Trace Metals In Fresh Waters Research Articles

Remediation of acid mine drainage and immobilization of rare earth elements: Comparison between natural and residual alkaline materials

Acid mine drainage (AMD) is a well-known source of toxic trace metals in freshwaters. Traditional passive treatment systems rely on AMD neutralization with limestone and removal of most common toxic transition metals such as Cu and Zn with little attention to rare earth elements (REE). Alkaline waste materials now receive increasing attention as low cost AMD treatment alternatives in the circular economy. This study was set up to identify the efficiency of alkaline waste materials remediating AMD and scavenging REE in addition to other toxic trace elements. An AMD sample was collected from a lixiviate coming from pyrite heaps in the Iberian Pyrite Belt (pH = 1.8, 30 μM ∑REY). The sample was treated with either blast furnace slag (BFS) generated during smelting of iron ore in a blast furnace or biomass ashes (BA) derived from combustion of biomass, thereby using analytical grade CaCO3, and NaOH as reference products. The batch alkalinization experiments were conducted by adding each alkaline material at an amount to obtain an equal pH to ≈6.5. The required amounts of the products were NaOH < CaCO3<BFS < BA in line with their acid neutralizing capacities. The largest removal of sulfate from water was obtained in the CaCO3 treatment suggesting gypsum precipitation which was lower with BA and BFS and virtually absent with NaOH, these trends were confirmed by SEM-EDX and XRD. Both BFS and BA removed more Fe than CaCO3 and NaOH. The REE elements were well removed by all treatments (>99%) and the remaining REE concentrations in the solutions were clearly lower than values for Cu and Zn. The Zn and Cu removals were not consistently high enough (except with NaOH) to meet environmental limits in the discharge waters. The largest efficiency for REE removals was obtained with CaCO3. Indirect evidence here suggests that gypsum is a better host for the trivalent REE than Fe(III) minerals in the precipitates. The ionic radii of trivalent REE are more similar to Ca2+ than to Fe3+, explaining the better potential of gypsum as REE host. This study showed also the potential of BFS as alkaline agent for the remediation of AMD in terms of its higher alkalinity generation potential as compared to BA, thus making BA less promising than BFS.

Effects of Biofilms on Trace Metal Adsorption on Plastics in Freshwater Systems.

The formation of plastisphere on plastics and their potential impact on freshwater ecosystems have drawn increasing attention. However, there is still limited information about the effects of plastisphere on the heavy metal adsorption capacity and the related mechanism of plastic debris in different freshwaters. Herein, the trace metal adsorption capacity, kinetics and adsorption mechanisms of virgin and biofilm-covered plastic debris were investigated. Polypropylene (PP) and polyethylene terephthalate (PET) plastic debris were placed in three freshwaters (Xuanwu Lake, Donghu Lake and the Qinhuai River) for 45 days to incubate biofilms. Batch adsorption experiments were performed to compare the adsorption processes of trace metal on virgin and biofilm-covered plastics. Results showed that biofilms increase the adsorption of metals on plastics, and the adsorption isotherms were well fitted by the Langmuir model. Furthermore, the adsorption capacities for lead (Pb(II)) were higher than that of cadmium (Cd(II)) and zinc (Zn(II)), with 256.21 and 277.38 μg/g (Pb(II)) adsorbed in biofilm-covered PP and PET, respectively, in Xuanwu Lake. The adsorption kinetics of metals on plastic debris were significantly affected by the biofilms, by switching the intraparticle diffusion for virgin plastic debris to film diffusion for the biofilm-covered plastic debris. Moreover, the complexation of functional groups within the biofilms might mainly contribute to the increases of metal adsorption, involving the participation of oxygen and nitrogen groups. Overall, these results suggested that biofilms reinforce the potential role of plastics as a carrier of trace metals in freshwaters.

