Este trabalho descreve um método simples e rápido para a determinação de BTEX (benzeno, tolueno, etilbenzeno e xileno) em resíduos sólidos e soluções lixiviadas de resíduos sólidos aplicando a Norma Brasileira ABNT NBR 10004/2004. O método proposto possibilita a detecção direta de BTEX usando microextração em fase sólida e cromatografia a gás com detector por ionização em chama (HS-SPME GC/FID). Os limites de quantificação obtidos para BTEX evidenciaram que o método é adequado para a classificação de resíduos sólidos.

This work describes a simple and fast method for the determination of BTEX (benzene, toluene, ethylbenzene and xylene) in solid waste and solutions obtained from leaching applying procedures detailed in the ABNT NBR 10004/2004 Brazilian standard for the classification of solid residues. The proposed method allows the direct detection of BTEX using solid-phase microextraction and gas chromatography with a flame ionization detector (HS-SPME GC/FID). Limits of quantification for BTEX showed that the developed method is suitable for the classification of solid wastes.

The toxicity of cadmium and chromium to Pseudokirchneriella subcapitata and Microcystis aeruginosa was evaluated through algal growth rate during 96h exposure bioassays. Free metal ion concentrations were obtained using MINEQL+ 4.61 and used for IC50 determination. Metal accumulations by the microorganisms were determined and they were found to be dependent on the concentration of Cd2+ and Cr6+. IC50 for P. subcapitata were 0.60 µmol L-1 free Cd2+ and 20 µmol L-1 free Cr6+, while the IC50 values for M. aeruginosa were 0.01 µmol L-1 Cd2+ and 11.07 µmol L-1 Cr6+ . P. subcapitata accumulated higher metal concentrations (0.001 -0.05 µmol Cd mg-1 dry wt. and 0.001 -0.04 µmol Cr mg-1 dry wt) than the cyanobacteria (0.001 -0.01 µmol Cd mg-1 dry wt and 0.001 -0.02 µmol Cr mg-1 dry wt). Cadmium was more toxic than chromium to both the microorganisms.

This work describes methodologies for speciation analysis of the metals copper and zinc as total, total dissolved, labile, as well as complexation capacity (conditional stability constants and available ligand concentration), using the same technique, differential pulse anodic stripping voltammetry (DPASV). Several supporting electrolytes were tested, and the results showed that KNO3 and HNO3 resulted in voltamograms without interferences as well as excellent resolution for the total and labile fractions. The methodology using the DPASV technique allows a simple and low cost analysis of copper and zinc speciation, with high precision and sensitivity, with limits of quantification (LOQ) of 1.8 nmol L-1 for copper and 2.1 nmol L-1 for zinc.