Trace metal methods for nutritional studies.

Livingston DM, Wacker WE.

PMID: 5094482 [PubMed - indexed for MEDLINE]

Algae columns with anodic stripping voltammetric detection.

Kubiak WW, Wang J, Darnall D.

The use of silica-immobilized algal cells for on-line column separation in conjunction with continuous monitoring of trace metals is described. Algae-silica preparations are highly suitable for flow analysis as they couple the unique reactivity patterns and high binding capacity of algal biomass with the hydrodynamic and mechanical features of porous silica. Such advantages are illustrated by using on-line anodic stripping voltammetry and the alga Chlorella pyrenidosa. Selective and exhaustive removal of interfering constituents circumvents common problems such as overlapping peaks and intermetallic effects. Effects of flow rate, pH, operation time, and other variables are reported. The system is characterized by high durability, simplicity, and economy and offers an attractive alternative to prevalent columns used for flow analysis.

PMID: 2719260 [PubMed - indexed for MEDLINE]

Flame atomic absorption spectrometric determination of trace amounts of manganese in alloys and biological samples after preconcentration with the ion pair of 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol and ammonium tetraphenylborate on microcrystalline naphthalene or by column method.

Taher MA.

Department of Chemistry, Shahid Bahonar University of Kerman, Kerman, Iran. [email protected]

Manganese is quantitatively retained on 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP)-ammonium tetraphenylborate with microcrystalline naphthalene or by a column method in the pH range 7.5-10.5 from large volumes of aqueous solutions of various samples. After filtration, each solid mass consisting of the manganese complex and naphthalene was dissolved with 5 ml of dimethylformamide and the metal was determined by flame atomic absorption spectrometry. Manganese complex can alternatively be quantitatively adsorbed on ammonium tetraphenylborate-naphthalene adsorbent packed in a column and determined similarly. About 0.1 microgram of manganese can be concentrated in a column from 500 ml of aqueous sample, where its concentration is as low as 0.2 ppb. Eight replicate determinations of 1.0 ppm of manganese gave a mean absorbance of 0.224 with a relative standard deviation of 1.8%. The sensitivity for 1% absorption was 19 ppb. The interference of a large number of anions and cations has been studied and the optimized conditions developed were utilized for the trace determination of manganese in various standard samples.

PMID: 11708102 [PubMed - indexed for MEDLINE]

Column chromatographic pre-concentration of iron(III) in alloys and biological samples with 1-nitroso-2-naphthol-3,6-disulphonate and benzyldimethyltetradecylammonium-perchlorate adsorbent supported on naphthalene using atomic absorption spectrometry.

Miura J, Arima S, Satake M.

Faculty of Engineering, Fukui University, Japan.

The solid ion-pair material produced from the reaction between benzyldimethyltetradecylammonium chloride (BDTA) and sodium perchlorate on naphthalene provides the basis for a simple, rapid and selective technique for pre-concentrating iron from up to 500 ml of aqueous solution. Iron reacts with disodium 1-nitroso-2-naphthol-3,6-disulphonate (Nitroso-R salt) to form a water-soluble coloured chelate anion. The iron chelate anion forms a water-insoluble, stable iron-Nitroso-R-BDTA complex on naphthalene packed in a column. Trace amounts of iron are quantitatively retained on naphthalene in the pH range 3.5-7.5 and at a flow-rate of 1-2 ml min-1. The solid mass is dissolved out from the column with 5 ml of N,N-dimethylformamide and iron is determined by means of an atomic absorption spectrometer at 248 nm. The calibration graph is linear for concentrations of iron over the range of 0.5-20 micrograms in 5 ml of final solution. The standard deviation and relative standard deviation were calculated. The detection limit of the method was 0.0196 micrograms ml-1 of iron. The sensitivity for 1% absorption was 0.072 microgram ml-1 (0.165 microgram ml-1 by direct atomic absorption spectrometry of aqueous solution). The proposed method was applied to the determination of iron in standard alloys and biological samples.

PMID: 2091489 [PubMed - indexed for MEDLINE]

Ultrastructural and electron energy loss spectroscopy studies of sequestration mechanisms of Cd and Cu in the marine diatom Skeletonema costatum.

Nassiri Y, Mansot JL, Wery J, Ginsburger-Vogel T, Amiard JC.

Laboratoire de Biologie Marine, Faculte des Sciences et Techniques, CNRS-EP 61, ISOMer, 2 Rue de la Houssiniere BP 92208, 44322 Nantes Cedex 03, France.

The marine diatom Skeletonema costatum was used to study mechanisms of detoxification when submitted to cadmium and copper contamination. After 96 h of growth, concentration corresponding to 50% growth inhibition (IC50, 96 h) was 0.224 mg/L for cadmium and 0.045 mg/L for copper, indicating that copper is more toxic for S. costatum than cadmium. Heavy cellular damages were observed for cadmium and copper concentrations close to the IC50. Exposure to these concentrations induced a migration of inclusions from the peripheral cytoplasm to the vacuole. Electron energy loss spectroscopy (EELS) investigations demonstrated that Cd and Cu were specifically trapped in these inclusions. However, Cu was less sequestered than cadmium in the vacuole. EELS determination of oxidation states evidenced that trace metals were sequestered as Cd2+ and Cu2+. Nitrogen and sulfur are involved in metallic storage, especially in the case of cadmium contamination.

PMID: 9294242 [PubMed - indexed for MEDLINE]

Patterns of metal accumulation in Laminaria longicruris from Long Island Sound (Connecticut).

Shimshock N, Sennefelder G, Dueker M, Thurberg F, Yarish C.

Department of Ecology and Evolutionary Biology, University of Connecticut, Stamford 06903.

Laminaria longicruris de la Pyl. samples were harvested from Long Island Sound (Connecticut) from January 1985 to January 1986. Cadmium and copper content was determined by atomic absorption spectrophotometry from four tissue types; young blade, old blade, young stipe and old stipe. The results were statistically analyzed for differences in both type and age of tissue. Concentrations of cadmium were consistently lower than copper concentrations for all months and all tissue types. Statistically significant differences (p greater than 0.05) were found between the four tissue types for copper in the months of March, June, July, October and December, and for cadmium in the months of February, March, June, July, October and November. Young blade tissue and young stipe tissue were the tissues which most frequently found to be statistically different from the other tissues. Young stipe tissue had the lowest trace metal concentrations (1.3 mean ppm, dry wt. Cu, 0.22 mean ppm, dry wt. Cd). Young blade tissue had significantly higher metal values in comparison to the other tissues for the months of June and October. Old tissue of L. longicruris is the most suitable for use in biomonitoring of trace metals due to the relatively little variation in metal content that was found throughout the study period.

PMID: 1616316 [PubMed - indexed for MEDLINE]

The role of vanadium in green plants. IV. Influence on the formation of delta-aminolevulinic acid in Chlorella.

Meisch HU, Bauer J.

In a series of experiments, it is demonstrated that the trace element vanadium (4.10(-7) g-at/1 as NH4VO3) has a considerable positive influence on the synthesis of delta-aminolevulinic acid(delta-ALA) in the autotrophically growing green alga Chlorella pyrenoidosa, the effect being visible by an enhanced output of the amino acid into the culture medium in presence of levulinic acid (LA). The level of intracellularly accumulated delta-ALA, however, is not changed in presence of the metal. The V-effect on exogenous found delta-ALA is suppressed, when LA is added to the nutrient medium at low pH (pH5), although V-uptake into the algal cells is not disturbed by LA. As demonstrated in culture media with various nitrogen sources (urea, partially hydrolized urea, ammonium salts), the development of the pH during the cultivation time is important for the presentation of the V-effect on delta-ALA. It is suggested that vanadium acts as a catalyst in the conversion of 4,5-dioxovaleric acid to delta-ALA by transamination.