Automated separation and measurement of 226Ra and trace metals in freshwater, seawater and fracking water by online ion exchange chromatography coupled with ICP-MS

An online solid-phase extraction method combined with ICP-MS was developed to separate and quantify low levels of 226Ra and other metals in drinking water, lake, river and sea water, and fracking fluids. A dual-column lab-on-valve and multi-syringe flow injection analysis (LOV-MSFIA) system was developed to provide precise measurement of 226Ra in samples with total dissolved solids (TDS) less than 2%. For samples with higher levels of TDS (up to 20%), a triple-column LOV-MSFIA system was developed, which used AG 50 W-X8 cation exchange, Sr spec andNobias Chelate resins. Compared to earlier automated systems for Ra analysis, the dual and triple column systems described here were optimized to accommodate smaller sample volumes, more precise flow control and lower limits of detection (LOD). The LOV-MSFIA system coupled with ICP-MS is a significant improvement over traditional methods for low level 226Ra measurements, which require extended sample holding and/or analysis time. External calibration and standard addition were used to quantify the concentration of Ra for the LOV-MSFIA system. After method optimization, LODs for 226Ra as low as 4.3 mBq L−1 (1.75 fg L−1) were obtained in different sample matrices. The concentrations of selected metals were also measured on the triple-column system, together with Ra, with a total online processing time of 28.5 min per sample. Thus, the online LOV-MSFIA system is shown to be a powerful tool for the rapid analysis of low levels of 226Ra, as well as other metals, in various types of aqueous samples.

Speciation of Inorganic Compounds in Aquatic Systems Using Diffusive Gradients in Thin-Films: A Review.

The speciation of trace metals in an aquatic system involves the determination of free ions, complexes (labile and non-labile), colloids, and the total dissolved concentration. In this paper, we review the integrated assessment of free ions and labile metal complexes using Diffusive Gradients in Thin-films (DGT), a dynamic speciation technique. The device consists of a diffusive hydrogel layer made of polyacrylamide, backed by a layer of resin (usually Chelex-100) for all trace metals except for Hg. The best results for Hg speciation are obtained with agarose as hydrogel and a thiol-based resin. The diffusive domain controls the diffusion flux of the metal ions and complexes to the resin, which strongly binds all free ions. By using DGT devices with different thicknesses of the diffusive or resin gels and exploiting expressions derived from kinetic models, one can determine the labile concentrations, mobilities, and labilities of different species of an element in an aquatic system. This procedure has been applied to the determination of the organic pool of trace metals in freshwaters or to the characterization of organic and inorganic complexes in sea waters. The concentrations that are obtained represent time-weighted averages (TWA) over the deployment period.

Microplastics as an emerging anthropogenic vector of trace metals in freshwater: Significance of biofilms and comparison with natural substrates

Microplastics (MPs) are ubiquitous in freshwater environments, and represent an emerging anthropogenic vector for contaminants, such as trace metals. In this study, virgin expanded polystyrene (PS) particles were placed in a eutrophic urban lake and a reservoir serving as the resource of domestic water for 4 weeks, to develop biofilms on the surface. For comparison, natural adsorbents in the form of suspended particles and surficial sediment were also sampled from these waterbodies. The trace metal adsorption properties of anthropogenic (virgin and biofilm covered microplastics) and natural substrates were investigated and compared via batch adsorption experiments. The adsorption isotherms fitted the Langmuir model, revealed that biofilms could enhance the trace metal adsorption capacity of MPs. However, natural substrates still had a greater adsorption capacity. Biofilms also alter the adsorption kinetics of trace metals onto MPs. The process of adsorption onto virgin MPs was dominated by intraparticle diffusion, whereas film diffusion governed adsorption onto biofilm covered microplastics and natural substrates. The trace metal adsorption of all the substrates was significantly dependent on pH and ionic strength. The adsorption mechanisms were further analyzed by SEM-EDS and FT-IR. The enhancement of adsorption was mainly attributed to complexation with functional groups contained in the biofilms, including carboxyl, amino, and phenyl-OH. Collectively, biofilm development intensifies the role of MPs in the migration and fate of trace metals in freshwater, since it does not give MPs an edge over natural substrates in adsorption.

