Sediments metal analysis

Figure 15-12 is a schematic illustration of a technique known as acid volatile sulfides/ simultaneously extracted metals analysis (AVS/SEM). Briefly, a strong acid is added to a sediment sample to release the sediment-associated sulfides, acid volatile sulfides, which are analyzed by a cold-acid purge-and-trap technique (e.g., Allen et ai, 1993). The assumption shown in Fig. 15-12 is that the sulfides are present in the sediments in the form of either FeS or MeS (a metal sulfide). In a parallel analysis, metals simultaneously released with the sulfides (the simultaneously extracted metals) are also quantified, for example, by graphite furnace atomic absorption spectrometry. Metals released during the acid attack are considered to be associated with the phases operationally defined as "exchangeable," "carbonate," "Fe and Mn oxides," "FeS," and "MeS."... 

Batley, G. E., and Giles, M. S. (1979). Solvent displacement of sediment interstitial waters before trace-metal analysis. Water Res. 13(9), 879-886. 

Tack, F. M. G., and Verloo, M. G. (1995). Chemical speciation and fractionation in soil and sediment heavy metal analysis A review. Int.J. Environ. Anal. Chem. 59(2—4), 225. 

The other popular sequential extraction procedure is the protocol proposed by the Community Bureau of Reference, Commission of the European Community (known as the BCR protocol). The method was proposed on the basis of interlaboratory smdies undertaken in order to harmonize conditions for soil and sediment sample analysis. Based on the research data, in 1992 it was stated that application of EDTA or acetic acid solution is appropriate and sufficient for elimination of the bioaccessible fi action of metals from soil samples [62]. In the case of other samples, best results were achieved after application of a three-stage procedure with the following extractants ... 

Salomons W. and Forstner U. (1980) Trace metal analysis on polluted sediments II. Evaluation of environmental impact. Environ. Technol. Lett. 1, 506—517. 

Figure 1. Apparatus for sampling water for trace metals analysis. It is designed to sample 0,1 m from the sediment-water interface and 0,5 m below the air-water interface.

Trace metal analysis of a specific grain size fraction of sediment < 64 pm (sieving) < 20 pm (sieving) < 2 pm (settling tube) O Reilly Wiese, Bubb Lester (1995) Ackermann, Bergmann Schleichert (1983) Banat, Forstner Muller (1972)... 

Carignan, R., Rapin, F. Tessier, A. (1985) Sediment pore water sampling for metal analysis A comparison of techniques. Geochim. Cosmochim. Acta 49., 2493-2497. 

Ackermann (1980) A procedure for correcting the grain size effect in heavy metal analysis of estuarine and coastal sediments. Environ. Technol. Lett. 1., 518-527. 

The analysis of trace metals in seawater, sediments, and marine organisms has always been a major preoccupation of marine chemists the analytical literature contains methods for almost every element in the periodic table. Most of these methods have never been adopted by anyone other than the original author, as improvements in machine methods overtook methods based on chemical manipulations. In my own case, my Ph.D. thesis [16] described a number of novel methods for trace-metal analysis in sediments, all of which became irrelevant with the advent of atomic absorption analysis. The newer machine methods pin-pointed the wide range of values found in the literature for many trace metals, and by the late 1960s it was obvious that some sort of intercomparison or intercalibration was needed for the trace metals most commonly measured. 

Guevara R, Rizzo A, Sanchez R (2005) Heavy metal inputs in northern Patagonia lakes from short sediment core analysis. J Radioanal Nucl Ghem 265(3) 481-493 Guo JN, Li JB, Wu JY (1983) Research on the distribution of Fe, Al, Mn in sediments of Bohai and its geochemical characteristics. Mar Sci 4 22-25 (in Chinese with English abstract)... 

Bufflap, S. E. Allen, H. E. 1995. Sediment pore water collection methods for trace metal analysis a review. Water Research, 29(1), 165-177. 

Sediment Analysis. Sediment is the most chemically and biologically active component of the aquatic environment. Benthic invertebrate and microbial life concentrate in the sediment, a natural sink for precipitated metal forms, and an excellent sorbent for many metal species. TTie extent to which potentially toxic trace element forms bind to sediment is determined by the sediment s binding intensity and capacity and various solution parameters, as well as the concentration and nature of the metal forms of interest. Under some conditions sediment analyses can readily indicate sources of discharged trace elements. 

Allen, H. E., Fu, G. and Deng, B. (1993). Analysis of acid-volatile sulfide (AVS) and simultaneously extracted metals (SEM) for the estimation of potential toxicity in aquatic sediments. Environ. Toxicol. Chem. 12,1441-1453. 

Krishnamurty, K. V. et al., At. Abs. Newslett., 1976, 15, 68-70 When preparing soil and sediment samples for atomic absorption spectral analysis for trace metals, pre-oxidation with nitric acid before addition of hydrogen peroxide eliminates the danger of explosion. 

Shipboard analysis for the sampling of trace metals in seawater has been discussed by Schuessler and Kremling [2] and Dunn et al. [3]. Teasdale et al. have reviewed methods for collection of sediment pore-waters using in situ dialysis samples [4]. Bufflap and Allen [5] compared centrifugation, squeezing, vacuum filtration, and dialysis methods for sediment pore-water sampling. 

A sample may be characterized by the determination of a number of different analytes. For example, a hydrocarbon mixture can be analysed by use of a series of UV absorption peaks. Alternatively, in a sediment sample a range of trace metals may be determined. Collectively, these data represent patterns characteristic of the samples, and similar samples will have similar patterns. Results may be compared by vectorial presentation of the variables, when the variables for similar samples will form clusters. Hence the term cluster analysis. Where only two variables are studied, clusters are readily recognized in a two-dimensional graphical presentation. For more complex systems with more variables, i.e. //, the clusters will be in -dimensional space. Principal component analysis (PCA) explores the interdependence of pairs of variables in order to reduce the number to certain principal components. A practical example could be drawn from the sediment analysis mentioned above. Trace metals are often attached to sediment particles by sorption on to the hydrous oxides of Al, Fe and Mn that are present. The Al content could be a principal component to which the other metal contents are related. Factor analysis is a more sophisticated form of principal component analysis. 

The actual analysis of the samples started with a qualitative survey to identify the principal metals present. ICP-AES was selected as being most suitable for this because it provided a permanent record, a multi-element analysis, and good sensitivity. Solutions of the shellfish tissue were prepared for analysis by wet oxidation, and the sediments were digested with 40% v/v... 

Chemical analysis of the Meza River and its tributaries revealed significant heavy metal pollution of the upper Meza River sediments with lead, zinc, and some molybdenum, cadmium and arsenic enrichments. The trend of Cd and As is similar to trend of Pb and Zn, which is in agreement with the fact that Cd and As are associated with Pb and Zn in ore minerals (Strucl, 1984 Fux Gosar, 2007). In the lower Meza valley, these heavy metal concentrations decreased somewhat. 

The freeze-dried sediments were subjected to both a total dissolution and a selective extraction. The latter, as described in Chester Hughes (1967), is carried out in a hydroxylamine hydrochloride and acetic acid (HA) solution and designed to isolate reactive phases. With the exception of total Se, extracted metals were determined by the method described for porewaters. Total solid Se concentrations were measured by AAS with HG-FIAS (analysis ongoing). 

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