Topic
Trace metal
About: Trace metal is a research topic. Over the lifetime, 5125 publications have been published within this topic receiving 181046 citations.
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TL;DR: In this paper, depth profiles for O2/H2S, Mn, Fe, Co, Ni, Cu and Cd are presented for the Gotland Deep, based on samples collected in 1981 and 1985.
134 citations
TL;DR: The surface precipitation model was originally developed by FArley et al. (1985) for the sorption of cations on metal oxides as discussed by the authors, which accounts for the formation of a surface phase with a composition that is described by a solid solution having as end members the sorbent calcium carbonate mineral and a pure carbonate precipitate of the sorbing trace metal.
134 citations
Journal Article•
TL;DR: In this paper, the ability of the sludge to move soluble metal species from wastewa ter and the affinity of the biological mass for selected heavy metals was investigated using a cation exchange technique, previously used by soil scientists to investigate metal-organic complexation in soil and its extracts.
Abstract: MANY MUNICIPAL ACTIVATED SLUDGE plants receive combined wastewater containing heavy metals. These metals typically include copper, zinc, nickel, and cadmium and originate predominantly from industrial dischargers. Historically, there has been little concern for the pres ence of these metals in the wastewater, as long as they were at subtoxic levels. In creasingly stringent effluent regulations, to gether with recent indications of the detri mental effects of trace metal discharges on the receiving environment and its biota, have resulted in a need to assess the inter action and removal efficiency of heavy metals within the activated sludge process. There are numerous reports in the tech nical literature of soluble metal removal through the activated sludge process. Stones1_5 reported that activated sludge treatment reduced influent levels of iron, copper, lead, nickel, and zinc by 30 to 90 percent. Barth et al.6*7 reported removals comparable with those found by Stones for copper, nickel, and zinc. In studying the toxic effects of mercury on activated sludge, Ghosh and Zugger8 observed 51 to 58 per cent removal of the soluble mercury that was added to the mixed liquor and sug gested as a mechanism of removal either adsorption or incorporation into the cells. The complex and variable nature of com bined wastewater and activated sludge su pernatant suggests that a variety of soluble metal species may exist within the process. These may include, in addition to the free metal ion, complex species involving both organic and inorganic ligands. Because relatively little is known about the physical-chemical interactions between the activated sludge process and soluble metal ions, this study was undertaken to investigate the ability of the sludge to re move soluble metal species from wastewa ter and the affinity of the biological mass for selected heavy metals. The degree to which metal ions associate with the sludge determines the extent of reduction of solu ble metal in the supernatant and the con sequent effluent metal concentrations. A strong affinity between the sludge and metal, resulting in accumulation of the metal within the sludge, may enhance toxic effects that are not easily alleviated if the metal is tightly bound into the sludge. These toxic properties may carry over to digestion processes receiving excess sludge. Determination of sludge and supernatant association constants with heavy metals provides a useful tool for the assessment of physical-chemical interaction between the metal and the sludge. A cation-exchange technique, previously used by soil scientists to investigate metal-organic complexation in soil and its extracts, was used to deter mine the "apparent" stability constants of metal-supernatant and metal-sludge asso ciation.
134 citations
TL;DR: The physical characteristics and concentrations of major and trace metals, in 6 m long sediment cores from five marine locations in Hong Kong have been determined as discussed by the authors, and the most critical pollutant in the cores, copper, had normalized enrichment factors between 2.8 and 312 at the five sites, and surficial concentrations >6 g kg−1 in the upper sediment of the Typhoon Shelter sampling site.
134 citations
TL;DR: In this article, the concentration of Pb in atmospheric particulates collected along the length of the Atlantic Ocean from a variety of air masses was analyzed and the results are listed in Table 1, and the ship's track is shown in Fig. 1.
Abstract: MAN-INDUCED changes affecting the trace metal composition of seawater through river runoff have their initial effects in coastal regions close to the source of pollution. It is now recognized, however1,2, that atmospheric transport can introduce pollutants directly to the open ocean. There are still few data on the trace metal compositions of atmospheric particulates from oceanic areas and those that are available3–5 are from latitudinally restricted locations. Recently, we have carried out a sampling programme6–8 in which particulates have been collected from seawater and from the lower atmosphere (∼15 m above the sea surface) over large tracts of the world ocean. The collection details have been described elsewhere6 and here we present data on the concentration of Pb in atmospheric particulates collected along the length of the Atlantic Ocean from a variety of air masses. The results are listed in Table 1, and the ship's track is shown in Fig. 1.
133 citations