Do biofilms affect the measurement of mercury by the DGT technique? Microcosm and field tests to prevent biofilm growth

The diffusive gradients in thin films (DGT) technique has been used routinely for monitoring the dissolved, bioavailable fraction of trace metals in freshwater during field campaigns. Nevertheless, for long deployment times, the biofilm formed on the filter of the DGT devices restricts trace metal uptake and hence interferes with the DGT measurements. In this work, we design different experiments to evaluate the potential of silver nanoparticles (AgNPs) in preventing the formation of biofilms on in-house manufactured mercury-specific DGTs. Laboratory tests were carried out by a microcosm system in independent glass containers, where biofilms obtained from field inocula were grown for weeks. Afterward, several experiments were performed with Hg-spiked river water, biofilms and DGTs treated and untreated with AgNPs to better understand biofilm colonization, inhibition and Hg uptake. The results showed that the treatment is very useful, since the mass of the biofilm accumulated at the surface of the treated DGT is significantly (p < 0.05) lower than in control (untreated) devices. Tests in colonized environments and Hg-spiked river water showed that the Hg uptake by the treated DGT matched the theoretical values and prevented biofilm formation up to 24 days post-deployment. Conversely, in deployments longer than two weeks using the untreated DGT, measurements could be underestimated by 35%. The results in the field reveal that in sampling stations with high levels of suspended matter, the filter becomes clogged despite there being no biofilm, thereby explaining its low efficiency for the uptake of Hg. In summary, the use of AgNPs inhibits biofilm formation and their use is especially recommended in eutrophic freshwaters with low amounts of suspended particulate matter.

The Study of Self-Assembled Au Nanoparticles As an Efficient SERS Substrate for Environmental Sensing Applications

The formation of self-assembled monolayers (SAM) of noble metals for optical sensing applications faces serious challenges when trying to achieve simplicity, cost efficacy, specificity, and versatility. Utilizing stable, SAM-forming alkanethiols, such as glutathione (GSH), enable for simple assembly and specific detection of proteins, trace metals, oxidants, etc., thus providing a sensing platform that not only can detect low levels of reactive oxygen species (ROS) for early determination of neurodegenerative diseases, but can also assess trace metals in freshwaters and marine waters, for example. Providing a universal device for detecting varieties of target materials would adapt, simplify, and reduce costs that come from current detection methods. Our research on improving these detection methods is demonstrated using the frequency-controlled self-assembly of a GSH-functionalized gold nanoparticle (Au NP) film as a platform for highly specific and sensitive sensing. We have previously demonstrated the use of an eco-friendly and highly sensitive surface enhanced Raman spectroscopy (SERS) substrate for biomedical diagnostic applications using an ultraviolet photochemical reaction of gold (III) chloride trihydrate (HAuCl4) to create a densely packed Au NP film that exhibits localized surface plasmon resonances [1]. By the firm anchoring of a thiol group to the Au NP surface, GSH assembles the Au NPs for SERS into a densely packed, dendritic structure. At a pH of ~1 in solution, GSH forms a y-shape [2], allowing its carboxyl and amino groups to create a hydrophilic interface and, therefore, be fully available for bonding to various functional molecules. Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), and ultraviolet-visible spectroscopy (UV-vis) were used to confirm the presence of GSH and enhancement capabilities of the SERS substrate. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) confirmed the Au NP film to be 90nm thick, with an average Au NP size of 125nm in diameter [1], and visually confirmed the dendritic assembly of the GSH-functionalized Au NPs. For application purposes, this study will evaluate the trace metal Pb2+ in water. The contamination of lead, and heavy metals in general, have a damaging impact on the health of both humans and our planet. The chelation of the GSH ligands with Pb2+ enables highly specific detection of Pb2+ in water. This method provides a simple, versatile SERS substrate with a dendritic assembly that creates intriguing optical properties and broadens the capability for potential applications. [1] G. Rutherford et al., ECS J. Solid State Sci. Tech. 4, S3071 (2015). [2] M. Bieri and T. Burgi, Langmuir 2005, 21, 1354-1362. Figure 1