PMID: 28098 [PubMed - indexed for MEDLINE]

Biomass yields of Chlorella from iron (Yx/Fe) in iron-limited batch cultures.

Pirt SJ, Walach M.

The maximum biomass in iron-limited photosynthetic batch cultures of chlorella increased as the logarithm of the iron concentration. The growth yield from iron (UxFe) showed a marked inverse relation to the specific growth rate. The maximum biomass yield, g dry biomass/g iron consumed, was 7.5 X 10(3) with specific growth rate 0.108h-1; the minimum was 0.79 X 10(3) with specific growth rate 0.145 h-1. The maximum specific growth rate in the exponential phase of Fe limited cultures varied as the initial Fe concentration. Fe-limited growth made the cells adhere to a glass surface.

PMID: 646583 [PubMed - indexed for MEDLINE]

The role of vanadium in green plants. III. Influence on cell division of Chlorella.

Meisch HU, Benzschawel H.

Vanadium, although essential for growth and chlorophyll formation in unicellular green algae, reveals toxic influences on cell division of Chlorella pyrenoidosa, these disturbances arising in the same range of V-concentrations as the known positive effects of the trace metal. In permanent light, as documented by cell volume statistics, vanadium (4-10(-7) g-at/1 as NH4VO3) causes a significant shift of the distribution maxima to higher values of the algal cell volume, the shift having its optimum at 10(-5) g-at V/1. It is documented in pH-constant liquid culture that this effect is not due to a change of pH in the nutrient medium. Under synchronous conditions of algal cultivation (16:8h), vanadium causes a total arrest of cell division after 3 periods; this stop lasts for the next 3 cycles. Afterwards, asynchronous divisions newly occur and lead to generally larger autospores. Staining of algal cell nuclei revealed an inhibitory V-effect on nuclear division, yielding giant nuclei with multiple sets of chromosomes, and thereby limiting cell division. Under these conditions, Chlorella pyrenoidosa is not synchronizable in presence of vanadium.

PMID: 23738 [PubMed - indexed for MEDLINE]

[Supplying dense cultures of green algae with manganese, vanadium and other trace elements]

[Article in German]

Payer HD, Trultzsch U.

PMID: 5053246 [PubMed - indexed for MEDLINE]

Trace metals, PCBs, and PAHs in benthic (epipelic) diatoms from intertidal sediments; a pilot study.

Stronkhorst J, Vos PC, Misdorp R.

National Institute for Marine and Coastal Management, The Hague, The Netherlands.

PMID: 8019075 [PubMed - indexed for MEDLINE]

The use of periphyton as a monitor of trace metals in two contaminated Indiana lakes.

Johnson GD, McIntosh AW, Atchison GJ.

PMID: 678687 [PubMed - indexed for MEDLINE]

An ecological risk assessment for the use of Irgarol 1051 as an algaecide for antifoulant paints.

Hall LW Jr, Giddings JM, Solomon KR, Balcomb R.

University of Maryland, Agricultural Experiment Station, Wye Research and Education Center, Queenstown 21658, USA.

Irgarol 1051 is an algaecide used in copper-based antifoulant paints for controlling fouling organisms on the hulls of recreational and commercial watercraft. Paints containing this algaecide have been used in Europe since the mid-1980s. In 1998, the first antifouling paints containing Irgarol 1051 were registered for use in the U. S. To examine the risk that Irgarol may pose to aquatic ecosystems, a probabilistic ecological risk assessment was conducted using distributions of exposure and toxicity data. Exposure data for this assessment were derived from 11 monitoring studies (146 stations) conducted in marinas, estuaries, and coastal waters from 1992 to 1997 in six European countries. A comparison of 90th percentile concentrations pooled by station types across all regions showed that concentrations in marinas (316 ng/l) were higher than in estuaries and coastal waters (41 and 19 ng/l, respectively). A 90th percentile of 133 ng/l was reported for all pooled stations. Temporal trends showed that Irgarol concentrations typically peaked in early summer after launching of small boats with much lower concentrations occurring during the spring, fall, and winter. Toxicity data used for this risk assessment were derived primarily from unpublished studies submitted to regulatory agencies. Because Irgarol is a photosynthesis-inhibiting herbicide, it is much more toxic to plants than animals. Toxicity values for animals (fish and invertebrates) were much greater than concentrations of Irgarol reported in the environment. Therefore, a conservative approach using a distribution of only plant toxicity data (EC50s for plant growth) was used to derive a 10th percentile of 136 ng/l. This plant toxicity benchmark of 136 ng/l was used for risk characterization. Results from probabilistic analysis showed that ecological risk from Irgarol exposure was low in estuaries, coastal areas, and various open-type marinas. However, 10% or more of the plant species in enclosed marinas with low flushing rates may be exposed to Irgarol concentrations that would reduce photosynthesis activity and growth during the summer. Ecological risk to these sensitive plant species in enclosed marinas will likely be moderated because of the reversibility of Irgarol's inhibition of photosynthesis and the rapid recovery potential of plant communities. The ecological significance of marinas that generally contain numerous stressors such as trace metals, tributyltin, petroleum hydrocarbons, high nutrient concentrations, and low dissolved oxygen concentrations is a management issue that needs to be addressed.

Publication Types:

Review

Review, Academic

PMID: 10451264 [PubMed - indexed for MEDLINE]

Symmetry breaking in the zygotes of the fucoid algae: controversies and recent progress.

Robinson KR, Wozniak M, Pu R, Messerli M.

Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907, USA.

Despite its many advantages as an experimental system for the study of the epigenesis of polarity, it is obvious that the fucoid zygote also presents many problems. The development of polarity proceeds largely independently of direct gene action and thus may be considered a problem in cellular physiology. Ca2+ appears to play an important role in the process, but the optical properties of the zygotes (opacity and autofluorescence) hamper the use of modern methods of visualizing the distribution of Ca2+ and other ions. Likewise, other approaches, such as injection of fluorescent-labeled G-actin, in order to study the dynamics of actin filaments, are subject to the same limitations. It may be that the application of two-photon microscopy will enable experimenters to avoid some of these problems. This technique uses excitation wavelengths that are twice the wavelength of maximum absorption by fluorophores, and sufficient photon density for absorption is achieved only in a thin section. The fucoid zygotes are considerably more transparent to longer wavelengths, so attenuation of the exciting light and autofluorescence should be significantly reduced. Perhaps we will then be able to see further into these opaque cells. Another problem concerns the use of different species and genera. This may be unavoidable; for example, those of us who are land-locked tend to rely on Pelvetia, as it travels and stores better than the various species of Fucus and is less seasonal. Our colleagues fortunate enough to work near the ocean prefer to use the species that are locally available. Nevertheless, it is important to be careful about cross-genus and cross-species generalizations. While it is unlikely, based on what we know, that there are fundamental differences in physiological mechanisms among species, there may be small but still important differences in details. Obviously, investigators should directly compare results in more than one species whenever possible. The area of greatest disagreement, perhaps, concerns the mechanism of polarity formation, as opposed to its overt manifestation, germination. Are Ca2+ and actin involved or not? Assuming Ca2+ is involved, is the source internal or external? One basis for the different findings may be the differences in the strength of the polarizing signal provided to the zygotes. Clearly, the cells have powerful mechanisms for amplifying a faint asymmetry and developing an axis in response to an external signal. Furthermore, the fucoids generally develop in the intertidal zone and thus must be adapted to meeting the challenge of a widely varying external environment. They may have alternate mechanisms for responding to unilateral light. We have adopted the approach of presenting the cells with a fairly weak light signal--the minimum required to induce a considerable degree of organization of a population of zygotes. We then determine the effects of various inhibitors on photopolarization. One advantage of this approach is that it has allowed us to find treatments that increase the sensitivity of the zygotes to light, something that would not be possible if the untreated controls were fully polarized. Some of the differences between our results and those of others may be related to their use of a stronger light stimulus. It may be that if given a strong stimulus, a sufficient trace is left in the cells so that they can organize an axis when an inhibitor is removed. Careful consideration of this point may help to reconcile apparently contradictory findings. Despite these difficulties, the fucoid zygotes are likely to continue to be an important experimental system. Technology, including the development of more specific inhibitory reagents, may allow some of the shortcomings of the system to be overcome, and careful consideration of experimental conditions may resolve some of the points of disagreement.

