The exchange membranes P81 and DE81 and Chelex-100 resin were used to perform in situ speciation of uranium in treated acid mine drainage at the Osamu Utsumi mining site, Poços de Caldas city, Southeast Brazil. To investigate possible chemical modifications in the samples during analysis, the three ligands were deployed in situ and in a laboratory (in lab). The results obtained in situ were also compared to a speciation performed using Visual MINTEQ software. Chelex-100 retained total labile U for a period of up to 48 h. The labile U fraction determined by Chelex 100 ranged from 107 ± 6% to 147 ± 44% in situ and from 115 ± 22% to 191 ± 5% in lab. DE81 retained anionic U species up to 8 h, with labile fractions ranging from 37 ± 2% to 76 ± 3% in situ and 34 ± 12% to 180 ± 17% in lab. P81 exhibited a lower efficiency in retaining U species, with concentrations ranging from 6± 2% to 19± 2% in situ and 3± 2% to 18± 2% in lab. The speciation obtained from MINTEQ suggests that the major U species were UOOH, UO(OH), UO(OH), CaUO(CO), CaUO(CO), UO(CO), and UO(CO). This result is in accordance with the results obtained in situ. Differences concerning speciation and the total and soluble U concentrations were observed between the deployments performed in situ and in the laboratory, indicating that U speciation must be performed in situ.

The toxic metal lead (Pb) can be harmful to human health in various manners, but is also considered as a distinguished tracer of environmental pollution since the relative abundance of its four stable isotopes with the atomic masses of 204, 206, 207, and 208 varies with the emission source. This study is focused on the Pb concentrations and isotope ratios in the particulate matter of the Brazilian city of Goiânia in order to determine the main Pb emission sources. Particulate matter samples were collected on clean Teflon filters during rainy and dry season in 2014 in the center of Goiânia city near main roads with a high traffic volume. Pb concentrations as well as stable Pb isotope ratios of the particulate matter samples were analyzed by inductively coupled plasma-mass spectrometry. To apply this analytical technique successfully, it was necessary to optimize parameters in case of acquisition time, detector dead time, and mass discrimination, which affect the measurement accuracy and precision. Results showed that Pb concentrations in Goiânia were different between rainy and dry season. Pb concentrations showed higher values and less variation in dry season than in rainy season. Pb isotope ratios demonstrated significant variations between dry and rainy season. An enrichment of Pb isotopes related toPb and Pb isotopes was observed in dry season. However, the comparison of the obtained isotopic Pb signature with data of potential Pb sources from previous studies indicated that traffic-related sources should be considered as main Pb source in the particulate matter of Goiânia. These assumptions were incorporated by the calculation of the contribution factor of Pb coming from traffic-related sources by applying binary mixing equations.

This work aims to evaluate the size and lability of Cu and Zn bound to proteins in the cytosol of fish liver of Oreochromis niloticus by employing solid phase extraction (SPE), Diffusive gradients in thin films (DGT) and ultrafiltration (UF). SPE was carried out using Chelex-100. DGT containing Chelex-100 as binding agent was employed. Analyte concentrations were determined by ICP-MS. Total Cu and Zn concentration in cytosol (1g of fish liver in 5mL of TRIS-HCl) ranged from 39.6 to 44.3 ng m L−1 and 1498 to 2106 ng mL−1, respectively. Data from UF (10-30 kDa) suggested that Cu and Zn in cytosol was associated to about 70% and 95%, respectively, with high-molecular weight proteins. Cu-metallothionein was not selectively detected (although 28% of Cu was associated with low-molecular weight proteins). However, information about the specific proteins in cytosol will require coupling UF with organic mass spectrometry. Data from SPE showed the presence of labile Cu species of about 17%, while the fraction of labile Zn species was higher than 55%. However, data from DGT suggested a fraction of labile Cu species only of 7% and a labile Zn fraction of 5%. This data, as compared with previous data from literature, suggests that the DGT technique gave a more plausible estimation of the labile pool of Zn and Cu in cytosol. The combination of results from UF and DGT is capable to contribute to the knowledge about the labile and low-molecular pool of Cu and Zn.

The world wide use of tilapia for different approaches in fish bioassay was exploited to assess the accumulation of copper and cadmium, in isolated forms and in combination in gills and muscular tissue in the specie Oreochromis niloticus, which is of economical relevance in fish consumption in the Sao Paulo State, Brazil. To reach for these goals, semi-static chronic toxicity tests were carried out during 21 days by using two dissolved concentrations of each trace element as follow: LC50/10 and the average of LC50/10 and LC50/100. Fish samplings to assess for the kinetic trace element absorptions with time were performed at 24, 96 hours, 7, 14 and 21 days. After 14 days of exposure gills had higher concentrations for both elements (5.20 mg Kg-1 Cu and 4.89 mg kg-1 Cd), than the muscular tissue (0.79 mg Kg-1 Cu e 0.32 mg Kg-1 Cd). A competition for absorption was established when both elements were in combination, being the maximum absorbed concentrations, 1.81 mg Kg-1 Cu and 1.54 mg Kg-1 Cd for the gills and 0.63 mg Kg-1 Cu and 0.12 mg Kg-1 Cd for the muscular tissue. The Tukey test used for the statistical evaluation of the exposure period times dissolved metal concentration interactions revealed the interference of the basal Cd and Cu contents of the fish on the results. Despite the verified bioaccumulation, in which BCF for Cd were lower than the BCF for Cu, the fractions of the LCs50 were not lethal to the fish. Tilapia did not concentrate Cu and Cd in the edible tissue at concentrations to bring restrictions for human consumption.