Trace metals in the NE Atlantic coastal zone of Finisterre (Iberian Peninsula): Terrestrial and marine sources and rates of sedimentation

The biogeochemical patterns of bioactive metals (Cd, Co, Cu, Ni, V and Zn) and Pb were studied in the Corcubión Sound, an area close to Cape Finisterre (NW Iberian Peninsula). Seasonal patterns of dissolved and particulate trace metals in freshwater and seawater, as well as in phytoplankton were determined during three upwelling events in the winter, late spring and summer of 2005. Metals were also analyzed in the surface and to 1m-depth in the sediments. Upwelling patterns permit the discrimination between those of the outer Sound and Corcubión Inlet. Dissolved trace metal concentrations in the seawater of the outer Sound were in the range of those reported for the Northeast Atlantic Ocean. Mean values of dissolved metal concentrations in the upwelled ENACW were: 0.07±0.03nMCd, 0.11±0.02nMCo, 2.6±1.6nMCu, 4.6±0.6nMNi, 0.20±0.10nMPb, 31±2nMV and 3.8±2.3nMZn. Higher values for dissolved Co, Cu and Zn were measured in two inflowing streams and in the Inlet. A severe–moderate contamination of these metals and Pb was detected in the sediments of the Inlet. Three different sediment layers were observed in cores located at the outer-Inlet boundary. The most recent showed the highest mass accumulation rates, mainly of Cu (e.g. 428mgCu·m−2·yr−1), Pb and Zn, during the last decade. The intermediate unit corresponds to the 20th century (e.g. 39mgCu·m−2·yr−1) and the deeper layer from the 19th to 14th centuries can be regarded as representing the pre-industrial period, and shows the lowest rates of metal accumulation (e.g. 7mgCu·m−2·yr−1). Diatoms were the main autochthonous source of metals in the sediments. The genera Chaetoceros and Lauderia dominate the overlaying seawater during winter and Pseudonitzschia and Leptocylindrus were typical of summer blooms while in the sediments Chaetoceros, Paralia, Leptocylindrus and Thalassionema were the main diatom genera. The comparison of the normalized metal vs. Si in the phytoplankton and vs. Si in the biogenic opal of the sediment shows a prevailing lithogenic–anthropogenic origin of metals such as Cu, Fe, Ni, Pb and V while the upwelling was the main source for Cd in the sediments because of the settling of diatoms. The continental influence and metal contamination are restricted to the innermost part of Sound during the last century where the anthropogenic activities supply Cd, Cu, Pb and Zn. Seasonally, dissolved trace metal concentrations in the outer Sound are within the normal range measured in the north-eastern Atlantic Ocean. The Sound system is pristine compared with the neighboring and anthropogenically disturbed rias, and may be a good reference of natural trace metal levels along the north-eastern Atlantic coast.

Interpretation of In Situ Speciation Measurements of Inorganic and Organically Complexed Trace Metals in Freshwater by DGT

The dynamic speciation technique, diffusive gradients in thin-films (DGT), has been used in freshwater to determine simultaneously, from a single set of in situ measurements, (1) the equilibrium distribution of metal ions between simple inorganic complexes and larger organic complexes and (2) information on the rates of dissociation of these complexes. DGT devices with different diffusion layer thicknesses (0.3, 0.54, 1.34, and 2.14 mm) were used to estimate the in situ dissociation kinetics. Information on the species distribution was obtained by using two types of gel, which allow relatively free (polyacrylamide, APA) and more retarded (restricted, RES) diffusion of the metal complexes. The full theoretical basis of the technique is developed and applied to in situ measurements of Mn, Fe, Co, Ni, Cu, Cd, and Pb in a pristine river (Wyre, U.K.), with high DOC(15mg L(-1)), assuming that organic complexes are dominated by fulvic acid. These first DGT measurements that do not rely on assumptions about complex lability or the distribution of species, are compared to total dissolved measurements, previously reported speciation calculations and measurements using alternative speciation techniques. Examination of calculation consistency suggests that the effective mean diffusion coefficients of metal complexes with organic matter under in situ conditions may be larger than those measured in the laboratory using extracted fulvic acid.