Publication Types:

Review

Review, Tutorial

PMID: 9891878 [PubMed - indexed for MEDLINE]

Monitoring of labile zinc in cultures of Skeletonema costatum using a salt groundwater.

Schintu M, Koussih L, Chevolot L, Amiard JC, Robert JM.

Dipartimento di Igiene e Sanita Pubblica, Universita di Cagliari, Via Porcell 4, Cagliari, 09100, Italy.

Labile Zn concentration was monitored by differential pulse anodic stripping voltammetry (DPASV) throughout the exponential growth phase of the marine diatom Skeletonema costatum (Grev.) Cleve. Algal blooms were induced both under natural conditions and in laboratory experiments using a salt groundwater (salinity 33) from the Bay of Bourgneuf, northwest coast of France. Salt groundwater is a very complex medium containing high concentrations of dissolved organic matter and other trace metal adsorbents, such as phosphate, iron oxyhydroxides, and manganese and silicon oxides, which can bind metal ions, reducing their availability and toxicity to algae. Besides metal uptake by algae and complexation of Zn by algal exudates, the rapid decrease in the labile Zn concentration during the algal blooms was ascribed mainly to the adsorption or coprecipitation of Zn ion onto freshly formed iron hydroxides. Copyright 1999 Academic Press.

PMID: 10090809 [PubMed - indexed for MEDLINE]

On the toxic effects of tetraethyl lead and its derivatives on the chrysophyte Poterioochromonas malhamensis. VII. Protective action of thiol compounds, vitamins, trace elements, and other agents.

Roderer G.

The influence of 45 different substances on the growth inhibiting effects of triethyl lead chloride (TriEL) in cultures of the unicellular alga Poterioochromonas malhamensis was studied. Ten thiol or disulfide compounds, 9 vitamins, 12 trace elements, 14 miscellaneous agents, and 9 combinations of these agents were tested. The agents were applied to the algal cultures in three different concentrations simultaneously with 10 microM TriEL and incubated for 72 hr. While none of the tested thiol and disulfide compounds remarkably protected the algae from TriEL toxicity, two vitamins (tocopheryl acetate, ascorbic acid), one trace element (zinc), adenosine-5'-triphosphate Na2 salt, cyclic AMP, and concanavalin A as well as combinations of some of these agents were found to suppress markedly the growth inhibiting effects of TriEL. Zinc was the most effective agent; it increased algal growth in TriEL-treated cultures by about 70 times as compared with cultures containing TriEL alone. A combination of 10 essential trace elements was even more protective and almost completely suppressed TriEL toxicity. In contrast to this, some of the other agents potentiated the toxic effects of TriEL (e.g., magnesium, molybdenum, caffeine, deuteriumoxide, chlorpromazine, dimethylsulfoxide) in the tested concentration ranges. The most protective agents Zn, VitC, and VitE did not prevent the inhibitory effects of TriEL on microtubule (MT) assembly in vitro, suggesting that their in vivo protection is based on mechanisms other than direct protecting MTs from the attack of the lead compound. Zn had no direct influence on the stability and half life of TriEL in the growth medium. The lack of protection found by the thiol compounds used suggests that most probably general thiol interaction of TriEL is not its major toxic mechanism of action. It is postulated that the protective action of Zn, VitE, and VitC is directly or indirectly mediated by suppression of TriEL-induced peroxidation processes in the poisoned algae. The protective agents found provide a basis for further screening experiments in order to test their "therapeutic" potency in experimental animals poisoned with organolead.

PMID: 3720621 [PubMed - indexed for MEDLINE]

Comparative studies on trace metal levels in marine biota. III. Typical levels and accumulation of toxic trace metals in muscle tissue and organs of marine organisms from different European seas.

Stoeppler M, Nurnberg HW.

PMID: 535554 [PubMed - indexed for MEDLINE]

Characterization of a highly negative and labile binding protein induced in Euglena gracilis by cadmium.

Gingrich DJ, Weber DN, Shaw CF, Garvey JS, Petering DH.

The physiochemical properties and physiological significance of the cadmium-binding protein (CdBP) of the algae Euglena gracilis have been studied. Following in vivo exposure of cells to 0.4 or 1.3 micrograms/mL of Cd2+, all the cytosolic Cd is bound to high molecular weight species. At 4.7 micrograms/mL, appreciable CdBP has formed in cells grown under illumination or in the dark. An analogous ZnBP could not be isolated from control or Zn-exposed (20 micrograms/mL) cells, but zinc and a trace of copper were bound to the CdBP when 2-mercaptoethanol (2-ME) is added to the homogenates of Cd-treated cells and the buffers used during isolation. The large pool of very low molecular weight zinc species previously reported is increased when cells are exposed to high cadmium levels. Two distinct species, BP-1 and BP-2 are resolved by ion-exchange chromatography on DEAE-Sephadex. Unusually high conductivities (25 and 40 mSiemen) are required to displace them, indicating that they are very negatively charged proteins at pH 8.6. The pH for half-titration of bound Cd2+ is between 5 and 6. EDTA (0.4 M) and the CdBP isolated by gel-exclusion chromatography react biphasically with pseudo-first-order rate constants of 4 +/- 3 X 10(-4) sec-1 and 7 +/- 2 X 10(-5) sec-1. Neither form of the CdBP cross-reacts with antibodies to rat liver metallothionein (MT) antibodies. The structural, chemical, and functional differences between the Euglena CdBPs and mammalian MTs are discussed.(ABSTRACT TRUNCATED AT 250 WORDS)

PMID: 3011392 [PubMed - indexed for MEDLINE]

Trace metal concentrations in marine macroalgae from different biotopes in the Aegean Sea.

Sawidis T, Brown MT, Zachariadis G, Sratis I.

Department of Botany, University of Thessaloniki, Greece.

