Seasonal Variations Of Trace Elements Research Articles

Seasonal variation in element concentrations in surface sediments of three rivers with different pollution input in Serbia

Purpose The main objective of this study was to evaluate the concentrations and seasonal variations of trace elements in surface sediments of three major rivers in Serbia—the Danube, the Zapadna Morava (ZM), and the Južna Morava (JM)—according to sediment quality guidelines. The ZM and the JM create the Velika Morava River, one of the most important tributaries of the Danube, which has been characterized as a source of heavy metal pollution.

Year-round record of dissolved and particulate metals in surface snow at Dome Concordia (East Antarctica)

From January to December 2010, surface snow samples were collected with monthly resolution at the Concordia station (75°06’S, 123°20’E), on the Antarctic plateau, and analysed for major and trace elements in both dissolved and particulate (i.e. insoluble particles, >0.45μm) phase. Additional surface snow samples were collected with daily resolution, for the determination of sea-salt sodium and not-sea-salt calcium, in order to support the discussion on the seasonal variations of trace elements. Concentrations of alkaline and alkaline-earth elements were higher in winter (April–October) than in summer (November–March) by a factor of 1.2–3.3, in agreement with the higher concentration of sea-salt atmospheric particles reaching the Antarctic plateau during the winter. Similarly, trace elements were generally higher in winter by a factor of 1.2–1.5, whereas Al and Fe did not show any significant seasonal trend.Partitioning between dissolved and particulate phases did not change with the sampling period, but it depended only on the element: alkaline and alkaline-earth elements, as well as Co, Cu, Mn, Pb and Zn were for the most part (>80%) in the dissolved phase, whereas Al and Fe were mainly associated with the particulate phase (>80%) and Cd, Cr, V were nearly equally distributed between the phases. Finally, the estimated marine and crustal enrichment factors indicated that Cd, Cr, Cu, Pb and Zn have a dominant anthropogenic origin, with a possible contribution from the Concordia station activities.

Seasonal variations of trace elements in precipitation at the largest city in Tibet, Lhasa

Precipitation samples were collected from March 2010 to August 2012 at an urban site in Lhasa, the capital and largest city of Tibet. The volume weighted mean (VWM) concentrations of 17 trace elements in precipitation were higher during the non-monsoon season than in the monsoon season, but inverse seasonal variations occurred for wet deposition fluxes of most of the trace elements. Concentrations for most of trace elements were negatively correlated with precipitation amount, indicating that below-cloud scavenging of trace elements was an important mechanism contributing to wet deposition of these elements. The elements Al, Sc, V, Cr, Mn, Fe, Mn, Ni, and U displayed low crustal enrichment factors (EFs), whereas Co, Cu, Zn, As, Cd Sn, Pb, and Bi showed high EF values in precipitation, suggesting that anthropogenic activities might be important contributors of these elements at Lhasa. However, this present work indicates a much lower anthropogenic emission at Lhasa than in seriously polluted regions. Our study will not only provide insights for assessing the current status of the atmospheric environment in Lhasa but also enhance our understanding for updating the baseline for environmental protection over the Tibetan Plateau.

Geochemical behavior of trace elements in sub-tidal marine sediments of the Belgian coast

High resolution profiles of trace elements (Fe, Mn, Co, As, Cu, Cr, Ni and Pb) were assessed using the DET (Diffusive Equilibrium in Thin films) and DGT (Diffusive Gradients in Thin films) techniques in silty, organically enriched, sub-tidal sediments of the Belgian coast during late winter and spring 2008. The general chemical properties of the sediments such as dissolved oxygen, pH, Eh and sulfide profiles, controlling precipitation/mobilization reactions, were determined with electrodes (pH and Eh) and microelectrodes (oxygen) and AgI-DGT probes (sulfide). Most trace elements show subsurface maxima and low concentrations beneath 8 cm of depth. The main physicochemical parameters controlling the vertical concentration profiles are dissolved oxygen and redox potential in the surface sediment and sulfide in the deeper sediment layers. Thermodynamic equilibrium calculations have been carried out verifying which solid phases can explain the dissolved trace metal concentrations. Seasonal variations of trace elements have been observed during the sampling period and sedimentation of fresh particulate organic matter (POM) derived from phytoplankton blooms appear to be the main cause of this temporal variability. Flux calculations based on DGT profiles (these fluxes are minimum ones) show that exchange fluxes of trace metals in February are slightly higher than in April. In addition, “DGT pistons” were deployed at the sediment water interface (SWI) to accumulate labile ions from below. This way all labile ions, binding onto the DGT Chelex resin, are pumped out of the pore waters and the solid sediment phase (only the mobile fraction). These results are a direct estimation of the amount of trace elements that can be released from the upper sediment to the water column (in the range of 4.4·10 − 5 to 0.10 mmol·m − 2 ·d − 1 for Co, Pb, Cr, As, Cu, Ni, Fe and Mn).

