We apply the chemical speciation model WHAM/Model VII to investigate the distribution of metal species of Fe(III) and the divalent cations of Ni, Cu, Zn, Cd, Hg and Pb, in the water column of estuaries and coastal areas. We compare, for the same locations, measured and modelled free ion and organically bound metal concentrations. The modelled free ion calculations show varying levels of agreement with experimental measurements. Where only natural organic matter is considered as the organic ligand, for Ni, Cd and Pb, agreement within one order of magnitude is found in 122 of 128 comparisons. For Fe and Zn comparisons 12 of 34 (Fe) and 10 of 18 (Zn) agree to within one order of magnitude, the remaining modelled values being over one order of magnitude higher than measurements. Copper measurements agree within one order of magnitude of modelled values in 314 of 533 (59%) cases and are more than one order of magnitude lower than modelled values in 202 cases. There is a general tendency for agreement between modelled and measured values to improve with increasing total metal concentrations. There are substantial variations among different analysis techniques but no systematic bias from the model is observed across techniques. It would be beneficial to crossvalidate the different analytical methods, in combination with further modelling. We also assessed the effect of including an anthropogenic organic ligand (EDTA) in the modelling, given its known presence in some coastal environments. Except for Cd, all metals were sensitive to the presence of EDTA, even at a low concentration of 50 nM. This article is protected by copyright. All rights reserved
Organic-rich sediment samples collected from a transect within, and below, the Oman Margin oxygen minimum zone (OMZ) were analysed using a sequential leaching technique to characterise the diagenetic behaviour and speciation of Mn and Fe in operationally defined sediment host fractions. Trace metals showed distinct diagenetic behaviour in the two contrasting environments that were sampled. The absence of non-detrital Mn in the cores below the OMZ site is attributed to the lack of easily reducible oxides in...
Solid-phase microextraction (SPME) has been used as an in situ sampling technique for a wide range of volatile organic chemicals, but SPME field sampling of nonvolatile organic pollutants has not been reported. This paper describes the development of an SPME-based sampling method employing a poly(dimethylsiloxane) (PDMS)-coated (100-ím thickness) fiber as the sorbent phase. The laboratory-calibrated PDMS-coated fibers were used to construct SPME samplers, and field tests were conducted at three coastal...
Selected ground water sampling and field-filtration methods were evaluated to determine their effects on field parameters and trace metal concentrations in samples collected under several types of field conditions. The study
focused on conditions where traditional approaches may produce turbid samples, which often leads to filtration
of suspended particles from the sample before laboratory chemical analysis. However, filtration may also remove
colloidal particles that may be important to the transport of...
The study estimates the influence of PVC on the quantity and hazardousness of flue gas residues from incineration. The analysis has been carried out on both theoretical and practical terms. A distinction between dry, semi-dry and wet gas treatment systems has been made. The influence of PVC has been assessed on the combustion steps and therefore on the distribution of chlorine and other pollutants (heavy metals, and trace elements) among the solid phase (bottom ash) and the gas phase (raw-gas). The additional...
ULTRAPURE WATER CRITERIA - AN OVERVIEW
`Pure water` is a relative term. Practically speaking, no water, naturally occurring or treated by man, consists solely of H2O molecules. Forever in pursuit of achieving equilibrium with its surroundings, water has unique characteristics that result in its ability to dissolve most matter. This property of water to dissolve and transport materials is employed by the electronics industry for the critical rinsing steps essential to the fabrication of integrated microcircuitry....
Abstract
The biodegradability and mineralization of five different types of biodegradable bags made of biodegradable polymers were examined. The starch based products disintegrated within two weeks of the rotting process. The polycaprolactone-based products started to disintegrate after a short lag time and the paper bag needed about twelve weeks to disintegrate. The study of the mineralization process has lead to similar results as the disintegration of the polymers in the compost reactors. The analysis of the...
Summary
The soil of large areas is contaminated by heavy metals: Agricultural land and gardens are affected. Additionally mine tailings and waste deposits contain metals. Conventional remediation methods (e.g. soil washing) to eliminate the problems are comparably expensive. Alternatives are needed: Certain wild plants as well as crop plants, so-called hyperaccumulators, are able to accumulate large amounts of heavy metals in aerial parts. This property may be exploited for the extraction of metals from soil or...
Heavy metals were evaporated from filter ashes (FA) of municipal solid waste incineration in the hot zone of a thermochromatographic tube to test the possibility of heavy metal separation by fractionated condensation. With help of the theoretical sublimation enthalpies and the experimental condensation temperatures a model was developed to predict the speciation in the gas phase and to interpret the observed condensation behavior. The condensation behavior strongly depends on the composition of the carrier gas...
Introduction
Pollution Prevention Guidelines to provide technical advice and guidance to staff and consultants involved in pollution-related projects. The guidelines represent state-of-the-art thinking on how to reduce pollution emissions from the production process. In many cases, the guidelines provide numerical targets for reducing pollution, as well as maximum emissions levels that are normally achievable through a combination of cleaner production and end-of-pipe treatment. The guidelines are designed to...
Introduction
Pollution Prevention Guidelines to provide technical advice and guidance to staff and consultants involved in pollution-related projects. The guidelines represent state-of-the-art thinking on how to reduce pollution emissions from the production process. In many cases, the guidelines provide numerical targets for reducing pollution, as well as maximum emissions levels that are normally achievable through a combination of cleaner production and end-of-pipe treatment. The guidelines are designed to...
Introduction
Pollution Prevention Guidelines to provide technical advice and guidance to staff and consultants involved in pollution-related projects. The guidelines represent state-of-the-art thinking on how to reduce pollution emissions from the production process. In many cases, the guidelines provide numerical targets for reducing pollution, as well as maximum emissions levels that are normally achievable through a combination of cleaner production and end-of-pipe treatment. The guidelines are designed to...
` Economic analysis of pollution prevention and abatement measures requires estimating the potential benefits from controlling pollution as well as the better-known costs of new equipment or processes. This note discusses the economic analysis of environmental externalities, using a wide range of valuation techniques.`
Industrial activities often produce various pollutants; these include air and water pollution as well as solid and/or toxic wastes. Since these pollutants may impose costs on society and individuals...
` In order to determine the impacts of a particular discharge on ambient water quality, it is usually necessary to model the diffusion and dispersion of the discharge in the relevant water body. The approach applies both to new discharges and to upgrading of existing sources. This note provides guidance on models that may be applicable in the context of typical Bank projects.`
Introduction
Mathematical models can be used to predict changes in ambient water quality due to changes in discharges of wastewater. In...
A treatment train is the combination of different treatment technologies. A system diagram of a common treatment train for inorganics is illustrated below. Metal contaminated soil is treated using the combination of electrokinetics and phytoremediation. Electrokinetics is used to remove metals from deep soil and ground water. A low density direct current is applied to mobilize charged species, causing ions and water to move toward the electrodes. Metal ions move toward the cathode, and anions move toward anode....
SummaryWaste discharges from municipal sewage treatment plants are a significant source of water quality problems throughout the country. States report that municipal discharges are the main source of impairment to estuaries and coastal waters, the second leading source of impaired rivers and streams, and also are a major source of pollution in lakes. Pollutants associated with municipal discharges include nutrients (which can stimulate growth of algae that deplete dissolved oxygen in surface water), bacteria and...
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