The commonest species of red, brown, and green macroalgae were sampled from a range of biotopes in the Aegean Sea and analysed for five different trace metals. Significant differences in metal concentrations were found among different seaweed species from the same biotope. The concentrations of metals in the various seaweed species may reflect their morphology, with those having a larger surface area having a greater internal content. Different species of seaweed have different affinities for different heavy metals. This may reflect competition between metals for binding or uptake sites in the seaweed. Comparing metal concentrations in algae among the studied sampling stations clearly indicates that the degree of accumulation depends not only on human activities but also on the geology of the specific area. While seaweed can be used successfully to assess the levels of heavy metals in the marine environment, not all elevated concentrations of heavy metals necessarily reflect increased levels of pollution. Indeed, the high concentrations of certain metals, e.g., Ni, found in our seaweed samples reflected the metaliferrous nature of the rock. It is therefore important to take account of a region's geology before attempting to interpret the data.

PMID: 11488389 [PubMed - indexed for MEDLINE]

The pollution status and the toxicity of surface sediments in Izmit Bay (Marmara Sea), Turkey.

Tolun LG, Okay OS, Gaines AF, Tolay M, Tufekci H, Kiratli N.

TUBITAK, Marmara Research Center, Energy Systems and Environmental Research Institute, Kocaeli, Turkey.

Izmit Bay is one of the most polluted and populated enclosed sea in Turkey. It has been the centre of industrial activities for the last 30 years. Seven major sources enter the bay waters along the north coastline of the bay. This investigation forms part of continuing ecotoxicology studies in the Izmit Bay designed to constrain and minimise the pollution caused by flourishing industry and a growing population. Sediments sampled from the mouths of the major discharges of Izmit Bay were analysed for their organic carbon, total polycyclic aromatic hydrocarbon (t-PAH) and trace inorganic element (Cd, Al, As, Pb, Hg and Cu) contents and compared with those found in the sediments from the reference station in the outer bay (in the Marmara Sea). The toxicity of sediments was determined in the bulk and elutriate samples by using algal (Phaeodactylum tricornutum) batch bioassays. Chemical data showed that the sediments collected from the inner sites of the bay have been contaminated with Cd, Hg, As and PAHs. Organic carbon contents were also found higher. All the major industrial discharges into the bay are now biologically treated but bioassays performed with bulk sediments revealed that the recent sediments are toxic to the microalgae throughout the bay. The results are consistent with the previous toxicity studies performed with the industrial discharges.

PMID: 11341701 [PubMed - indexed for MEDLINE]

Metal levels in feathers of cormorants, flamingos and gulls from the coast of Namibia in southern Africa.

Burger J, Gochfeld M.

Division of Life Sciences, Rutgers University, Piscataway, NJ, USA.

Arsenic, cadmium, chromium, lead, manganese, mercury, selemium, and tin concentrations were measured in the feathers of Cape cormorant (Phalacrocorax capensis), Hartlaub's gull (Larus hartlaubii), kelp gull (Larus dominicanus), and lesser flamingo (Phoeniconaias minor) from the coast of Namibia in southern Africa. Metal concentrations in feathers represent the concentrations in the blood supply at the time of feather formation. Cape Cormorants are piscivores; kelp gulls are primarily piscivores; Hartlaub's gull is an omnivore; and lesser flamingos eat primarily blue-green algae and invertebrates filtered from the water and sediment of hypersaline lagoons. We predicted that metal concentrations would reflect these trophic level differences. There were significant species differences in the concentrations of all metals, with flamingos having the lowest levels, and cormorants having the highest levels of 4 metals but not mercury. The gulls had the highest levels of mercury, perhaps reflecting their more scavenging behavior.

PMID: 11465667 [PubMed - indexed for MEDLINE]

Dredging impact on an urbanized Florida bayou: effects on benthos and algal-periphyton.

Lewis MA, Weber DE, Stanley RS, Moore JC.

US Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, Gulf Ecology Division, 1 Sabine Island Drive, Gulf Breeze, FL 32561-5299, USA. [email protected]

Environmental effects of dredging events have been uncommonly reported for shallow, residential estuaries characteristic of the Gulf of Mexico region. The objective of this study was to determine the impact of hydraulic dredging on an urbanized estuary. Physicochemical quality, benthic community composition, whole sediment toxicity, periphytic algal community composition and trace metal tissue quality were determined prior to and after dredging. The effects on surface water pH, dissolved oxygen, and temperature were negligible but photosynthetically active radiation was decreased at several stations. Dredging significantly reduced benthic diversity and density (P < 0.05). However, the sediments were not acutely toxic to the epibenthic, Americamysis bahia (formerly Mysidopsis bahia); survival averaged 93% (post-dredging) and to 98% (pre-dredging). There were several post-dredging taxonomic structural changes in the diatom-dominated, periphyton community but differences in mean density and three diversity indices were not significant. Trace metal concentration in periphyton after dredging were reduced from an average of 4-65% and significantly for mercury, zinc and chromium in several areas. It was concluded that the environmental impact of small-scale dredging events in urbanized near-coastal areas, based on the selected parameters, are likely to be localized and of short-term environmental consequence. The choice of the target biota, response parameters and chemical analysis are important considerations in the environmental impact assessment of these periodic episodic events.

PMID: 11706789 [PubMed - indexed for MEDLINE]

Trace metals in seagrass, algae and molluscs from an uncontaminated area in the Mediterranean.

Campanella L, Conti ME, Cubadda F, Sucapane C.

Dipartimento di Chimica, Universita di Roma La Sapienza, P.le A. Moro 5-00185, Rome, Italy. [email protected]

The concentrations of Cd, Cr, Cu, Pb and Zn were measured in specimens of four marine organisms--the seagrass Posidonia oceanica (L.) Delile, the brown algae Padina pavonica (L.) Thivy, and the two gastropod molluscs Monodonta turbinata Born and Patella caerulea L.--selected as possible cosmopolitan biomonitors of trace metals in the Mediterranean area. The organisms were collected at five coastal sites in Favignana Island (Sicily, Italy), an area virtually uninfluenced by anthropogenic activities. In order to gain a more complete picture of both the environmental conditions of the experimental area and the bioaccumulation patterns of the selected organisms, soluble and total metal concentrations were determined in coastal water samples collected at the same stations. The picture of bioavailable metal loads in the different sites of the selected area provided by the four species was rather univocal. An overall trend of increased metal concentrations at the station in which the local harbour is located was clear. On the other hand, the metal concentrations recorded at the 'clean' stations generally fall in the range of the lowest values available in the literature and may be considered as useful background levels to which to refer for intraspecific comparison within the Mediterranean area. Implications in biomonitoring of the observed accumulation patterns, especially in the different tissues of Posidonia oceanica, are discussed.

PMID: 11202705 [PubMed - indexed for MEDLINE]

Effects of major nutrient additions on metal uptake in phytoplankton.

Wang WX, Dei RC.

Department of Biology, Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong, People's Republic of China. [email protected]

We examined the influences of major nutrients (N, P, Si) on the accumulation of three trace metals [Cd, Se(IV), and Zn] in four species of marine phytoplankton (diatom, green alga, dinoflagellate, prasinophyte). Relative metal uptake was quantified by the kinetic measurements of metal concentration factor over a short exposure period. Our study demonstrated that nutrient addition significantly influenced the metal uptake rate and the cell growth rate in all four phytoplankton species. An increase in ambient N concentration considerably enhanced metal uptake by the cells. The dry weight concentration factor increased by 2.4-14.9 times for Cd, 1.1-4.0 times for Se, and 1.1-5.4 times for Zn in all four phytoplankton species with an addition of 176.4 microM N. The effects of P or Si addition on metal uptake and cell growth were less pronounced than the effects of N addition. Under most circumstances the rate of metal uptake increased exponentially with increasing cell growth rate constant. Only Se(IV) uptake in the diatom Phaeodactylum tricornutum was not correlated with cell growth rate. Se(IV) was not accumulated by the green algae Chlorella autotrophica at a high P concentration (7.2 microM), but appreciable accumulation was documented in cells inoculated without P addition. Our study therefore demonstrated that nutrient enrichments in many coastal waters can considerably affect trace metal uptake in phytoplankton and presumably metal trophic transfer in marine food chains.

