Assessing the deposition and remobilisation behaviour of metals between river water and river sediment using partial least squares regression

Partial least squares regression (PLS) as a method for multivariate data analysis has been applied to environmental data of the German rivers Saale, Ilm and Unstrut. Main aspects of the study are to describe the relationships of the distribution of metals between river water and river sediment using PLS. A simulation of the distribution of metals between the liquid and solid phase by variation of some parameters (e.g. conductivity, DOC, dissolved oxygen, pH, phosphate and suspended matter) is presented and compared with experimental results. Received: 15 July 1997 / Revised: 6 November 1997 / Accepted: 7 November 1997     

Chemometric investigations on the differentiated evaluation of element trace analysis in river waters

The combination of sequential leaching methods for a first assessment of the kind of species in river sediments with multivariate-statistical methods (like factor analysis) for identifying anthropogenic and/or geogenic loading is useful for the differentiated characterization of the pollution state of a river. Electrochemical investigations, planned on the basis of statistical design and following empirical modelling, enables quantitative conclusions on the binding forms of heavy metals in river waters. Deposition-remobilisation effects of heavy metals in the complex system river water-river sediment can be described by PLS modelling.     

Quantitative description of element concentrations in longitudinal river profiles by multiway PLS models

Partial least squares (PLS) models were used to examine the relationships between the distributions of elements in different compartments of a river. These relationships, if existing, enabled predictions to be made of the element concentrations in one compartment by knowing the concentrations in another compartment. The subjects of the study were the element concentrations measured in the water and the sediment of the river Saale as well as in the water and the suspended matter of the river Elbe. Special emphasis was placed on a comparison between two-way and three-way PLS.     

Quantitative description of element concentrations in longitudinal river profiles by multiway PLS models

Partial least squares (PLS) models were used to examine the relationships between the distributions of elements in different compartments of a river. These relationships, if existing, enabled predictions to be made of the element concentrations in one compartment by knowing the concentrations in another compartment. The subjects of the study were the element concentrations measured in the water and the sediment of the river Saale as well as in the water and the suspended matter of the river Elbe. Special emphasis was placed on a comparison between two-way and three-way PLS. Received: 13 March 1998 / Revised: 29 October 1998 / Accepted: 17 November 1998     

Heavy-metal pollution and its state in algae in Kakehashi river and Godani river at the foot of Ogoya mine, Ishikawa Prefecture.

Alga as Achnanthes minutissima among diatoms is a widely adaptable taxon on the state of an aquatic environment. In this study, it was found that diatom had a specific tolerance to heavy metals (Cu, Zn, Pb, and Cd etc.) in river water samples, because the diatom assemblage consisted of almost only Achnanthes minutissima in Kakehashi river and Godani river, which were polluted with waste water from Ogoya copper mine. The relationship between the concentrations of heavy metals (Cu, Zn, Pb and Cd) in river water and the attached substances (algae and silt etc.) and the relative abundances of diatom taxa were investigated in detail. The results indicated that the higher is the concentration of heavy metals in the river environment, the higher is only the relative abundances of Achnanthes minutissima. Thus, the taxon can be used as a bioindicator of heavy metal pollution. The relative rates of toxic chemical forms of copper in algae were 61 - 92% in the attached substances and 49-70% in the sediment on the river bed, respectively. Therefore, it was found that diatom as Achnanthes minutissima had a tolerance to heavy metals in river water, being able to live in such an environment. Since the water treated with calcium hydroxide from the deposition reservoir of Ogoya mine enters in Godani river, the river is polluted by heavy metals (Cu, Zn, Pb and Cd etc.). From the viewpoint of both biological and chemical analyses, Godani river is still polluted with heavy metals, because their concentrations in the river samples were very high. On the other hand, in Kakehashi river, the concentrations of heavy metals were very low and the distributions of some diatoms appeared in an unpolluted Nishimata river were observed. Therefore, Kakehashi river seems to be considerably recovered from heavy-metal pollution after closing the Ogoya mine.     

Multielement determination of trace metals in river water (certified reference material, JSAC 0301-1) by high efficiency nebulization ICP-MS after 100-fold preconcentration with a chelating resin-packed minicolumn.