On-line Preconcentration System Using Mini-column Packed with a Chelating Resin for the Characterization of Seasonal Variations of Trace Elements in Seawater by ICP-MS and ICP-AES

An on-line column preconcentration technique coupled with inductively coupled plasma-mass spectrometry (ICP-MS) and -atomic emission spectrometry (ICP-AES) was developed using a mini-column (ca. 3 mm i.d., 40 mm length), that was packed with chelating resin (0.2 g) of iminodiacetic acid groups, Muromac A-1. After the preconcentration step, the column was washed with ammonium acetate buffer (pH 5.5) and water to remove major elements, such as Ca and Mg, and then eluted with 4 ml of 2 mol l(-1) nitric acid. Eleven trace elements (Al, V, Fe, Co, Ni, Cu, Zn, Cd, Pb, Th and U) in seawater were determined by ICP-MS/AES. Recoveries for most of the elements tested were over 90%, although those for Al, V and Th were around 70%. The accuracy of the proposed method was evaluated by analyzing a standard reference material of seawater (NASS-4, NRC Canada). The values of Fe, Co, Ni, Cu, Zn, Cd and Pb obtained with the present method showed good agreement with the certified values as judged from the standard deviation. The method was successfully applied to characterize seasonal variations of trace elements in deep seawater (DSW) and surface seawater (SSW). In addition, no serious decrease in analytical performance of the present column system was observed during the experimental period of about 1 year.

Seasonal variations of trace elements in the shrimp Penaeus semisulcatus from the Arabian Gulf

Seasonal variations of trace elements in the shrimp Penaeus semisulcatus from the Arabian Gulf

Seasonal Variations of Trace Elements and Organic Carbon in Dissolved and Particulate Phases of Tropical River Waters (Nyong Basin, Cameroon)

In recent years, there have been a large number of field studies aimed at improving our knowledge of weathering mechanisms in humid tropical landscapes (Viers et al., 1997; Braun et al., 1998; White et al., 1998). The present study focusses on the seasonal variations of organic carbon and trace elements in a series of rivers flowing through tropical forests in south Cameroon, Africa. These variations have been observed in the dissolved (<0.22 lam) and bulk (i.e. unfiltered) river waters composition. Indeed, the relative proportion of the dissolved and particulate phases to the bulk river water composition and their respective temporal variations in response to water discharge fluctuations give indications on the mechanisms which control the concentration of these trace elements. Firstly, we worked at the scale of the small Mengong river (1 km length) which drains the NsimiZo&616 site (100 ha) southern Cameroon. Secondly, we attempt to enlarge our observations to a set of three rivers (Awout, Soo, and Nyong) characterized by a gradual increase in their drainage surfaces and water discharges.

Seasonal variations of trace elements in dissolved and suspended loads for coal ash ponds and pond effluents

Determinations were made of the concentrations of elements in solution and in suspended solids of a settling basin/creek system receiving bottom ash, cyclone ash, fly ash and electrostatic precipitator ash. The concentrations of As, Ca, Cd, Cr, Cu, Fe, Mg, Mn, and Zn as well as physico-chemical parameters were compared for multiple sites in the basin/creek system and a pond without ash inputs from autumn to late summer. Comparison with published results obtained 6 to 7 yr earlier would show no significant change. Chemical speciation calculations indicate that most of the elements remain in the free hydrated or sulfate form throughout the study period. Copper and Fe exhibit some shifts in the concentrations of the hydroxy and carbonate complexes in responses to seasonal and biological factors.

Tidal and seasonal variations of trace elements in two Cornish estuaries

Tidal and seasonal changes in trace element concentrations have been studied in solution, suspended particulates and bottom sediments at locations in two Cornish estuaries. Results show that considerable differences in concentrations and behaviour of trace elements occur on a tidal and seasonal basis. These differences have been related to the influences of freshwater input from mineralized catchments and discussed in terms of mixing of run-off with saline waters during diurnal and annual cycles.