PMID: 11202726 [PubMed - indexed for MEDLINE]

The effects of pH and surface composition on Pb adsorption to natural freshwater biofilms.

Wilson AR, Lion LW, Nelson YM, Shuler ML, Ghiorse WC.

School of Civil and Environmental Engineering, Cornell University, Ithaca, New York 14853, USA.

Two dominant variables that control the adsorption of toxic trace metals to suspended particulate materials and aquatic surface coatings are surface composition and solution pH. A model for the pH-dependent adsorption of Pbto heterogeneous particulate surface mixtures was derived from experimental evaluation of Pb adsorption to laboratory-derived surrogates. The surrogate materials were selected to represent natural reactive surface components. Pb adsorption to both the laboratory surrogates and natural biofilms was determined in chemically defined solutions under controlled laboratory conditions. Pb adsorption was measured over a pH range of 5-8, with an initial Pb concentration in solution of 2.0 microM. The surface components considered include amorphous Fe oxide, biogenic Mn oxide produced by a Mn(II) oxidizing bacterium (Leptothrix discophora SS-1), Al oxide, the common green alga Chlorella vulgaris, and Leptothrix discophora SS-1 cells. A linearization of Pb adsorption data for each adsorbent was used to quantify the relationship between Pb adsorption and pH. The parameters for individual adsorbents were incorporated into an additive model to predict the total Pb adsorption in multiple-adsorbent natural surface coatings that were collected from Cayuga Lake, NY. Pb adsorption experiments on the natural surface coatings at variable pH were utilized to verify the additive model predictions based on the pH dependent behavior of the experimental laboratory surrogates. Observed Pb adsorption is consistent with the model predictions (within 1-24%) over the range of solution pH values considered. The experimental results indicate that the combination of Fe and biogenic Mn oxides can contribute as much as 90% of Pb adsorbed on Cayuga Lake biofilms, with the dominant adsorbent switching from Mn to Fe oxide with increasing pH.

PMID: 11505999 [PubMed - indexed for MEDLINE]

Influence of N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid pH buffer on the biological response of marine algae.

Vasconcelos MT, Leal MF.

LAQUIPAI, Chemistry Department, Faculty of Science, University of Porto, Portugal. [email protected]

The N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES) is extensively used as pH buffer in culture media for testing chemicals. However, this study demonstrates that 0.01 M HEPES significantly reduces the rate of Cu, Pb, and Cd binding to Porphyra spp. and Enteromorpha spp. marine macroalgae. The HEPES also decreased the accumulation of Cu, Pb, and Cd but not Hg by these macroalgae. Both the extracellular adsorption and the intracellular uptake of the metals were influenced by HEPES to a similar extent. The HEPES also promoted the release of exudates by the algae, and these exudates form very stable complexes with Cu (and probably with other trace metal ions). The HEPES interference varied with the nature of the metal, the macroalga, and the season. The presence of 0.01 M HEPES in seawater cultures of the Emiliania huxleyi (a microalga) also interfered with E. huxleyi growth, liberation of Cu-complexing organic ligands, and Cu uptake. The HEPES, which displays surface activity, may facilitate the binding of metals to the algae for an initial exposure period. The metal taken up appears to stimulate the liberation of exudates that subsequently control the bioavailability of the metals and therefore metal uptake. Because HEPES can control the uptake of trace metals by algae and the production of organic ligands, the results obtained in cultures containing the HEPES pH buffer can be influenced by this component of the media.

PMID: 11837230 [PubMed - indexed for MEDLINE]

Interaction of toxic trace metals and mechanisms of detoxification in the planktonic diatoms Ditylum brightwellii and Thalassiosira pseudonana.

Rijstenbil JW, Sandee A, Van Drie J, Wijnholds JA.

Netherlands Institute of Ecology, Centre for Estuarine and Coastal Ecology, Yerseke, The Netherlands.

Effects of cadmium (10 nM), copper (80 nM) and zinc (150 nM) additions were studied in the marine diatom Ditylum brightwellii and the riverine diatom Thalassiosira pseudonana. Defense against oxidative stress via cellular thiol (SH) pools and superoxide dismutase (SOD) activation, detoxification via phytochelatins and cell damage were monitored in metal-exposed exponential-phase cells and controls, grown in estuarine medium. Total SH and reduced+oxidized glutathione (GSH+GSSG) in T. pseudonana were much higher than in D. brightwellii. In T. pseudonana, total SH and GSH decreased at 322 nM Zn, and GSH increased at 80 nM Cu but decreased at 119 nM Cu. GSH:GSSG ratios were low, while phytochelatins were not detectable in metal-exposed D. brightwellii. Cd-exposed T. pseudonana made more phytochelatins than Cu-exposed cells, and in different proportions. At 322 nM Zn, SOD activity decreased in T. pseudonana. Zn caused a major, and Cu a minor increase of SOD activity in D. brightwellii; inhibition of photosynthesis was observed in Cu-exposed D. brightwellii, probably due to oxidative damage. The C:N ratios were higher and protein contents lower in Cu-exposed cells of both species, which might indicate excretion due to a loss of cell membrane integrity. From these results, it is hypothesized that T. pseudonana has evolved an effective detoxification mechanism as a result of a more severe exposure to toxic metals in rivers and estuaries. In contrast, D. brightwellii, a marine-estuarine species, cannot adjust well to metal exposure. Its poor defense against metal toxicity was marked by low SH-contents.

PMID: 7917426 [PubMed - indexed for MEDLINE]

Effects of nutrients present in bold's basal medium on the green alga Stigeoclonium pascheri.

Agrawal SC, Sarma YS.

The effects of varying concentrations of nutrients present in Bold's basal medium on the extent of colony formation from vegetative fragments, sporulation and spore germination of the green alga Stigeoclonium pascheri were studied. A decrease of colony formation was observed in media deficient in MgSO4, NaNO3, phosphates, and containing a 10-fold increase of H3BO3. Sporulation decreased in the same media. However, sporulation was greater in an increasing order in media containing 2- to 10-fold increase in MgSO4. There was a decrease in spore germination in media deficient in phosphates, MgSO4, containing 5- or 10-fold MgSO4, or containing 2- to 10-fold of CaCl2, H3BO3 or microelements. Spore germination increased in media containing 2-fold MgSO4, deficient in H3BO3 or microelements or containing none of the three micronutrient solutions.

PMID: 7084823 [PubMed - indexed for MEDLINE]

Certification of trace and major elements and methylmercury concentrations in a macroalgae (Fucus sp.) reference material, IAEA-140.

Coquery M, Carvalho FP, Azemard S, Bachelez M, Horvat M.

International Atomic Energy Agency, Marine Environment Laboratory, Principality of Monaco.