Admicelle-mediated collection followed by flotation for the preconcentration of trace metals in fresh waters

Dithizone-impregnated admicelles were prepared by mixing silica particles with dithizone and cetyltrimethylammonium chloride in 0.1 mol L −1 aqueous ammonia. The resulting admicelles were added to 1000 mL of sample solution and dispersed by stirring for 15 min. Traces of Ni(II), Cu(II), Ga(III), Cd(II), Pb(II) and Bi(III) in the solution were simultaneously incorporated into the admicelles at pH 7.5–9. With the aid of a rising stream of numerous tiny bubbles, the admicelles were floated on the solution surface and collected in a small sampling vessel by suction. The metals were desorbed from the admicelles with dilute nitric acid and determined by inductively coupled plasma-mass spectrometry. The proposed method offered a 100-fold multielement preconcentration and it was applicable to the analysis of river and pond waters.

Use of the diffusion gradient thin film method to measure trace metals in fresh waters at low ionic strength

The diffusion gradients in thin films (DGT) method was investigated and used to measure trace metal concentrations in river water. The principle of DGT is that trace metal ions diffuse through a thin polyacrylamide gel film (the diffusion gel layer) and are subsequently immobilised and concentrated on a layer of Chelex-100 resin embedded in another polyacrylamide gel film (the resin gel layer). These layers are mounted in a plastic holder, which exposes a fixed area of the diffusion gel layer to the water being monitored. Replacement of the normal agarose cross-linked diffusion gel with bisacrylamide cross-linked gel altered the ion uptake properties of DGT. The bisacrylamide cross-linked gel weakly, and with little selectivity, bound metal ions prior to their irreversible binding to Chelex-100. Trace metal ion uptake by these DGT devices was thus dependent on ionic strength and temperature, although the ionic strength effect is relatively small for most natural waters and negligible in sea water. The concentrations of Cd, Co, Cu, Ni, Pb, and Zn in the Water of Leith, an urban stream in Dunedin, New Zealand, were measured by DGT and the results compared with total dissolved concentrations of these metals measured in conventional (bottle) samples collected in parallel with the DGT monitoring. Greater than 90% of the total dissolved Cd and Zn; 20–40% of the total dissolved Co, Ni, and Pb; and 5% of the total dissolved Cu was available to the DGT method.

Evidence for iron, copper and zinc complexation as multinuclear sulphide clusters in oxic rivers

The availability and toxicity of trace metals in fresh water are known to be regulated by the complexation of free metal ions with dissolved organic matter. The potential role of inorganic sulphides in binding trace metals has been largely ignored because of the reduced persistence of sulphides in these oxic waters. However, nanomolar concentrations of copper and zinc sulphides have been observed in four rivers in Connecticut and Maryland. Here we report dissolved (< 0.2 microm particle diameter) sulphide concentrations ranging up to 600 nM, with more than 90% being complexed by copper, iron and zinc. These complexes account for up to 20% of the total dissolved Fe and Zn and 45% of the total dissolved Cu. Fourier transform mass spectrometry reveals that these complexes are not simple M(HS)+ protonated species but are higher-order unprotonated clusters (M3S3, M4S6, M2S4), similar to those found in laboratory solutions and bio-inorganic molecules. These extended structures have high stability constants and are resistant to oxidation and dissociation, which may help control the toxicity of these and other less abundant, but more toxic, trace metals, such as silver, cadmium and mercury.

