to investigate the differences in heavy metal burden between the organisms and environmental compartments and to evaluate the role of Dreissena polymorpha as a bioindicator organism.

Methods

The concentrations of zinc, copper, cadmium and lead in whole soft body and selected tissues of D. polymorpha at two river habitats in Austria were examined using atomic absorption spectroscopy (AAS). Concentrations in organisms were compared to those in sediment and water.

Results and Conclusion

Zebra mussels of the river Drau showed generally higher heavy metal concentrations as compared to mussels of the river Danube and contained elevated zinc and cadmium levels as compared to metal concentrations found in soft tissues of zebra mussels from uncontaminated sites in Germany and The Netherlands. The essential metals zinc and copper were mainly accumulated in gills, foot and byssal gland tissue of the mussel, in contrast to the non-essential metals cadmium and lead which were found predominantly in the midgut gland. The heavy metal concentrations in both, sediments and mussel tissue, were higher than in water samples. There was no correlation between the concentrations in water and in the organisms except for zinc. In contrast, correlations were found between concentrations in sediments and mussel soft tissue.

Recommendation and Perspective

Further investigations should include the examination of sediments and consider the mechanism of food uptake to assess the role of D. polymorpha as a bioindicator organism.     

Metal interaction during accumulation by the mussel Mytilus edulis planulatus

Mytilus edulis planulatus (Lamarck) were collected from Howden, South-east Tasmania in autumn 1981. Interaction effects of cadmium, copper and zinc during accumulation by mussels exposed for ten days to all three metals simultaneously were examined in a series of experiments in which each metal was tested at three concentrations. In general, interaction effects were most evident at the highest concentrations tested (20 g l^-1 Cd; 20 g l^-1 Cu; 200 g l^-1 Zn) and led to a reduction in the accumulation of cadmium and an increase in that of copper and zinc. More specifically, high levels of zinc caused a decrease in cadmium uptake and an increase in copper accumulation. The presence of copper resulted in depressed cadmium accumulation while zinc accumulation increased. Cadmium tended to enhance zinc accumulation, but copper accumulation was only affected to any great extent when zinc was also present.     

The Influence of Anthropogenic Contamination On Metals Release From Coastal Sediment Suspensions with Aerated Sea Water

The zinc, cadmium, copper and lead release from the uncontaminated and contaminated coastal sediments with aerated sea water was studied. the metals transfer to the dissolved forms was monitored during one-two months by differential pulse anodic voltammetry (DPASV). the sediments with different initial degree of contamination were sampled in the Peter the Great Bay, Sea of Japan around Vladivostok-the biggest city in Russian Far East. Sediment contamination by metals led to increased release to solution of zinc due to sulphide oxidation and cadmium on account of organic matter decomposition. the copper behaviour was complicated by strong binding with organic matter and enhancements of copper release can only be seen in sediment with a low organic matter content. Significant lead transfer to dissolved forms was not observed regardless of sediment contamination. the temperature affected the release of cadmium and copper through enhanced organic matter destruction. the dissolved metal fluxes from the sediment transformation are compared with metal fluxes towards bottom. Such comparisons show that second contamination by dissolved metals of the studied coastal environment may be important for cadmium only.     

The Influence of Anthropogenic Contamination On Metals Release From Coastal Sediment Suspensions with Aerated Sea Water

The zinc, cadmium, copper and lead release from the uncontaminated and contaminated coastal sediments with aerated sea water was studied. the metals transfer to the dissolved forms was monitored during one-two months by differential pulse anodic voltammetry (DPASV). the sediments with different initial degree of contamination were sampled in the Peter the Great Bay, Sea of Japan around Vladivostok-the biggest city in Russian Far East. Sediment contamination by metals led to increased release to solution of zinc due to sulphide oxidation and cadmium on account of organic matter decomposition. the copper behaviour was complicated by strong binding with organic matter and enhancements of copper release can only be seen in sediment with a low organic matter content. Significant lead transfer to dissolved forms was not observed regardless of sediment contamination. the temperature affected the release of cadmium and copper through enhanced organic matter destruction. the dissolved metal fluxes from the sediment transformation are compared with metal fluxes towards bottom. Such comparisons show that second contamination by dissolved metals of the studied coastal environment may be important for cadmium only.     

Uptake and loss of radioactive cadmium by the sea-skater Halobates robustus (Heteroptera: Gerridae)

Sea-skaters, Halobates robustus Barber, caught around the Galápagos Islands, were exposed over a period of 3 days to radioactive cadmium dissolved in seawater. Although ^115mCd (metastable ¹¹⁵Cd) was accumulated by the insects, they did not concentrate it above the seawater level. The experiments clearly showed that cadmium is taken up into the body, not merely adsorbed onto surfaces. The uptake of Cd followed a biphasic time course. When sea-skaters labelled in this way were transferred back into unlabelled seawater, the rate of loss of Cd was likewise biphasic. During uptake and loss, the biological half-life times for the first compartments were almost identical (0.64 and 0.79 h), indicating that the same compartment might be involved. On the other hand, the biological half-life times for the second compartments were different (1.7 days during uptake, 19.5 days during loss), indicating that the site or chemical form of bound Cd in the sea-skater had changed. For an adult female, weighing about 8.5 mg wet weight, the drinking rate of seawater was estimated at 2.5 l day^-1, equivalent to 29% body weight.     

Chromium in intertidal sediments of the Clyde,UK: potential for remobilisation and bioaccumulation

Detailed surveys of intertidal sediments have been performed along the north and south shores of the Inner Clyde estuary, UK. Surface sediment data reveal significant spatial variation in Cr content and an association with major sediment characteristics and location within the estuary. Depth variation for Cr and other heavy metals cannot be explained by variation in major geochemical controls such as grain size and organic matter and highlights the impact of historical contamination on sediment quality. These elevated levels at depth may still have environmental impact through redox-reactivity, in association with iron and manganese. Sequential extraction of sediments and pore water analysis of Cr(VI) and Cr(III) provide detailed information on release potential from the sediments. The implication of Cr mobility for biota in the estuary has been assessed by the analysis of a common marine bivalve, Mytilus edulis (Blue Mussel) and a burrowing polychaete, Nereis diversicolor (rag worm) from a number of survey sites. Bioconcentration factors for Mytilus indicate that the weakly held portion of sediment Cr is available for uptake and in the case of Nereis, bioaccumulation appears to be inhibited by sediment organic matter.