The determination of 34 trace metals in a river water certified reference material (CRM), i.e. JSAC 0301-1, which was issued by the Japan Society for Analytical Chemistry in January 2004, was performed by ICP-MS with a high efficiency nebulizer after preconcentration with a laboratory-made chelating resin-packed minicolumn, with which trace metals were concentrated 100-fold from 50 mL of a river water sample to 0.5 mL of the final analysis solution. Trace metals in JSAC 0301-1 were observed in the concentration range from 19 microg L(-1) of Al to 0.000053 microg L(-1) of Bi. It was found that most of the concentrations of trace metals, including rare earth elements (REEs), in JSAC 0301-1 were lower than those in JAC 0031, which was also a previously issued CRM prepared with water from the same river as that of JSAC 0301-1. The low concentrations of trace metals in JSAC 0301-1 might be attributed to the fact that there was a heavy rain before collecting the original water sample to prepare the present CRM. Furthermore, the REE distribution patterns of JSAC 0301-1, JAC 0031 and the average values of river water samples in Japan were parallel to each other. These results indicate that the distributions of REEs in JSAC 0301-1 and JAC 0031 were the typical ones of river water samples in Japan.     

Simultaneous Anodic Stripping Voltammetric Determination of Pb and Cd,Using a Vibrating Gold Microwire Electrode,Assisted by Chemometric Techniques

Simultaneous anodic stripping voltammetric determination of Pb and Cd is restricted on gold electrodes as a result of the overlapping of these two peaks. This work describes the quantitative determination of a binary mixture system of Pb and Cd, at low concentration levels (up to 15.0 and 10.0 µg L^?1 for Pb and Cd, respectively) by differential pulse anodic stripping voltammetry (DPASV; deposition time of 30 s), using a green electrode (vibrating gold microwire electrode) without purging in a chloride medium (0.5 M NaCl) under moderate acidic conditions (HCl 1.0 mM), assisted by chemometric tools. The application of multivariate curve resolution alternating least squares (MCR‐ALS) for the resolution and quantification of both metals is shown. The optimized MCR‐ALS models showed good prediction ability with concentration prediction errors of 12.4 and 11.4 % for Pb and Cd, respectively. The quantitative results obtained by MCR‐ALS were compared to those obtained with partial least squares (PLS) and classical least squares (CLS) regression methods. For both metals, PLS and MCR‐ALS results are comparable and superior to CLS. For Cd, as a result of the peak shift problem, the application of CLS was unsuitable. MCR‐ALS provides additional advantage compared to PLS since it estimates the pure response of the analytes signal. Finally, the built up multivariate calibration models, based either in MCR‐ALS or PLS regression, allowed to quantify concentrations of Pb and Cd in surface river water samples, with satisfactory results.     

Simultaneous Determination of Chromium(VI) and Aluminum(III) by Adsorptive Stripping Voltammetry with Pyrocatechol Violet

A new methodology is presented for the simultaneous determination of chromium(VI) and aluminum(III) by differential‐pulse adsorptive stripping voltammetry (DPAdSV) with Pyrocatechol Violet (PCV) as a complexing agent. In this procedure, a partial least‐squares regression (PLS) is used for the resolution of the strongly overlapping voltammetric signals from mixtures of Cr^VI and Al^III in the presence of PCV. The procedure was successfully applied to the determination of these metals in river water.     

Heavy-metal distribution in river waters and sediments around a "firefly village", Shikoku, Japan: application of multivariate analysis.

River water and sediment samples were collected at the same site in a vicinity of an abandoned mine, and the concentrations of major elements and heavy metals were determined. The chemical correlations were observed by principal component analysis (PCA), and the samples were classified by cluster analysis (CA) based on the PCA scores. The PCA results presented a macroscopic viewpoint of covariance structure, i.e., the chemical elements could be classified into three groups: 1) major elements and heavy metals in the river water, 2) Cd, Fe and Mn in the sediments, and 3) Cu and Zn in the sediments. The CA results implied a similarity of chemical compositions in most parts of the study area, except the ranges close to the abandoned copper mine. At the mixing location of mining water with natural river water, major elements and cadmium showed simple physical mixing (conservative mixing). Other heavy metals (Cu, Fe, Mn and Zn) showed the massive precipitation at the mixing event. The PCA structure was mainly interpreted in terms of the mixing process between mining water and diluted natural river water.     

