J. C. Jiménez Sánchez

Heavy metal extractable forms in sludge from wastewater treatment plants

The analysis of heavy metals is a very important task to assess the potential environmental and health risk associated with the sludge coming from wastewater treatment plants (WWTPs). However, it is widely accepted that the determination of total elements does not give an accurate estimation of the potential environmental impact. So, it is necessary to apply sequential extraction techniques to obtain a suitable information about their bioavailability or toxicity. In this paper, a sequential extraction scheme according to the BCRs guidelines was applied to sludge samples collected from each sludge treatment step of five municipal activated sludge plants. Al. Cd, Co, Cu, Cr, Fe, Mn, Hg, Mo, Ni, Pb, Ti and Zn were determined in the sludge extracts by inductively coupled plasma atomic emission spectrometry. In relation to current international legislation for the use of sludge for agricultural purposes none of metal concentrations exceeded maximum permitted levels. In most of the metal elements under considerations, results showed a clear rise along the sludge treatment in the proportion of two less-available fractions (oxidizable metal and residual metal).

Assessment of metals in sediments in a tributary of Guadalquivir River (Spain). Heavy metal partitioning and relation between the water and sediment system.

A physical-chemical characterisation of the sedimentsof the Guadaira River in Southwest Spain has beencarried out, determining twenty-three parameters persample. Non-treated urban sewage and industrialwastewaters from olive oil and table olives affectthis river. The factor analysis of the data showshigh organic matter contents with metallicpollution. Consequently, points downstreamstand out because of very high organic and metallicpollution (Zn, Pb, Cr, Cu and Cd, in order ofabundance, showing concentrations in sediments rangingfrom 50–7500 times those of waters). Heavy metals partitioning studies can be a goodapproach to show the real activity of these metals in theaquatic environment. We applied Tessiers analytical sequential extraction scheme to sediments.Sediments would be in general mildly hazardous because wefound low levels of easily interchangeable metals in the first fraction. Nevertheless, that is not thecase in the rivers last stretch, precisely wheresediments are most abundant, the heavy metal levelslargest and dredgings are made periodically. Here,their disposal is of concern; since the actual use ofthese sediments as organic amendment for agriculturalsoils is unacceptable.Interaction between waters and sediments in theriverbed by means of correlation, factor and clusteranalysis on waters and sediments data, wasinvestigated. With this approach we concluded that inthe final stretch there is a problem of contaminationof both, sediments and waters. However, in the middlecourse only sediments are actually polluted. Thiscorresponds to the previous research, when thesituation of waters in this zone was even worse.A physical-chemical characterisation of the sedimentsof the Guadaira River in Southwest Spain has beencarried out, determining twenty-three parameters persample. Non-treated urban sewage and industrialwastewaters from olive oil and table olives affectthis river. The factor analysis of the data showshigh organic matter contents with metallicpollution. Consequently, points downstreamstand out because of very high organic and metallicpollution (Zn, Pb, Cr, Cu and Cd, in order ofabundance, showing concentrations in sediments rangingfrom 50–7500 times those of waters). Heavy metals partitioning studies can be a goodapproach to show the real activity of these metals in theaquatic environment. We applied Tessiers analytical sequential extraction scheme to sediments.Sediments would be in general mildly hazardous because wefound low levels of easily interchangeable metals in the first fraction. Nevertheless, that is not thecase in the rivers last stretch, precisely wheresediments are most abundant, the heavy metal levelslargest and dredgings are made periodically. Here,their disposal is of concern; since the actual use ofthese sediments as organic amendment for agriculturalsoils is unacceptable.Interaction between waters and sediments in theriverbed by means of correlation, factor and clusteranalysis on waters and sediments data, wasinvestigated. With this approach we concluded that inthe final stretch there is a problem of contaminationof both, sediments and waters. However, in the middlecourse only sediments are actually polluted. Thiscorresponds to the previous research, when thesituation of waters in this zone was even worse.

The 4-phenyl-3-thiosemicarbazone of biacetylmonoxime as an analytical reagent. spectrophotometric determination of manganese

Abstract The analytical possibilities of the 4-phenyl-3-thiosemicarbazone or biacetylmonoxime were examined and compared with those of the thiosemicarbazone of biacetylmonoxime. Extraction of metal complexes into amyl alcohol and chloroform was studied in relation to pH. The manganese(III) complex is proposed for the selective spectrophotometric determination of manganese, by means of extraction in amyl alcohol, at pH 10. Beers law is obeyed between 2 and 12 p.p.m. of manganese (550 nm), the molar absorptivity being 3600 l mol-1 cm-1. Cobalt, copper and iron interfere, but interference of iron(III) may be eliminated by masking with tartrate.