A marine reference material, IAEA-140, prepared with a macroalgae (Fucus sp.) was recently produced by the International Atomic Energy Agency and certified for trace and major elements and for methylmercury (MeHg). Certification of this material was achieved as an outcome of an international analytical intercomparison study which resulted in 116 independent sets of results reported by participants from 54 countries. The statistical evaluation of the collected data and the criteria used for assignment of the mean and uncertainty values are described. The analysis of data allowed to certify concentration values for 24 elements and MeHg, and to provide information values for another 10 elements. Regarding the elements which could be given certified values, between two and eight different instrumental methods were used to measure metal concentrations, and four independent analytical procedures were used to measure MeHg concentrations. In order to assess the results of the certification procedure, a comparison was made between the certified values obtained from the world-wide intercomparison results and the values obtained from a small subgroup of well-qualified laboratories. The means and 95% confidence intervals for reference values obtained by the two methods are similar for most elements showing that the usual method of certification used by the IAEA, based on large groups of participants, is indeed pertinent.

Publication Types:

Evaluation Studies

Multicenter Study

PMID: 11227410 [PubMed - indexed for MEDLINE]

 

Consistent fractionation of 13C in nature and in the laboratory: growth-rate effects in some haptophyte algae

Bidigare RR, Fluegge A, Freeman KH, Hanson KL, Hayes JM, Hollander D, Jasper JP, King LL, Laws EA, Milder J, Millero FJ, Pancost R, Popp BN, Steinberg PA, Wakeham SG.

Department of Oceanography, University of Hawaii, Honolulu, USA. [email protected]

The carbon isotopic fractionation accompanying formation of biomass by alkenone-producing algae in natural marine environments varies systematically with the concentration of dissolved phosphate. Specifically, if the fractionation is expressed by epsilon p approximately delta e - delta p, where delta e and delta p are the delta 13C values for dissolved CO2 and for algal biomass (determined by isotopic analysis of C37 alkadienones), respectively, and if Ce is the concentration of dissolved CO2, micromole kg-1, then b = 38 + 160*[PO4], where [PO4] is the concentration of dissolved phosphate, microM, and b = (25 - epsilon p)Ce. The correlation found between b and [PO4] is due to effects linking nutrient levels to growth rates and cellular carbon budgets for alkenone-containing algae, most likely by trace-metal limitations on algal growth. The relationship reported here is characteristic of 39 samples (r2 = 0.95) from the Santa Monica Basin (six different times during the annual cycle), the equatorial Pacific (boreal spring and fall cruises as well as during an iron-enrichment experiment), and the Peru upwelling zone. Points representative of samples from the Sargasso Sea ([PO4] < or = 0.1 microM) fall above the b = f[PO4] line. Analysis of correlations expected between mu (growth rate), epsilon p, and Ce shows that, for our entire data set, most variations in epsilon p result from variations in mu rather than Ce. Accordingly, before concentrations of dissolved CO2 can be estimated from isotopic fractionations, some means of accounting for variations in growth rate must be found, perhaps by drawing on relationships between [PO4] and Cd/Ca ratios in shells of planktonic foraminifera.

PMID: 11540616 [PubMed - indexed for MEDLINE]

The determination of trace transition elements in biological tissues using flameless atom reservoir atomic absorption.

Segar DA, Gilio JL.

PMID: 4752398 [PubMed - indexed for MEDLINE]

Determination of metal ions in algal solution samples by capillary electrophoresis.

Lopez CE, Castro JM, Gonzalez V, Gonzalez E, Perez J, Seco HM, Fernandez JM.

Departamento de Quimica Analitica, Escuela Universitaria Politecnica de Ferrol, Universidade da Coruna, Spain.

Trace metals determination in aqueous samples can be readily accomplished by capillary electrophoresis (CE) via indirect absorbance detection. A method for the separation of metal ions is presented and applied to the determination of seven metals in algal solution samples. 2-Hydroxyisobutyric acid background electrolyte (BGE) containing UV CAT-1 (an ultraviolet-absorbing amine) is used to perform capillary ion analysis. Acetic acid is used to adjust the pH value of BGE to 4.4. All ions can be separated in less than 15 min. All peaks are well separated and baseline resolved (i.e., no peaks overlapped). This work presents the applicability of CE to the quantitative analysis of algal solution samples and shows the adsorption process of seven metals in solution (Mn, Cd, Cr, Ni, Zn, Pb, Cu) to Chlorella vulgaris. The innovation of the application of CE in the determination of metals bound by Chlorella vulgaris is shown to be an improvement of the pH over what has been published previously. The detection limit is in the range of 13 (Mn) to 102 (Pb) ppb with electrokinetic injection mode (15 kV, 7 s). Reproducibility was 1.4% for the migration time, better than 5% for peak area for four of the metal ions (Cr, Mn, Cd, and Cu), and lower than 5% for the other three (Ni, Zn, and Pb). Calibration curves are linear for most ions in the 10(-7)-10(-5)M range (correlation coefficient r2 = 0.9933-0.9986) using electrokinetic injection mode.

PMID: 9679302 [PubMed - indexed for MEDLINE]

The molecular biology of Euglena gracilis. VII. Inorganic requirements for a minimal culture medium.

Kempner ES, Miller JH.

PMID: 4624303 [PubMed - indexed for MEDLINE]

[Dynamics of accumulation of microelements in Chlorella cells during prolonged cultivation]

[Article in Russian]

Pokrovskaia EI, Meleshko GI, Zhurenko VN, Filatkina LA, Zhukova LB.

PMID: 4431217 [PubMed - indexed for MEDLINE]

[Determination of copper, iron, cobalt, nickel and manganese in biological samples of plant origin]

[Article in Russian]

Krotova NB, Tereshchenko AP.

PMID: 4646604 [PubMed - indexed for MEDLINE]

A flow injection chemiluminescence method using Cr(III) as a catalyst for determining hydrogen peroxide. Application to H(2)O(2) determination in cultures of microalgae.

Escobar R, Garcia-Dominguez S, Guiraum A, Montes O, Galvan F, de La Rosa FF.

Department of Analytical Chemistry, University of Seville, Spain.

Flow injection analysis has been applied to the determination of hydrogen peroxide produced by some different species of microalgae. The method is based on the luminol-H(2)O(2) chemiluminescence reaction using Cr(III) as a catalyst. Optimum experimental conditions for the method have been studied and trace amounts of hydrogen peroxide determined with detection limits of 4 10(-8) mol/L. The method using Cr(III) was compared with that using horseradish peroxidase as the catalyst. Copyright 2000 John Wiley & Sons, Ltd.

PMID: 10862140 [PubMed - indexed for MEDLINE]

Temporal variation in the diversity and cover of sessile species in rocky intertidal communities affected by copper mine tailings in northern Chile.

Farina JM, Castilla JC.

Departamento de Ecologia, Facultad de Ciencias Biologicas, Pontificia Universidad Catolica de Chile, Alameda 340, C.P. 6513677, Santiago, Chile. [email protected]

Several coastal rocky shores in the northern Chile have been affected by the discharges of copper mine tailings. In spite of this, the temporal and spatial variation on the diversity and composition of their intertidal benthic communities has scarcely been studied. The objectives of the present study were to analyse and to compare quantitatively the temporal variation on the diversity, cover and composition of sessile species in rocky intertidal benthic communities of the northern Chilean coast, in relation to the presence of copper mine tailings. The results show that the drastic reduction on the sessile species diversity and the monopolization of the substrate exerted by the green algae Enteromorpha compressa, are common and permanent features of the intertidal rocky shores affected by copper mine tailings. Such spatial (between sites) and temporal (seasonal) variation of these changes has been associated with the relative concentrations of trace metals and inorganic particles of the mining wastes. Our results suggest that the mechanical effects of resuspended and settling tailings are a more likely cause.

