Determination of metals by total reflection X-ray fluorescence and evaluation of toxicity of a river impacted by coal mining in the south of Brazil.

Metal (Fe, Mn, Zn, Ni, Cd, and Pb) concentrations in the region of Criciuma (Brazil), a region impacted by coal mining, were determined in water and sediments using total reflection X-ray fluorescence (TXRF) spectroscopy. Samples were collected from the Mãe Luzia River (south Brazil) at five different stations, from the source down to the river mouth (Ararangua estuary). Water and sediment toxicity were also evaluated using bioassays with Daphnia magna as the bioindicator.

Evaluation of lead desorption from cement matrices.

Desorption of lead immobilized into cement and concrete matrices was evaluated in the pH range between 4 and 8 within a period of 2 h to 15 days. Lead-desorbed content in aqueous milieu was monitored by Graphite Furnace Atomic Absorption Spectroscopy, while matrices were directly analyzed by X-ray photoelectronic spectroscopy or Rutherford Backscattering spectrometry. For low pH, higher Pb desorption was observed, about 5-7 times higher than that measured in the case of concrete matrices.

Rapid screening method for determination of PCDDs and PCDFs in fly ashes using GC-ion trap MS/MS based on cellular disruptor extraction.

Identification and quantification of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in fly ashes from incinerator was carried out using capillary gas chromatography/tandem mass spectrometry (GC/MS/MS) with a low resolution ion trap mass spectrometer. Sample extraction was carried out in a cellular disruptor, in Soxhlet and in a conventional ultrasound for comparative purposes. Extraction with cellular disruptor was shown to be comparable to that obtained by the reference Soxhlet extraction, while low recoveries were observed with ultrasound.