Determination of heavy metals in sewage sludge by microwave acid digestion and inductively coupled plasma atomic emission spectrometry

A description is given of a method for the determination of metals in sewage sludge samples using an acid mixture of HNO3, HClO4 and HF and a microwave oven in open vessel. The elements Al, Cd, Co, Cu, Cr, Fe, Mn, Mo, Hg, Ni, Pb, Ti and Zn were measured by inductively coupled plasma atomic emission spectrometry. The results for the analysis of three reference materials (sewage sludge CRM 145R, sewage sludge from domestic origin CRM 144R and sewage sludge from industrial origin CRM 146R) after microwave acid digestion showed close agreement with the state values for all the metals studied (except Hg). The proposed method was applied to the analysis of Al, Cd, Co, Cu, Cr, Fe, Mn, Mo, Ni, Pb, Ti and Zn in a conventional sewage treatment work to the east of Seville.

Electrochemical oxidation of cisatracurium on carbon paste electrode and its analytical applications.

The electrochemical oxidation of cisatracurium was investigated by cyclic voltammetry and differential pulse voltammetry at a carbon paste electrode and the experimental parameters have been optimized in order to obtain the optimum analytical signal. A differential pulse voltammetric method with carbon paste electrode is described for the determination of cisatracurium with detection limit of 0.38 mug/ml and quantitation limit of 1.26 mug/ml. The proposed method was applied to determine the content of cisatracurium in human urine and human serum, obtaining accurate and precise results.

Electrochemical behaviour and determination of acrivastine in pharmaceuticals and human urine

Abstract The differential pulse polarography, DC-tast polarography and cyclic voltammetry behaviour of acrivastine was studied in Britton–Robinson buffer solutions (pH 2–11.7). In acidic media, a non-reversible diffusion controlled reduction process involving four electrons takes place. Two reduction waves appear at a E1/2=−0.6 and −0.99 V. The reduction mechanism is discussed. The linear relationship between peak current height and acrivastine concentration allowed the differential pulse polarographic determination of acrivastine over a wide concentration range, from 0.35 to 26.1 mg l−1at pH 2.5. The procedure was applied to determination of the drug in pharmaceutical formulations and human urine samples.

Differential-pulse polarographic determination of iron in acids, waters, fruit juices and wines

A method for the determination of iron by differential-pulse polarography, based on the formation of a 5,5-dimethylcyclohexane-1,2,3-trione 1,2-dioxime 3-thiosemicarbazone–iron(II) complex, is proposed. The method was applied to the determination of iron in acids, waters, wines and fruit juices.

Electrochemical Reduction of Cefepime at the Mercury Electrode

The differential pulse polarography, DC-tast polarography and cyclic voltammetry behavior of cefepime was studied in phosphate buffer solutions (pH 1.6–12.1). In acidic media, a non reversible diffusion controlled reduction process involving two electrons takes place. The reduction mechanism is discussed. The linear relationship between peak current intensity and cefepime concentration allowed the differential pulse polarographic determination of cefepime over a wide concentration range, from 10–6 to 10–4 M at pH 2.7, with a relative standard deviation of 1.7% (eleven determinations at the 4×10–5 M level). The described procedure has been applied to determination of the drug in pharmaceutical formulations and human urine samples.

Hydrochemical study of an aquifer system in an agricultural area in South West Spain

Abstract A hydrochemical study of an aquifer located in a wide agricultural region in the Guadalquivir river basin has been carried out. Samples of 51 points in the aquifer network have been taken, and 30 parameters, indicating its physical-chemical quality, have been determined for each sample. Classifications of the samples according to their hydrochemical facies have been established and the quality of waters for both agricultural and industrial uses has been tested. Its characteristics for processing to make them drinkable have also been assessed. Isocontent maps of some parameters have allowed to show the alarming pollution state of waters caused mainly by nitrates, and to a lesser extent by organic compounds and metals. Statistical Quality Indexes of both global and partial type has also been established.

A Voltammetry Procedure with Medium Exchange for the Speciation of Heavy Metals in Wastewater of a Sewage Treatment Plant

A scheme is proposed for the speciation of heavy metals based on the Nurnberg scheme with two modifications: the application of medium exchange to the anodic stripping voltammetric (ASV) measurement, and the destruction of organic matter and particulate. The protocol is suitable for making operational divisions of four categories for the elements zinc, cadmium, lead and copper in wastewater. Three of these elements can be simultaneously determined by ASV (cadmium is not detected). The parameters of the determination include: electrodeposition potential −1.2 V, time of deaerating 300 s, time of the electrolysis 90 s (with stirring) and the rest time 40 s. Medium exchange is done after the electrodeposition step. We have applied this procedure to the study of metal speciation in effluent from a conventional wastewater treatment plant of the city of Seville (Spain).