PMID: 11488236 [PubMed - indexed for MEDLINE]

Biochemistry of zinc.

Riordan JF.

The biochemistry of zinc has come under intensive investigation at the molecular level during the past 20 years. More than 70 zinc metalloenzymes are now known, and they span a broad range of biologic activities. Substitution of zinc by cobalt, for example, serves to locate a paramagnetic probe at the active site of the enzyme which can then provide information regarding the coordination properties of the metal and the active site environment.

Publication Types:

Review

PMID: 818453 [PubMed - indexed for MEDLINE]

[Trace element proportion in the nutrient medium as a factor in increasing the resistance of Chlorella to unfavorable cultivation conditions]

[Article in Russian]

Upitis VV, Pakalne DS, Nollendorf AF.

PMID: 4792251 [PubMed - indexed for MEDLINE]

Uptake of dissolved organic carbon and trace elements by zebra mussels.

Roditi HA, Fisher NS, Sanudo-Wilhelmy SA.

Marine Sciences Research Center, State University of New York, Stony Brook 11794-5000, USA.

Zebra mussels (Dreissena polymorpha) are widespread and abundant in major freshwater ecosystems in North America, even though the phytoplankton food resources in some of these systems seem to be too low to sustain them. Because phytoplankton biomass is greatly depleted in ecosystems with large D. polymorpha populations and bacteria do not seem to be an important food source for this species, exploitation of alternative carbon sources may explain the unexpected success of D. polymorpha in such environments. Here we examine the possibility that absorption of dissolved organic carbon (DOC) from water could provide a nutritional supplement to zebra mussels. We find that mussels absorb 14C-labelled DOC produced by cultured diatoms with an efficiency of 0.23%; this indicates that DOC in natural waters could contribute up to 50% of the carbon demand of zebra mussels. We also find that zebra mussels absorb some dissolved metals that have been complexed by the DOM; although absorption of dissolved selenium was unaffected by DOC, absorption of dissolved cadmium, silver and mercury by the mussels increased 32-, 8.7- and 3.6-fold, respectively, in the presence of high-molecular-weight DOC.

PMID: 10993076 [PubMed - indexed for MEDLINE]

dioxide in the marine diatom Thalassiosira weissflogii.

Lane TW, Morel FM.

Department of Geosciences, Guyot Hall, Princeton University, Princeton, New Jersey 08544-1003, USA. [email protected]

TWCA1 is the major Zn-requiring isoform of carbonic anhydrase (CA) in the marine diatom Thalassiosira weissflogii. We have examined the roles that trace metals and CO(2) play in the regulation of TWCA1 expression over ranges of concentrations that bracket those encountered in the marine environment. Both steady-state levels of TWCA1 and the kinetics of induction were measured by western analysis. TWCA1 levels correlated well with cellular CA activity levels. TWCA1 was induced at a low CO(2) concentration but the level of induction, as determined by western analysis, was dependent on the availability of Zn. Co effectively substituted for Zn in regulating TWCA1 expression and promoting TWCA1 activity. Upon shift from low to high CO(2), the concentration of TWCA1 decreased. The expression of TWCA1 is diel cycle regulated, and cellular TWCA1 decreased during the dark phase. These results provide the basis for studying the expression of CA in field populations and, taken together with previous radiolabeling studies, provide strong evidence of in vivo metal substitution of Co for Zn in a CA. Our data also support the conclusion that TWCA1 plays a central role in carbon acquisition in T. weissflogii.

PMID: 10806251 [PubMed - indexed for MEDLINE]

Phytochelatin production by marine phytoplankton at low free metal ion concentrations: laboratory studies and field data from Massachusetts Bay.

Ahner BA, Price NM, Morel FM.

R. M. Parsons Laboratory, Massachusetts Institute of Technology, Cambridge 02139.

Phytochelatins are small metal-binding polypeptides synthesized by algae in response to high metal concentrations. Using a very sensitive HPLC method, we have quantified phytochelatins from phytoplankton in laboratory cultures at environmentally relevant metal concentrations and in marine field samples. Intracellular concentrations of phytochelatin, in the diatom Thalassiosira weissflogii, exhibit a distinct dose-response relation with free Cd2+ concentration in the medium--not with total Cd(2+)--and are detectable even when the free Cd2+ concentration is less than 1 pM. In Massachusetts Bay, phytochelatin levels (normalized to chlorophyll a) in the particulate fraction are similar to those measured in laboratory cultures exposed to picomolar free Cd2+ concentrations and exhibit a decreasing seaward trend. Incubations of natural samples with added Cd2+ confirmed the induction of the peptides by this metal. Ambient phytochelatin concentrations thus appear to provide a measure of the metal stress resulting from the complex mixture of trace metals and chelators in natural waters.

PMID: 8078899 [PubMed - indexed for MEDLINE]

Metal accumulation in the green macroalga Ulva fasciata: effects of nitrate, ammonium and phosphate.

Lee WY, Wang WX.

Department of Biology, The Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon.

Coastal organisms are often exposed to both metal pollution and nutrient enrichment. The influences of major nutrients (nitrate, ammonium, and phosphate) on the accumulation of trace metals (Cd, Cr, Zn and Se) in Ulva fasciata were examined. The relative accumulation of metals was quantified by the kinetic measurements of accumulated metal concentration over a short exposure period (8 h). Our study demonstrated that macronutrients could markedly influence the rate of metal accumulation in the macroalgae. An increase in ambient nitrate concentration resulted in a significant increase in Cd accumulation rate, whereas the rate of accumulation of Cr and Zn was not greatly affected by the ambient nitrate level (between 10 and 100 microM). Zn uptake in nitrate-enriched macroalgae was, however, significantly higher than its uptake in N-starved macroalgae. The accumulation of Cd, Cr and Zn was not appreciably affected by the concentration of ammonium. Se accumulation was significantly inversely related to the ambient phosphate concentration, presumably due to the competitive inhibition by a high P concentration. Cr accumulation in the macroalgae increased significantly with increasing phosphate concentration. These data implied that the influences of major nutrients on cationic and anionic metal accumulation were highly metal-specific. The dependence of metal accumulation on major nutrients will appreciably affect our prediction of metal accumulation in macroalgae and the interpretation of biomonitoring data using the Ulva species.

PMID: 11669259 [PubMed - indexed for MEDLINE]

Elemental and radioactive analysis of commercially available seaweed.

van Netten C, Hoption Cann SA, Morley DR, van Netten JP.

Department of Health Care and Epidemiology, University of British Columbia, Vancouver, Canada. [email protected]

Edible seaweed products have been used in many countries, specifically Japan, as a food item. Recently these products have become popular in the food industry because of a number of interesting medicinal properties that have been associated with certain edible marine algae. Very little control exists over the composition of these products, which could be contaminated with a number of agents including heavy metals and certain radioactive isotopes. Fifteen seaweed samples (six local samples from the coast of British Columbia, seven from Japan, one from Norway and one undisclosed) were obtained. All samples were analyzed for multiple elements, using ICP mass spectrometry and for radioactive constituents. It was found that six of eight imported seaweed products had concentrations of mercury orders of magnitude higher than the local products. Lead was found at somewhat higher concentrations in only one local product. Laminaria japonica had the highest level of iodine content followed by Laminaria setchellii from local sources. Only traces of cesium-137 were found in a product from Norway and radium-226 was found in a product from Japan. Arsenic levels were found to be elevated. In order to estimate the effect of these levels on health, one needs to address the bioavailability and the speciation of arsenic in these samples.