Major and trace elements in sediments of the upper course of Lerma river

Summary The Lerma is one of the most important rivers of Mexico, where it drains highly populated and industrialized regions. The concentration of six major and trace elements: titanium, manganese, iron, zinc, copper and lead in the surface sediments of the upper course of Lerma river was investigated, in order to identify its distribution along the river and to recognize the principal sites of pollution. The surface sediment samples were collected at 8 sites distributed following the stream flow direction of the river. Major and trace elements concentrations were determined by energy dispersive X-ray spectrometry. The results show that the metal concentrations in the sediments decrease in the sequence: Fe > Ti > Mn > Zn > Cu > Pb. Concentration of Fe, Mn and Ti were significantly higher than the other metals in site 8,200 meters downstream the Alzate Dam. The high concentrations and spatial variations of Zn, Cu and Pb in the middle sites of the upper course of the Lerma River indicate that the river pollution is probably associated with urban and industrial discharges.     

Analysis of heavy metals and sulphur-rich compounds in the water moss Fontinalis antipyretica L. ex Hedw.

The water moss Fontinalis antipyretica has been investigated to estimate heavy metal pollution in the river Elbe (middle Germany). Procedures of plant separation, digestion as well as an analytical method for ICP-MS analyses have been evaluated. Reproducibility and accuracy have been demonstrated on BCR 61 (NIST) reference material and results have been compared with AAS and AES data. The distribution of heavy metals in different plant segments of indigenous material has been analyzed. Exposition of plant material in the river Elbe have shown no correlation between the heavy metal content in plants and that of water samples. Cd and Zn concentrations found in the plant material are significantly enriched relatively to control samples. To understand the sophisticated ‘real system’ experiments have been carried out under laboratory conditions to investigate induced sulphur-rich compounds in the presence of heavy metals using HPLC including on-line derivatization.     

Environmetric modeling and interpretation of river water monitoring data

This environmetric study deals with modeling and interpretation of river water monitoring data from the basin of the Saale river and its tributaries the Ilm and the Unstrut. For a period of one year of observation between September 1993 and August 1994 a data set from twelve campaigns at twenty-nine sampling sites from the Saale river and six campaigns from the river Ilm at seven sampling sites and from river Unstrut at ten sampling sites was collected. Twenty-seven chemical and physicochemical properties were measured to estimate the water quality. The application of cluster analysis, principal components analysis, and apportioning modeling on absolute principal components scores revealed important information about the ecological status of the region of interest:identification of two separate patterns of pollution (upper and lower stream of the rivers);identification of six latent factors responsible for the data structure with different content for the two identified pollution patterns; anddetermination of the contribution of each latent factor (source of emission) to the formation of the total concentration of the chemical burden of the river water.As a result more objective ecological policy and decision making is possible.     

Application of instrumental neutron activation analysis and inductively coupled plasma-mass spectrometry to studying the river pollution in the State of Minas Gerais

Instrumental neutron activation analysis (INAA) and inductively coupled plasma-mass spectrometry (ICP-MS) have been used for the determination of toxic heavy metals and other pollutants in the water of the Das Velhas river in the State of Minas Gerais, in south-east Brazil. Elemental concentrations of about 60 elements were measured in water samples collected to different parts of this river and from two affluents. There was a good agreement between the two analytical methods and the results were complementary. The results indicated an increase in the concentration of several polluting elements in the water from mining industry area.     

Characterization of anthropogenic sediment particles after a transboundary water pollution of river Tisza using synchrotron radiation

At the beginning of 2000, a major mining accident occurred in the Romanian part of the Tisza catchment area due to tailings dam failure releasing huge amounts of heavy metals to the river. Sediment samples were taken from the main riverbed at six sites in Hungary, on March 16, 2000. The objective of this work was to characterize the anthropogenic particles in river sediment previously selected by single-particle electron probe X-ray microanalysis (EPMA). The trace element composition, heterogeneity and heavy metal speciation of individual particles was studied using synchrotron radiation-based microbeam X-ray emission and absorption methods. Particles were selected only from samples regarded as polluted sediment. White-beam micro X-ray fluorescence (μ-XRF) allowed the quantitative determination of heavy metals such as cadmium in individual particles. The maximum observed concentration of cadmium (>700 μg/g) indicates that this highly toxic heavy metal is concentrated in individual anthropogenic particles. Using the combination of micro X-ray absorption near-edge structure and target-transformation principle component analysis, quantitative chemical speciation of copper and zinc was feasible on individual sediment particles. Heavy metals in most of the particles released from the pollution site remained in the sulfide form resulting in a limited mobility of these metals. Based on the information obtained using microanalytical methods, the estimation of the environmental mobility of heavy metals connected to microparticles becomes possible.     

