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The fractionation of heavy metals in riverbed sediments along the Tiete River basin, a highly polluted river in southeast region of Brazil, was investigated using a four-step sequential extraction procedure, in order to determine the concentration and distribution of Cu, Co, Cr, Cd, Zn, Ni and Pb, in the river bottom sediments, related to the potential mobility of geochemical phases. Around the metropolitan area of the City of Sao Paulo, which has 25 million people, the pollution is associated with municipal wastes and industrial effluents. Potentials of high mobility were observed for Cu and Zn along the entire river basin, associated mainly to the organic fraction, while at the Pirapora and Anhembi stations (upper and middle parts of the basin, respectively) the reactive forms of Ni and Pb were more associated to the Fe and Mn oxides. Near the mouth of the Tiete River, no significant contaminations caused by Cr and Ni in riverbed sediments was verified confirming the presence of these metals in ...

Inorganic components were surveyed of some Brazilian cigarette tobacco by INAA. Sixteen different brands were taken from the consumer market and analyzed for As, Ba, Br, Ca, Ce, Co, Cr, Cs, Eu, Fe, K, La, Na, Rb, Sc, Sm, Sr and Zn elements. Comparisons between the results from this work and those originated from several cigarette tobacco producing countries, indicate significant variation in the levels of some elements.

The elemental composition of pine trees as a function of age was achieved by the tree-ring method. By using instrumental neutron activation analysis, trace elements were determined in individual rings ofPinus elliottii var.elliottii of 32, 14 and 9 years, from an implanted forest ofPinus sp., Buri, Sao Paulo, far away from industrial pollution. Different components of the system such as needles, pith, bark, soil and litter were also analyzed for 18 elements (As, Br, Ce, Co, Cs, Eu, Fe, Hf, K, La, Mn, Na, Rb, Sc, Sm, Yb, Zn, and Zr). Al, B, Ba, Ca, Fe, K, Mg, and P concentrations were determined by atomic absorption and/or emission spectrometry (AAS; ICP-AES). Some elements have showed similar radial distribution of the concentration for the three ages. Abrupt concentration changes in the pith and ring-bark boundary corresponding to the first and last growth rings were observed.

The interactive processes operating on the continental shelf adjacent to the river mouth control the amount and the characteristics of the Amazon discharge reaching the Atlantic Ocean. In this study, the distribution of trace elemental concentrations, with emphasis to the rare-earth elements, in sediment cores collected at several stations from the Amazon continental shelf during the falling water period was investigated by instrumental neutron activation analysis. Cores from the terrigenous and blue water zones have relatively uniform REE concentrations throughout the profile. Cerium anomalies for samples of the upper section of the eight stations are consistently positive and of high values (normally >2). Similar variation in the elemental concentration ratios between the seabed sediments and Amazon River suspended sediments was seen for stations located in the biogenic and blue water zones, with an enrichment for Ce, Sm, Fe, Th, and Sc and a depletion for the La, Eu, Tb, Yb, Co, Cr, Cs, Hf, Ta, and Zn. The shale-normalized REE patterns from shelf sediments are enriched in LREE relative to HREE, with enrichment factors varying from 1.5 for stations near the river mouth (terrigenous zone) to 1.9 for stations located far in the blue water zone. Published data for the Amazon River suspended sediment agree remarkably well with this observation of LREE-enrichment.

A influência dos efluentes urbanos brutos na carga dissolvida do rio Piracicaba em termos de carga de poluição per capita das principais espécies químicas inorgânicas dissolvidas, foi estimada a partir de um modelo de aportes de efluentes pontuais sem tratamento prévio na zona urbana central do município de Piracicaba (SP). As cargas químicas inorgânicas, representadas pelos cátions e ânions principais e a sílica dissolvida foram determinadas nos efluentes brutos e no próprio rio, antes e depois da área urbana. O modelo utilizado permitiu estimar as contribuições dessas espécies químicas nas cargas totais dos efluentes para toda a bacia de drenagem e quantificar em termos mais específicos os respectivos aportes por habitante. The influence of urban raw sewage, in terms of per capita load pollution of major dissolved inorganic chemical species, in fluvial dissolved load was estimated using a model of punctual sewage contributions without previous treatment, in urban central area of Piracicaba city, SP. The inorganic loads represented by major cations, anions and dissolved silica, were determined in both raw sewage and in the river, before and after the river crossing the urban area. This model also allowed the contributions of these chemical species of total effluent loads to be estimated for the entire drainage basin, as well their respective contributions per capita.

Neutron activation analysis was performed on aluvial soil samples from several sites on the floodplains of the Amazon River and its major tributaries for trace elements determination. The spatial and temporal variations of chemical composition of floodland sediments in the Amazon basin are discussed. No significant difference was found in trace elemental distribution in the floodland soils along the Amazon main channel, even after the source material has been progressively diluted with that from lowland draining tributaires. It was also seen that the average chemical composition of floodplain soils compares well with that of the suspended sediments.