PMID: 10898404 [PubMed - indexed for MEDLINE]

Temporal changes of 210Po in temperate coastal waters.

Wildgust MA, McDonald P, White KN.

School of Biological Sciences, University of Manchester, UK. [email protected]

The temporal variation of Polonium-210 (210Po) was examined in coastal sea water, the mussel Mytilus edulis, the winkle Littorina littorea and green alga Ulva lactuca in order to investigate the entry of 210Po into the marine food chain. More than 99% of 210Po in the water column occurred in the particulate phase. Dissolved 210Po concentrations peaked during the spring phytoplankton bloom and it is suggested this is related to preferential scavenging of 210Po by the increased numbers of bacteria, viruses and small dissolved particulates. Changes in L. littorea 210Po specific activity are thought not to be related to food, but to a drop in body weight following spawning. Much of the 210Po accumulated by M. edulis was located in the digestive gland. The specific activity of 210Po in the digestive gland of M. edulis was shown to be strongly correlated with changes in sea water suspended particulate specific activity. Examination of other trace metal (Ag, Al, As, Ca, Cd, Cr, Co, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, Sb, Se, Sn and Zn) variations in the digestive gland revealed that class B and borderline metals had a strong positive correlation with 210Po. On-going work is investigating whether the accumulation and loss of 210Po is affected by the presence of metallothioneins.

PMID: 9646514 [PubMed - indexed for MEDLINE]

Statistical evaluation of ecosystem properties influencing the uptake of As, Cd, Co, Cu, Hg, Mn, Ni, Pb and Zn in seaweed (Eucus vesiculosus) and common mussel (Mytilus edulis).

Struck BD, Pelzer R, Ostapczuk P, Emons H, Mohl C.

Institut fur Angewandte Physikalische Chemie, Forschungszentrum Julich GmbH, Germany.

In order to evaluate the influence of geographically varying marine ecosystem properties on the uptake of trace elements in bioindicators, samples were taken of seaweed (Fucus vesiculosus) and common mussel (Mytilus edulis) along the North Sea and Baltic Sea coast. Seasonal variations of the bioindicator status were minimized by sampling within 1 month. Ecosystem properties considered were the geographical position, the salinity and the concentrations of the macroelements Ca, Fe, K, Mg, Na, P and S in the bioindicators. Trace elements studied were As, Cd, Co, Cu, Hg, Mn, Ni, Pb and Zn. Factor analysis of the concentration patterns in the bioindicators and of salinity as a function of location confirmed the influence of the geographically varying salinity on the biological uptake of macroelements and trace elements. This influence of salinity was higher in the case of seaweed than in the case of mussel. Comparison of the geographical courses of the macroelement and trace-element concentrations by cluster analysis revealed corresponding courses for As and Hg in both bioindicators. All other elements showed different courses in seaweed and mussel. Subsequent cluster analysis comparing locations with respect to the macroelement or trace-element concentration patterns in the bioindicators, indicated a clear separation of North and Baltic Sea locations. However, the trace-element concentration patterns provided a regionally less distinctive ecosystem arrangement than those of the macroelement ones. The results of the cluster analysis were verified by discriminant analysis forming groups of locations with respect to geographical position and salinity. Results of discriminant analysis demonstrated, both for seaweed and for mussel as bioindicators, that the location groups formed according to the macroelement concentration patterns corresponded well with the geographical regions in the order of salinity. On the other hand, location groups based on the trace-element concentration patterns again showed a modified less distinctive ecosystem arrangement than the location groups based on macroelement concentration patterns. This confirms modified conditions for the uptake of trace elements in seaweed or mussel in comparison to the uptake of macroelements.

PMID: 9397597 [PubMed - indexed for MEDLINE]

Measurement and distribution of various heavy metals in the Danube River and Danube Canal aquatic communities in the vicinity of Vienna, Austria.

Rehwoldt R, Karimian-Teherani D, Altmann H.

Samples of mud, water, algae and fish were collected from the Danube River and Danube Canal and analysed by neutron activation techniques for various trace metals. The study was conducted over a ten-months time period. Results show no significant variation in levels of Cr, Co, Sb, Zn, Fe and Sc during the period of study. Comparison of the results obtained for the river with those obtained for the canal indicate that, with the exception of one sampling site, there are no statistically significant differences. Generally the values lie in the range accepted as normal for most fresh water systems. One site in the canal was found to have high Cr content in the mud samples at a point where the Vienna River joins the canal.

PMID: 1145177 [PubMed - indexed for MEDLINE]

Iron isotope biosignatures.

Beard BL, Johnson CM, Cox L, Sun H, Nealson KH, Aguilar C.

Department of Geology and Geophysics, University of Wisconsin-Madison, 1215 West Dayton Street, Madison, WI 53706, USA. Laboratory, MS 183-301, 4800 Oak Grove Road, Pasadena, CA 91109-8009, USA. [email protected]

The (56)Fe/(54)Fe of Fe-bearing phases precipitated in sedimentary environments varies by 2.5 per mil (delta(56)Fe values of +0.9 to -1. 6 per mil). In contrast, the (56)Fe/(54)Fe of Fe-bearing phases in igneous rocks from Earth and the moon does not vary measurably (delta(56)Fe = 0.0 +/- 0.3 per mil). Experiments with dissimilatory Fe-reducing bacteria of the genus Shewanella algae grown on a ferrihydrite substrate indicate that the delta(56)Fe of ferrous Fe in solution is isotopically lighter than the ferrihydrite substrate by 1.3 per mil. Therefore, the range in delta(56)Fe values of sedimentary rocks may reflect biogenic fractionation, and the isotopic composition of Fe may be used to trace the distribution of microorganisms in modern and ancient Earth.

PMID: 10489362 [PubMed - indexed for MEDLINE]

Metal uptake in a coastal diatom influenced by major nutrients (N, P, and Si).

Wang WX, Dei RC.

Department of Biology, Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong. [email protected]

The influence of major nutrient additions on trace metal uptake (Cd, Se, and Zn) in a coastal diatom Thalassiosira pseudonana was investigated. A short-term exposure (5 h) was employed to measure the concentration factor (ratio of metal concentration in the cells to metal concentration in the medium) which was used as a kinetic parameter to quantify the relative rate of metal uptake in the cells. Following an initial rapid surface sorption, a linear pattern of uptake over time was typical for Cd, Se and Zn, indicating that these metals may have been transported intracellularly during the short-term exposure period. N addition significantly increased the rates of Cd uptake in the cells. Although the concentration factor of Zn increased with N addition, statistical analysis indicated that N addition did not significantly affect the rate of Zn uptake in the cells. Se uptake in the cells was independent of N additions, but was lowered with increasing Si concentration. Si addition did not significantly affect Cd and Zn uptake. Similarly, P addition did not influence the rates of metal uptake in the cells. There was a significant correlation between the rate of uptake of Cd and Zn and the cell growth rate. This study demonstrated that water quality brought about by a change in nutrient condition could considerably influence the uptake of metals by marine phytoplankton.

PMID: 11257887 [PubMed - indexed for MEDLINE]

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