Multicomponent determination of the pesticide naptalam and its metabolites in river water, by applying partial least squares calibration to the derivative spectrophotometric signals

A multivariate calibration method, partial least squares (types PLS-1 and PLS-2), was applied to the simultaneous determination of naptalam (N-(1-naphthyl) phthalamic acid) and its metabolites N-(1-naphthyl) phthalimide and 1-naphthylamine in mixtures by UV-visible absorption spectrophotometry. The absorption and first-derivative absorption spectra of mixtures were used to perform the optimization of the calibration matrices by the PLS method. Two different experimental designs for the three-component mixtures are assayed and the results are discussed. The proposed method with the derivative spectra was applied to the determination of these analytes in river water at the ppb level.     

Different strategies to assess Cu and Pb mobilization in polluted river sediments

Summary For studying the mechanisms of trace metal mobilization in sediments several strategies have been employed, such as single extraction, sequential extractions, ion exchange, or progressive acidification. Several authors assert that sequential extraction is the best option. In this study two procedures are used in order to assess the mobility of copper and lead in heavily polluted river sediments: sequential extraction using a modified Tessier procedure, and progressive acidification, using an automated method. Six heavily polluted sediment samples are studied by applying the two procedures. The amount of metal released at different pH-values (pH 5 and pH 2) is compared with the resulting distribution when the sequential extraction procedure is applied. The information obtained from the two different approaches is discussed. For both metals a different behaviour is observed when applying each of the two procedures. Thus, copper is more easily released than lead when progressive acidification is followed, whereas an inverse situation is observed when sequential extraction is applied.     

Application of a Cation-Exchange Membrane to Determine Cations of Trace Metals in River Water

Donnan-membrane-equilibrium graphite-furnace atomic-absorption spectrophotometry (DME-GFAAS) has been developed to determine cations of trace metals in river water. The method employs a cation-exchange membrane to separate metal cations from their complexes; both total and cationic forms of metals were determined by means of GFAAS. The sensitivity of the method for the measurement of trace metal cations is determined by the detection limits of GFAAS for the metals of interest. Comparable concentrations of metal cations in water from NBS and from the Erhjen river were obtained between the DME-GFAAS and calculated (WATEQ4F) methods, indicating that the developed method is promising for natural fresh waters. The effect of pH on the distribution of metal cation in the NBS river water is significant for Cu and Pb; concentrations of these cations increase with decreasing pH. However, the concentrations of Cd and Zn cations do not vary with pH except that the concentration of the Zn cation decreases significantly as the pH value increases beyond 9. The method was applied to measure the capacity of complexing Cu in Chung-Lu river water, which was estimated to be 2.3 μM.     

Metal content in river suspended particulate matter: data on Po River

The present study summarizes the last ten years of literature on heavy metal distribution in Suspended Particulate Matter (SPM) and dissolved phase in the Po River (Italy). The work compares different methodologies employed to collect, concentrate and fractionate the samples. The importance of metal speciation as a function of particle size is underlined and two approaches to metal speciation in the colloidal fraction of Po River SPM are presented: Sedimentation Field-Flow Fractionation (SdFFF) and pH-dependent extractions. Finally, emphasis is placed on the need for comparison with a reference "natural background level" of the metal load in Po River particulate matter in order to determine the real human contribution to river pollution. The high values of some trace transition elements, such as Cr and Ni, have been compared with clay sediments around Ferrara and with bricks in historic buildings. The highly comparable natural concentration of these metals in Po fine sedimentary rocks and in historic brick buildings of Ferrara (XII-XVI centuries) can provide information on natural geochemical anomalies.