A Critical Evaluation of Tangential-Flow Ultrafiltration for Trace Metal Studies in Freshwater Systems. 1. Organic Carbon

The utility of tangential flow ultrafiltration (TFUF) for size fractionation of natural organic matter (NOM) in freshwater streams was investigated, focusing on characterization or elimination of potential artifacts. Spiral-wound polyethersulfone (PES) and regenerated cellulose (RCL) membranes with nominal molecular weight limits of 10 kilodalton (kDa) and 100 kDa were compared as part of a large project assessing the utility of large volume (>5 L) ultrafiltration for determining trace metal speciation in freshwaters. With careful cleaning, reliable fractionations of carbon and trace metals in freshwater can be obtained, and a detailed protocol necessary to avoid potentially significant biases is presented. Both PES and RCL membranes can be cleaned efficiently to provide low carbon blanks (<0.03 mg C L-1) and recleaned at least 10 times without compromising membrane integrity. For RCL, residual acid from the cleaning procedure can lower the permeate pH to below 4 in low-alkalinity river samples, but this acid can be removed prior to sample filtration with a simple treatment. Mass balance experiments with stream NOM show good recovery (99.7% ± 9.5%, n = 67). Sorption losses are very low (on average, <2%) to RCL membranes but are higher for PES. Replicate precision is typically better than ±5% for carbon. There are significant differences between PES and RCL membranes: permeate carbon levels are similar, but RCL predicts a larger >10 kDa fraction and carbon sorption is more significant on PES. These findings could be explained by greater hydrophobic interactions of dissolved organic carbon with PES and charge interactions with RCL. A strong negative correlation is observed between the percent of colloidal carbon (10 kDa − 0.4 μm) and the log specific conductance of streamwaters (R 2 = 0.71).

The effect of freshwater UV-irradiation prior to resin preconcentration of trace metals

Trace metal concentrations in natural freshwater samples are often below detection limits for determination by inductively coupled plasma-mass spectrometry (ICP-MS). This is especially so following size fractionation of the sample. Preconcentration is therefore necessary, and sorption on a chelating resin such as Chelex-100 is often used. In order to chelate metals strongly complexed with organics, the metal–organic association has to be severed. In this study, ultra violet (UV)-irradiation was used to oxidize organic matter in a humic acid reference solution, and in a natural sample spiked with Ag, Cd, Cu and Pb, where the recoveries of the metals were calculated. Except for Ag, recoveries of Cd, Cu and Pb increased significantly up to almost 100% after irradiation. If preconcentration on Chelex-100 is used, UV-irradiation appears to be an essential step in achieving accurate concentrations of organically chelated trace metals in freshwater.

Temporal variation and distribution of trace metals in freshwater and fish from Calabar River, S.E. Nigeria

An investigation on the abundance and distribution of trace metals (Fe, Cu, Zn, Mn, Cr, Cd and Pb) in water, and nine species of fish samples from Calabar river was carried out in 1992. The concentrations of iron (6000–7240 μg l−1), zinc (4910–7230 μg l−1), and cadmium (3–7 μg l−1) showed moderate pollution while those of copper (420–630 μg l−1), manganese (23–48 μg l−1), chromium ( Zn > Cu > Mn > Pb > Cd = Cr and were within the limits that were safe for consumption.

Sources of Trace Metal Contamination Artifacts during Collection, Handling, and Analysis of Freshwaters

Clean techniques are necessary for reliable measurement of trace metals in freshwaters at ambient, though not necessarily regulatory concentrations. Conventional sample handling methods were compared to clean techniques for 35 individual steps used in protocols for analysis of filtrate and filter-retained forms of Ag, Cd, Cu, and Pb. Approximately two-thirds of all steps contributed statistically significant amounts of contamination in the measurement of dissolved and particulate Cd, Cu, and Pb. Average contamination for a single contributing step was 300%, 141%, and 200% for the three metals, respectively (where 100% represents no added contamination). Relative Cu contamination tended to be lower, partly because real levels in water are higher for this metal. Contamination generally was not a problem for Ag, when it was present in water at higher than background levels. With that exception, it does not seem possible to abridge clean technique protocols, even when measuring trace metals in polluted freshw...

