Trace metal

About: Trace metal is a research topic. Over the lifetime, 5125 publications have been published within this topic receiving 181046 citations.

Vertical distribution of the macrobenthic community and its relationships to trace metals and natural sediment characteristics in the lower douro estuary, portugal

Abstract: Vertical distribution (0–15 cm) of the macrobenthic community and its relationships to natural sediment characteristics and trace metal contents and bioavailability were studied at five locations in the lower Douro estuary, Portugal. An analysis of vertical metal distribution, for the interpretation of anthropogenic impact on the estuarine sediments, was also investigated. Sediment characterisation included organic matter, grain size, metals (Al, Fe, Cu, Pb, Cr, Ni, Cd, Zn and Mn), acid volatile sulphide (AVS) and simultaneously extracted metals (SEM). The macrobenthic community had low diversity (14 species), was dominated by small size opportunists and seemed to be controlled mainly by natural factors such as grain size distribution, Al and Fe contents and sediment depth. The vertically heterogeneous distribution of macrobenthic community appears to affect redox status of the sediments and consequently metal bioavailability. Despite anthropogenic contamination in terms of Zn, Cu, Pb, Cr and Ni having already been detected in the north bank, the analysis of vertical distribution was essential for the identification of current anthropogenic contamination in terms of Zn, Pb and Cd in the south bank.

Determination of trace amounts of cadmium, cobalt, chromium, iron, molybdenum, nickel, selenium, titanium, vanadium and zinc in blood and milk by neutron activation analysis

Abstract: The concentrations of Cd, Co, Cr, Fe, Mo, Ni, Se, Ti, V and Zn in biological fluids, human blood serum and market milk were determined by neutron activation analysis, with enrichment by coprecipitation. The pre-concentration of these trace elements was accomplished by converting the dissolved trace metal ions into their pyrrolidinedithiocarbamate (1-pyrrolidinecarbodithioate) chelates, followed by coprecipitation with a metal carrier such as Ni, Pb or Bi. The coprecipitation was carried out prior to irradiation for the short-lived nuclides (V, Ti and Se) and after irradiation for the other elements. The validity of the method was checked using certified biological reference materials; the concentrations of trace elements found by the proposed method agreed well with the published certified data. The limits of detection for Cd, Co, Cr, Fe, Mo, Ni, Se (obtained through the long-lived isotope 75Se) and Zn under the present experimental conditions were found to be 5, 5, 10, 520, 5, 70, 10 and 150 ng, respectively, for 5 ml of biological liquor. The limits of detection for Ti and V obtained (through their short-lived radionuclides 51Ti and 52V, respectively) were found to be 180 and 1.4 ng, respectively, for 50 ml of market milk, or 70 and 0.7 ng for 1 ml of blood serum.

Interactive effects of metal pollution and ocean acidification on physiology of marine organisms

Abstract: Changes in the global environment such as ocean acidification (OA) may interact with anthropogenic pollutants in- cluding trace metals threatening the integrity of marine ecosystems. We analyze recent studies on the interactive effects of OA and trace metals on marine organisms with a focus on the physiological basis of these interactions. Our analysis shows that the responses to elevated CO2 and metals are strongly dependent on the species, developmental stage, metal biochemistry and the degree of environmental hypercapnia, and cannot be directly predicted from the CO2-induced changes in metal solubility and speciation. The key physiological functions affected by both the OA and trace metal exposures involve acid-base regulation, pro- tein turnover and mitochondrial bioenergetics, reflecting the sensitivity of the underlying molecular and cellular pathways to CO2 and metals. Physiological interactions between elevated CO2 and metals may impact the organisms' capacity to maintain ac- id-base homeostasis and reduce the amount of energy available for fitness-related functions such as growth, development and re- production thereby affecting survival and performance of estuarine populations. Environmental hypercapnia may also affect the marine food webs by altering predator-prey interactions and the trophic transfer of metals in the food chain. However, our under- standing of the degree to which these effects can impact the function and integrity of marine ecosystems is limited due the scar- city of the published research and its bias towards certain taxonomic groups. Future research priorities should include studies of metal x PCO2 interactions focusing on critical physiological functions (including acid-base, protein and energy homeostasis) in a greater range of ecologically and economically important marine species, as well as including the field populations naturally ex- posed (and potentially adapted) to different levels of metals and CO2 in their environments (Current Zoology 61 (4): 653-668,

Artifacts in the Determination of Trace Metal Binding Forms in Anoxic Sediments by Sequential Extraction

Abstract: The binding forms of Co, Cd, Cu, Pb, and Zn in an anoxic, sulfide-bearing sediment were investigated by performing both thermodynamic equilibrium calculations and sequential extractions. Care was taken to maintain oxygen-free conditions during the whole experiment. The calculations suggested that trace metals were bound to sulfidic minerals. Sequential extraction results, however, showed increased importance of exchangeable and reducible fractions in the order Cu < Cd < Pb < Zn < Co. Thermodynamic equilibrium calculations of the chemical reactions during extraction showed that Cd, Co, Pb, and Zn sulfides are to a significant extent soluble in the acetate-exchangeable (step 1 + 2) and oxalate-reducible (step 3) fractions. Neglecting the dissolution of sulfide minerals would lead to a misinterpretation of the experimental results.