Multi-element speciation of trace metals in fresh water adapted to plasma source mass spectrometry

A method for speciation of trace metals at natural concentration levels has been developed. The speciation is carried out in a cleanroom laboratory and the determination is performed with an ICP-MS. The method is based on fractionation of metal species on three adsorbents. Chelex-100, Sep-Pak C-18 and Fractogel DEAE. The method distinguishes between labile complexes, non-polar organic adsorbable matter and ion exchangeable substances. The filtered water samples are pumped through columns with the adsorbents. Following a prefraction, samples for determination of metal concentrations are taken. The adsorbents are not eluted. After extensive cleaning, the used adsorbents have blank values that are low enough for trace metal analysis in fresh water. Concentration and speciation data for Al, Cd, Co, Cu, Fe, Pb, Mn, Mo, Ni and Zn are obtained.

Studies on metal speciation in the natural environment

A scheme for metal speciation has been developed and applied to samples of river water, rain and snow. The scheme combines physical speciation by size using ultrafiltration of the soluble metal species with chemical characterization of the metal species by their dissociation kinetics. The kinetics of metal complex dissociation was studied by anodic stripping voltammetry and by ion exchange at Chelex-100 cation-exchange resin, using both the Chelex column and the Chelex batch technique. These kinetic studies cover a time scale of measurement of ca. 2 ms for anodic stripping voltammetry and up to 6 days for Chelex batch technique, a range of about 8 orders of magnitude. The kinetic results suggest that the copper in the snow sample (pH 3.9) is probably bound to different sites having different bonding energies in polyfunctional complexing agents. Four different copper species having dissociation rate constants of 3.1 X 10 −2, 1.6 X 10 −3, 6.2 X 10 −5, and 8.8 X 10 −6, s −1 have been observed. All of these species fall in the small size fractions of ultrafiltration. The Al in the Rideau River water sample (pH 8) is probably bound to the different sites in humic materials to yield dissociation rate constants 1.6 X 10 −4, 1.0 X 10 −6 and < 10 −6 s −1. In the Rideau River water sample, most of the soluble Al species have a large molecular size and are probably associated with humic materials. On the other hand, most of the soluble Al species in the small size fraction are Chelex-nonlabile and are probably Al(OH) − 4. Use of graphite platform furnace atomic absorption spectrometer allows direct determination of trace metals in freshwaters, to be done routinely, rapidly, and inexpensively.

A Protocol for Minimizing Contamination in the Analysis of Trace Metals in Great Lakes Waters

The precautions and procedures aimed at minimizing contamination artifacts during the collection, filtration, and analysis of trace metals in fresh water are described. The techniques for proper decontamination of sample containers and labware and for field blanks are also presented. Samples are obtained using a portable clean laboratory and analyzed in a Class 100 pressurized room. Preliminary results obtained using the protocols described cast doubt on most of the published data on trace metal concentrations in the Great Lakes. The profiles of dissolved metal concentrations in the water column of Lake Ontario show very distinctive source-dependent features obfuscated in earlier studies by poor data quality.

Determination of trace metals in freshwaters by inductively coupled argon plasma atomic emission spectrometry with a heated spray chamber and desolvation

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDetermination of trace metals in freshwaters by inductively coupled argon plasma atomic emission spectrometry with a heated spray chamber and desolvationPeter D. Goulden and Donald H. J. AnthonyCite this: Anal. Chem. 1982, 54, 11, 1678–1681Publication Date (Print):September 1, 1982Publication History Published online1 May 2002Published inissue 1 September 1982https://doi.org/10.1021/ac00248a005RIGHTS & PERMISSIONSArticle Views65Altmetric-Citations25LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (492 KB) Get e-Alerts Get e-Alerts